A case report of transmission and disease caused by Mycobacterium caprae and Mycobacterium bovis in Lima, Peru

Complicated clinical course of zoonotic tuberculosis due to Mycobacterium Caprae: A case report and literature review

The incidence of human tuberculosis (TB) disease due to Mycobacterium caprae, an etiologic agent of zoonotic TB along with Mycobacterium bovis, is very low. There are no guidelines for human TB caused by M. caprae, and treatment protocols for infections caused by this microorganism are based on the recommendations for M. bovis infections. We report a 15-year-old girl diagnosed with cervical lymphadenitis due to M. caprae. She did not recover completely despite 6 months of anti-TB medication. Therefore, treatment was extended to 12 months. There is a lack of information about the treatment of human M. caprae infections. Further studies evaluating the treatment in detail are needed.

Evidence, Challenges, and Knowledge Gaps Regarding Latent Tuberculosis in Animals

Mycobacterium bovis and other Mycobacterium tuberculosis complex (MTBC) pathogens that cause domestic animal and wildlife tuberculosis have received considerably less attention than M. tuberculosis, the primary cause of human tuberculosis (TB). Human TB studies have shown that different stages of infection can exist, driven by host–pathogen interactions. This results in the emergence of heterogeneous subpopulations of mycobacteria in different phenotypic states, which range from actively replicating (AR) cells to viable but slowly or non-replicating (VBNR), viable but non-culturable (VBNC), and dormant mycobacteria. The VBNR, VBNC, and dormant subpopulations are believed to underlie latent tuberculosis (LTB) in humans; however, it is unclear if a similar phenomenon could be happening in animals. This review discusses the evidence, challenges, and knowledge gaps regarding LTB in animals, and possible host–pathogen differences in the MTBC strains M. tuberculosis and M. bovis during infection. We further consider models that might be adapted from human TB research to investigate how the different phenotypic states of bacteria could influence TB stages in animals. In addition, we explore potential host biomarkers and mycobacterial changes in the DosR regulon, transcriptional sigma factors, and resuscitation-promoting factors that may influence the development of LTB.