Mycobacteriosis in slaughter pigs from South Africa from 1991 to 2002: Mycobacterium spp. diversity and Mycobacterium avium complex genotypes

Nomakorinte Gcebe; Rian Ewald Pierneef; Anita Luise Michel; Motlatso Tiny Hlokwe

doi:10.3389/fmicb.2023.1284906

Mycobacteriosis in slaughter pigs from South Africa from 1991 to 2002: Mycobacterium spp. diversity and Mycobacterium avium complex genotypes

Front Microbiol. 2023 Nov 16:14:1284906. doi: 10.3389/fmicb.2023.1284906. eCollection 2023.

Authors

Nomakorinte Gcebe¹, Rian Ewald Pierneef^{2

3

4

5}, Anita Luise Michel⁶, Motlatso Tiny Hlokwe¹

Affiliations

¹ Bacteriology Laboratory, Agricultural Research Council-Onderstepoort Veterinary Research, Pretoria, South Africa.
² Agricultural Research Council-Biotechnology Platform, Pretoria, South Africa.
³ Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
⁴ Centre for Bioinformatics and Computational Biology, University of Pretoria, Pretoria, South Africa.
⁵ Microbiome@UP, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
⁶ Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.

Abstract

Introduction: Mycobacterium avium complex (MAC) bacteria are the most prominent etiological agents of lymphadenitis in pigs. M. avium subspecies hominissuis (MAH) is a member of MAC and has been reported in many parts of the world to be the most prevalent non-tuberculous mycobacteria (NTM) to cause mycobacteriosis in humans, mainly in children. Thus, the economic and zoonotic impact of MAC species are increasingly being recognized. In South Africa, little is known about the distribution of NTM and the molecular epidemiology of M. avium in pigs.

Materials and methods: In this study, lymph nodes including mandibular, mesenteric, submandibular, and retropharyngeal, with tuberculosis-like lesions were collected during routine meat inspection of slaughter pigs with no disease symptoms (n = 132), between 1991 and 2002. These pigs were slaughtered at 44 abattoirs distributed across seven of the nine South African provinces. Mycobacterial culture, polymerase chain reaction (PCR), and sequencing of the Mycobacterium specific 577 bp 16S rRNA gene fragment were performed for species and subspecies identification.

Results: The majority of the isolates (each per sample); 114 (86.4%) were identified as MAH, 8 (6%) as MAA/M. avium subsp. silvaticum, 4 (3%) were Mycobacterium tuberculosis, 2 (1.5%) as Mycobacterium intracellulare, and 1 (0.75%) as Mycobacterium bovis. The other isolates were identified as Mycobacterium lentiflavum (0.75%), Mycobacterium novocastrense (0.75%), and a Micrococcus spp. (0.75%). Using an eight-marker MLVA typing tool, we deciphered at least nine MIRU VNTR INMV types of MAH and MAA.

Discussion: Identification of known zoonotic mycobacteria, including MAH, MAA, M. intracellulare, M. bovis, and M. tuberculosis, from slaughter pigs has a potential public health impact and also strengthens recognition of the potential economic impact of MAC. This study has also for the first time in South Africa, revealed MAC MIRU VNTR INMV genotypes which will aid in the future epidemiological investigation of MAC in South Africa.

Keywords: MLVA; Mycobacterium avium complex; mycobacteriosis; non-tuberculous mycobacteria; porcine lymphadenitis; zoonosis.

Grants and funding

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.