Multi-Etiological Nature of Tuberculosis-Like Lesions in Condemned Pigs at the Slaughterhouse

PLoS One. 2015 Sep 29;10(9):e0139130. doi: 10.1371/journal.pone.0139130. eCollection 2015.

Abstract

Tuberculosis-like lesions (TBL) in pigs have been associated with microorganisms other than mycobacteria. In this work a histopathological and microbiological evaluation of TBL in pigs is shown. A total of 352 samples belonging to 171 pigs totally condemned at slaughterhouse due to generalized TBL were sampled and selected for analysis. Pyogranulomatous (56.2%) and granulomatous lesions (20.2%) were observed in all analysed organs. Most of the granulomas observed in both lymph nodes and lungs belonged to more advanced stages of development (stages III and IV) whereas in the liver and the spleen most of lesions belonged to intermediate stages (stages II and III). Different microorganisms were simultaneously detected from TBL in the 42.7% of the animals. Mycobacterium tuberculosis complex (MTC) (38%), coryneform bacteria (40.3%) and streptococci (28.1%) were the main groups of microorganisms detected after bacteriological analysis, with Trueperella pyogenes and Streptococcus suis as the most frequently isolated species. Mycobacteria belonging to MTC were the most frequently detected pathogens in granulomatous and pyogranulomatous lesions in submandibular lymph nodes (32.7%) and coryneform bacteria were the microorganisms more frequently isolated from lungs (25.9%) and spleen samples (37.2%). These results may provide new insights into the pathogenesis and diagnosis of this pathology. The importance of coryneform bacteria and streptococci in such processes must be evaluated in future studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abattoirs
  • Animals
  • Corynebacterium / isolation & purification
  • Granuloma / microbiology*
  • Lymph Nodes / microbiology
  • Lymph Nodes / pathology
  • Mycobacterium tuberculosis / isolation & purification
  • RNA, Ribosomal, 16S / genetics
  • Staphylococcus / isolation & purification
  • Streptococcus suis / isolation & purification
  • Swine / microbiology*
  • Swine Diseases / microbiology*
  • Tuberculosis / diagnosis
  • Tuberculosis / microbiology*

Substances

  • RNA, Ribosomal, 16S

Grants and funding

This study was financially supported by the Council of Economy, Science, Innovation and Employment of the Andalusian Government (AGR-2685-2012) and by the Centre for the Development of Industrial Technology (CDTI) of Spain (project reference IDI-20111632/IDI-20111633). Cardoso-Toset F was funded by a grant of the Agrifood Campus of International Excellence Programme (ceiA3) from the Ministry of Education, Culture and Sport and by the Santander Universities Global Division.