Quantification and rep‐PCR characterization of Salmonella spp. in retail meats and hospital patients in Northern Thailand

Abstract

Human salmonellosis is a major public health problem worldwide. Infections can pass to humans by contact with contaminated substances in the food chain. This study aimed to determine the prevalence and contamination levels of Salmonella isolated from pork, chicken and beef sold in different types of retail stores in Chiang Mai and Lamphun provinces and to investigate the genetic relatedness among Salmonella isolates in food chains in that area. A total of 360 meat samples from supermarkets, mini‐grocery stores and fresh markets were obtained. Salmonella Rissen and S. Weltevreden were found in all meat sample types and in human cases. The overall prevalence of Salmonella in the chicken, pork and beef samples was 34.17%, 32.50% and 3.33%, respectively. Quantitatively, Salmonella contamination was highest in pork (1.24 log10MPN/g), followed by chicken (1.08 log10MPN/g), and beef (0.75 log10MPN/g). The highest frequency of Salmonella contamination was found at the fresh markets (85.71%), whereas the highest quantity of contamination level was from mini‐grocery stores (1.27 log10MPN/g). The rep‐PCR analysis results revealed that some of the Salmonella from meat samples and human cases were identical clones.

Multidrug Resistance and Serotype Distribution of Salmonella Enterica Isolated from Homemade Recipe Fermented Ground Pork (Nham) in Northeastern Thailand

“…Sample size was calculated by using the "Estimate Percentage" function [6]. Considering "85 %" to be the approximate rate of Salmonella contamination in pork samples in Thailand [4], this value was used as the expected prevalence. The "e" and "Z1-α/2" values were selected as 10 % and 0.95, respectively, as the necessary feature parameters.…”

“…While systematic public health monitoring is on-going, a local survey is necessary to assess specific factors and the risks of infection in the food chain. In Thailand, the prevalence of pigs carrying Salmonella has been reported to be around 35 % [2], but Salmonella contamination rates in pork were 82 -86 % [3,4]. This huge detection gap is probably due to cross-carcass contamination during cutting at lairages or handling at retail markets.…”

Characterisation of Salmonella enterica clones carrying mcr-1 plasmids in meat products and patients in Northern Thailand using long read sequencing

“…Ten Salmonella isolates were selected from three clones with previously published identical rep-PCR profiles (Prasertsee et al, 2019). Selected Salmonella isolates comprised of S. Rissen (n=4), S. Weltevreden (n=4), and S. Stanley (n=2) clones which were isolated from meat (chicken meat, pork, and beef) and human cases in Maharaj Nakhon Chiang Mai Hospital from January to July, 2017.…”

“…Salmonella is an important foodborne zoonotic pathogen, associated with consumption of contaminated food (Akbar and Anal, 2015) and several studies have described transmission from livestock to humans (Bodhidatta et al, 2013;Fearnley et al, 2011;Prasertsee et al, 2019). Emerging AMR in NTS in food production is a serious issue for public health globally (Wang et al, 2019).…”

“…Complications with infection such as bacteraemia occur most often in high-risk groups of patients, thus antimicrobial agents will often be used for medical treatment (Prasertsee et al, 2019).…”