Genomic Insights of First B-Positive ST338-SCCV/CC59 Taiwan Clone of Community-Associated Methicillin-Resistant in Poland.

We report the first Polish representative of community-associated methicillin-resistant (CA-MRSA), S/F-PV-positive, encoding the B gene, as a genetic determinant of constitutive resistance to macrolides, lincosamides, and streptogramin B antibiotics, cMLS-B. This is the first detection of the CA-MRSA strain responsible for nosocomial infection in the Warsaw Clinical Hospital. Resistance to β-lactams associates with a composite genetic element, SCC cassette type V (5C2&5). We assigned the strain to sequence type ST338 (single-locus variant of ST59), clonal complex CC59, -type t437, and -type I. Genomic-based comparison was designated SO574/12 as an international Taiwan clone, which has been so far described mainly in the Asia-Pacific region. The B gene locates on the chromosome within the 14,690 bp mobile element structure, i.e., the MES structure, which also encodes aminoglycoside- and streptothricin-resistance genes. The MES structure is a composite transposon containing Tn551, flanked by direct repeats of IS1216V insertion sequences, which probably originates from . The B is preceded by the 273 bp regulatory region that contains the regulatory 84 bp BL ORF, encoding the 27 amino acid leader peptides. The latest research suggests that a new leader peptide, BL2, also exists in the B regulatory region. Therefore, the detailed function of BL2 requires further investigations.