Whole-genome analysis of qacA-harboring ST45-SCCmec Vc-t1081 MRSA from skin exudate in a Chinese patient with severe drug eruption.

OBJECTIVE

The methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 is a significant global lineage of MRSA, known for its vast strain diversity and substantial clinical impact. This study aimed to characterize the genomic characteristics and diversity of the ST45-SCCmec Vc-t1081 MRSA strains.

METHODS

MRSA strain SA0907 was isolated from the skin exudate of a patient with severe drug eruption in China. The complete genome of MSRA strain SA0907 was sequenced using both Illumina (Novaseq 6000) and PacBio (Sequel II) platforms, followed by hybrid assembly of the sequences. The identification of mobile genetic elements and antibiotic resistance genes was accomplished through bioinformatics tools.

RESULTS

The SCCmec type Vc in SA0907 was comprised of the class C2 mec gene complex (IS431-mecA-ΔmecR1-IS431) and type 5 ccr gene complex (ccrC1 allele 2 and ccrC1 allele 8). Notably, the MRSA strain SA0907 was the first complete genome data for the ST45-SCCmec Vc-t1081 MRSA in Mainland of China. The disinfectant resistance genes qacA/qacR were chromosomally located within a variable region containing Tn552 and Tn4001 in MRSA strain SA0907. The 2.46-kb plasmid pSA0907-2 from MRSA strain SA0907 harbored erm(C), which conferred MLSB (macrolides-lincosamides-streptogramins B) resistance. Small plasmids similar to the 2.46-kb plasmid pSA0907-2 were prevalent across the Staphylococcus genus, particularly in S. aureus.

CONCLUSION

MRSA strain SA0907 represents the first complete genome report of a qacA-harboring ST45-SCCmec Vc-t1081 MRSA in Mainland of China. One 2.46-kb erm(C)-harboring plasmid pSA0907-2 carried by the MRSA strain SA0907 was widely present in S. aureus and other staphylococci.