Identification of Acid-Fast Organisms Isolated From Slaughtered Cattle in the Sudan.

Abstract

One hundred and twenty samples suspected for bovine tuberculosis (BTB) were collected; 119 (99.17%) samples were collected from Omdurman, El-Sahafa, El-Halfaya, Kassala and Gedarif slaughterhouses, and one sample (0.83%) from a cow in El-Bagair, Khartoum State. Acid-fast organisms (AFO) were detected in 32 (26.67%) of the sample using direct Ziehl-Nelseen, (ZN) stained smears, and in 64 (53.33%) using in-direct ZN stained smears. 22 samples showed branching filamentous organisms, 21 were strongly acid-fast bacteria and tentatively identified as M. farcinogense, and the remaining organisms were partially acid-fast and consequently identified as Nocardia spp. 33 of the 120 samples revealed AFO on Lowenstein-Jensen medium. One of them (3.03%) was Nocarida spp. and the remainders (96.97%) were mycobaterial strains which were subjected to analysis using polymerase chain reaction (PCR) on the insertion element IS6110.29 strains (90.625%) were positive and hence identified as M. tuberculosis complex, and three strains (9.375%) were negative. Two strains (6.25%) were found to belong to the rapidly growing mycobateria, and one strain (3.125%) was submitted to PCR on the insertion element IS1245 (specific for M. avium) and it was positive and, therefore, identified as M. avium. Six strains which produced considerable amounts of cells were analyzed for their mycolic acid constituents. Four stains revealed mycolic acid patterns which were characteristic for M. tuberculosis, and one strain (SD114) revealed mycolic acids pattern which was characteristic of M. avium, and one strain (SD166) revealed one spot of mycolic acids, which was characteristic of Nocardia spp. M. tuberculosis complex strains were identified according to their morphological, cultural, molecular characteristics and their mycolic acid patterns. Twenty five of them (78.63%) were M. bovis and 4 strains (12.5%) were M. tuberculosis. The overall percentages of different caseous infections in the 120 samples were 25 (20.83%) M. bovis, 21 (17.5%) M. farcinogense, 4 (3.33%) M. tuberculosis, one (0.83%) rapidly growing mycobacteria, one (0.83%) was M. avium, one (0.83%) Nocardia spp. and 54 (55%) other caseous infections.