Incidence and antimicrobial resistance of Salmonella serovars in fresh retail aquatic products from China

Infections due to aquatic products that are contaminated with Salmonella spp. are great risks to public health, however, epidemiological information and risk factors regarding these Salmonella contamianted food are limited in China. The study aimed to examine the incidence of Salmonella spp. in fresh aquatic products in China, and the MLST patterns and antimicrobial-resistance profiles of the Salmonella isolates identified. Out of the 300 aquatic food samples purchased from retail markets in 15 provincial Chinese capitals during 2015.6–2016.6, sixteen (5.3%) were found to be positive for Salmonella spp. and fifteen distinct serovars were detected. Clinically-important serovars predominated the isolates recovered, with almost all other identified serovars also implicated in human diseases. Antimicrobial susceptibility analysis of the 18 non-repetitive isolates showed that 14 isolates (77.8%) present drug resistance and seven isolates (38.9%) showed multidrug resistance phenotypes. High frequencies of resistance to streptomycin (66.7%), ampicillin (38.9%), and tetracycline (33.3%) were observed. Of particular concern, 22.2% of isolates were resistant to ciprofloxacin. The incidence of Salmonella serovars in the retail aquatic products and their high antimicrobial-resistance frequencies could constitute potential risks to public health. This study is valuable for supporting risk assessment, epidemiological investigation, and disease prevention.