An association of genotypes and antimicrobial resistance patterns among Salmonella isolates from pigs and humans in Taiwan.

Hung-Chih Kuo,Jung-Che Kuo,Chien-Shun Chiou,Chi-Sen Tsao,Pei-Chen Chen,Chun-Hsing Liao,Dan-Yuan Lo,Tsai-Ling Lauderdale,Chiou-Lin Chen,Shiu-Yun Liang,Ying-Shu Liao,Jan Kluytmans

doi:10.1371/journal.pone.0095772

Hung-Chih Kuo, Jung-Che Kuo + Show 10 more

Open Access

https://doi.org/10.1371/journal.pone.0095772

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Abstract

We collected 110 Salmonella enterica isolates from sick pigs and determined their serotypes, genotypes using pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility to 12 antimicrobials and compared the data with a collection of 18,280 isolates obtained from humans. The pig isolates fell into 12 common serovars for human salmonellosis in Taiwan; S. Typhimurium, S. Choleraesuis, S. Derby, S. Livingstone, and S. Schwarzengrund were the 5 most common serovars and accounted for a total of 84% of the collection. Of the 110 isolates, 106 (96%) were multidrug resistant (MDR) and 48 (44%) had PFGE patterns found in human isolates. S. Typhimurium, S. Choleraesuis, and S. Schwarzengrund were among the most highly resistant serovars. The majority of the 3 serovars were resistant to 8–11 of the tested antimicrobials. The isolates from pigs and humans sharing a common PFGE pattern displayed identical or very similar resistance patterns and Salmonella strains that caused severe infection in pigs were also capable of causing infections in humans. The results indicate that pigs are one of the major reservoirs to human salmonellosis in Taiwan. Almost all of the pig isolates were MDR, which highlights the necessity of strictly regulating the use of antimicrobials in the agriculture sector in Taiwan.

Highlights

Non-typhoidal Salmonella (NTS) is a zoonotic foodborne pathogen that is found worldwide
Comparison of serovars and pulsed-field gel electrophoresis (PFGE) genotypes A total of 18,280 human isolates were collected from hospitals across the country between 2004 and 2012
The 110 pig isolates fell into 12 serovars and 44 PFGE types

Summary

Introduction

Non-typhoidal Salmonella (NTS) is a zoonotic foodborne pathogen that is found worldwide. It is estimated to cause 93.8 million cases of gastroenteritis and 155,000 deaths each year worldwide and approximately 86% of these cases are the result of foodborne infections [1]. In the United States, NTS is responsible for approximately 1 million episodes of salmonellosis each year among all foodborne illnesses that are caused by 31 known pathogens [2]. Domestic and wild animals are the primary reservoirs of NTS. Food animals, including poultry, pigs, and cattle, are the key reservoirs for human salmonellosis [3]. The emergence of antimicrobial resistance and the transmission of resistant strains from animals to humans are mostly associated with the nontherapeutic use of various classes of antimicrobials in large quantities in food animals [4]

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