Molecular Characterization of Methicillin-ResistantStaphylococcus aureusfrom Outpatients in Northern Japan: Increasing Tendency of ST5/ST764 MRSA-IIa with Arginine Catabolic Mobile Element

Abstract

Arginine catabolic mobile element (ACME) is a genomic island of staphylococcus and is considered to confer enhanced ability to survive and growth on host bacterial cells. ACME has been typically identified in Panton-Valentine Leukocidin (PVL)-positive ST8 methicillin-resistant Staphylococcus aureus (MRSA) with SCCmec type IVa (USA300 clone), and it is also found in other lineages at low frequency. Prevalence and molecular characteristics of PVLand/or ACME MRSA were investigated for 624 clinical isolates collected from outpatients in northern Japan from 2013 to 2014. Both PVL genes and ACME type I were detected in nine isolates (1.4%), which were ST8-MRSA-SCCmec IVa/spa type t008/agr-I; whereas solely PVL genes were positive in two isolates, ST30-MRSA-SCCmec IV and ST59-MRSA-SCCmec V. ACME type II' (previously referred to as ACME ΔII) was detected in 36 isolates (5.8%) with SCCmec II and V (32 and 4 isolates, respectively), exhibiting an increased rate within SCCmec II-MRSA (7.1%) compared with our previous studies (0.86-4.5%, 2008-2011). ACME II'-positive MRSA strains were classified into ST5-SCCmec IIa/V or ST764-SCCmec IIa belonging to five different spa types, with t002 being dominant. They harbored mostly enterotoxin gene clusters (seg-sei-sem-sen-seo-seu) and some more enterotoxin genes (seb1, seb2, sec3, sel, sep), showing resistance to more antimicrobials than ST8-MRSA-SCCmec IVa. ACME-SCCmec composite island (CI) of the 36 ACME II'-positive MRSA was classified into five types (ii)-(vi), among which type (ii) (orfX-ΨSCC-ACME II'-SCCmec II) was dominant and subdivided into the A3 variant and the less common A2 variant. CI types (v) and (vi) were considered novel genetic organizations having speG (acetyltransferase genes for polyamines) in inserted SCC4610/SCC266-like genetic elements. The present study revealed increased prevalence and genetic diversity of the ST5/ST764-MRSA-SCCmec II with ACME II' in northern Japan.

Molecular Epidemiological Characterization of Staphylococcus argenteus Clinical Isolates in Japan: Identification of Three Clones (ST1223, ST2198, and ST2550) and a Novel Staphylocoagulase Genotype XV

“…The presence of 28 staphylococcal enterotoxin (SE) (-like) genes ( sea-see , seg-selu , selx , sey , selw , selz , sel26 and sel27 ), the TSST-1 gene ( tst-1 ) and exfoliative toxin genes ( eta , etb and etd ), leukocidins ( lukDE and lukM ), haemolysins ( hla , hlb , hld and hlg ), adhesin genes ( eno , cna , sdrC , sdrD , sdrE , fib , clfA , clfB , fnbA , fnbB , icaA , icaD , ednA , ednB , bap and vWbp ), modulators of host defense ( sak , chp and scn ) were analyzed by multiplex or uniplex PCRs [38,39,40]. For detection of selz , sel26 , and sel27 by PCR, primers shown in Table S1 were newly designed based on selz sequence reported for bovine S. aureus strain RF122 (GenBank accession no.…”

“…Genes conferring resistance to penicillin (blaZ), tetracycline (tet(K), tet(L), and tet(M)), macrolide (ermA, ermB, ermC, and msrA), aminoglycoside (aac(6′)-Im, aac(6′)-Ie-aph(2”)-Ia, ant(3”)-Ia, ant(4′)-Ia, ant(6)-Ia, ant(9)-Ia, ant(9)-Ib, aph(2”)-Ib, aph(2”)-Ic, aph(2”)-Id, and aph(3′)-IIIa) were detected by uniplex or multiplex PCR using the primers previously reported [38,39,40].…”

Global Evolution of Pathogenic Bacteria With Extensive Use of Fluoroquinolone Agents

“…Nevertheless, the carriage of ACME should certainly confer an advantage to antibiotic susceptible CA-MRSA strains facilitating transmission in a fluoroquinolone-free environment (Aung et al, 2017;Strauß et al, 2017;Murai et al, 2019).…”

Prevalence and Genetic Diversity of Staphylococcal Enterotoxin (-Like) Genes sey, selw, selx, selz, sel26 and sel27 in Community-Acquired Methicillin-Resistant Staphylococcus aureus

“…We previously analyzed 624 CA-MRSA clinical isolates that were derived from outpatients in Hokkaido, Northern main island of Japan, for their molecular epidemiological and genetic characteristics [33], and reported the predominance of SCCmec IIa MRSA, and also the presence of SCCmec IVa-ST8 isolates (USA300 clone) carrying Panton-Valentine leukocidine (PVL) genes and ST5/ST764 MRSA-harboring arginine catabolic mobile element (ACME). Furthermore, we identified ST8 MRSA as having SCCmec IVl, which had been designated "CA-MRSA-J" and presumably emerged in Japan and other regions of Asia.…”