Next-Generation Sequence Analysis Reveals Transfer of Methicillin Resistance to a Methicillin-Susceptible Staphylococcus aureus Strain That Subsequently Caused a Methicillin-Resistant Staphylococcus aureus Outbreak: a Descriptive Study

作者：Weterings Veronica; Bosch Thijs; Witteveen Sandra; Landman Fabian; Schouls Leo; Kluytmans Jan

来源：Journal of Clinical Microbiology, 2017, 55(9): 2808-2816.

DOI：10.1128/JCM.00459-17

<jats:title>ABSTRACT</jats:title>
<jats:p>
Resistance to methicillin in
<jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content>
is caused primarily by the
<jats:italic>mecA</jats:italic>
gene, which is carried on a mobile genetic element, the staphylococcal cassette chromosome
<jats:italic>mec</jats:italic>
(SCC
<jats:italic>mec</jats:italic>
). Horizontal transfer of this element is supposed to be an important factor in the emergence of new clones of methicillin-resistant
<jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content>
(MRSA) but has been rarely observed in real time. In 2012, an outbreak occurred involving a health care worker (HCW) and three patients, all carrying a fusidic acid-resistant MRSA strain. The husband of the HCW was screened for MRSA carriage, but only a methicillin-susceptible
<jats:named-content content-type="genus-species">S. aureus</jats:named-content>
(MSSA) strain, which was also resistant to fusidic acid, was detected. Multiple-locus variable-number tandem-repeat analysis (MLVA) typing showed that both the MSSA and MRSA isolates were MT4053-MC0005. This finding led to the hypothesis that the MSSA strain acquired the SCC
<jats:italic>mec</jats:italic>
and subsequently caused an outbreak. To support this hypothesis, next-generation sequencing of the MSSA and MRSA isolates was performed. This study showed that the MSSA isolate clustered closely with the outbreak isolates based on whole-genome multilocus sequence typing and single-nucleotide polymorphism (SNP) analysis, with a genetic distance of 17 genes and 44 SNPs, respectively. Remarkably, there were relatively large differences in the mobile genetic elements in strains within and between individuals. The limited genetic distance between the MSSA and MRSA isolates in combination with a clear epidemiologic link supports the hypothesis that the MSSA isolate acquired a SCC
<jats:italic>mec</jats:italic>
and that the resulting MRSA strain caused an outbreak.
</jats:p>

• 出版日期2017-9