Detection ofSalmonellaspp. in Retail Raw Food Samples from Vietnam and Characterization of Their Antibiotic Resistance

A study was conducted to examine the levels ofSalmonella spp. contamination in raw food samples, including chicken, beef, pork, and shellfish, from Vietnam and to determine their antibiotic resistance characteristics. A total of 180 samples were collected and examined for the presence ofSalmonella spp., yielding 91Salmonella isolates. Sixty-one percent of meat and 18% of shellfish samples were contaminated withSalmonella spp. Susceptibility of all isolates to a variety of antimicrobial agents was tested, and resistance to tetracycline, ampicillin/amoxicillin, nalidixic acid, sulfafurazole, and streptomycin was found in 40.7%, 22.0%, 18.7%, 16.5%, and 14.3% of the isolates, respectively. Resistance to enrofloxacin, trimethoprim, chloramphenicol, kanamycin, and gentamicin was also detected (8.8 to 2.2%). About half (50.5%) of the isolates were resistant to at least one antibiotic, and multiresistantSalmonella isolates, resistant to at least three different classes of antibiotics, were isolated from all food types. One isolate from chicken (serovar Albany) contained a variant of theSalmonella genomic island 1 antibiotic resistance gene cluster. The results show that antibiotic resistance inSalmonella spp. in raw food samples from Vietnam is significant.