Phenotypic and Molecular Typing of Tuberculous and Nontuberculous Mycobacterium Species from Slaughtered Pigs in Egypt

Abstract

Abstract. A total of 745 slaughtered pigs were examined during routine meat inspection for suspected tuberculous lesions. Specimens from suspected lesions were collected for conventional mycobacteriologic examinations. Suspected mycobacterial colonies were subjected to molecular typing based on the Mycobacterium species-specific intergenic spacer (IGS) target. The study resulted in detection of suspected lesions in 110 (14.8%) carcasses, from which only 67 specimens produced suspected mycobacterial colonies. Conventional examination was only able to identify 56 isolates as Mycobacterium species, which was confirmed by polymerase chain reaction amplification of the IGS target. Interestingly, out of these, 18 and 12 isolates were Mycobacterium tuberculosis and Mycobacterium bovis, respectively. Sequence analysis of IGS resolved the identities of 10 of the 11 conventionally unidentified isolates as being 4 different nontuberculous Mycobacterium species. The last isolate was proposed as a non-Mycobacterium species and was confirmed by its identification as Rhodococcus equi based on the 16S ribosomal DNA sequence analysis. The study described the isolation of Mycobacterium tuberculosis from pigs and revealed high burden of infection with both tuberculous and nontuberculous mycobacterial species among pigs in Egypt. In addition, the study showed the usefulness of IGS sequence analysis as a reliable molecular tool that would be useful for further epidemiologic and public health studies.

Prevalence and associated risk factors of mycobacterial infections in slaughter pigs from Mubende district in Uganda

“…In comparison to the findings in Netherlands and Finland where the prevalence was 0.34% and 0.5%, respectively (Komijn et al 1999;Tirkkonen et al 2007), the prevalence is considerably higher in Mubende. It was, however, lower than the 10% in Egypt and 15% in Germany (Tirkkonen et al 2007 Table 4 Multivariable logistic regression model identifying factors associated with occurrence of mycobacteria in tissues of TB-exposed pigs in Mubende district, Uganda Mohamed et al 2009). Our finding showed a remarkable difference with results obtained in South Africa's 5-year study on porcine lymph nodes which showed that 75% of the lesions positive were due to Mycobacterium species (Coetzer and Tustin 2004).…”

“…Economic losses due to swine mycobacteriosis range from mortality to morbidity as well as dissemination of nontuberculous Mycobacterium species which sensitise cattle, resulting in non-specific reaction to tuberculin skin test (Mohamed et al 2009). Therefore, the false-positive reactors are rejected during selection for animal meat export, thus costing the farmers heavily and, in a wider context, the national economy.…”

Mycobacterium bovis at the animal–human interface: A problem, or not?

“…Nowadays M. tuberculosis is still occasionally diagnosed in domestic pigs where they are exposed to humans shedding the disease (Mohamed et al, 2009). Hence screening of slaughter pigs for typical caseous lesions in the parotid lymph nodes can be of value as a sentinel detection system for human tuberculosis in low incidence countries.…”

Rapid identification of veterinary-relevant Mycobacterium tuberculosis complex species using 16S rDNA, IS6110 and Regions of Difference-targeted dual-labelled hydrolysis probes

“…No other MTC species were ever isolated in our lab, with the exception of a few M. tuberculosis isolates collected from zoo captive mandrills and a dog (Amado et al, 2006;Botelho et al, 2014). Although a rare event, infection with M. tuberculosis mostly occurs in animals living in close contact with humans, such as pets, pigs, cattle and captive animals (Michel et al, 2003;Mikota et al, 2001;Mohamed et al, 2009;Schmidt et al, 2008;Berg et al, 2009;Chen et al, 2009;Erwin et al, 2004), and reference veterinary diagnostic laboratories should be aware for these infections as they raise important public health concerns. Taking into account the abovementioned considerations, we selected M. bovis, M. caprae and M. tuberculosis as the relevant target species for the implementation of a real-time PCR-based identification assay.…”