The Study of Genetic Relationship Among Third Generation Cephalosporin-resistant Salmonella enterica Strains by ERIC-PCR

BACKGROUND AND OBJECTIVES Salmonella is an important food-borne pathogen responsible for disease in humans and animals. The aim of this study was to investigate the genetic relationship among third generation cephalosporin-resistant Salmonella enterica strains by Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR. METHODS The study included all Salmonella isolates obtained from clinical cases in a pediatric hospital in Tehran, Iran during 2006 to 2009. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The genetic relationship between third generation cephalosporins-resistant Salmonella enterica strains was determined using ERIC-PCR. RESULTS Of 136 Salmonella enterica isolates recovered from pediatric patients, six isolates including four Salmonella enterica serotype Infantis and two Salmonella enterica serotype Enteritidis showed an extended-spectrum cephalosporins resistant phenotype. ERIC-PCR differentiated Salmonella enterica serotypes Infantis and Enteritidis into 2 distinct clusters arbitrarily named as E1 and E2. Profile E1 was found in two Salmonella enterica serotype Enteritidis isolates, and profile E2 was found in four Salmonella enterica serotype Infantis isolates. CONCLUSION Extended-spectrum cephalosporins resistant Salmonella could be attributed to a few predominant serotypes including Enteritidis and Infantis in this study. Genetic analysis using ERIC-PCR showed that closely related clones are responsible for the occurrence of extended-spectrum cephalosporins resistant Salmonella infection in Tehran.