Genomic Information on Linezolid-Resistant Sequence-Type 398 Livestock-Associated Methicillin-Resistant Isolated from a Pig.

The frequent occurrence of sequence-type 398 (ST398) livestock-associated methicillin-resistant (LA-MRSA) in pigs has become a major public health concern owing to the increased zoonotic potential of the pathogen. Recently, a novel oxazolidinone resistance gene, chloramphenicol-florfenicol resistant (), conferring multiresistance phenotypes to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A (PhLOPS), has been found among ST398 LA-MRSA strains isolated from pigs. In this study, we report the first genome analysis of a linezolid-resistant ST398 LA-MRSA strain, designated PJFA-521M, recovered from a pig in Korea. Genomic analyses revealed that the presence of the gene was responsible for the observed linezolid resistance in the PJFA-521M strain. Moreover, newer antimicrobial resistance genes, such as the , , , (E), (B), and genes, were found in the PJFA-521M strain. In addition to the genetic elements for antimicrobial resistance, the carriage of various virulence genes for adherence, invasion, and immunomodulation was identified in the genome, especially within several mobile genetic elements (MGEs). The presence of multiple antimicrobial resistance genes and virulence genes on MGEs in the genome of a linezolid-resistant ST398 LA-MRSA should raise awareness regarding the use of other antimicrobial agents in pig farms and may also provide selective pressure for the prevalence of the gene and the associated multidrug-resistant phenotype.