Prevalence of genes encoding pyrogenic toxin superantigens and exfoliative toxins among strains of Staphylococcus aureus isolated from blood and nasal specimens.
A total of 429 different Staphylococcus aureus isolates encompassing 219 blood isolates and 210 isolates taken from anterior nares were systematically searched by two multiplex PCR-DNA enzyme immunoassays (PCR-DEIA) for exfoliative toxin (ET) genes eta and etb, as well as for the classical members of the pyrogenic toxin superantigen (PTSAg) gene family comprising the staphylococcal enterotoxin (SE) genes sea-see and the toxic shock syndrome toxin 1 gene tst. In addition, a third PCR-DEIA was established to investigate the possession of four recently described SE genes, viz. seg-sej. The most frequent PTSAg/ET genes amplified were seg and sei, which were found strictly in combination in 55.0% of the S. aureus isolates tested. Other frequently detected toxin genes were tst (20.3%), sea (15.9%), and sec (11.2%). Only five isolates harbored ET genes. Regarding the origin of the S. aureus isolates, a significant difference (P = 0.037) was found for the possession of the sed/sej gene combination (10.5% of blood isolates versus 3.3% of nasal strains). Overall, about half of S. aureus isolates tested harbored genes of the classical members of the PTSAg family and ETs (50.8%), whereas 73.0% of S. aureus isolates were toxin gene positive if the recently described SE genes were included. This notable higher prevalence indicates that the possession of PTSAg genes in particular seems to be a habitual feature of S. aureus. Moreover, mainly due to the fixed combinations of seg plus sei, as well as sed plus sej, the possession of multiple PTSAg genes (62.9%) is more frequent than assumed so far.
Becker
Karsten
K
Institute of Medical Microbiology. Institute for Hygiene, University Hospital of Münster, 48149 Münster, Germany. kbecker@uni-muenster.de
Friedrich
Alexander W
AW
Lubritz
Gabriele
G
Weilert
Maria
M
Peters
Georg
G
Von Eiff
Christof
C
D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics; D001769:Blood / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis; D004768:Enterotoxins / Q000235:genetics*; D005083:Exfoliatins / Q000235:genetics*; D006801:Humans; D007124:Immunoenzyme Techniques; D009666:Nose / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D018089:Superantigens / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004768:Enterotoxins; D005083:Exfoliatins; D018089:Superantigens