Subclinical Mastitis in Camels in Oman: A Pilot Study

Camels are important and multipurpose animals in many parts of the world including Middle East. Camel milk may harbor different bacteria. Centuries old tradition of consumption of raw camel milk is still a common practice in Oman. This study was carried out to conduct a microbiological analysis of camel milk samples with subclinical mastitis in the region of Muscat, Sultanate of Oman. A total of 61 camel (Camelus dromedarius) milk samples were collected from various animal holdings in and around Muscat. Onsite California Mastitis Test (CMT) revealed 18 (29%) camels positive for subclinical mastitis. Positive milk samples were subjected to routine microbiological workup for bacterial isolation and identification. A total of 7 (47%) Enterobacter cloacae isolates, 4 (27%) Escherichia. coli, 3 (20%) coagulase negative Staphylococci spp. (CNS) and 1 (7%) Micrococcus spp. were identified out of 15 milk samples. Three milk samples did not yield any growth after two repeat attempts. Isolates belonging to Enterobacteriaceae were further subjected to antimicrobial sensitivity testing. All E. cloacae samples 7 (100%) were found to be resistant to penicillin, ampicillin, amoxicillin-clavulanic acid, first generation cephalosporins, and the macrolide group of antibiotics whereas 3 (43%) E. cloacae isolates were found to be intermediately resistant to the phenicol group of antibiotics. All four E. coli (100%) isolates were found resistant to penicillin, ampicillin, amoxicillin-clavulanic acid, first generation cephalosporins, and 2 (50%) showed resistance to macrolides, whereas 1 (25%) isolate was found to be resistant to tetracyclines. Conclusion: In this study, Enterobacteriaceae were the most common group of bacteria isolated from camels with subclinical mastitis. Enterobacter cloacae and E. coli were the predominant organisms.