Evaluate the distribution of virulence genes and to investigate antibiotic resistance pattern among Shigella species isolated from children with shigellosis in Iran

Abstract

The present study was performed to evaluate the frequency of virulence genes, including ipaH, ial, set1A, set1B, sen, virF, invE, sat, sigA, pic and sepA and assess antibiotic resistance pattern among Shigella isolates acquired from pediatric patients in Shiraz, Iran. Three hundred and nine isolates were isolated, from October 2018 to March 2019 from the feces of children with diarrhea; we used standard microbiological and serological tests for Shigella species. Overall, 73 (23.6%) isolates were positive for Shigella spp. The highest rate species of Shigella was S. sonnei (61.64%), followed by S. flexneri (37%) and S. boydii (1.36%). All the isolates were positive for ipaH gene, followed by ial (95.8%), virF (85%), InvE (75.3%), sen (28.7%), set1A (10.9%) and set1B (10.9%). The presence of sigA, sepA, sat and pic genes as SPATE genes was confirmed among 80.8%, 32.8%, 24.6% and 6.8% of Shigella isolates, respectively. Our investigations also indicated a high resistance percentage against trimethoprim-sulfamethoxazole and ampicillin in Shigella isolates. Our results displayed that S. sonnei was the predominant serogroup detected from children with shigellosis in Shiraz, Iran. As demonstrated in this study, most of the isolates showed a high prevalence rate of drug-resistance. S. flexneri carried a higher number of virulence genes. Our results indicated that certain symptoms were found to be related to the presence of specific different virulence factors. In addition, this study provided information that can increase our knowledge of the contribution of virulence genes in disease severity.