AUTHOR=Burgold-Voigt Sindy , Monecke Stefan , Simbeck Alexandra , Holzmann Thomas , Kieninger Bärbel , Liebler-Tenorio Elisabeth M. , Braun Sascha D. , Collatz Maximilian , Diezel Celia , Müller Elke , Schneider-Brachert Wulf , Ehricht Ralf 

TITLE=Characterisation and Molecular Analysis of an Unusual Chimeric Methicillin Resistant Staphylococcus Aureus Strain and its Bacteriophages

JOURNAL=Frontiers in Genetics

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.723958

DOI=10.3389/fgene.2021.723958

ISSN=1664-8021

ABSTRACT=<p>In the context of microarray-based epidemiological typing of the clonal organism <italic>Staphylococcus aureus</italic>/MRSA<italic>,</italic> a strain was identified that did not belong to known clonal complexes. The molecular analysis by microarray-based typing yielded signals suggesting that it was a mosaic or hybrid strain of two lineages. To verify this result, the isolate was sequenced with both, short-read Illumina and long-read Nanopore technologies and analysed in detail. This supported the hypothesis that the genome of this strain, ST6610-MRSA-IVg comprised of segments originating from two different clonal complexes (CC). While the backbone of the strain’s genome, i.e., roughly 2 megabases, belongs to CC8, a continuous insert of 894 kb (approx. 30% of the genome) originated from CC140. Beside core genomic markers in the normal succession and orientation, this insert also included the <italic>mecA</italic> gene, coding for PbP2a and causing <ext-link ext-link-type="uri" xlink:href="https://en.wikipedia.org/wiki/Methicillin" xmlns:xlink="http://www.w3.org/1999/xlink">methicillin</ext-link> resistance, localised on an SCC<italic>mec</italic> IVg element. This particular SCC<italic>mec</italic> type was also previously observed in CC140 MRSA from African countries. A second conspicuous observation was the presence of the trimethoprim resistance gene <italic>dfrG</italic> within on a prophage that occupied an attachment site normally used by Panton-Valentine Leucocidin phages. This observation could indicate a role of large-scale chromosomal recombination in the evolution of <italic>S. aureus</italic> as well as a role of phages in the dissemination of antibiotic resistance genes.</p>