Enterotoxin production and DNA fingerprinting in Staphylococcus aureus isolated from human and food samples. Relations between genetic types and enterotoxins

A total of 224 Staphylococcus aureus strains from human carriers (110 strai ns) and manually handled foods (114 strains) collected in the Principality of Asturias, Spain over 1995-1999 were analysed for the production of enter otoxins (SEs) A, B, C, and D by a reversed passive latex agglutination test and by amplification of ent genes (A, B, C, D, E, and J) using PCR, Sixty- two strains were enterotoxigenic and a good relation between detection of S Es and their ent genes was found. No strain carried entE and all strains pr oducing SED carried entD and entJ genes. Among the enterotoxigenic strains the percentages registered were 29, 8, 35, 18, 2, 2, and 6 for SEA, SEE, SE C, SEDJ, SEAC, SEADJ and SECDJ, respectively. DNA fingerprinting of 77 stra ins (the SE prototypes, 62 enterotoxigenic and 10 non-enterotoxigenic [NEI) was carried out by randomly amplified polymorphic DNA using two selected p rimers independently. Combining results from both primers, 10 genetic types were defined, which showed a different degree of relationship (similarity coefficient: 0.9-0.36) and were clustered into three lineages. One lineage clustered five genetic types and a wide diversity of strains, mainly SEA, S EE, SEDJ, and NE. Another lineage clustered only SEC, SECDJ and NE strains. These two lineages showed a low genetic relationship and appeared as endem ic in healthy humans living in the Principality of Asturias. The third line age included only the prototype strains for SEA and SEE. (C) 2001 Elsevier Science B.V. All rights reserved.