Studies On Caprine Mastitis Caused By Nocardiae And Related Actinomycetes

Abstract

In the present study 100 mastitic and 100 normal milk sample were collected from goats in Khartoum State. Out of the 100 mastitic mil sample, 27revealed growth of actinomyces - like org1nism on tryptic so agar (TSA) medium when inoculated aerobically at 37fC for up to 5 days Where as the remaining 73 samples revealed growth of various Gram not the interest 0 positive cocci and loccobacilli organismsI Ithis study. Twenty-five samples revealed growth both colonies 0 nocardiae and I Grampositive cocci (mixed infectipns); whereas the remaining Three samples revealed pure growth of nocatdiae-like colonies. Out of 1100 apparently normal milk samples from non-clinical which had been cultured lonto TSA, 10 revealed growth pf nocardiae, one revealed growth of streptomyces, 25 were positive for other bacteria and 64 revealed no growth. The isolated 39 strains in addition to two references strains of N. farcinlca SD 761 and N. asteroids SD 1902 were SUbj1cted to phenotypic characterization using morphological, cultural, biochemical and antibiotics sensitivity Tests. According to phenotypic characterization the isolated 39 strains were classified into four cluster: cluster 1, was typically N. brastlliensis; clus,ter 2, was typically N. asteroides and cluster 4, was I Nocardae- likeorganisms. Representative strains from these cluster were submitted to genotype analysis using 16s rDNA sequences. Two cluster were identified; cluster A xiii was found to be N. farcinica and cluster B contained strains belongs t9 the genus Streptomyces. To determine the pathogenicity of the predominantly and the well characterized strains, two strains S01800 and S01828 (N. farcincica) and one strain SO 1925 (Streptomyces sp.) were choeson for experimental infection in of three Nubian goats. Nocardiae strains were found to IDe highly pathogenic for the goats II. However one strain (SOI828) caused cOr)1plete destruction to udder parenchyma. Clinically the goats showed 1110 systemic reaction but localized udder changes were typical of an acute mastitis. Histopathologically, mammary tissue inflammatory cells, extensive fibrosis and atrophy of acini surrounded with extensive fibrous ti1ssues. The organism was excrete~ intermittently in the milk stream and had been demonstrated in smears and culturer. Streptomyces sppI(SD1925) caused mild infection with high increase in leukocytes count (range from 3x 106- 50x 106), and milk return to normal I after injection of combination of streptomycin and p (intra muscular injection). all~ The study emphysised that a significant 0 of mastitis N. farcinica, which is responsible for many mastitis cases and thus It constitutes serious hazard to goat dairy industry. The prevalence of mastitis among the investigated herds war estimated to be 5%. Nocardiae represents about 24% from out of the 100 mastitic cases, which revealed growth.