Virulence Markers of Staphylococcus aureus Isolated from Food Sold in Jos, Nigeria

Abstract

Staphylococcal food poisoning ranks as one of the most prevalent causes of gastroenteritis worldwide. The etiological agent of Staphylococcal food poisoning are members of the genus Staphylococcus aureus which have been extensively characterized. A total of 100 food samples (rice) were obtained from different restaurants and eateries in Jos, Nigeria. They were examined for staphylococuss spp using standard microscopy and culture. A total of 104 isolates were recovered and subjected to various biochemical tests which included catalase. coagulase, DNAse and Haemolysis tests. Of the 104 isolates tested, 82 (78.85%) were identified as Saureus of which 53 (64.60%) were isolatedfrom garnished rice. The remaining 29 (35.40%) were from white rice and stew. All the 104 gram positive cocci isolated were catalase positive. Coagulase test showed 82 (78.85%) to be coagulase positive while 80 (76.92%) produced the enzyme DNAse. The haemolysis test showed 72 (59.76%) of these were fJ- haemolytic. 23 (28.05%) were ahaemolytic. The fJ- haemolytic are more of animal strains and less toxigenic to man while the a-haemolytic are of human biotype and more toxigenic. The isolation of these toxigenic strains is of health significance since there is the possibility that they could multiply in the food releasing toxins if not consumed soon after preparation. The high level of contamination observed is probably as a result of poor sanitary conditions. The need for proper sanitary conditions is therefore indicated.