Integron-Associated Antibiotic Resistance in Salmonella enterica

Eighteen of 25 isolates of Salmonella enterica serovar Typhi were multidrug resistant and contained class 1 integrons with a single cassette, dfrVII or aadA1. The dfrVII-containing integron was likely borne on an IncHI1 plasmid. Salmonella serovar Typhi could become resistant to broad-spectrum cephalosporins by integrating cassettes, such as veb-1, a common cassette in Asia. Integrons are genetic elements that can integrate, by site-specific recombination, gene cassettes, which usually confer antibiotic resistance. Three classes of integrons have been characterized in detail and are involved in antibiotic resistance. The occurrence of multidrug resistance (MDR) (to amoxi-cillin, chloramphenicol, sulfonamides, streptomycin, tetracy-cline, and trimethoprim) in Salmonella enterica serovar Typh