Methicillin-Resistant Staphylococcus aureus Sequence Type (ST) 5 Isolates from Health Care and Agricultural Sources Adhere Equivalently to Human Keratinocytes

Abstract

is part of the nasal microbiome of many humans and has become a significant public health burden due to infections with antibiotic-resistant strains, including methicillin-resistant (MRSA) strains. Several lineages of, including MRSA, are found in livestock species and can be acquired by humans through contact with animals. These livestock-associated MRSA (LA-MRSA) isolates raise public health concerns because of the potential for livestock to act as reservoirs for MRSA outside the hospital setting. In the United States, swine harbor a mixed population of LA-MRSA isolates, with the sequence type 398 (ST398), ST9, and ST5 lineages being detected. LA-MRSA ST5 isolates are particularly concerning to the public health community because, unlike the isolates in the ST398 and ST9 lineages, isolates in the ST5 lineage are a significant cause of human disease in both the hospital and community settings globally. The ability of swine-associated LA-MRSA ST5 isolates to adhere to human keratinocytes was investigated, and the adherence genes harbored by these isolates were evaluated and compared to those in clinical MRSA ST5 isolates from humans with no swine contact. The two subsets of isolates adhered equivalently to human keratinocytes and contained an indistinguishable complement of adherence genes that possessed a high degree of sequence identity. Collectively, our data indicate that, unlike LA-MRSA ST398 isolates, LA-MRSA ST5 isolates do not exhibit a reduced genotypic or phenotypic capacity to adhere to human keratinocytes. Our data indicate that swine-associated livestock-associated methicillin-resistant (LA-MRSA) ST5 isolates are as capable of adhering to human skin and have the same genetic potential to adhere as clinical MRSA ST5 isolates from humans. This suggests that humans in contact with livestock have the potential to become colonized with LA-MRSA ST5 isolates; however, the genes that contribute to the persistence of on human skin were absent in LA-MRSA ST5 isolates. The data presented here are important evidence in evaluating the potential risks that LA-MRSA ST5 isolates pose to humans who come into contact with livestock.

Genomic differences between nasal Staphylococcus aureus from hog slaughterhouse workers and their communities

“…The ST5 lineage is comprised of both animal and human strains, and MGEs have contributed to the success of globally distributed ST5 human strains and the pathogenicity of frequently emerged ST5 CA-MRSA [ 13 , 31 , 65 ]. Based on swine herds from major swine producing regions in 11 states, ST5 also represents one dominant lineage in swine in the United States [ 61 ], and the selected swine-associated ST5 MRSA isolates showed in vitro adherence to human keratinocytes equivalent to clinical ST5 MRSA isolates, suggesting humans in contact with swine have the potential to be colonized with those isolates [ 66 ]. Our observations, based on WGS analysis, could suggest distinct origins of this lineage in hog workers and non-workers in North Carolina and warrants further research on its dynamics at the livestock-human interface.…”

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) colonisation and infection among livestock workers and veterinarians: a systematic review and meta-analysis

“…[12][13][14] LA-MRSA isolates have a strong adherence capacity to human keratinocytes, and humans working closely with livestock harbouring LA-MRSA isolates may become colonised. 15 LA-MRSA can cause severe SSTIs, which mainly occur in persons with occupational exposure to livestock. LA-MRSA is capable of being established in hospital settings via colonised or infected patients, which can lead to nosocomial infections, although the incidence of these infections is rare.…”

Alternative Enzyme Protection Assay To Overcome the Drawbacks of the Gentamicin Protection Assay for Measuring Entry and Intracellular Survival of Staphylococci

“…The intracellular killing of S. aureus during the GPA versus the EPA was analyzed using Student's t tests. ns, nonsignificant; **, P Ͻ 0.01. methicillin-sensitive S. aureus strains (ST630, RN4220, and MSSA29213) and methicillinresistant S. aureus strains (ST5, ST239, and USA300) (35)(36)(37). All the tested strains were found to be susceptible to lysostaphin, and CFU could not be recovered when strains were incubated for 5 min with 2 U of lysostaphin ( Fig.…”