Salmonella enterica: Serotyping, Drug Resistance & Extended Spectrum of β-Lactamase (ESBLs)

Background & Objective: Genus Salmonella has more than 2400 serotypes. The two major groups are S.enterica and S.bongori. Important serotypes are situated in S.enterica group. 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 of resistance in Salmonella, specially, ESBL producing species is an important issue in salmonellosis. We evaluated serotyping, drug resistance and extended spectrum beta lactamase (ESBL) in Salmonella enterica, collected from patients. Materials & Methods: We collected fecal samples in an 18 months period of time. Samples were cultured on selective, differential Medias. Serotyping was done with Biomérieux serotyping kit. After antibiogram, MIC was evaluated with E-test strips. By using ESBL disks in Double- Disk synergy method, ESBL phenotypes were distinguished. Results: We isolated 96 S.enterica serotypes, including: 35Typhimurium, 22Enteritidis, 11Typhi, 8Paratyphi B, 4Newport, 3Derby, 1Virchow, 1Infantis and 11untypable serotypes. 36isolates were sensitive to all of antibiotics, but, in 60 isolates, there were 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. ESBL evaluation shown producing cefotaxime ESBL in 5 isolates and ceftazidim ESBL in 4 isolates. Conclusion: With furthermore epidemiologic studies on Salmonella serotyping and antibiotic resistance, using suitable drugs in treatment, we can restrict the spreading of resistant Salmonella (specially, species with animal source).