Title of article :
Subtyping β -lactamase-producing Escherichia coli strains isolated from patients with UTI by MLVA and PFGE methods
Author/Authors :
Dolatyar Dehkharghani ، Alireza Department of Microbiology - Faculty of Advanced Sciences and Technology - Islamic Azad University, Tehran Medical Sciences branch , Haghighat ، Setareh Department of Microbiology - Faculty of Advanced Sciences and Technology - Islamic Azad University, Tehran Medical Sciences branch , Rahnamaye-Farzami ، Marjan Department of Microbiology - Research Center of Reference Health Laboratory - Ministry of Health and Medical Education , Douraghi ، Masoumeh Division of Microbiology, Department of Pathobiology - School of Public Health - Tehran University of Medical Sciences , Rahbar ، Mohammad Department of Microbiology - Research Center of Reference Health Laboratory - Ministry of Health and Medical Education
Abstract :
Objective(s): Strain subtyping is an important epidemiological tool to trace contamination, determine clonal relationships between different strains, and the cause of outbreaks. Current subtyping methods, however, yield less than optimal subtype discrimination. Pulsed-field gel electrophoresis is the gold standard method for Escherichia coli and Multiple-Locus Variable-number tandem repeat Analysis (MLVA) is a rapid PCR-based method. The purpose of this study was to evaluate MLVA and pulsed-field gel electrophoresis (PFGE) methods for subtyping β -lactamase-producing E. coli strains isolated from urinary tract infections. Materials and Methods: Overall, 230 E. coli isolates from patients with urinary tract infections were examined for antimicrobial susceptibility testing. 10-loci and 7-loci MLVA and PFGE methods were used for molecular typing of β -lactamase-producing E. coli isolates. Results: Out of 230 isolates, 130 (56.5%) β -lactamase-producing E. coli isolates were found in this study. The diversity indices of the VNTR loci showed an average diversity of 0.48 and 0.54 for 7-loci and 10-loci MLVA, respectively. The discriminatory power of PFGE showed a value of 0.87. The discordance between the methods was high. Conclusion: Our study showed that PFGE is more discriminatory than MVLA. MLVA is a PCR- based method and can generate unmistakable data, in contrast to PFGE. Optimization of polymorphic VNTR is essential to improve the discriminatory power of MLVA based on geographical region.
Keywords :
Beta , lactamase , Escherichia coli , Molecular typing , Pulsed , field gelelectrophoresis , VNTR
Journal title :
Iranian Journal of Basic Medical Sciences
Journal title :
Iranian Journal of Basic Medical Sciences