Enterotoxins and phage typing of Staphylococcus aureus isolated from clinical material and food in Libya

Enterotoxin was detected in 22 (61.1%) of the 36 S. aureus strains isolated from clinical materials and in 3 (13%) of the 23 S. aureus strains from food samples (P < 0.05). On the basis of individual types of enterotoxin, staphylococcal enterotoxin A (SEA) was produced by 11.1%, SEB by 38.9% and SEC by 22.2% of SS. aureus strains from clinical material. Of the food S. aureus strains, SEC and SED produced by 8.7% and 4.3% respectively. Of the clinical and food S. aureus strains, 52.8% and 39.1%, respectively, were typeable by the 23 phages of International Phage Set. The majority of the typeable S. aureus strains from clinical and food sources belonged to group II being at 22.2% and 17.4% respectively. Furthermore, of the 14 SEB-producing S. aureus, 42.9% were of phage group II. In conclusion, the results obtained indicate that enterotoxin-producing S. aureus strains from clinical materials in Libya are not uncommon; however, certain foods appear not to be the source of such strains. Because of the low susceptibility to bacteriophages shown by S. aureus isolated in Libya, compared to reports from several countries, other methods of typing should be used in conjunction with phage typing in epidemiological investigations concerning this organism.