Abstract
Shigella species (spp) are the common gram-negative bacilli isolated from patients with diarrhea. Treatment of infections caused by this genus of bacteria remains a global challenge due to increasing resistance to antibiotics. This study aimed to assess the prevalence of ESBLs, plasmid-mediated AmpC-beta-lactamase (pAmpC) genes, and plasmid replicon types among 210 clinical isolates of Shigella spp, collected from different cities across Iran. Antibacterial susceptibility of the isolates to antibiotics, as well as ESBLs production, were assessed in accordance with Clinical & Laboratory Standards Institute (CLSI) guidlines. ESBLs, pAmpC genes, and plasmid replicon types of the isolates were detected using PCR and multiplex PCR methods. The highest rate of antibiotic resistance was observed with trimethoprim-sulfamethoxazole, while the lowest rate of resistance was observed with cefoxitin. Fifty-four percent of the isolates were considered ESBL-producers. Beta-lactamase genes, including bla(CTX-M) , bla(TEM) , and bla(DHA) were detected in 93 (44%), 84 (40%), and 3 (1.4%) of the isolates, respectively. Ten distinct plasmid replicon types, including I1-Iγ, K, W, FIB, Y, P, FIC, FIA, HI1, and B/O were identified among the isolates. The study sheds light on the persistent challenges posed by multidrug-resistant (MDR) shigellosis to public health in different regions of Iran. Despite advancements in hygiene practices, the prevalence and population composition of Shigella species have remained largely unchanged. Also, the spread of beta-lactamase genes and various plasmid replicon types is increasing among the Shigella spp across Iran, which poses challenges for their treatment. More efficient strategies and monitoring efforts should be considered to prevent their further spread.