Clinical Features of Mycobacterium canettii Infection: A Retrospective Study of 20 Cases Among French Soldiers and Relatives

Abstract

Background Mycobacterium canettii forms part of the Mycobacterium tuberculosis complex. Mycobacterium canettii infections are mainly described in the Horn of Africa. The permanent presence of French soldiers in Djibouti raises the question of the risk of being infected with M. canettii. Here, we describe M. canettii infections among French military and their families between 1998 and 2015. Methods This retrospective study relied on 3 sources of data: the reference center for mycobacteria in the Biology Department at Percy Military Hospital in Paris, the French Military Center for Epidemiology and Public Health, and the scientific literature. After an exhaustive census of the strains, we studied the epidemiological data on 20 cases among French soldiers and their families. Results Twenty cases of M. canettii infections are reported, including 5 unpublished cases. Adenitis predominates (n = 15), especially in the cervico facial area and among children; 1 case was observed 1 month after dental care in Djibouti. The pulmonary forms were less frequent (n = 6), and 3 atypical forms are described. All patients had stayed in Djibouti. Conclusions Cases of M. canettii infection among the French military consisted mainly of adenitis; disseminated forms were possible with immunodeficiency. Their evolution under specific treatments was comparable to that of tuberculosis. The presumed origin of the infection seemed to be environmental, possibly a water reservoir, and not due to human-to-human contagion.

Ancient and recent differences in the intrinsic susceptibility of Mycobacterium tuberculosis complex to pretomanid

“…However, given that Group A appeared to be most susceptible and Group D (M. canettii) is exceptionally rare globally, neither group were our focus. 36 Feuerriegel et al 16 had previously reported that M. canettii is less susceptible to pretomanid. Here, we tested a total of 21 M. canettii strains across two laboratories and consistently obtained MICs of 2-4 mg/L.…”

“…The provisional CC of 1 mg/L set by EMA is too high for Groups A and B and too low for Groups C and D. 2 Fewer than 200 cases of M. canettii infection (Group D) have been described to date, mostly from patients with links to the Horn of Africa. 36 Consequently, it is unlikely that robust clinical evidence for pretomanid treatment in this group will ever become available. In contrast, L1 strains (Group C) are estimated to account for 28% of the global TB burden.…”

Underestimated Manipulative Roles of Mycobacterium tuberculosis Cell Envelope Glycolipids During Infection

“…In this regard, the role of the cell envelope lipids in the transition of environmental mycobacteria becoming highly transmissible, pathogenic and host-dependent is pointed out (102). The possibility that ancient M. tuberculosis complex strains such as M. canettii, mainly isolated in the horn of Africa (172,173), have evolved has been explored, that is, changing their metabolism and increasing their cell envelope hydrophobicity as they evolved to the modern M. tuberculosis complex strains, e.g., changing their cell envelope's outmost exposed lipid polarity and thus evolving into a more hydrophobic organism. This was achieved by stopping the production of polar lipids such as LOSs or PGLs (which currently are just described in a subset of M. tuberculosis complex modern strains, Beijing clinical isolates), reducing their polarity (e.g., by losing sugars or adding acyl chains in their cell envelope glycolipids, e.g., DAT, TAT, PAT, SLs, TDM, TMM), and increasing the presence of apolar lipids in their cell envelopes [e.g., dimycocerosates of the phthiocerol family (PDIMs)] (102).…”

Revised Interpretation of the Hain Lifescience GenoType MTBC To Differentiate Mycobacterium canettii and Members of the Mycobacterium tuberculosis Complex

“…Given the highly recombinogenic nature of M. canettii, it is not surprising that this species yields two different patterns (10,11). All representatives of this species, including the two strains that gave the new binding pattern experimentally and in silico, have been found to be resistant to pyrazinamide when tested with the Bactec MGIT 960 at 100 g/ml, the only critical concentration recognized by the Clinical and Laboratory Standards Institute and the World Health Organization (WHO) (9,(12)(13)(14)(15)(16)(17). Although it is unclear whether this phenotype is due to a single mechanism shared by all strains (e.g., rpsA T5A) or whether different mutations are responsible in different strains (e.g., panD M117T or a series of pncA mutations [Table S3]), we recommend that the package insert is updated to include this novel pattern as "M. canettii (intrinsically resistant to pyrazinamide)" (14, 18-20).…”