Determination of blaTEM, blaSHV and blaCTX-M genes by polymerase chain reaction method in Escherichia coli clinical isolates

Unconscious antibiotic use increases the prevalence of resistant bacteria and causes problems in treatment programs. Patient mortality rates increase due to resistance development. Infections caused by multidrug-resistant bacteria cause extra health costs. Escherichia coli (E. coli) is a member of the family Enterobacteriaceae. It is one of the most common pathogens in the gastrointestinal systems of human and warm-blooded animals. The most common forms of E. coli infections are urinary tract infections caused by uropathogenic isolates and diarrhea caused by enteropathogenic isolates. The isolates of E. coli used in our study were obtained from the Trabzon Fatih State Hospital Microbiology Laboratory between September 2018 and January 2019. Of the 158 E. coli isolates, 145 (%92) were isolated from urine, 5 (%3) from wound, 3 (%2) from aspirate, 3 (%2) from blood and 2 (%1) from sputum samples. VITEK 2 system was used to identify and to determine antibiotic susceptibility of E. coli isolates. Evaluation of antibiotic susceptibility profiles was performed using Eucast (Eucast Version 9.0). Glycerol stocks of E. coli isolates were made. The DNAs to be used as a template for PCR were obtained by total DNA isolation. In E. coli isolates blaTEM, blaSHV, blaCTX-M1 and blaCTX-M9 genes were screened by PCR method and the results were visualized by gel imaging device. When the antibiotic susceptibility profiles of 158 E. coli isolates were examined, the highest resistance rate was found to be against ampicillin with 99.4% and the lowest resistance rate was against 1.3% with ertapenem. According to PCR results, blaTEM was detected in 65 (%41.1) isolates, blaSHV in 3 (%1.9) isolates, blaCTX-M1 in 97 (%61.4) isolates and blaCTX-M9 in 14 (%8.9) isolates. TEM + CTX-M1 gene combination is the most common gene combination between isolates with 26% ratio.