Detection of class 1 integron-associated gene cassettes of multi-drug resistant Salmonella strains isolated from food at conventional markets in Ho Chi Minh city

Abstract

After Salmonella strains were isolated from food samples collected randomly at conventional markets in several districts in Ho Chi Minh city, we evaluated antibiotic resistance by Kirby-Bauer methods, and the serotype name was assigned according to ISO/TR 6579-3:2014 and class 1 integron was investigated by PCR technique. As a result, there were seven distinguished serovars, including S. Kentucky (8 strains); S. Infantis (4 strains); S. Agona and S. Potsdam (2 strains); S. Saintpaul, S. Braenderup, S. Indiana (01 strain); OMF:1,z6:UT and 7:1,z6:UT (01 strain). The rate of multidrug-resistance Salmonella serovars carrying class 1 integron was 100% (21/21). The gene cassette region of class 1 integron accounted for 85.71% (18/21). The presence of mobile genetic factors in Salmonella in the study suggests that the bacteria can transmit or receive antibiotic resistance genes from other bacterial species in the natural environment. In addition, the research results provide scientific evidence for management decisions and raise awareness of effective antibiotic use in Ho Chi Minh City, Vietnam.