Publication Date: 2024
Tehran University Medical Journal (16831764)82(7)pp. 528-537
Background: Biofilm producing uropathogenic Escherichia coli (UPEC) strains are of major concern in clinical settings which display increased resistance to conventional antimicrobial therapy. Nitric oxide (NO) has shown to exhibit anti-biofilm effects in a variety of bacterial species. In this study we aimed to evaluate the effectiveness of NO on the formation and eradication of biofilm of UPEC strains isolated from patients with urinary infection (UI) in Tehran. Methods: During May 2022 to April 2023, a total of 3814 suspected isolates of UPEC were collected from a pathobiology laboratory in Tehran and confirmed as E. coli strains using specific primers for elongation factor Tu (tufA) gene. All strains were screened for the ability to form biofilm by the microtiter plate (MTP) and Congo red agar (CRA) assays, and also the presence of biofilm genes were detected among biofilm producing strains. Moreover, the effect of NO on biofilm formation and its dispersal was evaluated by the high (30 mM) and low (125 nM) concentrations of sodium nitroprusside (SNP) as NO donor. Results: All collected isolates were confirmed by the polymerase chain reaction (PCR) using specific primers, in which 1309 strains (34%) were able to form colonies with red, dry and rough (rdar, curli and cellulose positive) (n=682, 52%), brown, dry and rough (bdar, curli positive and cellulose negative) (n=353, 27%) and pink, dry and rough (pdar, cellulose positive and curli negative) (n=274, 21%) morphotypes on CRA and selected as biofilm positive strains. Furthermore, 228 (17%), 402 (31%) and 679 (52%) strains were able to form a weak, moderate, and strong biofilm, respectively, and csgA, csgD, yedQ, and bcsA genes were found among 87, 98, 100 and 79% of biofilm-positive strains, respectively. The 30 mM concentration of SNP significantly decreased the biofilm formation (17-40%) and increased biofilm dispersal (20-45%) among UPEC strains. Conclusion: These findings confirmed the applicability of nitric oxide as an anti-biofilm agent for UPEC strains. These findings contribute to the development of novel strategies for fighting biofilm-associated infections. Copyright © 2024 Rahimi et al.
Publication Date: 2024
Tehran University Medical Journal (17357322)82(7)pp. 528-537
Background: Biofilm producing uropathogenic Escherichia coli (UPEC) strains are of major concern in clinical settings which display increased resistance to conventional antimicrobial therapy. Nitric oxide (NO) has shown to exhibit anti-biofilm effects in a variety of bacterial species. In this study we aimed to evaluate the effectiveness of NO on the formation and eradication of biofilm of UPEC strains isolated from patients with urinary infection (UI) in Tehran. Methods: During May 2022 to April 2023, a total of 3814 suspected isolates of UPEC were collected from a pathobiology laboratory in Tehran and confirmed as E. coli strains using specific primers for elongation factor Tu (tufA) gene. All strains were screened for the ability to form biofilm by the microtiter plate (MTP) and Congo red agar (CRA) assays, and also the presence of biofilm genes were detected among biofilm producing strains. Moreover, the effect of NO on biofilm formation and its dispersal was evaluated by the high (30 mM) and low (125 nM) concentrations of sodium nitroprusside (SNP) as NO donor. Results: All collected isolates were confirmed by the polymerase chain reaction (PCR) using specific primers, in which 1309 strains (34%) were able to form colonies with red, dry and rough (rdar, curli and cellulose positive) (n=682, 52%), brown, dry and rough (bdar, curli positive and cellulose negative) (n=353, 27%) and pink, dry and rough (pdar, cellulose positive and curli negative) (n=274, 21%) morphotypes on CRA and selected as biofilm positive strains. Furthermore, 228 (17%), 402 (31%) and 679 (52%) strains were able to form a weak, moderate, and strong biofilm, respectively, and csgA, csgD, yedQ, and bcsA genes were found among 87, 98, 100 and 79% of biofilm-positive strains, respectively. The 30 mM concentration of SNP significantly decreased the biofilm formation (17-40%) and increased biofilm dispersal (20-45%) among UPEC strains. Conclusion: These findings confirmed the applicability of nitric oxide as an anti-biofilm agent for UPEC strains. These findings contribute to the development of novel strategies for fighting biofilm-associated infections. Copyright © 2024 Rahimi et al.
Publication Date: 2024
Archives Of Clinical Infectious Diseases (23452641)19(3)
Background: The increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant challenge in the treatment of diabetic foot infections (DFIs). Objectives: This study aimed to investigate the prevalence and diversity of clonal groups of MRSA strains isolated from patients with DFIs in a major referral hospital in Tehran. Methods: We determined the prevalence, diversity, and antibiotic susceptibility profiles of MRSA isolated from patients with DFIs attending a referral hospital in Tehran, Iran, during 2019-2020. Staphylococcal cassette chromosome mec (SCCmec) typing, ccr typing, PhP typing, and detection of the Panton-Valentine Leukocidin (pvl) gene were performed to explore the diversity of the strains. Antibiotic susceptibility profiles of the strains were determined using the disk diffusion method and broth microdilution assay. Results: Of the 238 S. aureus strains isolated, 73 were identified as MRSA. The highest antibiotic resistance was observed against ciprofloxacin (86%), followed by kanamycin and tobramycin (84%). Additionally, 49% of the strains exhibited high-level oxacillin resistance (MIC ≥ 256 µg/mL). SCCmec type III and type 3 ccr were detected in 86% of the strains, classifying them as hospital-acquired (HA)-MRSA. PhP typing revealed the presence of 8 common types (CTs) and 11 single types (STs), with CT2 comprising 41% of the strains. Conclusions: Our data suggest that MRSA strains isolated from DFIs in this region are diverse and resistant to clinically important antibiotics. Diabetic patients can serve as a reservoir for the dissemination of these bacteria between community and clinical environments. © 2024, Rahimi et al.
Publication Date: 2023
Infection, Epidemiology And Microbiology (25884107)9(1)pp. 15-23
Backgrounds: Diabetic patients are at risk of developing serious foot infections with methicillin-resistant Staphylococcus aureus (MRSA) strains, which are associated with high morbidity and mortality. This study aimed to investigate the frequency of different prophage types and virulence factors among MRSA strains isolated from patients with diabetic foot infections (DFIs) in a referral hospital in Tehran, Iran during 2019 and 2020. Materials & Methods: A total of 238 S. aureus isolates were collected and confirmed using specific primers. The presence of staphylococcal enterotoxins (sea-seq) and hlb, sak, eta, etb, and tsst-1 genes among MRSA isolates was tested using separate polymerase chain reaction (PCR) assays. Also, multiplex PCR was employed for prophage typing of MRSA isolates. Findings: A total of 73 (31%) isolates were confirmed as MRSA, among which four prophage types and 13 different prophage patterns were identified, and prophage type SGF and prophage pattern 7 consisting of SGB, SGF, SGFa, and SGFb types were the dominant ones. Also, 11 enterotoxin-encoding genes and four virulence factor genes were detected among the isolates. All MRSA isolates were positive for sea, sek, seq, and hlb genes. Moreover, out of 12 different enterotoxin patterns, most MRSA isolates were classified into enterotoxin pattern 1, harboring three enterotoxin genes (sea, sek, and seq). Conclusion: This study results indicated the presence of different prophage types and virulence factor genes among MRSA strains isolated from DFI patients, which enable them to produce a variety of diseases. © 2023, TMU Press.
Publication Date: 2022
Pathogens and Global Health (20477724)116(8)pp. 485-497
Pathogenicity of a bacterium is affected by the social characteristics of the population and environmental factors. The ability of biofilm formation among β-lactamase-producing uropathogenic Escherichia coli (UPEC) could facilitate the exchange of antibiotic-resistance genes, which resulted in widespread dissemination of antibacterial drug resistance. We investigated the prevalence of biofilm and β-lactamase producing UPECs among patients with urinary tract infection (UTI) in two cities with different demographics and climates in Iran. A total of 265 E. coli was isolated from patients with UTIs from two referral hospitals (n = 191) and two outpatient clinics (n = 74) in Isfahan and Zahedan, Iran. Production of curli and cellulose, and, biofilm formation was investigated using Congo red agar and microtiter plate methods, respectively. Biofilm producing (BFP) isolates (n = 107) were further characterized using rep-PCR, antimicrobial susceptibility testing and extended-spectrum β-lactamase (ESBL)/AmpC phenotypic production. Isolates were also screened for the presence of carbapenemase, ESBL and AmpC genes using multiplex PCR. High diversity was found among BFP strains in both cities, with 58% strains producing ESBL and 21% producing AmpC. ESBL (98%), AmpC (50%) and carbapenemase genes (40%) were identified in BFP strains with ESBL-positive phenotype, respectively. The prevalence of BFP strains, antibiotic resistance and β-lactamase genes in Zahedan, a low socioeconomic city with a warm climate, was significantly higher than that of Isfahan. High prevalence of biofilm and β-lactamase producing UPEC strains among strains from Zahedan suggests that socioeconomic status and environmental factors might have a role in pathogenicity of the strains. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
Publication Date: 2022
International Microbiology (11396709)25(2)pp. 297-307
Uropathogenic E. coli (UPEC) strains exhibit different levels of biofilm formation that help adhesion of the bacteria to uroepithelial cells. We investigated the genetic diversity and virulence-associated genes (VAGs) of biofilm-producing UPEC. A collection of 107 biofilm-producing (BFP) UPEC strains isolated from patients with UTI in Iran were divided into three groups of strong, moderate, and weak BFPs after a quantitative microtiter plate assay, and the involvement of curli and cellulose in adhesion of the strains to T24 cell line was confirmed by the construction of csgD and yedQ mutants of two representative UPEC strains. BFP strains were tested for their genetic diversity, phylogenetic groups, and the presence of 15 VAGs. A significant decrease in adhesion of csgD and yedQ mutant strains confirmed the role of biofilm production in adhesion to uroepithelial cells. A high diversity was found among all three groups of strong (Di = 0.998), moderate (Di = 0.998), and weak (Di = 0.988) BFPs with majority of the strains belonging to phylogroups B2 (44.9%) and A (24.3%). Strong BFP strains carried significantly higher level papEF, hlyA, and iutA than other BFP groups. In contrast, the presence of fimH, focG, sfaS, set-1, and cvaC was more pronounced among weak BFP strains. There exists a high genetic diversity among the BFP strains with different VGA profiles. However, the high prevalence of phylogroup A among BFP strains suggests the fitness of commensal E. coli strains to cause UTI in this country. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Publication Date: 2021
Infection, Epidemiology And Microbiology (25884107)7(3)pp. 215-227
Backgrounds: Hospital sewage is known as an important source of human pathogenic bacteria such as methicillin resistant Staphylococcus aureus (MRSA) strains disseminated from hospital to the environment. This study aimed to investigate the presence of MRSA in the treated outgoing wastewater collected from a referral hospital in Tehran, Iran. Materials & Methods: During 2015, sampling was carried out at two stages from a hospital wastewater. All black colonies with halos on HiCrome aureus agar medium supplemented with oxacillin were collected and identified as MRSA using specific primers for nucA and mecA genes. Isolates susceptibility to 18 antibiotics was determined according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). Bacterial typing was performed for the isolates using a combination of Phene plate (PhP) typing, prophage typing, staphylococcal cassette chromosome mec (SCCmec) and ccr typing methods. Findings: A total of 79 MRSA isolates were confirmed using specific primers and showed susceptibility to quinupristin-dalfopristin, vancomycin, chloramphenicol, and linezolid. High resistance to penicillin, ciprofloxacin, kanamycin, tobramycin, and erythromycin was reported. Sixteen PhP types consisting of eight common types (CTs) and eight single types (STs) were identified among the strains, among which CT1 was the dominant type. Also, two prophage patterns and four prophage types were identified, and all the strains were positive for SCCmec type III and ccr type 3. Conclusion: The results of this study revealed that sewage-treatment process was able to remove community-acquired MRSA (CA-MRSA) strains; however, hospital-acquired MRSA (HA-MRSA) strains were able to survive during the treatment process in this hospital. © 2021, TMU Press.
Publication Date: 2021
Infection, Epidemiology And Microbiology (25884107)7(1)pp. 1-15
Background: Staphylococcus epidermidis isolates are among the most important causes of nosocomial infections and could be classified as health threatening agents. This study aimed to determine the biofilm formation ability and clonal dissemination of S. epidermidis strains isolated from patients and healthy people in Isfahan during 2016 and 2017. Materials & Methods: A total of 139 and 123 suspected colonies of S. epidermidis were collected from different clinical specimens and the arm of healthy people, respectively. The ability to form biofilm was determined using a combination of Congo-red agar (CRA) and microtiter plate (MTP) assays. The presence of genes involved in biofilm formation was also tested by the polymerase chain reaction (PCR) test. The susceptibility of all strains to 12 antibiotics was evaluated using the disk diffusion method according to the Clinical & Laboratory Standards Institute (CLSI) guidelines. Moreover, all biofilm-producing strains were typed using PhenePlate system as well as cassette chromosome mec (SCCmec) and accessory gene regulator (agr) locus typing method. Findings: A total of 43 biofilm-producing S. epidermidis strains were identified among 107 and 123 confirmed strains isolated from hospitalized patients and healthy people, respectively; all of which were positive for aap gene, and the presence of ica operon was limited to 86 and 27% of the strains isolated from patients and healthy people, respectively. All the strains showed susceptibility to vancomycin, quinupristin-dalfopristin, and linezolid. Moreover, SCCmec Types III, IV, and V were detected among all methicillin-resistant S. epidermidis (MRSE) strains, and agr Type I was the most frequent one. Among all biofilm-positive strains, 3 common types (CTs) and 7 single types (STs) were determined; CT1 and CT2 were the most common types among the strains isolated from hospitalized patients and healthy people. Conclusion: These findings indicated the presence and persistence of diverse clone types of biofilm-producing S. epidermidis strains with common types of PhP, agr, and SCCmec in the hospital and the community of Isfahan. © 2021, TMU Press.
Publication Date: 2021
Journal of Water and Health (14778920)19(2)pp. 216-228
Multidrug-resistant Staphylococcus aureus strains have been commonly found in hospitals and communities causing wide ranges of infections among humans and animals. Typing of these strains is a key factor to reveal their clonal dissemination in different regions. We investigated the prevalence and dissemination of different clonal groups of S. aureus with resistance phenotype to multiple antibiotics in two sewage treatment plants (STPs) in Tehran, Iran over four sampling occasions. A total of 576 S. aureus were isolated from the inlet, sludge and outlet. Of these, 80 were identified as methicillin-resistant S. aureus (MRSA) and were further characterized using a combination of Phene Plate (PhP) typing, staphylococcal cassette chromosome mec (SCCmec), ccr types, prophage and antibiotic-resistant profiling. In all, eight common type (CT) and 13 single PhP type were identified in both STPs, with one major CT accounting for 38.8% of the MRSA strains. These strains belonged to three prophage patterns and five prophage types with SCCmec type III being the predominant type. Resistance to 11 out of the 17 antibiotics tested was significantly (P < 0.0059) higher among the MRSA isolates than methicillin-sensitive S. aureus (MSSA) strains. The persistence of the strains in samples collected from the outlet of both STPs was 31.9% for MRSA and 23.1% for MSSA. These data indicated that while the sewage treatment process, in general, is still useful for removing most MRSA populations, some strains with SCCmec type III may have a better ability to survive the STP process. © 2021 IWA Publishing. All rights reserved.
Publication Date: 2021
Medicine (United States) (00257974)100(36)
The emergence of carbapenem-resistant Enterobacteriaceae made the treatment difficult, which has become a significant issue of public health. A sharp increase of carbapenem-resistance rate in Klebsiella pneumoniae was observed in a maternity and child health care hospital in Zunyi, China, in 2014.In 2015 to 2016, carbapenem-resistant Klebsiella pneumoniae (CRKp) isolated from all the clinical samples were analyzed to identify the carbapenem-resistance genes. They were then fingerprinted in order to determine their genetic relationship. Clinical data such as usage of imipenem in 2012 to 2016 and the nosocomial infection surveillance data were analyzed.Thirty-five isolates of CRKp out of 4328 various pathogens were obtained, and blaNDM-1was identified to be the most common resistant gene present in the CRKp isolates. The fingerprint analysis identified 15 major clusters of CRKp isolates. The bacteria with close proximity relationship tended to be from the same wards. However, a few CRKp isolates from different wards were found to be genetically highly related. The clinical data showed a significantly higher usage of carbapenems in 2012 to 2013 before the CRKp rate sharply increased in 2014. The nosocomial infection surveillance showed an unexpectedly high rate of failures to meet the requirement of the hospital environment hygiene and hand hygiene in the neonatal ward.The increasing isolation rate of CRKp was associated with poorly regulated usage of carbapenems, impropriate medical practices, and the poor hospital environmental hygiene and hand hygiene. © 2021 Lippincott Williams and Wilkins. All rights reserved.
Publication Date: 2020
Medicine (United States) (00257974)99(42)
Background:What affects the efficacy of alendronate for prevention of glucocorticoid-induced (GI) fractures remains unclear. We aimed to explore the factors affecting alendronate's efficacy, and further identify subgroup effects of alendronate in preventing GI fractures.Methods:We searched 3 databases. Random-effects meta-analysis was conducted to synthesize risk ratio (RR) and 95% confidence interval (CI) for each endpoint. Meta-regression analysis was used to explore sources of heterogeneity, and subgroup analysis was used to address heterogeneity and evaluate subgroup effects. We detected publication bias using funnel plots and Egger tests.Results:We included 13 papers from 12 unique studies involving 46431 participants. Glucocorticoid (GC) dosage (P = .053) and proportion of previous vertebral fracture (PVF) (P = .047) were probably 2 sources of heterogeneity in meta-analysis for vertebral fractures, while GC duration (P = .020) was probably 1 for nonvertebral fractures. Alendronate reduced vertebral fractures in the high dosage subgroup (RR 0.61, 95% CI 0.44-0.86), but didn't in the low dosage subgroup (RR 1.56, 95% CI 0.20-12.02). Alendronate reduced vertebral fractures (RR 0.53, 95% CI 0.40-0.68) in the subgroup of PVF proportion <5%, but didn't (RR 0.76, 95% CI 0.42-1.37) in the subgroup of this proportion ≥5%. Alendronate reduced nonvertebral and hip fractures, whether in primary or in secondary prevention subgroup.Conclusions:The findings in our study support that alendronate is used for the primary and secondary prevention of GI fractures, but do not support that alendronate is recommended as a first-line agent for patients receiving a low dose of GCs or patients with PVF. © 2020 Lippincott Williams and Wilkins. All rights reserved.
Publication Date: 2019
Journal fur Verbraucherschutz und Lebensmittelsicherheit (16615751)14(4)pp. 389-398
In this study, we investigated the clonality, antibiotic susceptibility and presence of different enterotoxin genes among 49 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 131 fresh raw meat samples in Tehran, Iran during 2016. 47% of beef, 30% of chicken and 27% of turkey samples were MRSA positive. PhenePlate (PhP typing) revealed the presence of 12 PhP types consisting of five common types and seven single types, and 86% of the strains harbored staphylococcal cassette chromosome mec (SCCmec) type III and type 3 cassette chromosome recombinases (ccr). Moreover, SCCmec type IVa was positive in all isolates with SGA prophage types. High level resistance to ciprofloxacin, erythromycin, tobramycin and kanamycin was also observed. The rate of resistance to most of the antibiotics tested was higher in chicken samples compared to other meat samples. Out of eleven different enterotoxin genes found, sea, sek and seq were the dominant genes in all strains. Our results illustrate the presence and persistence of highly resistant clonal groups of enterotoxin-producing MRSA in meat samples. These isolates had PhP and SCCmec types and prophage patterns which were similar to the clinical isolates previously reported in Iran, supporting the notion of dissemination of the MRSA in the hospital, community, as well food products in Iran. © 2019, Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL).
Publication Date: 2019
Infectious Diseases in Clinical Practice (10569103)27(3)pp. 163-169
Background: Methicillin-resistant Staphylococcus aureus (MRSA) strains are known as one of the most important multidrug-resistant organisms causing infections in humans and animals. The objectives of this experimental study were to characterize the clonality and antibiotic resistance of MRSA strains isolated from patients in 2 different cities in Iran. Methods: During 2 years, a total of 536 S. aureus isolates were collected from 2 reference hospitals in Tehran and Isfahan and were identified as MRSA using specific primers. The antibiotic susceptibility and their clonality were determined using the PhenePlate typing system. Furthermore, the presence of different classes of prophages and the structure of staphylococcal cassette chromosome mec elements and cassette chromosome recombinases types were characterized. Results: Of the 536 strains, 129 MRSA were identified using species-specific primers and discriminated into 26 PhenePlate types consisted of 12 common types (CTs) and 14 single types, in which CT2 was the predominant type and 6 CTs were common among MRSA isolated in both cities. Staphylococcal cassette chromosome mec types III and IV were also detected in 89% and 11% of the strains, and SGF prophage type was the dominant one. Thirty-four antibiotic patterns were detected among the MRSA strains, and none of the isolates showed resistance to linezolid, quinupristin-dalfopristin, and vancomycin. Conclusions: High prevalence of antibiotic-resistant common clonal groups of MRSA strains in 2 different cities in this study indicated the spread of these clonal types in north and center of Iran and highlighted the common origin of such strains, which are believed to be endemic in various sources. © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Publication Date: 2018
Archives Of Clinical Infectious Diseases (23452641)13(5)
Background: Methicillin-resistant Staphylococcus aureus (MRSA) has been considered as an important pathogen with a variety of virulence factors in communities and hospitals worldwide. Objectives: In this study, we focused on the detection of different virulence factors and enterotoxin genes of MRSA strains isolated from a referral hospital in Tehran, Iran. Moreover, the presence of different prophage types was studied. Methods: A total of 491 MRSA strains were isolated during three years from a referral hospital in Tehran. The staphylococcal enterotoxin (sea-seq) and pvl, hlb, sak, eta and tst genes were detected. A multiplex-polymerase chain reaction (PCR) assay was used for prophage typing of MRSA isolates. Results: Totally, 11 enterotoxin and 5 virulence factor genes were detected in MRSA strains. The sea, sek, seq, and hlb genes were present in all the MRSA and other enterotoxin genes. sel, seg, sem, sei, sen, seo, sec and sep were detected in 32.8%, 20.3%, 12.6%, 8.3%, 4.1%, 2.6%, 1.6% and 0.4% of the strains, respectively. A total of 93%, 81%, 15.9% and 5.7% of the strains harbored the sak, eta, tst and pvl genes, respectively. SGF, SGFa and SGFb proghage type genes were detected in 100% of the MRSA strains, and four different prophage patterns were identified among the strains. Conclusions: The presence of different prophage-encoded virulence factors among MRSA strains enable MRSA to produce a broad range of diseases, indicating MRSA strains as a potential threat to patients’ health. © 2018, Archives of Clinical Infectious Diseases.
Publication Date: 2018
Archives Of Clinical Infectious Diseases (23452641)13(6)
Background: Coagulase-negative Staphylococcus epidermidis is the most prevalent member of the human skin normal biota that plays an important role as a common cause of catheter and prosthetic device-related infections from, for example, indwelling catheters. Objectives: This study aimed to characterize the clonality of biofilm-producing methicillin-resistant S. epidermidis (MRSE) strains isolated from catheterized patients with urinary tract infection at a referral hospital in Tehran, Iran. Methods: Between 2014 and 2016, a total of 56 methicillin-resistant S. epidermidis (MRSE) strains were recovered from catheterized patients. The MRSE isolates were tested for biofilm formation and different genes involved in this process were detected. Clonal dissemination of MRSE isolates was determined using the combination of pulsed-field gel electrophoresis (PFGE) and SCCmec typing. Results: Out of the 56 MRSE strains, 50 (89%) formed biofilm and were positive for icaA and icaD genes, and 73% (n = 41) harbored IS256. The PFGE patterns revealed a total of 32 different pulsotypes consisting of 16 single types (STs), 16 common types (CTs), and 2 SCCmec types (III and IV) were detected. Moreover, all STs carried SCCmec type IV and classified as community-acquired strains. Four CTs were common among biofilm and non-biofilm producing strains. Conclusions: The presence of icaA and icaD genes with a high prevalence of IS256 element in clonal groups of MRSE strains suggests that ica, IS256, and biofilm forming ability occur simultaneously in specific S. epidermidis clones and spread preferentially in hospitals and community. © 2018, Archives of Clinical Infectious Diseases.
Publication Date: 2017
Iranian Red Crescent Medical Journal (20741804)19(2)
Background: Approximately 80% of nosocomial infections are caused by strains of Klebsiella pneumoniae. Resistance to β-lactam antibiotics is a result of expression of extended-spectrum β-lactamase (ESBL) genes. Recently, phage therapy has gained increasing attention due to its many advantages over chemotherapy. Objectives: The aim of this study was to isolate ESBL-positive Klebsiella pneumoniae strains from different types of wounds, and a lytic bacteriophage against them. Methods: During a two-year period from January 2013 to February 2015, in a cross-sectional study, 41 K. pneumoniae strains were isolated from 193 categories of infected wounds at three hospitals in Isfahan, Iran. Phenotypic and genotypic methods were used to detect the ESBL-positive strains. A lytic phage against K. pneumoniae was isolated, and its host range, morphology, thermal and pH stability, saline stress, and estimated genome size were determined. Results: Of the 41 K. pneumoniae isolates, 18 were ESBL-producing and 36 carried antibiotic-resistance genes. A total of 36 out of 41 isolated samples carried one or more resistance genes. The results showed that the differences between phenotypic and genotypic identification methods were significant (P = 0.0001). The SHV, CTX-M, and TEM genes were detected in 29, 10, and 9 isolates of the tested bacteria, respectively. No bacteria contained both the SHV and the CTX-M genes. The frequency of the SHV gene was significantly higher than that of the other genes (P = 0.0001). The phage’s morphology features placed it in the Myoviridae family. Only 38 out of 41 clinical isolates were susceptible to the phage. Phage titers were completely preserved after one hour of incubation at 30°C and 40°C, and they were stable at different pH values. The phage’s survival decreased when the salt concentration was increased. Conclusions: The high rate of isolation of antibiotic-resistant strains of K. pneumoniae was consistent with other studies. As the phage was virulent and specific for K. pneumoniae, and was stable and active at different pH values, salt concentrations, and temperatures, its application in phage therapy of infected wounds is suggested. © 2016, Iranian Red Crescent Medical Journal.
Publication Date: 2016
Archives Of Clinical Infectious Diseases (23452641)11(3)
Background: Staphylococcus epidermidis is well documented as an opportunistic pathogen causing biofilm in patients and healthy individuals. Objectives: The aim of this experimental study was to describe the antibiotic resistance patterns of biofilm producing S. epidermidis strains isolated from clinical samples in Tehran, Iran. Moreover, the role of different genes in biofilm formation was also described. Patients and Methods: A total of 250 S. epidermidis strains were isolated from patients in a private hospital of Tehran, Iran from February to December 2014. The biofilm formation of each strain was determined using combination of qualitative Congo-Red agar and quantitative microtiter plate assay, and presence of different genes involved in control and formation of biofilm was detected by the polymerase chain reaction (PCR). Susceptibility of S. epidermidis strains to 19 antibiotics was examined. Results: The results of the biofilm assay revealed that 82% of strains produced black colonies on Congo red agar plates and 68% were able to attach strongly to polystyrene microplates. One hundred percent, 88%, 84%, 64% and 60% of biofilm-producing strains were resistant to penicillin, cefoxitin, erythromycin, trimethoprim-sulfamethoxazole and kanamycin, respectively. On the other hand, none of the strains showed resistance to vancomycin, linezolid, quinupristin/dalfopristin. The icaA, icaD, aap and atlE genes were detected in all biofilm-producing strains and presence of IS256 transposon was limited to 84% of biofilm positive strains. Conclusions: The results of this study illustrated the high prevalence of antibiotic resistant biofilm-producing S. epidermidis strains in this hospital, which could be a reservoir for antibiotic resistance genes. © 2016, Infectious Diseases and Tropical Medicine Research Center.
Publication Date: 2016
Microbial Pathogenesis (08824010)98pp. 69-76
Between June 2011 and May 2014, we isolated a total of 419 Staphylococcus aureus strains from catheterized patients with UTI in a referral hospital in Tehran. Of these, 108 were identified as methicillin resistant (MRSA) based on their phenotypic resistance to oxacillin and the presence of mecA gene. The MRSA isolates were tested for their clonality using a combination of PFGE, prophage typing, SCCmec and ccr typing and examined for their biofilm formation as well as their resistance against 17 antibiotics. In all, 15 common pulsotypes consisted of 105 isolates and 3 single types were identified among the MRSA strains of which, 97% carried SCCmec type III and type 3 ccr. Eighty three (77%) strains were positive for biofilm formation and also carried icaA and icaD genes. Moreover, agr group III and its related tst gene were detected in 81% and 77% of biofilm producing strains, respectively 105 of the 108 MRSA were multidrug resistant with 82.4% being resistant to more than 10 antibiotics. Strains with SCCmec type IV and type 2 ccr, contained SGA and SGL prophage types, were positive for pvl gene and belonged to single PFGE types. This study highlights the important role of biofilm formation and virulence factors of MRSA strains in catheterized patients. © 2016 Elsevier Ltd
Publication Date: 2016
Archives Of Clinical Infectious Diseases (23452641)11(1)
Background: Methicillin-resistant Staphylococcus aureus (MRSA) has been known as one of the most important nosocomial pathogens that able to produce a variety of virulence factors. Objectives: In this study, we aimed to describe the prevalence, presence of different virulence factors, staphylococcal cassette chromosome mec (SCCmec) and prophage typing of MRSA strains isolated from a referral hospital in Tehran, Iran. Materials and Methods: A total of 279 S. aureus strains were collected from a referral hospital in Tehran during August to December of 2013. All isolates were confirmed using species specific primers and were tested for susceptibility to oxacillin and cefoxitin disks by the recommendations of clinical and laboratory standards institute (CLSI). The staphylococcal enterotoxin (sea-seq) and pvl, hlb and sak genes were detected and typed using prophage typing and SCCmec typing methods. Results: Out of the 279 S. aureus isolates, 91 (32.6%) strains were confirmed as MRSA. Totally, 6 enterotoxin and 2 virulence factor genes were detected in MRSA strains. The sea, sek, seq and hlb genes were present in all MRSA and sak, seg, sei and sel were detected in 85%, 35%, 23% and 44% of the strains. Only SCCmec type III and type 3 ccr and 2 different prophage patterns were identified among the strains. Conclusions: Our results show the presence of clonal groups of enterotoxin-producing MRSA strains in this hospital in Tehran. The presence of bacteriophage encoded virulence factors and resistance to oxacillin enable bacteria to produce a broad spectrum range of diseases. © 2016 Infectious Desieases and Tropical Medicine Research Center.
Publication Date: 2016
Minerva Biotecnologica (11204826)28(1)pp. 19-28
BACKGROUND: Probiotics mainly Bacillus species can be advantageous to the host by promoting its intestinal balance. Attempts were made to isolate and identify Bacillus strains from rhizosphere environment. METHODS: The in vitro probiotic criteria were used for screening and characterizing potential Bacillus probiotics. Morphological, physiological and biochemical characteristics as well as 16S rRNA gene sequence analysis were utilized for identification of the isolates. Seven isolates were chosen based on withstanding to acidic condition (pH 2.5) and various bile salt concentrations (1-4%(w/v)). RESULTS: Isolates found to have the least antimicrobial activity against Listeria monocytogenes PTCC 1163, Staphylococcus aureus ATCC 1912 and Bacillus cereus PTCC 1015; however, no activity against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 25922 was observed. The Bacillus Isolates showed different variation in auto-aggregation features and adhesion to hydrocarbons ranging from 60% to 90% and 10% to 60%, respectively. Excluding isolate 14 that exhibited resistance to penicillin and ampicillin, all the other Bacillus strains were sensitive to the tested antibiotics. All isolates showed relatively low cytotoxic effect on HepG2 cell line except strains 12 and 14. CONCLUSION: Taking together, among the investigated Bacillus isolates, strains 17 and S10 found to be the most promising candidates to fulfill in vitro probiotic specifications. © 2016 EDIZIONI MINERVA MEDICA.
Publication Date: 2016
Microbial Pathogenesis (08824010)97pp. 89-93
Methicillin resistant Staphylococcus aureus is one of the most common causes of a variety of infections ranging from wound infections to urinary tract infections (UTI) in hospital and community. In this study during 3 years we characterized the antibiotic resistance patterns of 491 hospital acquired MRSA and community associated MRSA strains by the guidelines of clinical and laboratory standard institute. A combination of high resolution PhP typing method and SCCmec typing were used for clonal dissemination of isolates. Among all 491 MRSA strains, diverse PhP types consisting of 29 common types (CTs) and 4 single types (STs) and also 2 different SCCmec types (III and IVa) were detected. In addition, 18 CTs were common among CA- and HA-MRSA strains and the presence of all 4 STs was limited to HA-MRSA strains. All isolates were resistant to penicillin and high level resistance was observed against ciprofloxacin, erythromycin, tobramycin and kanamycin and the rate of resistance to most of the antibiotic tested among HA-MRSA was significantly higher than CA-MRSA isolates. Moreover, all isolates showed susceptibility to linezolid, vancomycin and quinupristin-dalfopristin and very low resistance to fusidic acid, nitrofurantoin and chloramphenicol were detected. Our findings illustrated the increasing rate of clonal dissemination and persistence of highly antibiotic resistant CA-MRSA strains in Tehran hospitals, and also indicated the important role of the hospitals as the reservoir of MRSA strains. © 2016 Elsevier Ltd.
Publication Date: 2016
Jundishapur Journal Of Microbiology (20084161)9(1)
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens which can cause a broad spectrum of infections. Objectives: The current study aimed to describe the frequency and antibiotic susceptibility patterns of clonal groups of gentamicin-resistant strains of MRSA isolated from a tertiary care hospital in Tehran, Iran. Materials and Methods: A total of 301 S. aureus isolates were collected during January to November 2012. All of the isolates were identified at the species level and typed using the Phene-Plate (PhP) system. The antibiotic susceptibility patterns of the MRSA strains and the presence of different aminoglycoside resistance genes were determined. Results: Of the 301 S. aureus isolates, 90 (29.9%) strains were confirmed as MRSA, and they showed high resistance to penicillin, ciprofloxacin, kanamycin, tobramycin, erythromycin, and tetracycline. On the other hand, 43 of the 90 strains (47.8%) were resistant to gentamicin. Aac (6’)-Ie + aph (2”), ant (4’)-Ia, aph (3’)-IIIa, and ant (6)-Ia were detected in 65.6%, 42.2%, 20%, and 47.8% of the gentamicin-resistant strains, respectively. Diverse PhP types consisting of seven common types and four single types were identified among the strains. Conclusions: Our results illustrated the presence of clonal groups of highly gentamicin-resistant strains of MRSA in hospitals in Tehran. The PhP typing method provided useful information for both clonal dissemination and determining the epidemiological links of the clonal groups of the MRSA strains. © 2016, Ahvaz Jundishapur University of Medical Sciences.
Publication Date: 2016
Iranian Journal of Microbiology (20083289)8(2)pp. 93-100
Background and Objectives: The most prevalent and worldwide oral disease is dental caries that affects a significant proportion of the world population. There are some classical approaches for control, prevention and treatment of this pathologic condition; however, the results are still not completely successful. Therefore new methods are needed for better management of this important challenge. Chitosan is a natural and non-toxic polysaccharide with many biological applications, particularly as an antimicrobial agent. Chitosan nanoparticle is a bioactive and environment friendly material with unique physicochemical properties. The aim of the present study was to investigate the antimicrobial effect of chitosan and nano-chitosan on the most important cariogenic streptococci. Materials and Methods: For evaluation of antimicrobial effect of chitosan and nano-chitosan against oral streptococci broth micro-dilution method was carried out for four bacterial species; Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguis and Streptococcus salivarius. Also the effect of these materials on adhesion of above bacteria was evaluated. One-way ANOVA and post hoc Tukey test were used for statistical analysis. Results: The MICs of chitosan for S. mutans, S. sanguis, S. salivarius and S. sobrinus were 1.25, 1.25, 0.625 and 0.625 mg/mL, respectively. The MIC of chitosan nanoparticle for S. mutans, S. salivarius and S. sobrinus was 0.625 mg/mL and for S. sanguis was 0.312 mg/mL. Chitosan and chitosan nanoparticles at a concentration of 5 mg/mL also reduced biofilm formation of S. mutans up to 92.5% and 93.4%, respectively. Conclusion: The results of this study supported the use of chitosan and chitosan nanoparticles as antimicrobial agents against cariogenic Streptococci. © 2016, Tehran University of Medical Science. All rights reserved.
Publication Date: 2016
Archives Of Clinical Infectious Diseases (23452641)11(4)
Background: Methicillin-resistant Staphylococcus aureus (MRSA) strains are known as one of the most common causes of infection in humans and animals can produce a variety of virulence factors such as enterotoxins. Staphylococcal food poisoning is one of the most common food-borne diseases in the world. Objectives: The current experimental study aimed to isolate and determine the clonality of MRSA strains isolated from chicken meat samples, and describe the presence of different prophage types, enterotoxin genes and also the expression of Staphylococcus cassette chromosome mec (SCCmec) gene types. Methods: During six months in 2014, a total of 36 chicken meat samples were collected from Isfahan local markets and analyzed to screen MRSA strains. All isolates were typed using high resolution automated Phene plate (PhP) system and tested for the presence of different enterotoxin genes. Different staphylococcal cassette chromosome mec (SCCmec) and prophage types were determined. Results: All 116 isolated MRSA strains were discriminated into seven PhP types consisting of seven common types (CTs) and were positive for mecA gene. All isolates harbored SCCmec type III and SGF, SGFa and SGFb prophage types. Genes encoding enterotoxins SEA, SEK and SEQ were detected in all MRSA isolates. Conclusions: These findings illustrated the presence and persistence of clonal groups of MRSA strains, in chicken meat in Isfahan, Iran, that serve as reservoirs to disseminate bacteriophage encoded enterotoxin and virulence agents. © 2016, Infectious Diseases and Tropical Medicine Research Center.
Publication Date: 2015
Jundishapur Journal Of Microbiology (20084161)8(6)pp. 1-5
acquired infections. Sewage acts as an environmental reservoir and may have a significant role in development and dissemination of antibiotic resistance. Objectives: This study was undertaken to determine the epidemiological relatedness between the MRSA isolated from sewage and human infections. Materials and Methods: Samples were collected from a referral hospital and also a sewage treatment plant in Tehran, Iran, during 2010. All the MRSA isolates were identified at the species level and typed using Phene plate (PhP) system and SCCmec typing. Antibiotic susceptibility tests were also performed. Results: Of the 1142 isolates, 200 MRSA strains from the sewage (n = 100) and the clinic (n = 100) were isolated. Distinct PhP types, consisting of 16 common types and 13 single types, and also 3 different staphylococcal cassette chromosome mec (SCCmec) types (III, IVa and IVc) were found amongst the MRSA isolated from the two different sources. The results of antibiotic susceptibility testing showed an increased resistance to penicillin, ciprofloxacin, erythromycin, clindamycin and tetracycline. In addition, none of the isolates showed resistance to vancomycin, quinupristin -dalfopristin and linezolid. Conclusions: The presence of common PhP types and also SCCmec type III, as an indicator for hospital strains, among the isolates, may indicate an epidemiological link between clinical and sewage MRSA isolates in Tehran. © 2015, Ahvaz Jundishapur University of Medical Sciences.
Publication Date: 2015
Archives Of Clinical Infectious Diseases (23452641)10(4)
Background: Staphylococci are some of the most common causes of infections in birds. Worldwide, the dramatic increase in the prevalence of antimicrobial-resistant Staphylococcus aureus (S. aureus) is receiving widespread attention, due to multi-resistant strains, diminishing the usefulness of antibiotics in human medicine and, thereby limiting therapeutic options. Objectives: In this study, we characterized the distribution and antibiotic resistance patterns of methicillin resistant S. aureus (MRSA) strains, isolated from lying hen farms in Karaj, Iran. The pulsed field gel electrophoresis patterns and the staphylococcus cassette chromosome mec (SCCmec) types were also determined. Materials and Methods: Over a period of 90 days (collected at days: 0, 45, 90) during 2013, nine samplings, consisting of swab samples and litter collection, were done from three poultry farms (three each) and a total of 55 MRSA isolates were isolated from chromogenic MRSA selective agar. The clonality of MRSA strains was determined using pulsed field gel electrophoresis (PFGE) and the diversity in the structure of SCCmec elements and also different ccr types was studied. Susceptibility to seventeen antibiotics was determined, using disc diffusion method, according to Clinical and Laboratory Standards Institute recommendation. Results: Out of the 55 MRSA strains, all isolates were at least resistant to penicillin, 58% showed resistance to erythromycin and 55% were resistant to ciprofloxacin. On the other hand, all isolates showed susceptibility to vancomycin, quinuprostin-dalfopristin, linezolid, fusidic acid, nitrofurantoin and minocycline. The results of PFGE showed diverse pulsotypes, consisting of 13 common types and 18 single types, with seven common PFGE types, which were found among the MRSA strains, isolated from different farms, suggestive of an epidemiological link. Moreover, 67% of MRSA isolates shared SCCmec type III and showed type 3 ccr, indicating the hospital origin of the strains. Conclusions: The results of this study illustrated the persistence of resistant bacteria in the environment, and highlight the reservoir of resistance, associated with use of antibiotics, as feed additive in poultry production. © 2015, Infectious Diseases and Tropical Medicine Research Center.
Publication Date: 2015
Jundishapur Journal Of Microbiology (20083645)(4)
Background: Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens and food chain has been considered as an assumed source for dissemination of VRE to human. Objectives: The presence of VRE isolates from food samples and typing of these isolates with Phene plate, a biochemical fingerprinting method, were investigated. Materials and Methods: Thirty samples of meat, chicken and cheese were analyzed for VRE during 2010. Antibiotic susceptibility tests and minimum inhibitory concentration (MIC) were also examined. VRE isolates were typed with the Phene plate system (PhPlate), a biochemical fingerprinting method. Results: A total of 70 VRE isolates were obtained and identified as Enterococcus faecium by species-specific PCR. All the isolates carried vanA, while none of them harbored vanB. The VRE isolates included 35, 27, and 8 isolates from meat, chicken and cheese, respectively. Typing with the PhPlate revealed a diversity index of 0.78 for E. faecium, containing 10 common and four single types. The results of antibiotic susceptibility and MIC tests showed an increased resistance to ciprofloxacin, erythromycin, ampicillin and gentamicin, to which, 100%, 100%, 100%, and 95% of VRE isolates were resistant, respectively. Only 5% of the isolates were resistant to chloramphenicol and the MIC of the isolates for vancomycin and teicoplanin was ≥ 256 μg/mL and for gentamicin-resistant isolates it was 1024 μg/mL. Conventional and molecular identification tests exhibited that all the isolates were E. faecium carrying vanA. None of the isolates harbored vanB. Conclusions: The results showed that enterococci are common contaminants in food. Indeed, this study indicates a high prevalence of multidrug-resistant enterococci in food of animal origin in Iran. Isolating some persisting enterococcal isolates revealed that continuous surveillance of antimicrobial resistance in enterococci from food is essential. © 2015, Ahvaz Jundishapur University of Medical Sciences.
Publication Date: 2015
Archives of Iranian Medicine (10292977)18(10)pp. 638-642
Background: The worldwide emergence of multi-drug resistant (MDR) bacteria in recent years has caused many problems for hospitals and patients, especially intensive care unit patients. Among these clinically important MDR bacteria are Acinetobacter baumannii complex species (A. baumannii, Acinetobacter genomic species 3 and Acinetobacter genomic species 13TU) that cause a wide range of infections. Methods: The sequencing and bioinformatics analysis of a part of the Zone 1 of rpoB gene was performed for species identification of Acinetobacter isolates obtained from ICU patients with infected burns hospitalized in a hospital in Isfahan, Iran, over a 9-month period. Antibiotic sensitivity of Acinetobacter isolates was investigated using the disk diffusion method and different classes of antibiotics including amikacin, cefotaxime, ceftriaxone, ciprofloxacin, imipenem and piperacillin. Results: Acinetobacterspp. were isolated from 10 of 80 (12.5%) investigated patients. All of the 10 Ac/netobacterisolates were identified as Acinetobacter baumannii and multi-drug resistant according to antibiotic susceptibility tests. Conclusion: Of the Acinetobacter baumannii complex members, only A. baumannii species was identified among the isolates obtained from patients with infected burns in an Isfahan hospital over a 9-month period. © 2015 Academy of Medical Sciences of I.R. Iran. All rights reserved.
Publication Date: 2015
Jundishapur Journal Of Microbiology (20084161)8(4)
Background: Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens and food chain has been considered as an assumed source for dissemination of VRE to human. Objectives: The presence of VRE isolates from food samples and typing of these isolates with Phene plate, a biochemical fingerprinting method, were investigated. Materials and Methods: Thirty samples of meat, chicken and cheese were analyzed for VRE during 2010. Antibiotic susceptibility tests and minimum inhibitory concentration (MIC) were also examined. VRE isolates were typed with the Phene plate system (PhPlate), a biochemical fingerprinting method. Results: A total of 70 VRE isolates were obtained and identified as Enterococcus faecium by species-specific PCR. All the isolates carried vanA, while none of them harbored vanB. The VRE isolates included 35, 27, and 8 isolates from meat, chicken and cheese, respectively. Typing with the PhPlate revealed a diversity index of 0.78 for E. faecium, containing 10 common and four single types. The results of antibiotic susceptibility and MIC tests showed an increased resistance to ciprofloxacin, erythromycin, ampicillin and gentamicin, to which, 100%, 100%, 100%, and 95% of VRE isolates were resistant, respectively. Only 5% of the isolates were resistant to chloramphenicol and the MIC of the isolates for vancomycin and teicoplanin was >= 256 mu g/mL and for gentamicin-resistant isolates it was 1024 mu g/mL. Conventional and molecular identification tests exhibited that all the isolates were E. faecium carrying vanA. None of the isolates harbored vanB. Conclusions: The results showed that enterococci are common contaminants in food. Indeed, this study indicates a high prevalence of multidrug-resistant enterococci in food of animal origin in Iran. Isolating some persisting enterococcal isolates revealed that continuous surveillance of antimicrobial resistance in enterococci from food is essential.
Publication Date: 2014
Journal of Medical Microbiology (00222615)63(PART 6)pp. 796-804
Staphylococcus aureus is a leading cause of hospital-acquired (HA) and community-acquired (CA) infections worldwide. Recently, S. aureus strains resistant to meticillin (MRSA) have become established within both communities. We isolated 314 isolates of MRSA from hospitalized patients in a referral hospital (HA isolates) and 268 isolates from its outpatient clinic (CA isolates) in Tehran, Iran, between February 2008 and December 2010. These isolates were tested for their susceptibility to 17 antibiotics and typed using the PhPlate system. The diversity in the structures of staphylococcal cassette chromosome mec (SCCmec) elements and ccr types was also detected using a multiplex-PCR assay and isolates were examined for the presence of different classes of prophages. Whilst all isolates were resistant to penicillin, the HA isolates were significantly more resistant to all other antibiotics tested than the CA isolates. Isolates carrying only SCCmec type III and ccr type 3 were dominant (91 %), but 20% of the CA isolates belonging to less prevalent types carried only SCCmec types IVa, c and ccr type 2. These isolates also carried pvl genes and contained SGA prophage type. Our results indicate that whilst the dominant clonal groups of HA- and CA-MRSA belong to SCCmec type III and carry ccr type 3 genes, several distinct but less prevalent types of CA-MRSA carrying SCCmec type IVa, c and type 2 ccr are also found in Tehran. These strains carry pvl genes and the SGA prophage type, a characteristic that might be used as a marker for detection of CA-MRSA in this country. © 2014 The Authors.
Publication Date: 2014
Jundishapur Journal Of Microbiology (20083645)7(2)
Background: Sewage treatment plants are considered to be the hotspots for antibiotic resistance transfer among bacterial species. Many fecal bacteria including Enterococci circulate and are exposed to antibiotic residues in this environment. Being as one of the most common cause of nosocomial infections, special concerns have risen worldwide about the rate and characteristics of Enterococci (especially, isolates with high resistance against glycopeptides) which are available in raw sewages. Objectives: Study on the vancomycin Resistant E. faecium diversity in Tehran sewage by plasmid profile, biochemical fingerprinting and antibiotic resistance Materials and Methods: Forty isolates recovered from an urban sewage treatment plant were studied during 2009-2010. The antibiotic resistance of isolates against 7 antibiotics was examined by disk diffusion method. Extraction of plasmid DNA was performed and identification of van genotype (vanA and vanB) was done by PCR. Biochemical fingerprinting was done by the use of Phene-Plate system (PhP). Results: All isolates were found to be resistant to erythromycin, ampicillin and ciprofloxacin. The PCR analyses showed that all E. faecium isolates harbored vanA gene and 5 (13%) isolates harbored vanA and vanB concomitantly. By plasmid profiling the VRE isolates differentiated into 11 types. PhP showed that VRE isolates were grouped into 23 biochemical types. Conclusions: The combination of plasmid profiling and PhP techniques revealed the presence of diverse population of VRE in sewage treatment plant in Tehran. Furthermore, the results showed that the PhP technique is a reliable method in determining the VRE clonal diversity. © 2014, Ahvaz Jundishapur University of Medical Sciences; Published by Kowsar Corp.
Publication Date: 2014
Journal of Mazandaran University of Medical Sciences (17359279)24(117)pp. 92-102
Background and purpose: Multi-resistant enterococci are important nosocomial pathogens that are shown to have high prevalence in recent years. Knowledge of antimicrobial resistance pattern is essential to formulate treatment guidelines for infections caused by enterococci. The aim of this study was to investigate the antimicrobial resistance among enterococci isolated from Hamedan hospitals.
Publication Date: 2014
Iranian Journal Of Blood And Cancer (20084595)7(1)pp. 25-29
Background: Approximately 600,000 deaths occur every year as a result of the acute and chronic consequences of hepatitis B virus infection. Ten different hepatitis B virus genotypes have been identified with distinct geographical distributions. Different clinical outcomes, including the rate of mutations, development of hepatocellular carcinoma, chronicity, response to treatment, transplantation rejection and occult infections, are affected by specific genotypes. The aim of the present study was to determine the frequency of genotype D of the virus in Isfahan, Iran. Patients and Methods: In this study primarily hepatitis B virus positive patients were identified by the detection of HBs antigen using ELISA test and then PCR was used as a confirmatory test. Fifty five patients that were identified as hepatitis B positive were tested for hepatitis D genotype using type - specific PCR. Results: The patients included 30 (54.5%) females and 25 (45.5%) males. In total, frequency of genotype D was 29 out of 55 cases (52.7%). Genotype D was detected in 19 (63.3%) females and 10 (40.0%) males indicating no statistically significant difference. The difference in the level of liver enzymes in patients infected with genotype D and non-genotype D hepatitis B virus were not significant. Conclusion: In the present study the frequency of genotype D among patients with hepatitis B virus infection in Isfahan, Iran, was 52.7%. No significant relation was observed between the level of liver enzymes and infection with the genotype D. © 2014, Iranian Pediatric Hematology and Oncology Society. All rights reserved.
Publication Date: 2013
Jundishapur Journal Of Microbiology (20083645)6(2)pp. 144-149
Background: Staphylococcus aureus is associated with different infections ranging from skin and soft tissue infections to endocarditis and fatal pneumonia. S. aureus is still the most common bacterial species isolated from inpatient specimens and the second most common from outpatient specimens. Today, methicillin resistant S. aureus (MRSA) isolates are present in the hospitals of most countries and are often resistant to several antibiotics. Objectives: This study was conducted from 2007 to 2011 to detect prevalence and antibiotic resistance patterns among MRSA and methicillin sensitive S. aureus (MSSA) isolated from hospitals in Tehran, Iran. Materials and Methods: Totally 726 isolates of S. aureus were collected from three referral hospitals in Tehran. All isolates were identified at the species level by standard biochemical tests. Susceptibility to eighteen antibiotics was determined by disc diffusion method. Then oxacillin and vancomycin minimum inhibitory concentration (MIC) of resistant isolates was also determined using Etest. mecA gene was detected using specific primers. Results: A total of 216 (30%) strains were found to be MRSA isolates. The highest antibiotic resistance was to penicillin, clindamycin, tobramycin and tetracycline respectively. Ninety three and 61% of MRSA and MSSA isolates were multidrug resistant (MDR) respectively. However, no strain was resistant to vancomycin, synercid, linezolid and chloramphenicol. Sixty nine percent of MRSA isolates showed high level of resistance to oxacillin (MIC ≥ 256 μg/mL). mecA gene was detected among all MRSA isolates. Conclusions: Although the frequency of MRSA isolates in the current study was low, resistance to other antibiotics was high and most of the isolates were found to be MDR. Regular surveillance of hospital-associated infections and monitoring of their antibiotic sensitivity patterns are required to reduce MRSA prevalence. High frequency of MDR isolates of S. aureus could be considered as an urgent warning for public health. © 2013, Kowsar Corp.; Published by Kowsar Corp.
Publication Date: 2013
Jundishapur Journal Of Microbiology (20083645)6(1)pp. 80-85
Background: Staphylococcus aureus is a common cause of infections among humans and animals and it is known as a community-acquired and nosocomial pathogen. Most of the isolates contain lysogenic phages which are responsible for production of various virulence factors such as enterotoxins, staphylokinase, β-lysin, lipase, exfoliative toxin A and Pantone-vlaentine leukociden (PVL). All staphylococcus isolates are classified in 6 Objectives: This study was performed to detect the presence of bacteriophage types and determine antibiotic resistance pattern of methicillin resistant S. aureus (MRSA) isolates obtained from a tertiary care hospital in Tehran, Iran from 2008 to 2010. Materials and Methods: A total of 968 S. aureus isolates were collected from a tertiary care hospital in Tehran, Iran and identified at the species level by PCR and biochemical Susceptibility to 17 antibiotics was determined. Then oxacillin and vancomycin minimum inhibitory concentration (MIC) of the resistant isolates were determined. Multiplex-PCR was used to detect 6 classes of prophages. Results: Out of the 968 isolates 247 isolates were resistant to methicillin. Highest antibiotic resistance was seen to penicillin (100%), erythromycin (89.8%), kanamycin (89.4%), ciprofloxacin (88.6%) and tobramycin (87.4) respectively. None of the MRSA isolates showed resistance to vancomycin, synercid and linezolid. MIC results indicated that 46.1 and 4.4% of isolates with high (MIC ≥ 128 μg/ml) and low level (MIC ≥ 4 μg/ml) showed resistance to oxacillin, respectively. Four different phage types and eight patterns of prophages were detected. All MRSA isolates contained at least one prophage. Totally, 2.8, 69.2 and 27.9% contained 5, 4 and 3 different prophage types, respectively. Conclusions: High prevalence of different classes of prophages indicating the potential to carry a broad spectrum of virulence factors and high oxacillin resistance were found in the MRSA isolates. Detection of SGF phage in 100% of the isolates indicates the ability of these isolates to produce virulence factors. © 2013 Ahvaz Jundishapur University of Medical Sciences; Published by Kowsar Corp.
Publication Date: 2013
Jundishapur Journal Of Microbiology (20083645)6(1)pp. 20-23
Background: Cholera is a severe diarrheal illness caused by Vibrio cholerae, which produces a virulence factor named El Tor hemolysin encoded by the hlyA gene. Objectives: This study meant to analyze the phenotypic characteristics and presence of hlyA gene in V. cholerae isolated from patients in Iran. The hlyA gene which codes for hemolysin, plays an essential role in manifestation of cholera,and could be used to diagnose pathogenic V. cholerae El Tor O1 strains. Patients and Methods: One hundred stool samples from the patients with cholera during 2002-2003 were collected from Tehran, Kashan, Kermanshah and Ahvaz cities, which were subject to diagnostic tests. Serotyping, and antibiotic susceptibility tests were applied and polymerase chain reaction (PCR) was also used to detect the hlyA gene.Results: The group specific antisera identified the isolates as Ogawa, Inaba, Hikojima and NAG (Non-agglutinable) in 74%, 3%, 0% and 23% of the isolates, respectively. Antibiotic susceptibility test showed that all of the strains were sensitive to ciprofloxacin, gentamycin and doxycyclin but the isolates showed resistance to sulfamethoxazole/tri- methoprim (74%), erythromycin (64%) and tetracycline (50%). V. cholerae El Tor isolates were 100% positive for hlyA gene, but hemolysis phenotype characteristics were found in 95% of the cases. Conclusions:The results indicated that Ogawa serotype was identified as the dominant serotype which revealed multiple antibiotic resistances to sulfamethoxazole/trim- ethoprim, oxytetracycline, erythromycin, tetracycline and chloramphenicol. The presence of hlyA gene in nonhemolytic strains of V. cholerae O1 biotype El Tor indicated that some factors prevent expression of the hemolysin gene. © 2013 Ahvaz Jundishapur University of Medical Sciences; Published by Kowsar Corp.
Publication Date: 2012
Journal of Pure and Applied Microbiology (09737510)6(2)pp. 621-625
Enterococci are part of the normal flora of humans and animals. Recently, Enterococci have caused great concern due to developing of resistance to many antimicrobial agents. Their ubiquity in animal and human digestive tracts , medical importance, frequent multiple antibiotic resistance and their seemingly unlimited capacity for horizontal gene transfer via numerous mobile genetic elements make this bacterial group ideal for investigating the ecology of antibiotic resistance. The aim of this study was to investigate and identify the prevalence of VRE (Vancomycin Resistant Enterococcus) within isolated Enterococci taken from a number of Tehran Livestock husbandry units. Putative Enterococci (n = 242) were isolated on Membrane Filter Enterococcus Selective Agar Medium , supplemented with 2 , 4 and 8 μgr/ml vancomycin from cow samples. A total isolates passed the standard biochemistry tests for the genus and species as well as specific genus and species primers. The antibiotic susceptibility was determined by the disc diffusion method for 6 antibiotics. MIC of vancomycin was also done using broth micro-dilution assay by CLSI recommendations. Results showed that 138, 90 and 14 of the isolates were E. faecium , E. feacalis and E. gallinarum, respectively. 41, 25, 18, 10, 21 and 22 of the isolates were resistant to vancomycin , tetracycline, gentamicin , chroramphenicol, ciprofloxacin and erythromycin, respectively. An MIC test on 65% of the isolates was > 256 μgr/ml. Diversity of VRE isolates was restricted to 3 species. E. faecium had high resistance to a broad range of antibiotics. The results of this study suggest that more attention should be paid to the livestock samples as a reservoir of resistance elements. Surveillance of VRE reservoirs in animal husbandry to clarify the mechanism of transfer are urgently required.
Publication Date: 2012
Archives of Virology (03048608)157(9)pp. 1807-1811
A total of 114 isolates of methicillin-resistant Staphylococcus aureus (MRSA) were collected from hospitals in Tehran, Iran. A multiplex PCR was designed to examine the presence of six different prophage classes. The results showed high diversity of bacteriophages, with four different prophage types and eight prophage patterns. An important S. aureus phage coding for several virulence factors, Φ-77-like phage, was detected in 97 % of the isolates. We found a high rate of resistance of MRSA isolates to penicillin, ciprofloxacin, tobramycin and kanamycin. This is the first study showing high prevalence and diverse bacteriophage populations in MRSA strains in Iranian hospitals. © 2012 Springer-Verlag.
Publication Date: 2010
Shiraz E-Medical Journal (17351391)11(3)pp. 137-147
Background and Objectives: The objective of this study was to find out the prevalence of anxiety and depression in adult hospitalized patients in internal and surgical wards of Shiraz University Hospitals in year 2008. Materials and Methods: The study was designed as a cross sectional study. A validated measurement tool was used in this study was the Hospital Anxiety and Depression Scale (HADS) (the questionnaire of case ness). Data collection was carried out in two major university hospitals and two private hospitals in Shiraz. Statistical analysis included the Student's t test, and chi-square test and logistic regression analysis. Results: Thirty (4.3%) patients were normal within anxiety and depression, 216 (30.9%) were borderline cases of anxiety, 454 (64.9%) were probable cases of anxiety, 373 (53.4%) were borderline cases of depression and 296 (42.3%) were probable cases of depression. There was significant association between normal, borderline and probable groups of depression according to times of admissions and also between normal, borderline and probable groups of anxiety and depression according to duration of hospitalization and ward of admission. Most of borderline and probable cases of anxiety were admitted in internal ward. Most of normal and probable cases of depression were admitted in internal ward too. Discussion and conclusion: Prevalence of anxiety and depression in hospitalized medical patients is grate. The high levels of anxiety and depression detected in this sample suggests that screening for psychological co-morbidity is important in rehabilitation settings and should be included in the clinical interview carried out by the nurse at the duration of admission to the ward. Accurate diagnosis of co-morbid depressive and anxiety disorders in patients who admitted in medical care services is essential in understanding the cause and in optimizing the management of somatic symptom burden. Copyright © 2010, Shiraz E Medical Journal. All rights reserved.
Publication Date: 2009
Iranian Journal of Clinical Infectious Diseases (20081081)4(3)pp. 143-150
Background: Staphylococcus aureus is a major pathogen in hospital setting and in the community and causes a wide range of diseases. MRSA infection has recently become a serious problem in anti-microbial chemotherapy. The aim of the study was to detect and analyze the antibiotic diversity and isolation of methicillin resistance gene (mecA) of S. aureus isolated from Tehran hospitals as a rapid and reliable method. Patients and methods: We studied 585 isolates of staphylococcus spp. recovered from patients at 3 clinical centers in Tehran from October 2005 to October 2006. Antibiotic susceptibility test of isolates was achieved with 13 antibiotics by disc diffusion. The MIC of methicillin was also performed by broth micro dilution assay. PCR was used for detection of mecA gene. Results: Totally, 321 (54.7%) isolates were identified as S. aureus. 66, 65, 88, 88, 100, 41, 38, 41, 0, 40, 93, 20 and 64% of S. aureus isolates were resistant to kanamycin, cephotaxim, methicillin, oxacillin, ampicillin, erythromycin, clindamycin, sulphamethoxazole-trimethoprime, vancomycin, chloramphenicol, ciprofloxacin, gentamicin and tetracycline, respectively. All MRSA and 63% of intermediate isolates carried mecA gene. Conclusion: In contrary to other studies in Iran, the prevalence of methicillin resistance is rising up in Tehran and most of MRSA isolates were resistance to 5 antibiotics at least. Vancomycin, chloramphenicol, gentamicin and clindamycin are the most effective antibiotics. All MRSA isolates had mecA gene with different expression. Detection of mecA gene is a rapid and reliable method for identification of MRSA isolates. ©2009 IDTMRC, Infectious Diseases and Tropical Medicine Research Center.
Publication Date: 2009
Letters in Applied Microbiology (02668254)48(2)pp. 157-161
Aims: This study aimed to analyse the diversity of the vanB gene cluster in enterococcal species isolated from sewage treatment plants (STP) in Tehran, Iran. Methods and Results: The enterococcal isolates were collected from three sewage treatment plants in Tehran, Iran, during 2005. A total of 203 enterococcal isolates, collected over six rounds of sampling from three STPs were tested for the presence of vanB gene. Long-PCR showed that amongst the isolates, three Enterococcus faecium, one Enterococcus gallinarum and one Enterococcus casseliflavus harboured the complete vanB gene cluster. Restriction fragment length polymorphism (RFLP) of the vanB1 gene cluster (5900 bp) from the isolates showed an identical pattern to a standard strain of Enterococcus faecalis (V583). None of the isolates were able to transfer the vanB gene in conjugation experiments. Different pulsed-field gel electrophoresis patterns were obtained for the three E. faecium isolates with vanB gene clusters. Conclusions: Our results indicated that the dissemination of vanB is not widespread in Tehran. Although only a few vanB positive isolates were detected, vanB was found in several enterococcal species. Significance and Impact of the study: In view of the lack of information on vanB resistance genes and their diversity in Iran, knowledge of the global dissemination of vanB genes in Enterococcus spp. is noteworthy. © 2008 The Authors.
Publication Date: 2008
Current Microbiology (14320991)56(5)pp. 468-473
We investigated the prevalence of vancomycin-resistant enterococci (VRE) isolated from wastewater (n = 593) and clinical (n = 450) samples, and the genetic linkage between the isolates was compared. Out of the total samples, 38 Enterococcus faecium (3.6%) from sewage (n = 19) and clinical (n = 19) isolates were found to be highly resistant to vancomycin. The majority of the VRE isolates from the two sources showed distinct phenotyping and genotyping patterns. At the same time, one common pulsed-field gel electrophoresis pattern was found among the VRE obtained from wastewater and human clinical isolates, suggestive of an epidemiological link. © 2008 Springer Science+Business Media, LLC.
Publication Date: 2007
Iranian Biomedical Journal (1028852X)11(3)pp. 161-167
Background: Enterococci are important because of their role as the leading cause of nosocomial infections which have a significant role in the dissemination and persistence of antimicrobial resistance genes. Methods: In this study, we determined the distribution of enterococcal species in the sewage treatment plants in Iran. Furthermore, we improved a rapid and specific PCR method using primers (sodA and ddl genes) for identification of enterococci spp. Results and Conclusion: A total number of 712 enterococci spp. were isolated and the results showed that 56%, 24%, 12%, 4%, 2%, 1% and 1% isolates were E. faecium, E. hirae, E. faecalis, E. gallinarum, E. casseliflavus, E. mundtii and other enterococcal spp., respectively. The use of species-specific PCR was in agreement with the biochemical tests. Furthermore, multiplex PCR was developed to study the presence of vancomycin resistant genes in E. faecium or E. faecalis. The multiplex PCR appeared to be a useful, rapid and specific method for detecting and discriminating genotypes for vancomycin-resistant Enterococcus.
Publication Date: 2007
Water, Air, and Soil Pollution (15732932)185(1-4)pp. 111-119
We investigated for the first time the occurrence, stability and antibiotic resistance of 593 enterococci in six samples collected from three urban sewage treatment plants (STPs) located in the north, south and west part of Tehran, Iran between October 2004 and September of 2005. Isolates were typed with a biochemical fingerprinting method (the PhPlate system) and tested for their resistance to six antibiotics. The most prevalent species in all three STPs were E. faecium followed by E. hirae and E. faecalis accounting for 93% of the total isolates examined. In all, 317 (55%) isolates were susceptible to all six antibiotics tested and the remaining isolates were resistant to between 1 and 6 antibiotics. Biochemical fingerprinting with PhPlate system showed a high diversity for E. faecalis (D i = 0.95), E. hirae (D i = 0.93) and E. faecium (D i = 0.95) populations with an overall diversity of D i = 0.97 for the whole enterococcal populations found in all three STPs. Our data indicate a high degree of polyclonality among the enterococci populations of human origin. This study suggest that the municipal wastewaters might be an important source of dissemination of antibiotic-resistant enterococci in Iran. © 2007 Springer Science+Business Media B.V.
