Isolation and Molecular Identification and Sequencings of Nocardia and Nocardia- like spp Isolated from Soil and Milk of Goats, Sheep, Cattle and with Mastitis in Khartoum Stats

Abstract

This work was intended to investigate the role of Nocardia and Nocardia -likeorganisms as causative agents of mastitis in soil sample and milk sample from goats ,cow and sheep. It was carried out at different farms in Khartoum Stat. A total of three hundred milk samples of cow ,sheep and goat and twenty soil samples were collected from the same farms in different sites for isolation and identification of Nocardia and Nocardia —likeorganisms. All milk samples were cultivated onto Tryptic Soya Agar (TSA) ,and soil cultured on to Tryptic Soya Agar medium (TSA) supplemented with a combination of tetracycline (5mg/ml) and nystatin (50 mg/ml). All isolates 11(11%) from milk of goats,13(13%) from milk of cow and 7(35%)from soil sample were identified phenotypically as Nocardia sppby cultural, morphological, and biochemical tests (urease test, catalase test and degradation of xanthine, tyrosinc, casein, sugar fermentation , growth at 45°C), mycolic acid content and antimicrobial susceptibility test. The isolates were tentatively identified as member of the genus Nocardia on the morphological, biochemical and mycolic acid pattern. Comparative analysis of the 16S RNA gene sequencing confirm that the isolates fall within the phylogenic branch whichaccommodates member genus Mycobacteria, Dietzia spp and Rhodococcusspp. In this study we consider the recognition of Nocardia and Nocardia-like based on phenotypic tests was strenuous, but definitive identification was attainable by molecular methods.