Genetic diversity of emerging Panton–Valentine leukocidine/arginine catabolic mobile element (ACME)-positive ST8 SCCmec-IVa meticillin-resistant Staphylococcus aureus (MRSA) strains and ACME-positive CC5 (ST5/ST764) MRSA strains in northern Japan

Abstract

Panton-Valentine leukocidine (PVL) is a distinctive virulence factor of community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA), and arginine catabolic mobile element (ACME) is a staphylococcal genomic island that enhances fitness and the ability of bacterial cells to colonize on skin and mucous membranes. ACME is characteristically found in USA300, which is a predominant CA-MRSA clone [sequence type (ST) 8] in the USA and is spreading globally, and has also been detected in non-ST8 MRSA at low frequency. In Japan, spread of MRSA with PVL and/or ACME and their genetic traits have not yet been well characterized. In the present study, the prevalence and genetic diversity of PVL + /ACME + MRSA were investigated for 422 MRSA clinical isolates collected from outpatients in northern Japan over a period of 1 year. All the isolates were genotyped for the staphylococcal cassette chromosome mec (SCCmec) and coagulase genes (coa), and screened for PVL and ACME genes. The PVL + /ACME + isolates were studied further by genetic analysis, including single-nucleotide polymorphism (SNP) analysis based on PVL genes (lukS-PV-lukF-PV), ACME (arc and opp3 clusters) and the sarU promoter region. Among all the isolates examined, PVL genes and ACME were detected in eight (SCCmec-II, n51; SCCmec-IV, n56; SCCmec-V, n51) and 20 (SCCmec-II, n514; SCCmec-IV, n55; SCCmec-V, n51) isolates, respectively. Five isolates were found to have both PVL genes and ACME (type I), and were classified into ST8/spa-t008/agr-I/coa-IIIa, which is the same genetic traits as USA300. Fifteen PVL " /ACME + isolates had type DII-ACME, belonging to either ST5 or ST764 [clonal complex (CC) 5], and spa-t001, -t002 or -t3557. All the ST8 PVL + /ACME-I + MRSA had identical sequences of PVL genes (haplotype R) and ACME arc/opp3 clusters as those of USA300. In contrast, in the CC5 PVL " /ACME-DII + MRSA, SNPs in the arc cluster were detected in 11 sites (four haplotypes), with some different profiles of virulence/resistance factors. These results indicated single clonality of ST8 PVL + /ACME-I + MRSA and heterogeneity of CC5 PVL " /ACME-DII + MRSA, and suggest their potential spread in northern Japan.

Novel Structures and Temporal Changes of Arginine Catabolic Mobile Elements in Methicillin-Resistant Staphylococcus aureus Genotypes ST5-MRSA-II and ST764-MRSA-II in Japan

“…It consisted of the following three SCCs: SCC containing the truncated J1 region of SCCmec I (⌿SCC ⌬J1SCCmecI ) (11)(12)(13)(14)(15), ⌬ACME II, and SCCmec II. The same ACME-SCCmec CI was found in ST764-MRSA, which is closely related to ST5 (9,14). Here, the term ACME II= is used to describe our partially deleted ACME II in accordance with recommendations from the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC).…”

“…A partially deleted ACME II (ca. 12.5 kb and referred to as ⌬ACME II or SCCarc) has been detected in MRSA with the following lineages: ST5-II, ST5-IV, ST5-V, ST8-IVa, ST22-IVh, ST239-III, ST398-IV, and ST764-II (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). The truncated ACME II is similarly predicted to enhance survival and growth of the host MRSA (7,8,13).…”

“…A total of 1,212 MRSA isolates were obtained, and 1,103 isolates were determined to be type II SCCmec (MRSA-II) (9,10,17). Twenty-two of the 1,103 MRSA-II isolates possessed ACME II= SR388 , and all of them were subjected to further analysis; these isolates had previously undergone spa typing, multilocus sequence typing (MLST), ACME typing, and antibiotic susceptibility testing (9,10,17). Analysis of the SCCmec-associated direct-repeat unit (dru) was performed in the present study (18).…”

“…Clinical isolates were collected at various hospitals in Hokkaido from February 2008 to December 2011 (9,10,17). Only one isolate per patient was used as a study subject.…”

Epidemiological study on the relationship between toxin production and psm‐mec mutations in MRSA isolates in Thailand

“…ST5‐MRSA strains carrying Type II SCC mec (ST5‐MRSA‐II) are globally disseminated around the world, including Asia, Europe, and United States . A new variant of ST5‐MRSA‐II, called ST764‐MRSA‐II, was isolated from necrotizing fasciitis, keratitis, the nasal cavity, and urine in Japan . The isolation frequency of ST764‐MRSA‐II has increased in recent years in long‐term care facilities and hospitals .…”