Molecular typing of nasal carriage isolates of Staphylococcus aureus from an Irish university student population based on toxin gene PCR, agr locus types and multiple locus, variable number tandem repeat analysis.
Forty-eight Staphylococcus aureus isolates collected from a young, healthy, Irish university student population from 1995 to 2004 were screened for 16 enterotoxin (SE) and enterotoxin-like (SEl) genes (sea-see, seg-sei, selj-selo, selq, selu), and for the toxic shock toxin syndrome toxin-1 gene, tst. All of the isolates harboured at least one SE or SEl gene and 66.7 % possessed a classical SE gene (sea, seb, sec), the commonest being the seb gene. Most of the isolates (85.4 %) had a complete egc locus (selo, selm, sei, seln, seg). The intergenic sei-seln region of the egc locus was typed by PCR-RFLP in 34 isolates, 15 possessing pseudogenes psient1 and psient2 and 19 having the selu gene. The seh and sell genes, the selk-selq gene combination, and the tst gene were each found in <15 % of isolates. The agr genotype distribution was agr type III, 37.5 %; agr type I, 35.4 %; agr type II, 25 %; and agr type IV, 2.1 %. There was no association between SE-SEl genotype and agr type. All tst gene-positive isolates were of agr type III and harboured a classical SE gene. Multiple locus, variable number tandem repeat analysis (MLVA) produced 47 different patterns. While the sdr locus was present in all isolates, half of them lacked one or two of the sdr gene amplimers. Twenty isolates harboured the bbp gene, its presence being associated with agr type III, but not with the SE-SEl gene profile. The agr types of isolates were associated with MLVA subclusters. Selective MLST analysis revealed seven novel sequence types and a new aroE allele. Five clonal clusters (CCs), including CCs comprising major pandemic clones CC30, CC5 and CC22 and minor lineages CC6 and CC9, and three singletons were identified.
Collery
Mark M
MM
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
Smyth
Davida S
DS
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
Twohig
Jane M
JM
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
Shore
Anna C
AC
Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School and Hospital, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
Coleman
David C
DC
Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School and Hospital, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
Smyth
Cyril J
CJ
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, University of Dublin, Dublin 2, Republic of Ireland.
D000293:Adolescent; D000328:Adult; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D002353:Carrier State / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D004768:Enterotoxins / Q000235:genetics; D006801:Humans; D007494:Ireland; D018598:Minisatellite Repeats / Q000235:genetics; D009666:Nose / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D013334:Students; D018089:Superantigens / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D014495:Universities
C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004768:Enterotoxins; D018089:Superantigens; D015534:Trans-Activators; C030107:enterotoxin F, Staphylococcal