Articles
Khashei, S.,
Fazeli, H.,
Rahimi, F.,
Karbasizadeh V. Frontiers in Pharmacology (16639812)
Introduction: This research aimed to examine the action of commercial antibiotics against extensively drug-resistant (XDR) A. baumannii clinical strains when combined with Rosmarinus officinalis extracts. Methods: Agar well diffusion and broth microdilution were used to screen the antibacterial activity of crude ethanol extract and its fractions (hexane, intermediate, ethyl acetate, and water). The interactions between the extracts and antibiotics (gentamicin, tetracycline, cefepime, and ciprofloxacin) were evaluated by checkerboard assay. The anti-biofilm and efflux pump inhibition activities were determined by the microtiter plate method and dye accumulation assay using flow cytometry, respectively. The potential phytochemicals that contribute to the antibacterial effects of R. officinalis were identified using the liquid chromatography-mass spectrometry (LC–MS). Results: R. officinalis crude extract (CE) demonstrated the best antibacterial activity with MIC values ranging from 300 to 600 μg/mL. The combination of CE and tetracycline exhibited the highest overall synergistic effect. This combination hindered biofilm formation ranging from 21.4% to 57.31% and caused a significant increase (up to 14%) in the fluorescence intensity in 75% of the studied strains. The LC-MS analysis of CE exhibited eleven compounds in which rosmarinic acid (55.53%) was the most abundant phenolic compound followed by cirsimaritin (11.46%), and p-coumaroyl hexoside acid (10.5%). Discussion: Overall, this is the first direct report that demonstrated the efficacy of R. officinalis when applied with conventional antibiotics on biofilm formation and efflux pump activity in XDR A. baumannii clinical strains. Copyright © 2025 Khashei, Fazeli, Rahimi and Karbasizadeh.
Archives Of Clinical Infectious Diseases (23452641)(4)
Background: Over the past decades, the role of biofilm-forming Staphylococcus aureus strains in urinary tract infections (UTIs) has garnered significant attention. Objectives: This study aimed to determine the epidemiological characteristics and diversity of S. aureus strains isolated from patients with UTIs in Isfahan, Iran, in 2017, with regard to their antimicrobial resistance, biofilm formation, and phylogenetic profiles. Additionally, the study investigated potential relationships among these factors statistically to develop efficient control and treatment approaches. Methods: All patients with symptomatic UTIs who had positive urine cultures for S. aureus during the study period at the laboratory of a referral hospital in Isfahan were included. All isolates were identified using specific primers for the nucA gene. Their biofilm formation capacity was evaluated using a combination of the microtiter plate and Congo-red agar methods. Antibiotic susceptibility testing was performed using the disk diffusion method. The presence of genes involved in biofilm formation and resistance to cefoxitin, aminoglycosides, and fluoroquinolones was detected using polymerase chain reaction (PCR). Staphylococcal cassette chromosome mec (SCCmec) typing, agr typing, and phene plate (PhP) typing were employed to investigate the diversity of collected strains. Results: Results showed that 19%, 57%, and 24% of confirmed S. aureus strains were strong, intermediate, and non-biofilm formers, respectively. The highest rate of resistance was against nalidixic acid (77%), followed by streptomycin (73%). The icaD and icaA genes had the highest frequency among biofilm-producing strains. gyrA (44%) and grlA (35%) were the most frequent genes among fluoroquinolone-resistant strains, while aph(3′)-IIIa was the most prevalent aminoglycoside-modifying enzyme gene. The majority of bacterial strains harbored SCCmec type III and agr type I. PhP typing of strains revealed the presence of 8 common types (CTs) and 14 single types (STs), with CT2 being the dominant type. Conclusions: The present investigation revealed various biofilm production capacities, antimicrobial resistance profiles, and clonal lineages in S. aureus isolated from patients with UTIs. These findings provide further insights into the epidemiology and pathogenicity of S. aureus strains in Iran, thereby improving the quality of surveillance and therapeutic protocols. © 2024, Mostafavi et al.
Tehran University Medical Journal (16831764)(7)
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.
