ANTIBIOTIC RESISTANCE PATTERN AND PREVALENCE OF BETA-LACTAMASE CTX-M GENE IN ISOLATED ESBL-PRODUCING E.COLI IN MAZANDARAN, IRAN

E. coli is one of the prevalent factors in human infections, especially urinary tract infections. Extended-spectrum ß-lactamase (ESBL) producing bacteria causes resistance to cephalosporin. Furthermore, the enzyme with the origin of plasmid causes the bacterial resistance to beta-lactam antibiotics. The aim of this study was to determine antibiotic susceptibility patterns and prevalence of CTX-M-type ESBL in E. coli strains isolated from urine samples by phenotypic and genotypic methods.
This descriptive, cross-sectional study of six-month duration (from December to April 2016) was undertaken to investigate patients’ antibiotic susceptibility. To fulfill that purpose, the urine samples of patients referred to seven clinics of the armed forces of the Mazandaran province were collected and antibiotic susceptibility of isolates by disk diffusion method on Mueller-Hinton agar was tested. To do confirmatory tests, the combined disk test method was performed. The test results were compared using standards Clinical and Laboratory standards (CLSIS). Ultimately, after DNA extraction by PCR method, isolates of ESBL positive for the presence of the CTX-M gene were examined and data were analyzed with SPSS software.
Of the total 180 patients, 41 isolates of Escherichia coli were separated. From those, 21 isolates (51.21%) had produced ESBL. In PCR, 4(9.75%) of the ESBL positive isolates contained CTX-M gene. The highest resistance to antibiotics was observed for ampicillin (75.6%), cefalotin (58.5%), and cefazolin (60.9%) and the highest amount of sensitivity to antibiotics was seen for imipenem (75.6%), gentamicin (70.7%), and cefotaxime (60.9%).
Based on the observed high percentage of resistance to the third-generation-sfalspvryn, it is vitally important to perform precise and accurate antibiogram. Avoiding excessive over-prescription of antibiotics for infections caused by ESBL-producing organism is an inevitable necessity.