Methicillin resistance and enterotoxigenicity of Staphylococci isolated from milk and white cheese in Iraq | ||
| Iraqi Journal of Science | ||
| Article 1, Volume 55, Issue 1, March 2014, Pages 40-49 | ||
| Authors | ||
| Marwa. H. Al-Khafaji; May.T. Flayyih; Majeed. A. Sabah | ||
| Abstract | ||
| Two hundred staphylococcal isolates isolated from milk and white cheese samples, which were collected from local markets in Baghdad. The predominant species was Staphylococcus aureus 97 isolates (48.5%), followed by S.chromogenes 82 (41%) and 21 (10.5%) S.epidermidis isolates. The pattern of antibiotic susceptibility of Coagulase Positive Staphylococci (COPS) and Coagulase Negative Staphylococci (CONS) isolates to 3 antibiotics (Methicillin, Tetracyclin and Vancomycin) was determined using disc diffusion method; the results revealed that 80 S. aureus isolates (82.47%) found to be methicillin resistant (MRSA) while 8 isolates (8.24%) were vancomycin resistant (VRSA) and 18 S. aureus isolates (18.5%) resist tetracycline antibiotic. Sixty four CONS isolates (62.13%) were methicillin resistant, 28 CONS isolates (27.18%) resist tetracycline, and 5 CONS isolates (4.85%) were vancomycin resistant. Suckling mouse bioassay was tested to investigate the staphylococcal enterotoxin biological activity. Results showed that 131 isolates which constitutes 65.5% of the examined isolates, gave a positive result. Both COPS and CONS isolates were shown to be enterotoxigenic, COPS represented by S. aureus species occupied the higher ratio of the enterotoxigenic staphylococci, 86 S.aureus isolates (65.64% of the enterotoxigenic staphylococci) gave the positive ratio of the intestine weight to the body weight which was ≥ 0.083 while 45 CONS isolates (34.35%) were enterotoxin producers. These toxins were thermostable staphylococcal enterotoxins which gave the same toxic effect after heating to 100°C for 30 minutes. | ||
| Keywords | ||
| Staphylococci; Methicillin resistance; Enterotoxin; Milk and cheese | ||
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