Pulmonary tuberculosis due to Mycobacterium microti: a study of six recent cases in France

Abstract

Human tuberculosis caused by Mycobacterium microti is rare, but its prevalence and clinical significance may have been underestimated. To the best of our knowledge, 21 cases have been reported in the literature in the last decade. We report six recent pulmonary cases caused by M. microti over a period of 5 years detected in French clinical mycobacteriology laboratories of the hospital network. Our data confirm the potential of M. microti to cause clinical illness in immunocompetent patients. M. microti grew slowly from specimens, delaying the final microbiological diagnosis. Therefore, patients with tuberculosis caused by M. microti could benefit from the use of rapid diagnostic molecular techniques directly on clinical samples. From a review of the literature and this study, a classical antituberculous therapy seems effective in treating patients with M. microti disease.

Infection with Mycobacterium microti in Animals in France

“…However, Smith et al (15) recently showed that this species is more diverse than was expected, and they described 15 new spoligotype patterns for M. microti. Moreover, a number of spoligopatterns described in M. microti infection cases in humans have also been reported, although they were not submitted to the spoligotype database, confirming an even larger diversity for this mycobacterium (4,12).…”

“…The first case of M. microti infection described in France was identified by isolating this agent from a dog (9). Some years later, a study of six human cases of pulmonary TB due to M. microti was published (12). Recently, a case of feline cutaneous TB was described in Burgundy, eastern central France (18), but molecular characterization for this case was not performed.…”

“…However, an increasing number of cases have also been reported in domestic and wild mammals (2), such as cats (3,4), pigs (5), European wild boar (Sus scrofa) (6), ferrets (Mustela putorius), badgers (Meles meles) (4), New World camelids (Lama glama and Vicugna pacos) (4), squirrel monkeys (Saimiri sciureus) (7), meerkats (Suricata suricatta) (8), and a dog (9). Until now, 27 cases of M. microti infection in both immunocompetent (10) and immunocompromised human patients (11) have been described (12), demonstrating its capacity for causing clinical illness and thus for being a potential zoonotic agent.…”

Zoonotic diseases in South American camelids in England and Wales

“…[12] Mycobacterium microti infection is even more uncommon in humans and only 25 human cases have been reported worldwide in the published literature. [13][14][15] In SAC, clinical signs of TB may include weight loss, inappetence, exercise intolerance and an intermittent cough. In some animals there is a short period of illness terminating with respiratory signs.…”

Long-term survival of tuberculosis complex mycobacteria in soil

“…Humans are infected worldwide by sympatric M. tuberculosis sensu stricto families (Gagneux et al, 2006), whereas patients who are exposed in Africa may also be infected by Mycobacterium africanum (de Jong et al, 2010) and Mycobacterium canettii (Koeck et al, 2011;Van Soolingen et al, 1997). Zoonotic tuberculosis can be due to Mycobacterium caprae, Mycobacterium microti (Panteix et al, 2010) or the bovine tuberculosis agent Mycobacterium bovis (Thoen & LoBue, 2007). Conversely, captive mammals that are in close contact with humans, such as non-human primates and Asian elephants, can be infected by M. tuberculosis (Ghodbane & Drancourt, 2013).…”