TECHNIQUES OF MOLECULAR EPIDEMIOLOGY IN T HE STUDY OF FOODBORNE POISONING BY STAPHYLOCOCCUS-AUREUS

Background: The use of molecular epidemiology techniques has provided better knowledge as to the clonal organization of bacterian population s and thus allows better follow up of epidemics. An alimentary toxiinf ection in a Barcelona school produced by Staphylococcus aureus was ana lyzed by the combination of epidemiologic, phenotype and genotype mark ers with the aim of determining the source of the alimentary contaimin ation. Methods: Nine strains of Staphylococcus aureus isolated in 6 fo od manipulators and 3 patiens were studied with the following markers: biotype, antibiotype, phagotype, plasmid profile, polymorphism of the size of the restriction fragments of total DNA and ribotype. Results: Epidemiologic study of the strains analyzed showed that both the phen otype markers and the plasmid profile are tecniques of little discrimi natory value. The only clearly discriminatory technique used was ribot yping which defined 3 clones in the 9 strains of Staphylococcus aureus studied. Conclusions: Molecular study of isolated strains of Staphylo coccus aureus was able to identify the causal origin of the alimentary toxiinfection in one of the 6 food manipulators studied.