Multiplex PCR assay for rapid determination of bla(TEM), bla(SHV) and bla(CTX-M) genes in diarrheagenic Escherichia coli isolated from Iran, Shiraz

Introduction: The emergence of Escherichia coli that produce extended spectrum b-lactamases (ESBLs) and are multidrug resistant poses antibiotic management problems. ESBLs are cephalosporinases that confer resistance to a wide variety of oxyimino cephalosporins and create serious therapeutic problems. The objective of this study was to determine the blaTEM, blaSHV and blaCTX-M Genes of diarrheagenic E. coli. Methods: We conducted a cross sectional-descriptive study on 150 E. coli strains, isolated from patients who had diarrhea at 3 major hospitals in Shiraz from April to November 2010. Initially, E. coli strains isolated by biochemical analysis. Finally, prevalence of blaTEM, blaSHV and blaCTX-M were determined by multiplex PCR assay. Statistical analyses were performed using the c2 test. Pvalues less than 0.05 were taken to indicate statistical significance. Results: Overall, ESBL-related bla genes were detected in 143 (95.33%) isolates which were identified as 79 (52.66%) TEM, 7 (4.66%) SHV, 4 (2.66%) CTX-M, 12 (8%) TEM/SHV, 16 (10.66%) TEM/CTX-M, 7 (4.66%) SHV/CTX-M and 18 (12%) TEM/SHV/CTX-M. Statistical analysis revealed that more relationships between blaSHV and age 48 60 (p = 0.009) and blaCTX-M age 12 17 (p = 0.009). Conclusion: ESBLs in E. coli has increased in the last few years and increase in cephalosporin resistance is mainly due to an increase in the proportion of isolates carrying the blaTEM gene in Shiraz. ESBL-producing E. coli infections have a significant impact on several important clinical outcomes, and efforts to control outbreaks of infection with ESBLproducing E. coli should emphasize judicious use of all antibiotics as well as barrier precautions to reduce spread.