Comparative genomics of community-acquired ST59 methicillin-resistant Staphylococcus aureus in Taiwan: novel mobile resistance structures with IS1216V.
Methicillin-resistant Staphylococcus aureus (MRSA) with ST59/SCCmecV and Panton-Valentine leukocidin gene is a major community-acquired MRSA (CA-MRSA) lineage in Taiwan and has been multidrug-resistant since its initial isolation. In this study, we studied the acquisition mechanism of multidrug resistance in an ST59 CA-MRSA strain (PM1) by comparative genomics. PM1's non-β-lactam resistance was encoded by two unique genetic traits. One was a 21,832-bp composite mobile element structure (MES(PM1)), which was flanked by direct repeats of enterococcal IS1216V and was inserted into the chromosomal sasK gene; the target sequence (att) was 8 bp long and was duplicated at both ends of MES(PM1). MES(PM1) consisted of two regions: the 5'-end side 12.4-kb region carrying Tn551 (with ermB) and Tn5405-like (with aph[3']-IIIa and aadE), similar to an Enterococcus faecalis plasmid, and the 3'-end side 6,587-bp region (MES(cat)) that carries cat and is flanked by inverted repeats of IS1216V. MES(cat) possessed att duplication at both ends and additional two copies of IS1216V inside. MES(PM1) represents the first enterococcal IS1216V-mediated composite transposon emerged in MRSA. IS1216V-mediated deletion likely occurred in IS1216V-rich MES(PM1), resulting in distinct resistance patterns in PM1-derivative strains. Another structure was a 6,025-bp tet-carrying element (MES(tet)) on a 25,961-bp novel mosaic penicillinase plasmid (pPM1); MES(tet) was flanked by direct repeats of IS431, but with no target sequence repeats. Moreover, the PM1 genome was deficient in a copy of the restriction and modification genes (hsdM and hsdS), which might have contributed to the acquisition of enterococcal multidrug resistance.
Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Wei-Chun
WC
Hung
Tomomi
T
Takano
Wataru
W
Higuchi
Yasuhisa
Y
Iwao
Olga
O
Khokhlova
Lee-Jene
LJ
Teng
Tatsuo
T
Yamamoto
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D002876:Chromosomes, Bacterial; D017714:Community-Acquired Infections / Q000382:microbiology; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D013293:Enterococcus faecalis / Q000235:genetics; D005098:Exotoxins / Q000235:genetics; D016680:Genome, Bacterial; D023281:Genomics / Q000379:methods; D006801:Humans; D020071:Interspersed Repetitive Sequences; D007956:Leukocidins / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D013203:Staphylococcal Infections / Q000382:microbiology*; D013624:Taiwan; D013752:Tetracycline / Q000494:pharmacology; D047090:beta-Lactams / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015280:DNA Restriction-Modification Enzymes; D005098:Exotoxins; C113046:HSDS protein, Bacteria; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D047090:beta-Lactams; C109829:HsdM protein, Bacteria; D013752:Tetracycline