REFAI, M., YOUSSEF, S., SALEH, N., ATTIA, S., ZAKI, H., TAWAKKOL, W., MOSIIREF, B. (2005). STUDIES ON VIRULENCE FACTORS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MASTITIC BUFFALOES. test, 53(2), 253-265. doi: 10.21608/vmjg.2005.384683
M REFAI; S YOUSSEF; NAGAT A SALEH; S ATTIA; HODA M ZAKI; W TAWAKKOL; BADIA S MOSIIREF. "STUDIES ON VIRULENCE FACTORS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MASTITIC BUFFALOES". test, 53, 2, 2005, 253-265. doi: 10.21608/vmjg.2005.384683
REFAI, M., YOUSSEF, S., SALEH, N., ATTIA, S., ZAKI, H., TAWAKKOL, W., MOSIIREF, B. (2005). 'STUDIES ON VIRULENCE FACTORS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MASTITIC BUFFALOES', test, 53(2), pp. 253-265. doi: 10.21608/vmjg.2005.384683
REFAI, M., YOUSSEF, S., SALEH, N., ATTIA, S., ZAKI, H., TAWAKKOL, W., MOSIIREF, B. STUDIES ON VIRULENCE FACTORS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MASTITIC BUFFALOES. test, 2005; 53(2): 253-265. doi: 10.21608/vmjg.2005.384683

STUDIES ON VIRULENCE FACTORS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MASTITIC BUFFALOES

Veterinary Medical Journal (Giza)
Volume 53, Issue 2, April 2005, Pages 253-265    PDF (4.81 M)
Document Type: Original Article
DOI: 10.21608/vmjg.2005.384683
Authors
M REFAI* 1; S YOUSSEF2; NAGAT A SALEH2; S ATTIA1; HODA M ZAKI3; W TAWAKKOL4; BADIA S MOSIIREF3
1Department of Microbiology, Faculty of Veterinary Medicine, Cairo University.
2Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University.
3Animal Health Research Institute
4Department of Microbiology, Faculty of Pharmacy, Cairo University
Abstract
Staphylococci were isolated from 103 out of 393 mastitic quarters of buffaloes (26.2%), of which 62 isolates (36.7%) were recovered from clini­cal cases and 41 (18.3%) from subclinical cases. S. aureus was isolated from 23.7% and 13.7% of quarters of clinical and subclinical mastitic cases, respectively. Studies of virulence factors of S. au­reus revealed that the majority of S. aureus iso­lates recovered from clinical mastitis (65%) grew as diffuse colonies on serum soft agar, indicating the presence of capsules, whereas almost the same percent of isolates from subclincal mastitis (64.3%) grew as compact colonies, which means they lacked capsules. Out of 40 S. aureus isolates obtained from clinical mastitic milk samples, 14 (35.0%) and 32 (80%) were positive for clumping factor and tube coagulase respectively, while out of 14 isolates recovered from subclinical mastitic milk samples, 9 (64.3%) and 10 (71.4%) isolates were positive for the same tests. 85.2% of the ex­amined S. aureus isolates were positive for hae­molysin production and the rate was higher among isolates detected from the clinical cases (90%) in comparison to that of subclinical cases (71.4%). 36 isolates (66.7%) were found to be toxigenic. Enterotoxin C was the most common as it was detected in 21 isolates (38.9 %), fol­lowed by enterotoxin A from 8 (14.8%) and en­terotoxin B from 7 (13.0%). Mortality rate was higher among mice infected I/P with S. aureus re­covered from clinical mastitic milk samples (73.3%), when compared with those infected with isolates obtained from subclinical mastitic milk samples (52.4%). The encapsulated isolates that produced toxins were highly virulent to mice. 100% mortality was caused by 12 isolates, of which 9 isolates produced enterotoxin C, 1 iso­late produced B and 2 produced A.
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