BACTEC MGIT 960 TM system for screening of Mycobacterium tuberculosis complex among cattle

Abstract

Bovine tuberculosis remains a disease of economic and public health importance in developing countries. The largest number of new cases of tuberculosis usually occurs in South-East Asia region and Africa. This study was aimed to evaluate the recent technique (BACTEC MGIT 960 ^TM system) for screening of Mycobacterium tuberculosis complex among cattle in Egypt. From the 1180 cattle examined in three different Governorates (El-Sharkia, El-Gharbia and El-Monefeia) by single intradermal tuberculin test, 29 animals (2.46%) were positive reactors. The post mortem examination of the positive reactors showed that 22 animals (75.9%) had visible lesions [respiratory form (31.0%), digestive form (13.8%), mixed form (20.7%) and generalized form (10.3%)], while seven (24.1%) did not show visible lesions. The results of isolation and identification using conventional culture method (Lowenstein- Jensen medium) were 22 mycobacterial isolates (75.9%), 20 (68.97%) Mycobacterium bovis and 2 (6.9%) unidentified slow growth. The BACTEC MGIT 960 ^TM system was used for recovery of Mycobacteria and compared with conventional culture method (Lowenstein-Jensen medium). The recovery rate of BACTEC MGIT 960 ^TM system was 82.8%, while that of Lowenstein-Jensen medium was 75.9%. The mean time for detection of Mycobacteria was 17.8 ± 0.9 days and 46.5 ± 0.4 days for BACTEC MGIT 960 ^TM system and Lowenstein-Jensen medium, respectively while the contamination rate with BACTEC MGIT 960 ^TM system was 6.9% and 10.3% in Lowenstein-Jensen medium.

Key words: Bovine tuberculosis, tuberculin test, Lowenstein-Jensen medium, BACTEC system.