Isolation of staphylococcus aureus from different affections in cows and study its virulence and sensitivity to antibiotics. A comparative study | ||
| The Iraqi Journal of Veterinary Medicine (IJVM) | ||
| Article 3, Volume 38, Issue 1, June 2014, Pages 9-14 PDF (0 K) | ||
| Author | ||
| Majid Mohammed Mahmood | ||
| Abstract | ||
| The study was conducted to detect the presence of Staphylococcus aureus in different affections like abscesses, acute mastitis, diarrhea, urinary tract infection, and cough in cows, with evaluation their virulence and antibiotic sensitivity test ; therefore, 162 different samples were collected then cultured on brain heart infusion (BHI) broth , subcultured on blood agar and mannitol salt agar. Moreover, gram stain was done and a set of biochemical tests as well as sugar fermentation tests. Furthermore, mice were injected 0.5 ml of 1.2 × 109 cfu/ml intraperitoneally (I/P) with bacterial suspension and antibiotic sensitivity test was applied. Results showed isolation of 79 (48.77%) S. aureus isolates out of 162 as a total which included 7 isolates (31.82%) out of 22 abscesses' samples, 31 isolates (55.36%) out of 56 milk samples from acute mastitis, 17 isolates (41.46%) out of 41 fecal samples, 9 isolates (36.00%) out of 25 vaginal swabs, and 15 isolates (83.33%) out of 18 sputum samples. The colonies presented as rounded, smooth, convex, shiny, β-hemolytic, and shown gram +ve diplococci, quadrates or grape like under light microscope, whereas colonies seen on mannitol salt agar as small, spherical, smooth, convex, yellowish in color which cover all background of plate. Results of biochemical tests revealed that all isolates were +ve to the following : catalase, slide and tube coagulase (except 2 isolates from milk) nitrate reduction test, (O-F glucose), gelatin hydrolysis test (except 3 isolates) Methyl Red – Voges Proskauer (MR-VP), urease, acid phosphatase, and variable to DNase production test, however all isolates were negative to oxidase and indol. The isolates fermented glucose, sucrose, maltose, fructose, trehalose, lactose, mannitol, mannose, galactose, ribose, while they were negative to xylose and arabinose. The results of virulence test revealed death of majority number of mice within first 24 hours after I/P injection which was demonstrated strongly in the isolates of diarrhea. Finally, the results of antibiotic sensitivity show high resistance against different types of broad spectrum antibiotics except Azithromycin and Doxycycline which were sensitive. It can be concluded that S. aureus could be found in different affections of cows and they do not respond to the treatment with classical antibiotics because of their virulence. Therefore, random uses of antibiotics must be avoided. | ||
| Keywords | ||
| Staphylococcus aureus; virulence test; mice | ||
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