The molecular epidemiology and evolution of the Panton-Valentine leukocidin-positive, methicillin-resistant Staphylococcus aureus strain USA300 in Western Australia.
Between 2003 and 2008, 76 clinical isolates of the Panton-Valentine leukocidin-positive Staphylococcus aureus strain 'West Australian methicillin-resistant Staphylococcus aureus (MRSA)-12' (WA MRSA-12) were recovered from 72 patients living in the Perth area in Western Australia. These isolates were found to belong to multilocus sequence type 8, and had a USA300-like pulsed-field gel electrophoresis pulsotype. All isolates were genotyped using diagnostic DNA arrays covering species markers, resistance factors, virulence-associated, as well as MSCRAMM (microbial surface components recognizing adhesive matrix molecules) genes to prove the identity between WA MRSA-12 and the pandemic strain USA300, as well as to detect possible genetic variability. In general, WA MRSA-12 isolates were similar to USA300, and the most common variant was identical to USA300-TC1516. From this clone, most of the other variants may have evolved by a limited number of gene losses or acquisitions. Variations in carriage of virulence and resistance-associated genes allow distinction of variants or sub-clones. Altogether, 16 variants could be distinguished. They differed in the carriage of resistance genes (blaZ/I/R, ermC, msrA + mpbBM, aadD + mupR, aphA3 + sat, tetK, qacC, merA/B/R/T) of beta-haemolysin-converting phages and of enterotoxins (sek + seq, which were deleted in four isolates). Notably, the arginine catabolic mobile element (ACME) was absent in 12 isolates (15.8%). The mercury resistance (mer) operon, which is usually associated with SCCmec type III elements, was found in several ACME-negative isolates. The present study emphasises the importance of genotyping in detecting the introduction and evolution of significant MRSA strains within a community.
Monecke
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S
Institute for Medical Microbiology and Hygiene, Faculty of Medicine Carl Gustav Carus, Technical University of Dresden, D-01307 Dresden, Germany. monecke@rocketmail.com
Ehricht
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R
Slickers
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Tan
H-L
HL
Coombs
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G
D000328:Adult; D001427:Bacterial Toxins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D019143:Evolution, Molecular; D005098:Exotoxins / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D007956:Leukocidins / Q000235:genetics*; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D017720:Molecular Epidemiology; D011110:Polymorphism, Genetic; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics; D014904:Western Australia / Q000453:epidemiology
D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D037521:Virulence Factors