Enterotoxigenic potential of Staphylococcus intermedius

Staphylococcal food poisoning (SFP) caused by enterotoxigenic staphylococci is one of the main food-borne diseases. In contrast to Staphylococcus aure us, a systematic screening for the enterotoxins has not yet been performed on the genomic level for the coagulase-positive species S. intermedius. The refore, the enterotoxigenic potential of 281 different veterinary (canine, n = 247; equine, n = 23; feline, n = 9; other, n = 2) and 11 human isolates of S. intermedius was tested by using a multiplex PCR DNA-enzyme immunoass ay system targeting the staphylococcal enterotoxin genes sea, seb, see, sed , and see. Molecular results were compared by in vitro testing of enterotox in production by two immunoassays. A total of 33 (11.3%) S. intermedius iso lates, including 31 (12.6%) canine isolates, 1 equine isolate, and 1 human isolate, tested positive for the see gene. In vitro production of the respe ctive enterotoxins was detected in 30 (90.9%) of these isolates by using im munological tests. In contrast, none of 65 veterinary specimen-derived isol ates additionally tested and comprising 13 (sub)species of coagulase-negati ve staphylococci were found to be enterotoxigenic. This study shows on both molecular and immunological levels that a substantial number of S. interme dius isolates harbor the potential for enterotoxin production. Since eviden ce for noninvasive zoonotic transmission of S. intermedius from animal host s to humans has been documented, an enterotoxigenic role of this microorgan ism in SFP via contamination of food products may be assumed.