AUTHOR=Yoon Eun-Jeong , Lee Hyukmin , Kim Dokyun , Shin Jong Hee , Shin Jeong Hwan , Jeong Seok Hoon 

TITLE=Methicillin-Resistant Staphylococcus aureus Blood Isolates Harboring a Novel Pseudo-staphylococcal Cassette Chromosome mec Element

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00540

DOI=10.3389/fmicb.2019.00540

ISSN=1664-302X

ABSTRACT=<p>The aim of this work was to assess a novel pseudo-staphylococcal cassette chromosome <italic>mec</italic> (ΨSCC<italic>mec</italic>) element in methicillin-resistant <italic>Staphylococcus aureus</italic> (MRSA) blood isolates. Community-associated MRSA E16SA093 and healthcare-associated MRSA F17SA003 isolates were recovered from the blood specimens of patients with <italic>S. aureus</italic> bacteremia in 2016 and in 2017, respectively. Antimicrobial susceptibility was determined <italic>via</italic> the disk diffusion method, and SCC<italic>mec</italic> typing was conducted by multiplex polymerase chain reaction. Whole genome sequencing was carried out by single molecule real-time long-read sequencing. Both isolates belonged to sequence type 72 and <italic>agr</italic>-type I, and they were negative for Panton-Valentine leukocidin and toxic shock syndrome toxin. The <italic>spa</italic>-types of E16SA093 and F17SA003 were t324 and t2460, respectively. They had a SCC<italic>mec</italic> IV-like element devoid of the cassette chromosome recombinase (<italic>ccr</italic>) gene complex, designated as ΨSCC<italic>mec</italic><sub>E16SA093</sub>. The element was manufactured from SCC<italic>mec</italic> type IV and the deletion of the <italic>ccr</italic> gene complex and a 7.0- and 31.9-kb portion of each chromosome. The deficiency of the <italic>ccr</italic> gene complex in the SCC<italic>mec</italic> unit is likely resulting in mobility loss, which would be an adaptive evolutionary mechanism. The dissemination of this clone should be monitored closely.</p>