Prevalence and Antimicrobial Resistance of Salmonella Isolates Recovered from Retail Pork in Major Village Markets in Tai'an Region, China.

The current study was undertaken to evaluate Salmonella contamination in retail pork at major village markets of the Tai'an region, China. In total, 200 retail pork samples were collected from four village markets between June 2015 and February 2016, of which 69 samples (34.5%) were determined to be positive for Salmonella. Eleven serotypes were identified from the 69 Salmonella isolates, and Salmonella Derby was the most common (18 of 69, 26.1%), followed by Typhimurium (17 of 69, 24.6%) and Meleagridis (11 of 69, 15.9%). Antimicrobial susceptibility testing showed that antimicrobial resistance against tetracycline was the most prevalent (42 of 69, 60.9%), but antimicrobial resistance against both ceftriaxone and cefotaxime was 1.4% (1 of 69) and 2.9% (2 of 69), respectively. Multilocus sequence typing revealed that the 69 Salmonella isolates were divided into 11 sequence types (STs), among which ST40 (18 of 69, 26.1%) was the most common, followed by ST34 (15 of 69, 21.7%) and ST64 (13 of 69, 18.8%). Collectively, retail pork at village markets in the Tai'an region has a high Salmonella contamination rate, and these isolates exhibit broad-spectrum antimicrobial resistance. However, the absence of a dominant ST demonstrates that the Salmonella isolates from retail pork may be of diverse origins.