Antibiotic resistance and molecular characterization of clinical Shigella spp. isolated from hospitals located in Tehran and Qazvin cities, Iran

Using pulsed-field gel electrophoresis (PFGE) as the primary typing method, the isolates were classified into 13 distinct clusters, revealing a dominant pattern that has persisted for over twenty years. This persistence may be attributed to factors such as poor hygiene, personal contact, immigration, and antibiotic resistance. Genetic analysis indicated clonal expansion among the isolates over the two-decade period. Notably, the highest resistance was observed against amoxicillin, with several isolates exhibiting multidrug resistance.