# Extended spectrum β-lactamase and integron genes among Shigella flexneri and Shigella sonnei isolated from children with diarrhea in shiraz, Southwest Iran

## TL;DR

This study found high antibiotic resistance and common ESBL genes in Shigella bacteria from children in Iran, highlighting a growing public health concern.

## Contribution

The study reports the prevalence of ESBL genes and integrons in Shigella isolates from children in southwest Iran.

## Key findings

- All Shigella isolates showed multidrug resistance to common antibiotics.
- The blaCTX−M gene was most prevalent among ESBL-mediated genes in both Shigella species.
- High detection rates of intI1 and intI2 integron genes were observed in S. flexneri and S. sonnei isolates.

## Abstract

Shigellosis, a bacterial infection marked by dysentery, is typically a self-limiting disease and can be effectively managed with oral rehydration. However, antibiotics may help reduce the severity and duration of Shigellosis despite rising antimicrobial resistance. This study examines the prevalence of ESBL-producing isolates and the presence of blaTEM, blaCTX−M, blaSHV, intI1, and intI2 genes among Shigella sonnei and Shigella flexneri isolates from children with diarrhea in Shiraz, southwest Iran. From October 2019 to March 2020, 50 S. flexneri and 50 S. sonnei were isolated from children under 13 years old with diarrhea. Antimicrobial susceptibility and ESBL production were assessed, and the presence of ESBL-mediated genes, also intI1 and intI2 genes, was investigated using polymerase chain reaction methods. Resistance rates of 100% were observed against cefotaxime, ceftriaxone, streptomycin, and trimethoprim/sulfamethoxazole in all S. flexneri and S. sonnei isolates, with all isolates exhibiting multidrug resistance (MDR). ESBL positivity was found in (68%) of S. flexneri and (64%) of S. sonnei isolates. The blaCTX−M gene was prevalent in (56%) of S. flexneri and (70%) of S. sonnei isolates. Remarkably, intI1 and intI2 were detected in (80%) and (86%) of S. flexneri isolates and (18%) and (90%) of S. sonnei isolates, respectively. In conclusion, the increasing resistance to first- and second-line antibiotics for treating shigellosis in Iran is a significant concern. The high prevalence of MDR Shigella spp. isolates in our region underscores the critical need to address the spread of antibiotic resistance and integrons in Shigella spp., making it an urgent priority.