Molecular Epidemiology of Mycobacterium Tuberculosis Complex at Nekemte Municipality Abattoir, Western Ethiopia

Abstract

Article Information A cross-sectional study was conducted at Nekemte Manicipality Abattoir from September 2009 to May 2010 to estimate the prevalence of bovine tuberculosis (BTB), and characterize its causative agents. Post mortem examination, bacteriological culturing, Zeihl Neelsen staining, multiplex polymerase chain reaction (PCR), and region of difference-4 (RD4) deletion typing were used for investigation. Cattles (1168) were recruited for the study and the prevalence was found to be 5.9% (70/1186) on the basis of gross lesion. 70% of the gross lesion was detected in the thoracic cavity while 25% of the lesion was found in the abdominal cavity. Only 31.4% (22/70) of the suspicious lesions yielded colonies of which 19 were acid-fast positive. Further identification of these 19 isolates using multiplex PCR revealed that 17 isolates belong to the Genus Mycobacterium while the remaining two isolates did not show signal to the Genus. Of the 17 isolates that showed signal to the Genus Mycobacterium, 7 were members of Mycobacterium tuberculosis (M. tuberculosis) complex while the remaining 10 isolates were members of the non-M. tuberculosis complex. Further identification and characterization of the M. tuberculosis complex members using RD4 deletion typing identified four isolates with intact RD4 which could be either M. tuberculosis or M. africanum and three isolates with deleted RD4 thus confirmed to be M. bovis. In conclusion, TB lesions were caused by both the members of M. tuberculosis complex and the non-M. tuberculosis complex Mycobacteria. Hence, as the majority of the isolates was the non-M. tuberculosis complex members, the pathogenecity of these members in cattle needs further study.

Isolation and Molecular Identification of Mycobacterium bovis from Slaughtered Cattle in Nekemte Municipality Abattoir, Ethiopia

“…The present study showed that crossbred cattle were found to be more susceptible to bovine tuberculosis (BTB) than local zebu breeds. This finding was consistent with results from previous studies, such as [ 13 ], which reported a 17.9% prevalence of BTB in crossbreeds and 4.4% in the local breeds, and similar findings were also reported by [ 18 , 23 , 47 – 49 ] across different Ethiopian abattoirs, which indicated that crossbreeds are more at risk for BTB clinical disease than Zebus.…”

“…In this study, sex was not a risk factor for tuberculosis lesions, consistent with studies by [ 11 , 23 , 49 ] from Ethiopian abattoirs. However, Shewatatek [ 48 ] found that sex was a risk factor for bovine tuberculosis in North Gondar.…”

“…The current finding shows a moderate increase compared to previous studies conducted at Nekemte municipal abattoir (5.9%) [ 23 ], Hawasa municipal abattoir (5.84%) [ 13 ], Bishoftu municipal abattoir (5.7%) [ 40 ], and Jima municipal abattoir (5.4%) [ 41 ]. However, it is still lower than the findings from Gambela municipal abattoir, which recorded 13.2% [ 18 ], and Gondar Elfora abattoir with 11.7% [ 42 ] and 15.9% [ 11 ].…”

“…The Thrusfield [ 22 ] formula was used to calculate the sample size. The previous work of Woyyesa et al [ 23 ] used the expected prevalence (Pexp) which was 5.9%, and the 95% confidence interval (CI) with 5% accuracy and sample size was determined as follows: where N is the required sample size, Pexp represents the expected prevalence, and d represents the desired absolute accuracy (5%). As a consequence, the sample size for bovine TB lesions was determined for each district to be 85.…”

Pathological characterization of lesions and bacteriological isolation of causative agents of swine tuberculosis at Bishoftu and Addis Ababa Abattoirs, Bishoftu, Ethiopia

“…Furthermore, Teklu et al, 33 indicated the presence of caseous and/or calcified lesions may not be truly tuberculous lesions; Pritchard 49 and Diguimbaye Djaibe et al, 50 also implied that viable mycobacteria may not be present in calcified lesions. The 7.5% culture positivity from the lesion current finding, was lower than 47% reported by Ameni et al, 51 35% reported by Müller et al, 52 32% reported by Shimeles, 53 31.4% reported by Woyessa et al, 54 and 23.6% reported by Araujo et al, 55 in slaughtered cattle, and 30.6% by Arega et al, 10 in swine. However, the present finding was higher than that of Aknaw et al, 56 who reported 2.9% in slaughtered cattle at Bishoftu abattoir.…”