Research article Mixed infections of Corynebacterium pseudotuberculosis and non-tuberculous mycobacteria in South African antelopes presenting with tuberculosis-like lesions Borna Mu ¨ ller a, *, Lin-Mari de Klerk-Lorist b , Marijke M. Henton c , Emily Lane d , Sven Parsons a , Nicolaas C. Gey van Pittius a , Antoinette Kotze d,e , Paul D. van Helden a,1 , Manfred Tanner f,1 a DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Sciences, Stellenbosch University, Francie van Zyl Avenue, Tygerberg 7505, Cape Town, South Africa b Chief State Veterinarian, Skukuza, South Africa c Idexx Laboratories, Woodmead, South Africa d Wildlife Epidemiology Research Program, National Zoological Gardens of South Africa, Pretoria, South Africa e Genetics Department, University of the Free State, Bloemfontein, South Africa f Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany 1. Introduction Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), a disease of considerable economic importance, which primarily affects small ruminants (Dorella et al., 2006; Baird and Fontaine, 2007). Infections with C. pseudotuberculosis on the African continent are poorly documented (Dome- nech, 1980; Kariuki and Poulton, 1982; Martrenchar et al., 1995; Selim, 2001). However, in South Africa, the disease is known to be common in sheep from semi-arid farming areas and was first described in 1909 (Paton et al., 2004). Veterinary Microbiology 147 (2011) 340–345 ARTICLE INFO Article history: Received 19 February 2010 Received in revised form 15 July 2010 Accepted 20 July 2010 Keywords: Caseous lymphadenitis Wildlife Africa Bovine tuberculosis Decontamination ABSTRACT Routine meat inspection of antelope carcasses from a South African game reserve revealed a high prevalence of tuberculosis-like lesions. This study aimed to identify the causative agent of this disease and to describe its pathological features. In total, 139 antelopes were randomly harvested from the game reserve and subjected to meat inspection. Of these animals, 46 (33%) showed gross visible, tuberculosis-like lesions. Histopathological examination revealed the presence of encapsulated necrogranulomas in organs and/or lymph nodes of 22 of 27 animals tested. Tissue samples from lesions were processed for both non-selective bacterial culture and mycobacterial culture following decontamination. In non-selective cultures of lesions from 25 of 31 animals tested, Corynebacterium pseudotuberculosis was detected. Isolation of C. pseudotuberculosis was closely associated with the presence of necrogranulomas. In mycobacterial cultures of lesions from 9 of 41 animals tested, different species of non-tuberculous mycobacteria (NTMs) were detected. In 5 instances, depending on the culture procedure that was applied, either C. pseudotubercu- losis or NTMs were isolated from the same tissue sample. Our results suggest that the disease has been caused by infections with C. pseudotuberculosis. In sub-Saharan Africa, the role of pathogens other than Mycobacterium bovis may be underestimated in causing tuberculosis- like lesions. In cases where potentially pathogenic NTMs are isolated from mycobacterial cultures of tuberculosis-like lesions, the non-use of additional non-selective culture techniques could lead to misinterpretations of the diagnostic test results. ß 2010 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +27 21 938 9482; fax: +27 21 938 9476. E-mail address: bmuller@sun.ac.za (B. Mu ¨ ller). 1 These authors contributed equally to this work. Contents lists available at ScienceDirect Veterinary Microbiology journal homepage: www.elsevier.com/locate/vetmic 0378-1135/$ – see front matter ß 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.vetmic.2010.07.017