J Vet Sci.  2019 Nov;20(6):e69. 10.4142/jvs.2019.20.e69.

Prevalence and characteristics of livestock-associated methicillin-susceptible Staphylococcus aureus in the pork production chain in Korea

• Eom HS
• Back SH
• Lee HH
• Lee GY
• Yang SJ

• KMID: 2464085
• DOI: http://doi.org/10.4142/jvs.2019.20.e69

Abstract

The emergence and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in livestock animals have become a worldwide public health concern. While the prevalence and genetic profiles of MRSA strains in pigs and pork meat have been actively studied, livestock-associated MSSA strains have only been characterized in a few small-scale studies. In this investigation, we assessed the nationwide prevalence of MSSA in the Korean pig production chain, including pig farms, slaughterhouses, and retail markets. Among the 41 MSSA strains, the predominant clonal lineages were sequence type (ST) 398 (n = 15, 37%) and ST5 (n = 13, 32%). Although the overall prevalence of MSSA (2.58%) was low and mostly restricted to pig farms, ST398 MSSA strains showed higher level of multidrug resistance phenotype versus non-ST398 MSSA strains. In addition to the MDR phenotype, all of the ST398 MSSA strains exhibited resistance to tetracycline as they harbored the tet(K), tet(L), and/or tet(M) genes. However, ST398 MSSA strains did not exhibit increased resistance to zinc compared with the non-ST398 strains. This study is the first to provide evidence of ST398 MSSA emergence in livestock animals in Korea. Further studies are necessary to elucidate the potential of ST398 MSSA strains for human transmission. Our findings suggest that the MDR phenotype and high levels of tetracycline resistance may have played an important role in the emergence and prevalence of ST398 MSSA in pig farms in Korea.

Keyword

MSSA; ST398; pig; antimicrobial resistance; zinc resistance

MeSH Terms

Abattoirs
Agriculture
Animals
Drug Resistance, Multiple
Humans
Korea*
Livestock
Meat
Methicillin-Resistant Staphylococcus aureus
Phenotype
Prevalence*
Public Health
Red Meat*
Staphylococcus aureus*
Staphylococcus*
Swine
Tetracycline
Tetracycline Resistance
Zinc
Tetracycline
Zinc