Genetic Characterization of Salmonella Typhimurium Isolates from Faeces of Children with Gastroenteritis Hospitalized in Baqiatollah-Azam Hospital, Tehran, Iran

Introduction: In Iran, invasive nontyphoidal Salmonella (iNTS) disease causes severe bacteremic illness among children <5 years old. The global yearly incidence of iNTS disease in children was reported to be in the 3.4 (range&nbsp; 2.1-6.5) million cases,&nbsp; (overall incidence 49 cases (range 30-94) per 100,000 population), the iNTS case-fatality ratio (CFR) of 20% yielded 681,316&nbsp; deaths annually. Methods: The microarray analysis enables identification of the strains that have the 90kb Salmonella typhimurium virulence plasmid, presence or absence of the Salmonella pathogenicity islands (SPIs), adherence factors and other&nbsp; virulence determinants. Twelve isolates of S. typhimurium obtained from faeces of children with gastroenteritis were analyzed&nbsp; by microarray technique. Results: The virulence plasmid was present in 83.33% of isolates and all the isolates contained the&nbsp; SPI-4 and SPI-5. None of the strains had the cytolethal distending toxin, cdtB. All strains were positive for rck and mig-14. The adherence genes were present in all the strains in the range of&nbsp; 51.55%&nbsp; to 73.20% of the adherence genes interrogated in the&nbsp; microarray. Two strains were the least pathogenic S. typhimurium. Conclusion: Microarray analysis proved to be a valuable tool in confirmation of serotyping results and genetic characterization of S. Typhimurium.