Staphylococcal food poisoning occurs most often in foods that require hand preparation, such as potato salad, ham salad, sandwich spreads, raw foods; unpasteurized milk. S. aureus found on humans (skin, infected cuts, pimples, noses and throats).When S. aureus is allowed to grow in foods, can produce a toxin that causes illness. Although cooking destroys the bacteria, the toxin produced is heat stable and may not be destroyed. Symptoms of Staphylococcus aureus food borne illnesses are severe nausea, fever, abdominal cramps, vomiting and diarrhea. Beta- Lactamase confers penicillin resistance to various bacterial organisms by cleaving the beta-lactam ring of penicillin's and cephalosporin antibiotics. The subject of this study was survey of the prevalence of Beta lactamase enzyme in Staphylococcus species isolated of foods in Isfahan city in Iran. This laboratory study was performed during 2009-2010 years in Isfahan. In this study, 150 food samples including, ketchup, mayonnaise, biscuits and chocolate were randomly sampled and cultured on Blood Agar; and incubated for 24 hours. Identification of bacteria were based on microbiological methods (staining, biochemical test). Identification of β- lactamase, was performed with the Acidometric method with Penicillin G5000000 Unit and Phenol Red. A positive test was indicated by the mixture turning yellow in color. From 150 samples collected, 142(95%) samples were contaminated with Staphylococcus species. According to the acidometric result, the frequency of β- lactamase in the Staphylococcus species was 112 (75%). Antibiotic resistance may be intrinsic or result from either mutation of existing genetic material or from acquisition of new genetic material. The results of this study represented vast spread of beta lactamase in Staphylococcus species in food. Beta lactamase enzyme leads to bacterial resistance against beta Lactame antibiotics
کلید واژگان :Staphylococcus aureus, Coagulase Negative Staphylococci, β-lactamase, Foods
ارزش ریالی : 300000 ریال
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