Emergence of Bla-Ctx-M-Type Gene in Salmonella Enterica Serotypes Isolated From Patients Stool



Abdollahi A^{1, 2} ; Mohammadi A³ ; Fasihi M⁴ ; Shayan R⁵ ; Radmanesh R⁶ Show Affiliations
Source: Journal of Isfahan Medical School Published:2011

Abstract

Background: Salmonellosis is one of the most important prevalent bacterial infections, after a decade of its recognition. Antibiotic therapy in salmonellosis is restricted to typhoid fever and acute infections. After the first reporting of resistance in S. Typhimurium DT 104, nowadays, developing resistance in Salmonella, specially, ESBL (such as CTX-M) species is an important issue in salmonellosis. In this study, we evaluated bla-ctx-m-type gene in clinical isolates of Salmonella enterica. Methods: In this cross-sectional study, we collected clinical isolates of patients in 18 months. Initially, we surveyed drug sensitivity with disk diffusion method, and then determined MIC of resistant isolates with E-test stripes. The existence of ESBL (extended spectrum beta-lactamase) enzymes was examined by ESBL disks in Double Disk method, and these resistances was evaluated with PCR by using a pair of universal primers. Finding: 36 isolates were sensitive to all of antibiotics, but, in 60 isolates there was at least one resistance. In 45 isolates, there were multi drug resistance (MDR) phenotypes. Resistance to ampicilin was the highest percent, whereas, there was not any resistance to imipenem and ciprofloxacin, which were improved with E-test strips. ESBL evaluation, showed producing cefotaxime ESBL in 5 isolates and ceftazidim ESBL in 4 isolates; 2 isolates of these had bla-ctx-m-type gene in plasmid. Conclusion: Detection of MDR trait, especially extended spectrum beta-lactamases in resistant clinical Salmonella isolates, point to the attention in usage of extended spectrum cephalosporins and detection of resistance rate in a nation level.