Open AccessDiverse Enterotoxin Gene Profiles among Clonal Complexes of Staphylococcus aureus Isolates from the Bronx, New York
Author(s) -
Ankur Nandan Varshney,
José R. Mediavilla,
Natalie Robiou,
Alice Guh,
Xiabo Wang,
Philip Gialanella,
Michael H. Levi,
Barry N. Kreiswirth,
Bettina C. Fries
Publication year - 2009
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.00272-09
Subject(s) - enterotoxin , multilocus sequence typing , staphylococcus aureus , biology , microbiology and biotechnology , virulence , typing , gene , staphylococcal infections , superantigen , pulsed field gel electrophoresis , toxic shock syndrome , genetics , escherichia coli , genotype , bacteria
Staphylococcal enterotoxins (SE) can cause toxin-mediated disease, and those that function as superantigens are implicated in the pathogenesis of allergic diseases. The prevalence of 19 enterotoxin genes was determined by PCR in clinicalS. aureus strains derived from wounds (108) and blood (99). We performedspa typing and multilocus sequence typing (MLST) to determine clonal origin, and for selected strains staphylococcal enterotoxin B (SEB) production was measured by enzyme-linked immunosorbent assay. Strains carried a median of five SE genes. For most SE genes, the prevalence rates among methicillin-resistant and methicillin-sensitiveS. aureus isolates, as well as wound- and blood-derived isolates, did not differ. At least one SE gene was detected in all except twoS. aureus isolates (>99%). Completeegc clusters were found in only 11% ofS. aureus isolates, whereas the combination ofsed ,sej , andser was detected in 24% of clinical strains.S. aureus strains exhibited distinct combinations of SE genes, even if their pulsed-field gel electrophoresis and MLST patterns demonstrated clonality. USA300 strains also showed considerable variability in SE content, although they contained a lower number of SE genes (mean, 3). By contrast, SE content was unchanged in five pairs of serial isolates. SEB production by individual strains varied up to 200-fold, and even up to 15-fold in a pair of serial isolates. In conclusion, our results illustrate the genetic diversity ofS. aureus strains with respect to enterotoxin genes and suggest that horizontal transfer of mobile genetic elements encoding virulence genes occurs frequently.