الفهرس 
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Abstract
MRSA considered one of the zoonotic agents which have the ability for transmission from animal to human causing wide variety of infections. These infections ranged from minor skin abscesses to life threatening diseases as endocarditis, pneumonia, septicemia and bone and soft tissue infection.
In last decades, the importance of MRSA increased in veterinary medicine due to its ability for transmission between man and animal and vice versa. In addition to its finding in surrounding environment, veterinary foundations and hospitals representing an occupational hazard on veterinary staff including veterinary doctors and nurses.
The aim of the present study was to investigate the prevalence of MRSA from wound and skin affection in man and animal at Assiut Governorate, molecular identification of resistant genes in MRSA in man and animal and antibiotic sensitivity of the isolated MRSA strains to the commonly used antibiotics in the veterinary and human Egyptian field.
Samples collected from skin lesions and abscesses from 103 animals (66 from sheep, 26 from cattle and 11 from equine). 63 human samples from both sex male (40) and female (23) from different regions urban (16) and rural (47) and different ages. Human samples categorizes according to age into 3 groups from >2: 20years, 21:40years and 41:70 years.
Collected samples were cultured on blood agar base supplemented with 5% citrated sheep’s blood and incubated for 24-48 hours under 37°c for detection of growth, morphological features and hemolytic characteristics of Staphylococci. Isolated bacteria were examined under microscope with gram stain and examined biochemically (culturing on mannitol-salt agar, catalase
test).Positive Staphylococci were cultured on Baired-Parker medium as a selective media for S. aureus (white to grey-black surrounded by an opaque zone).
All isolates identified as S. aureus were examined by using PCR for the presence of mecA gene to test if these isolates are MRSA or not using specific primers. MecA gene positive MRSA isolates were examined by using PCR for the presence of some antibiotic resistance genes (ermA, ermC, tetM and tetK genes) using specific primers. MecA gene positive MRSA strains were tested for their sensitivity towards the most commonly used antibiotics in the human and veterinary field. MIC of antibiotics was evaluated with the broth micro dilution technique.
S. aureus could be isolated from 28 out of 103 animal samples (27.18
%): 10 out of 66 (15.15%) examined sheep, 7 out of 11(63.64%) examined equine and 11 out of 26 (42.31%) examined cow. Meanwhile, MRSA isolates could be detected in 3.03% of examined sheep, 27.27% of examined equines, and 7.69% of examined cows. In human samples, the prevalence of
S. aureus was 23.81%. Meanwhile, the prevalence of MRSA among human individuals was 14.29%.
Statistical analysis revealed that there was a highly significant difference (P=0.001) in MRSA prevalence among different animal species.
There wasn’t significant variation related to sex and age in human samples (P=0.45, 0.35 in arrangement) while there was highly significant variation related to residence (P=0.03) where prevalence of MRSA in patients from rural areas (17.02%) higher than those from urban areas (8.69%).
Molecular identification for resistant genes of MRSA isolates found that all MRSA isolates had tet k, tet M and erm A genes, while erm C found in 80% of human isolates only.
Antibiotic sensitivity test detected that all human and animal MRSA isolates were resistant to penicillin and ampicillin antibiotics. Sheep and cow MRSA isolates were resistant to oxytetracycline, while equine isolates were sensitive to it. About 44.4% of human isolates were resistant to oxytetracycline. All animal MRSA isolates were resistant to cefixime and more than 55% of human isolates were also resistant to it. All MRSA isolates were sensitive to clindamycin except for cow,s strains. Enrofloxacin and ciprofloxacin were the most effective antibiotics against all MRSA isolates due to all human and animal MRSA isolates sensitive to them with MICs lying in the >0.03125-2 µg/ml range . None of the 16 MRSA isolates had reduced susceptibility to vancomycin with MICs lying in the 0.5-4
µg/ml range.
The similarity of most MRSA isolates in phenotypic and genotypic antibiotic susceptibility recovered from human and different animal patients, despite the difference in the frequently used antibiotics in veterinary and human hospitals, suggesting the possibility of zoonotic circulation of those isolates between them.