Determination of ESBLs, pAmpC-beta-lactamase genes, and plasmid replicon types among Shigella species from different cities in Iran

Shigella species (spp) are the common gram-negative bacilli isolated from patients with diarrhea. Infection treatment of these genus of bacteria due to increasing resistance to antibiotic agents remains a global challenge. Herein, we determined the frequency of ESBLs, plasmid-mediated AmpC-beta-lactamase (pAmpC) genes, and plasmid replicon types in 210 clinical isolates of Shigella spp from different cities in Iran. The antibacterial susceptibility of isolates to antibiotic agents and ESBLs production were determined according to the Clinical & Laboratory Standards Institute (CLSI) recommendations. ESBLs, pAmpC genes, and plasmid replicon types of isolates were detected using PCR and multiplex PCR methods. The highest rate of antibiotic resistance was observed to trimethoprim-sulfamethoxazole and the lowest rate of resistance was observed to cefoxitin. Fifty-four percent of the isolates were considered as ESBL-producers. Beta-lactamase genes including blaCTX-M, blaTEM, and blaDHA were detected in 93 (44%), 84 (40%), and 3 (1.4%) of isolates, respectively. Ten various 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 in 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 are increasing among the Shigella spp in our country which can be challenging to treat their infection and more efficient strategies, and monitoring should be considered to prevent the spread of them.