en Epidemiologic studies including microbial genotyping, phenotyping and serotyping Epidemiologic studies including microbial genotyping, phenotyping and serotyping Original article Original article <p dir="ltr"><strong>Introduction:</strong> 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. <strong>Methods:</strong> The microarray analysis enables identification of the strains that have the 90kb <em>Salmonella typhimurium</em> virulence plasmid, presence or absence of the <em>Salmonella</em> pathogenicity islands (SPIs), adherence factors and other&nbsp; virulence determinants. Twelve isolates of <em>S. typhimurium</em> obtained from faeces of children with gastroenteritis were analyzed&nbsp; by microarray technique. <strong>Results</strong>: 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, <em>cdtB.</em> All strains were positive for <em>rck</em> and <em>mig-14</em>. 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 <em>S. typhimurium</em>. <strong>Conclusion:</strong> Microarray analysis proved to be a valuable tool in confirmation of serotyping results and genetic characterization of <em>S. Typhimurium.</em></p> Salmonella typhimurium, Gastroenteritis, Microarray Analysis 29 34 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-102-1&slc_lang=en&sid=1 Hamid Staji hstaji@semnan.ac.ir Yes Department of Pathobiology, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran. Alfreda Tonelli a.tonelli@izs.it No Istituto ‘‘G. Caporale’’, Campo Boario, 64100 Teramo, Italy. Taghi Zahraei Salehi tsalehi@ut.ac.ir No Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Mariangela Iorio m.iorio@izs.it No Istituto ‘‘G. Caporale’’, Campo Boario, 64100 Teramo, Italy. Federica Lopes f.lopes@izs.it No Istituto ‘‘G. Caporale’’, Campo Boario, 64100 Teramo, Italy.