Induction of mastitis in Nubian goats by soil isolates of Nocardia farcinica

The objective of study was to test the ability of soil isolate of Nocardia farcinica to induce mastitis in goats. Nocardia species were isolated from soil samples collected from 30 sites representing Khartoum State using Tryptic Soy Agar medium supplemented with tetracycline and nystatin followed by aerobic incubation at 37°C for 5 days. The isolates were identified based on morphological and biochemical characteristics and mycolic acids analysis. Experimental mastitis in Nubian goats was induced by two soil isolates of N. farcinica and one recovered from a clinical case of mastitis. Affected goats were treated using intra-mammary broad spectrum antibacterial preparations (Neomastipra and Gentamst). N. farcinica was isolated from two out of 30 soil samples collected. Two of the soil isolates induced mastitis with high leukocyte count and decreased milk yield without systemic reaction, similar to N. farcinica isolated from the natural case. The organisms were constantly shed in the milk and were successfully demonstrated in smears and cultures. Treatments of the experimentally induced mastitis with Neomastipra and Gentamst failed to cure the infection and after the withdrawal period of both drugs, nocardiae continued to be shed from the udder. Nocardiae can be isolated from soil, notably from the soil of animal beddings, which were found to be pathogenic. The findings of the present study represent an important base towards establishing the soil as a source of Nocardia organism and give idea towards diagnosis and control of mastitis in goats.