No abstract

Background:Urinary tract infection (UTI) is one of the most common childhood bacterial infections and Escherichia coli is the major pathogen. Producing β-lactamase enzymes are the most common mechanism of bacterial resistance.Objectives:This study aimed to determine the prevalence of Extended-Spectrum β-Lactamases (ESBLs) and Quinolone Resistance (qnr) genes in E. coli strains isolated from UTIs.Materials and Methods:In this study, a total of 120 isolates of E. coli from urinary tract infections of the children were collected at Besat Hospital in Hamadan, Iran, from October 2010 to October 2011. The bacterial isolates were identified by standard biochemical methods. Antimicrobial susceptibilities were determined by disk diffusion method, and ESBLs-producing was confirmed phenotypically using the double-disk synergy (DDS) test. The presence and identification of ESBLs and qnr genes were determined by Polymerase Chain Reaction (PCR).Results:The highest sensitivity was seen to imipenem (96.7%), amikacin (92.5%), nitrofurantoin (93.3%), ofloxacin (81.7%), gentamicin norfloxacin (70.8%), and ciprofloxacin (79.2%). In contrast, the highest rate of resistance was seen to co-trimoxazole (77%) and nalidixic acid (40.9%). The results showed that 6 (2.18%) and 4 (1.12%) isolates of ESBL-producing E. coli were positive with respect to having qnrB and qnrS genes, respectively. No isolates was found to have qnrA.Conclusions:CTX-M was the most prevalent ESBL genotype in uropathogenic E. coli (UPEC) isolated from UTI. In addition, a high frequency of qnr genes among ESBL-producing E. coli was identified in this study. In order to avoid treatment failures, we recommend using phenotypic and molecular methods to diagnose these enzymes and qnr genes.

Our results could reflect some hospital multidrug-resistant strains in nosocomial infections. The widespread emergence of carbapenem-resistant isolates has caused increasing concern in recent years. Therefore, specific strategies should be designed and evaluated for the control of resistant strains.

No abstract

Background: Staphylococcus aureus is an important cause of hospital and community acquired infections. Food borne diseases are an important problem in public health. Protein A is a protein 42 KDa, which is expressed in all strains of this bacterium. Objectives: This study aimed to evaluate the relationship between antibiotic resistances with spa gene polymorphism. Methods: A total of 1,050 food samples were collected during 8 months in Hamedan, Iran. Food samples were evaluated for the presence of spa genes of S. aureus. The antibiotic susceptibility testing was performed using disk diffusion agar. After extraction of genomic DNA, nuc and spa genes were detected. Finally, with the PCR-RFLP method, spa typing was performed. The relationship between the antibiotic resistance rate and Spa types were analyzed by the SPSS software. Results: Results showed that the 98 cases (9.33%) of S. aureus were isolated. The most frequent resistance was observed against tetracycline (8.41%). Spa gene was reported in all isolates and 4 different patterns of spa gene was seen. Furthermore, a significant correlation between different strains isolated from diverse foodstuffs and different patterns of spa (P < 0.05) was also found. In addition, the relationship between resistance to different antibiotics with obtained types showed that there is a significant correlation between resistance to erythromycin (P = 0.014) and clindamycin (P = 0.016) with different spa types. Conclusions: In regards to the increased resistance to antibiotics in strains isolated from foodstuffs, rapid and accurate typing of S. aureus to identify transmission of the infectious organisms is very important. Molecular typing of Spa protein can prevent epidemics and reduce the infections and costs of nosocomial infections.