Prevalence and Multidrug Resistance of Salmonella in Swine Production Chain in a Central Province, Thailand

Kaknokrat Chonsin; Ruchirada Changkwanyeun; Achiraya Siriphap; Apiradee Intarapuk; Watsawan Prapasawat; Kanjana Changkaew; Chaiwat Pulsrikarn; Norikazu Isoda; Chie Nakajima; Yasuhiko Suzuki; Orasa Suthienkul

doi:10.4315/JFP-21-003

Prevalence and Multidrug Resistance of Salmonella in Swine Production Chain in a Central Province, Thailand

J Food Prot. 2021 Dec 1;84(12):2174-2184. doi: 10.4315/JFP-21-003.

Authors

Affiliations

¹ Faculty of Science and Technology, Suratthani Rajabhat University, Surat Thani 84100, Thailand.
² Faculty of Public Health, Thammasart University, Pathum Thani 12121, Thailand.
³ Department of Microbiology and Parasitology, School of Medical Sciences, University of Phayao, Phayao 56000 Thailand.
⁴ Department of Clinic, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok 10530, Thailand.
⁵ National Institute of Health, Department of Medical Science, Ministry of Public Health, Nonthaburi 11000, Thailand.
⁶ International Collaboration Unit, Hokkaido University International Institute for Zoonosis Control, Sapporo, Hokkaido 060-0808, Japan.
⁷ Division of Bioresources, Hokkaido University International Institute for Zoonosis Control, Sapporo, Hokkaido 001-0020, Japan.
⁸ Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand.

PMID: 34410408
DOI: 10.4315/JFP-21-003

Abstract

Abstract: Salmonella causes foodborne disease outbreaks worldwide and raises concerns about public health and economic losses. To determine prevalence, serovar, antimicrobial resistance patterns, and the presence of extended-spectrum β-lactamase (ESBL) genes in a cross-sectional study, 418 total samples from feces and carcasses (from three slaughterhouses) and pork and cutting boards (from four markets) were collected in a central Thailand province in 2017 and 2018. Of the 418 samples, 272 (65.1%) were positive for Salmonella. The prevalence of Salmonella-positive samples from markets (158 of 178; 88.8%) was significantly higher than that among samples from slaughterhouses (114 of 240; 47.5%) (P < 0.05). A total of 1,030 isolates were identified; 409 were assigned to 45 serovars, with Salmonella Rissen the most common (82 of 409; 20%). Two serovars, Salmonella Cannstatt and Salmonella Braubach, were identified for the first time in Thailand in market and slaughterhouse samples, respectively. Among 180 isolates representing 19 serovars, 133 (73.9%) exhibited multidrug resistance. Screening for ESBL production revealed that 41 (10.3%) of 399 isolates were ESBL positive. The prevalence of ESBL-producing Salmonella isolates was significantly higher among the market isolates (31 of 41; 75.6%) than among the slaughterhouse isolates in (10 of 41; 24.4%) (P < 0.05). In market samples, 24 (77.4%) of 31 isolates were recovered from pork and 7 (22.6%) were recovered from cutting boards. Nine ESBL-producing isolates carried single ESBL genes, either blaTEM (4 of 41 isolates; 9.8%) or blaCTX-M (5 of 41 isolates; 12.2%), whereas 11 (26.8%) carried both blaTEM and blaCTX-M. No ESBL-producing Salmonella isolate carried the blaSHV gene. These results suggest that pigs, their flesh, and cutting boards used for processing pork could be reservoirs for widespread ESBL-producing Salmonella isolates with multidrug resistance and outbreak potential across the food chain.

Keywords: Salmonella; Antimicrobial resistance; Extended-spectrum β-lactamase; Market; Slaughterhouse; Swine.

MeSH terms

Animals
Anti-Bacterial Agents* / pharmacology
Cross-Sectional Studies
Drug Resistance, Multiple
Prevalence
Salmonella / genetics
Swine
Thailand
beta-Lactamases*

Substances

Anti-Bacterial Agents
beta-Lactamases