Zahra Askari, Zeynab Mirzapour, Tooba Shafighi, Reyhaneh Ghorbanpour,
Volume 19, Issue 1 (Jan-Feb 2025)
Abstract
Background: Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) represent a significant global health concern. Virulence factors (VFs) expressed by UPEC strains play a crucial role in promoting bacterial pathogenicity within the urinary tract. Effective treatment of these infections is frequently complicated by the high prevalence of antimicrobial resistance exhibited by Escherichia coli. The objective of this study was to investigate the VFs and antibiotic susceptibility profiles of UPEC strains isolated in the northern region of Iran.
Methods: One hundred and five urine specimens were collected from female patients diagnosed with UTIs in Rasht, located in the north of Iran. These samples underwent culturing on both Eosin Methylene Blue (EMB) agar and MacConkey agar. Following a 24-hour incubation period at 37°C, pure bacterial isolates were identified through Gram staining and a battery of standard biochemical assays. The prevalence of six VF genes - papC, sfa/foc, fimH, afa, ibeA, and neuC - within UPEC strains was determined utilizing polymerase chain reaction (PCR) and subsequently confirmed via direct sequencing. Antibiotic susceptibility testing (AST) was conducted using the disk diffusion method, adhering to the guidelines established by the Clinical and Laboratory Standards Institute (CLSI M02).
Results: The study identified 65.71% of the isolates as Escherichia coli. Among the virulence genes examined, fimH exhibited the highest prevalence (100%), while afa was the least frequent (1.44%). Antibiotic resistance analysis revealed the highest rate against Cefazolin (66.66%) and the lowest against Gentamicin (24.63%). Notably, the prevalence of multi-drug resistance (MDR) was determined to be 73.91%.
Conclusion: This study underscored the significance of localized surveillance of UPEC isolates. This emphasis stems from the pathogen's considerable capacity for genetic mutation, coupled with the influence of environmental variables and individual patient characteristics. Understanding these dynamic factors at a local level is crucial for formulating the most effective strategies to combat UTIs.
Zahra Nasirzadeh, Seyedeh Tooba Shafighi,
Volume 20, Issue 2 (6-2026)
Abstract
Abstract
Background and Objective: Currently, healthcare-associated infections (HAIs) are rising alarmingly due to antibiotic-resistant gram-negative bacteria, particularly Pseudomonas aeruginosa and Acinetobacter species. The study in Rasht focuses on identifying phenotypic and molecular metallo-β-lactamases (MBLs) in clinical isolates of Pseudomonas aeruginosa and Acinetobacter that display resistance to Imipenem.
Methods: In this study, 52 Acinetobacter and 25 Pseudomonas aeruginosa samples were collected from medical centers in Rasht. The clinical isolates were analyzed using various biochemical tests. The antibiotic resistance patterns of the isolates were determined by the disk diffusion method, following CLSI guidelines. Isolates producing metallo-β-lactamases (MBLs) were identified using the IPM+EDTA combined test method. Genomic DNA was subsequently extracted from the isolates using a commercial kit, and the presence of blaIMP and blaVIM genes was determined by PCR.
Results: According to the findings of this study, the highest percentage of resistance in Acinetobacter was observed with cefotaxime antibiotics at 94.23%, and in Pseudomonas aeruginosa with ceftazidime at 84%. Among the clinical isolates not susceptible to Imipenem, 18 (40%) were Acinetobacter and 2 (15.38%) were Pseudomonas aeruginosa, as determined by the combined disc method. The blaIMP and blaVIM genes were detected in 7 (13.46%) and 11 (21.15%) of the Acinetobacter samples, respectively, and in 8 (32%) and 5 (20%) of the Pseudomonas aeruginosa samples, respectively.
Conclusion: These results suggest that the blaIMP and blaVIM genes play important roles in the antibiotic resistance and potentially influence the virulence of Acinetobacter species and Pseudomonas aeruginosa in the region
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