Abstract
The current study focused on determination of the prevalence of Methicillin- resistant Staphylococcus aureus (MRSA) in health care workers (HCWs), farm workers and dairy cattle (apparently healthy and mastitic) and studied the effects of some demographic factors on the estimated prevalence. Also, the antibiotic sensitivity of the obtained isolates was investigated. A total of 127 human samples were collected including nasal and hand swabs; 89 from HCWs in four hospitals mainly from surgical department and 38 from farm workers in three different dairy cattle farms. In addition, a total of 116 samples were obtained from dairy cattle farms including; 62 nasal swabs of dairy cattle (apparently healthy and mastitic), 26 swabs from cups of milking machine and 28 milk samples. The recorded results clarified that the overall estimated prevalence of MRSA in the examined human and cattle samples was 31.5 and 52.65%, respectively. Fisher’s exact test showed higher prevalence in cattle than in humans (P < 0.001). Concerning human samples, it was noticed that farm workers (36.8%) showed higher prevalence than healthcare workers (29.2%). Also, it was found that females (32.05%) showed higher prevalence than males (30.61%) and the age group (20 – 40 years) showed the highest prevalence (38.46%) followed by the age group (> 40 years) (23.25%). Concerning dairy cattle farms, it was estimated that the prevalence of MRSA was 53.23, 21.43 and 84.62% in the examined samples of nasal swabs, milk and milking machine swabs, respectively. In addition, the prevalence of MRSA in nasal swabs of mastitis free cattle (54.55%) was higher than in mastitis infected cattle (45.45%). On the other side, mastitic milk samples (66.67%) showed higher prevalence that milk samples of mastitis free cattle (33.33%). Finally, antibiotic sensitivity testing showed that human isolates were resistant to cefoxitin (92.5%), vancomycin (12.5%), linezolid 10 (25%) and tetracycline (42%) while those of dairy cattle farms were resistant to cefoxitin (78.7%), vancomycin (24.6%), linezolid (16.4%) and tetracycline (42.6%). On conclusion, detection of MRSA in both cattle and human samples constituted a public hazard as well as the development of antibiotic resistance.

Key words: MRSA, Human, Cattle, Colonization, Prevalence, Susceptibility