Mycobacterium Canettii Research Articles

Comparison of Tuberculosis Cases in Military Personnel Versus Civilians: A Retrospective Descriptive Study.

Tuberculosis (TB) remains a leading cause of death from infectious diseases worldwide. Military personnel are particularly vulnerable to TB because of the factors like deployments to endemic regions and close-quarters living. This study aims to compare the characteristics and outcomes of symptomatic TB cases between military and civilian patients treated at 2 French military hospitals, with a specific focus on diagnostic delay. This retrospective observational study included patients over 18 years old with culture-confirmed symptomatic TB treated between 2008 and 2021. Military patients (Group A) were compared to civilian patients (Group B), matched by age and sex. Data collected included demographic details, diagnostic delay, clinical presentations, and treatment outcomes. Statistical analyses were performed using chi-squared tests and Mann-Whitney tests, with significance set at P < .05. A total of 17 military and 38 civilian patients were included in the study. The median diagnostic delay was shorter for military patients at 49 days, compared to 64 days for civilians, although this difference was not statistically significant (P = .42). In the military group, 59% had been deployed to TB endemic regions, with 35% showing symptoms during operational missions. Clinical presentations and microbiological findings were similar between the two groups. Notably, two military patients were infected with Mycobacterium canettii, likely linked to deployments in Djibouti, where this strain is endemic. The military population showed a significant burden of physical sequelae, with 25% experiencing lasting physical impairments post-treatment. Tuberculosis presentation and outcomes in military and civilian patients were generally comparable. Early diagnosis remains essential to minimize disease severity and operational impact, particularly in military settings.

Draft genome sequences of clinical Mycobacterium canettii strains in Canada.

Mycobacterium canettii is a rare pathogen causing tuberculosis in humans and presents a risk to public health. Here, we report the genome sequences of two M. canettii strains. The genomes will assist in creating sequence-based tools for M. canettii and serve as references for identification, surveillance, and epidemiological investigations.

Genomic and phenotypic characterization of Mycobacterium tuberculosis' closest-related non-tuberculous mycobacteria.

Four species of non-tuberculous mycobacteria (NTM) rated as biosafety level 1 or 2 (BSL-1/BSL-2) organisms and showing higher genomic similarity with Mycobacterium tuberculosis (Mtb) than previous comparator species Mycobacterium kansasii and Mycobacterium marinum were subjected to genomic and phenotypic characterization. These species named Mycobacterium decipiens, Mycobacterium lacus, Mycobacterium riyadhense, and Mycobacterium shinjukuense might represent "missing links" between low-virulent mycobacterial opportunists and the highly virulent obligate pathogen Mtb. We confirmed that M. decipiens is the closest NTM species to Mtb currently known and found that it has an optimal growth temperature of 32°C-35°C and not 37°C. M. decipiens showed resistance to rifampicin, isoniazid, and ethambutol, whereas M. lacus and M. riyadhense showed resistance to isoniazid and ethambutol. M. shinjukuense was sensitive to all three first-line TB drugs, and all four species were sensitive to bedaquiline, a third-generation anti-TB drug. Our results suggest these four NTM may be useful models for the identification and study of new anti-TB molecules, facilitated by their culture under non-BSL-3 conditions as compared to Mtb. M. riyadhense was the most virulent of the four species in cellular and mouse infection models. M. decipiens also multiplied in THP-1 cells at 35°C but was growth impaired at 37°C. Genomic comparisons showed that the espACD locus, essential for the secretion of ESX-1 proteins in Mtb, was present only in M. decipiens, which was able to secrete ESAT-6 and CFP-10, whereas secretion of these antigens varied in the other species, making the four species interesting examples for studying ESX-1 secretion mechanisms.IMPORTANCEIn this work, we investigated recently identified opportunistic mycobacterial pathogens that are genomically more closely related to Mycobacterium tuberculosis (Mtb) than previously used comparator species Mycobacterium kansasii and Mycobacterium marinum. We confirmed that Mycobacterium decipiens is the currently closest known species to the tubercle bacilli, represented by Mycobacterium canettii and Mtb strains. Surprisingly, the reference strain of Mycobacterium riyadhense (DSM 45176), which was purchased as a biosafety level 1 (BSL-1)-rated organism, was the most virulent of the four species in the tested cellular and mouse infection models, suggesting that a BSL-2 rating might be more appropriate for this strain than the current BSL-1 rating. Our work establishes the four NTM species as interesting study models to obtain new insights into the evolutionary mechanisms and phenotypic particularities of mycobacterial pathogens that likely have also impacted the evolution of the key pathogen Mtb.

The application of metagenomics, radiomics and machine learning for diagnosis of sepsis.

Sepsis poses a serious threat to individual life and health. Early and accessible diagnosis and targeted treatment are crucial. This study aims to explore the relationship between microbes, metabolic pathways, and blood test indicators in sepsis patients and develop a machine learning model for clinical diagnosis. Blood samples from sepsis patients were sequenced. α-diversity and β-diversity analyses were performed to compare the microbial diversity between the sepsis group and the normal group. Correlation analysis was conducted on microbes, metabolic pathways, and blood test indicators. In addition, a model was developed based on medical records and radiomic features using machine learning algorithms. The results of α-diversity and β-diversity analyses showed that the microbial diversity of sepsis group was significantly higher than that of normal group (p < 0.05). The top 10 microbial abundances in the sepsis and normal groups were Vitis vinifera, Mycobacterium canettii, Solanum pennellii, Ralstonia insidiosa, Ananas comosus, Moraxella osloensis, Escherichia coli, Staphylococcus hominis, Camelina sativa, and Cutibacterium acnes. The enriched metabolic pathways mainly included Protein families: genetic information processing, Translation, Protein families: signaling and cellular processes, and Unclassified: genetic information processing. The correlation analysis revealed a significant positive correlation (p < 0.05) between IL-6 and Membrane transport. Metabolism of other amino acids showed a significant positive correlation (p < 0.05) with Cutibacterium acnes, Ralstonia insidiosa, Moraxella osloensis, and Staphylococcus hominis. Ananas comosus showed a significant positive correlation (p < 0.05) with Poorly characterized and Unclassified: metabolism. Blood test-related indicators showed a significant negative correlation (p < 0.05) with microorganisms. Logistic regression (LR) was used as the optimal model in six machine learning models based on medical records and radiomic features. The nomogram, calibration curves, and AUC values demonstrated that LR performed best for prediction. This study provides insights into the relationship between microbes, metabolic pathways, and blood test indicators in sepsis. The developed machine learning model shows potential for aiding in clinical diagnosis. However, further research is needed to validate and improve the model.

Cold Cas: reevaluating the occurrence of CRISPR/Cas systems in Mycobacteriaceae.

Bacterial CRISPR/Cas systems target foreign genetic elements such as phages and regulate gene expression by some pathogens, even in the host. The system is a marker for evolutionary history and has been used for inferences in Mycobacterium tuberculosis for 30 years. However, knowledge about mycobacterial CRISPR/Cas systems remains limited. It is believed that Type III-A Cas systems are exclusive to Mycobacterium canettii and the M. tuberculosis complex (MTBC) of organisms and that very few of the >200 diverse species of non-tuberculous mycobacteria (NTM) possess any CRISPR/Cas system. This study sought unreported CRISPR/Cas loci across NTM to better understand mycobacterial evolution, particularly in species phylogenetically near the MTBC. An analysis of available mycobacterial genomes revealed that Cas systems are widespread across Mycobacteriaceae and that some species contain multiple types. The phylogeny of Cas loci shows scattered presence in many NTM, with variation even within species, suggesting gains/losses of these loci occur frequently. Cas Type III-A systems were identified in pathogenic Mycobacterium heckeshornense and the geological environmental isolate Mycobacterium SM1. In summary, mycobacterial CRISPR/Cas systems are numerous, Type III-A systems are unreliable as markers for MTBC evolution, and mycobacterial horizontal gene transfer appears to be a frequent source of genetic variation.

The Enterococcus secretome inhibits the growth of Mycobacterium tuberculosis complex mycobacteria.

Enterococcus mundtii , a commensal intestinal bacterium, was demonstrated to inhibit the growth of some Mycobacterium tuberculosis complex (MTC) species that cause tuberculosis in humans and mammals. To further explore this preliminary observation, we cross-investigated five E. mundtii strains and seven MTC strains representative of four MTC species using a standardized quantitative agar well diffusion assay. All five E. mundtii strains, calibrated at 10 MacFarland, inhibited the growth of all M. tuberculosis strains with various susceptibility profiles, but no inhibition was observed with lower inoculums. Further, eight E. mundtii freeze-dried cell-free culture supernatants (CFCS) inhibited the growth of M. tuberculosis , Mycobacterium africanum, Mycobacterium bovis and Mycobacterium canettii, the most susceptible MTC species (inhibition diameter 25±1 mm), proportionally to CFCS protein concentrations. The data reported here indicate that the E. mundtii secretome inhibited growth of all MTC species of medical interest, which broadens previously reported data. In the gut, the E. mundtii secretome may modulate the expression of tuberculosis, exhibiting an anti-tuberculosis effect, with some protective roles in human and animal health.

MYCOBACTERIUM CANETTII TUBERCULOSIS LYMPHADENOPATHY IN A 3-YEAR-OLD CHILD.

A 3-year-old male originating from Djibouti presented with a cervical mass evolving for 2 months. Tuberculous lymphadenopathy was suspected based on biopsy results, and he improved quickly on standard antituberculous quadritherapy. Subsequently some features of the mycobacterium that grew in culture were unusual. The isolate was eventually identified as Mycobacterium canettii, a peculiar species of the Mycobacterium tuberculosis complex.

The rate and role of pseudogenes of the Mycobacterium tuberculosis complex.

Whole-genome sequence analyses have significantly contributed to the understanding of virulence and evolution of the Mycobacterium tuberculosis complex (MTBC), the causative pathogens of tuberculosis. Most MTBC evolutionary studies are focused on single nucleotide polymorphisms and deletions, but rare studies have evaluated gene content, whereas none has comprehensively evaluated pseudogenes. Accordingly, we describe an extensive study focused on quantifying and predicting possible functions of MTBC and Mycobacterium canettii pseudogenes. Using NCBI's PGAP-detected pseudogenes, we analysed 25 837 pseudogenes from 158 MTBC and M. canetii strains and combined transcriptomics and proteomics of M. tuberculosis H37Rv to gain insights about pseudogenes' expression. Our results indicate significant variability concerning rate and conservancy of in silico predicted pseudogenes among different ecotypes and lineages of tuberculous mycobacteria and pseudogenization of important virulence factors and genes of the metabolism and antimicrobial resistance/tolerance. We show that in silico predicted pseudogenes contribute considerably to MTBC genetic diversity at the population level. Moreover, the transcription machinery of M. tuberculosis can fully transcribe most pseudogenes, indicating intact promoters and recent pseudogene evolutionary emergence. Proteomics of M. tuberculosis and close evaluation of mutational lesions driving pseudogenization suggest that few in silico predicted pseudogenes are likely capable of neofunctionalization, nonsense mutation reversal, or phase variation, contradicting the classical definition of pseudogenes. Such findings indicate that genome annotation should be accompanied by proteomics and protein function assays to improve its accuracy. While indels and insertion sequences are the main drivers of the observed mutational lesions in these species, population bottlenecks and genetic drift are likely the evolutionary processes acting on pseudogenes' emergence over time. Our findings unveil a new perspective on MTBC's evolution and genetic diversity.

Inhibition of the Niemann-Pick C1 protein is a conserved feature of multiple strains of pathogenic mycobacteria

Mycobacterium tuberculosis (Mtb) survives and replicates within host macrophages (MΦ) and subverts multiple antimicrobial defense mechanisms. Previously, we reported that lipids shed by pathogenic mycobacteria inhibit NPC1, the lysosomal membrane protein deficient in the lysosomal storage disorder Niemann-Pick disease type C (NPC). Inhibition of NPC1 leads to a drop in lysosomal calcium levels, blocking phagosome-lysosome fusion leading to mycobacterial survival. We speculated that the production of specific cell wall lipid(s) that inhibit NPC1 could have been a critical step in the evolution of pathogenicity. We therefore investigated whether lipid extracts from clinical Mtb strains from multiple Mtb lineages, Mtb complex (MTBC) members and non-tubercular mycobacteria (NTM) inhibit the NPC pathway. We report that inhibition of the NPC pathway was present in all clinical isolates from Mtb lineages 1, 2, 3 and 4, Mycobacterium bovis and the NTM, Mycobacterium abscessus and Mycobacterium avium. However, lipid extract from Mycobacterium canettii, which is considered to resemble the common ancestor of the MTBC did not inhibit the NPC1 pathway. We conclude that the evolution of NPC1 inhibitory mycobacterial cell wall lipids evolved early and post divergence from Mycobacterium canettii-related mycobacteria and that this activity contributes significantly to the promotion of disease.

The impact of frequently neglected model violations on bacterial recombination rate estimation: a case study in Mycobacterium canettii and Mycobacterium tuberculosis.

Mycobacterium canettii is a causative agent of tuberculosis in humans, along with the members of the Mycobacterium tuberculosis complex. Frequently used as an outgroup to the M. tuberculosis complex in phylogenetic analyses, M. canettii is thought to offer the best proxy for the progenitor species that gave rise to the complex. Here, we leverage whole-genome sequencing data and biologically relevant population genomic models to compare the evolutionary dynamics driving variation in the recombining M. canettii with that in the nonrecombining M. tuberculosis complex, and discuss differences in observed genomic diversity in the light of expected levels of Hill–Robertson interference. In doing so, we highlight the methodological challenges of estimating recombination rates through traditional population genetic approaches using sequences called from populations of microorganisms and evaluate the likely mis-inference that arises owing to a neglect of common model violations including purifying selection, background selection, progeny skew, and population size change. In addition, we compare performance when full within-host polymorphism data are utilized, versus the more common approach of basing analyses on within-host consensus sequences.

Emergence of persistent tubercle bacilli.

Experimental evolution of persistence during Mycobacterium canettii infections of mice sheds light on the origins of virulence in ancestral Mycobacterium tuberculosis.

Parallel in vivo experimental evolution reveals that increased stress resistance was key for the emergence of persistent tuberculosis bacilli

Pathogenomic evidence suggests that Mycobacterium tuberculosis (MTB) evolved from an environmental ancestor similar to Mycobacterium canettii, a rare human pathogen. Although the adaptations responsible for this transition are poorly characterized, the ability to persist in humans seems to be important. We set out to identify the adaptations contributing to the evolution of persistence in MTB. We performed an experimental evolution of eight M. canettii populations in mice; four populations were derived from the isolate STB-K (phylogenomically furthest from MTB) and four from STB-D (closest to MTB), which were monitored for 15 and 6 cycles, respectively. We selected M. canettii mutants with enhanced persistence in vivo compared with the parental strains, which were phenotypically closer to MTB. Genome sequencing of 140 mutants and complementation analysis revealed that mutations in two loci were responsible for enhanced persistence. Most of the tested mutants were more resistant than their parental strains to nitric oxide, an important effector of immunity. Modern MTB were similarly more resistant to nitric oxide than M. canettii. Our findings demonstrate phenotypic convergence during experimental evolution of M. canettii, which mirrors natural evolution of MTB. Furthermore, they indicate that the ability to withstand host-induced stresses was key for the emergence of persistent MTB.

Culturomics Discloses Anti-Tubercular Enterococci Exclusive of Pulmonary Tuberculosis: A Preliminary Report.

Mycobacterium tuberculosis causes pulmonary tuberculosis, a deadly infection of which the clinical expression and prognosis are not fully understood at the individual level, apart from genetic susceptibility traits. We investigated whether individual gut microbiota may correlate with pulmonary tuberculosis status. Culturomics investigations of gut microbiota in two pulmonary tuberculosis patients and two controls in Burkina Faso found 60 different bacterial species in patients and 97 in controls, including 45 in common. Further analysis of the results at the individual level indicated seven bacteria, including Enterococcus mundtii and Enterococcus casseliflavus, which were exclusively cultured in controls. Blind quantitative PCR-based exploration of faeces samples in two cohorts in Burkina Faso and in France confirmed a nonsignificant association of E. mundtii and E. casseliflavus with controls. Further in vitro explorations found four E. mundtii and E. casseliflavus strains inhibiting the growth of M. tuberculosis strains representative of four different lineages as well as Mycobacterium africanum, Mycobacterium canettii, and Mycobacterium bovis, in an inoculum-dependent manner. Heat-killed E. mundtii or E. casseliflavus were ineffective. These unprecedented observations of direct interactions between gut E. mundtii and E. casseliflavus with M. tuberculosis complex mycobacteria suggest that gut microbiota may modulate the expression of pulmonary tuberculosis.

Deep amplicon sequencing for culture-free prediction of susceptibility or resistance to 13 anti-tuberculous drugs.

Conventional molecular tests for detecting Mycobacterium tuberculosis complex (MTBC) drug resistance on clinical samples cover a limited set of mutations. Whole-genome sequencing (WGS) typically requires culture.Here, we evaluated the Deeplex Myc-TB targeted deep-sequencing assay for prediction of resistance to 13 anti-tuberculous drugs/drug classes, directly applicable on sputum.With MTBC DNA tests, the limit of detection was 100–1000 genome copies for fixed resistance mutations. Deeplex Myc-TB captured in silico 97.1–99.3% of resistance phenotypes correctly predicted by WGS from 3651 MTBC genomes. On 429 isolates, the assay predicted 92.2% of 2369 first- and second-line phenotypes, with a sensitivity of 95.3% and a specificity of 97.4%. 56 out of 69 (81.2%) residual discrepancies with phenotypic results involved pyrazinamide, ethambutol and ethionamide, and low-level rifampicin or isoniazid resistance mutations, all notoriously prone to phenotypic testing variability. Only two out of 91 (2.2%) resistance phenotypes undetected by Deeplex Myc-TB had known resistance-associated mutations by WGS analysis outside Deeplex Myc-TB targets. Phenotype predictions from Deeplex Myc-TB analysis directly on 109 sputa from a Djibouti survey matched those of MTBSeq/PhyResSE/Mykrobe, fed with WGS data from subsequent cultures, with a sensitivity of 93.5/98.5/93.1% and a specificity of 98.5/97.2/95.3%, respectively. Most residual discordances involved gene deletions/indels and 3–12% heteroresistant calls undetected by WGS analysis or natural pyrazinamide resistance of globally rare “Mycobacterium canettii” strains then unreported by Deeplex Myc-TB. On 1494 arduous sputa from a Democratic Republic of the Congo survey, 14 902 out of 19 422 (76.7%) possible susceptible or resistance phenotypes could be predicted culture-free.Deeplex Myc-TB may enable fast, tailored tuberculosis treatment.

Cell surface lipid composition and hydrophobicity governs tuberculosis evolution and pathogenicity

The evolution of tubercle bacilli correlates closely with changes in cell envelope surface lipid composition (Donoghue et al. Diversity 2017, 9:46; Jankute et al. Scientific Reports 2017, 7:1315). Smooth, hydrophilic “Mycobacterium canettii” is the first recognisable member of the Mycobacterium tuberculosis complex, but it has reduced pathogenicity and poor aerosol transmission. In contrast, rough M. tuberculosis is very hydrophobic and readily spread in aerosols. Starting from hydrophilic surface lipids in environmental Mycobacterium kansasii, intermediate “M. canettii” adds hydrophobic lipids but retains overall cell hydrophilicity. Eliminating hydrophilic lipooligosaccharides (LOSs) and phenolic glycolipids (PGLs) from “M. canettii” leads to M. tuberculosis with a refined selection of hydrophobic lipids, namely phthiocerol dimycocerosates (PDIMs), pentaacyl trehaloses (PATs) and sulfoglycolipids (SGLs). The relative hydrophobicity of M. tuberculosis is double that of representatives of M. kansasii and “M. canettii”. The above changes have implications both for the onset of tuberculosis and pinpointing evolutionary hosts. Tuberculosis has not been found in Homo sapiens during the Late Pleistocene, but megafauna are the most likely hosts; characteristic bone lesions have been validated by TB DNA amplification and lipid biomarkers in bison metacarpals up to 17,000 years old. Late Pleistocene enhanced TB hydrophobicity and aerosolisation may have produced megafaunal pandemics, with extinction of bison, mastodons and contemporary taxa. The oldest H. sapiens tuberculosis is from the “Fertile Crescent” back to 9-11ka BP at the start of the Holocene. Naïve humans arriving “Out of Africa” may have encountered newly virulent tubercle bacilli of megafaunal origin, recently refined through a distinct “bottleneck”.

An ancestral genomic locus in Mycobacterium tuberculosis clinical isolates from India hints the genetic link with Mycobacterium canettii.

Tuberculosis remains a worldwide public health emergency. To better understand M. tuberculosis and to identify genomic variations characteristic to the Indian clinical isolates by a low-cost method, a genomic subtractive hybridization between M. tuberculosis H37Rv and a clinical isolate from South India was performed. This revealed a novel 0.4-kb subtractive fragment which was used as a handle to pull out a 4.5-kb genomic region characteristic to the clinical isolate and was absent in H37Rv. On further studies, this 4.5-kb region was found to be present in 91% of the M. tuberculosis clinical isolates screened from Kerala, a state in South India. Interestingly, this novel region has 99% identity (with 100% query coverage) with genomic regions of M. canettii. The present study hypothesizes that this locus was present in the recent common environmental ancestor of mycobacteria, retained to the maximum extent in M. canettii and ancestral isolates of M. tuberculosis, and later deleted in other modern lineages of M. tuberculosis. Thus, this region may serve as one of the links between the pathogenic mycobacteria and the environmental species. We also propose that the Indian isolates of M. tuberculosis might be closely related to the putative progenitor M. prototuberculosis with respect to this locus. More studies on other genomic loci from different strains of M. tuberculosis are required to establish more links in this direction.

Translocation of Mycobacterium tuberculosis after experimental ingestion

Human tuberculosis is a life-threatening infection following the inhalation of Mycobacterium tuberculosis, while the closely related bacteria Mycobacterium bovis and Mycobacterium canettii are thought to be transmitted by ingestion. To explore whether M. tuberculosis could also infect individuals by ingestion, male BALBc mice were fed 2 x 106 CFUs of M. tuberculosis Beijing or phosphate-buffered saline as a negative control, over a 28-day experiment. While eight negative control mice remained disease-free, M. tuberculosis was identified in the lymph nodes and lungs of 8/14 mice and in the spleens of 4/14 mice by microscopy, PCR-based detection and culture. Whole-genome sequencing confirmed the identity of the inoculum and the tissue isolates. In these genetically identical mice, the dissemination of M. tuberculosis correlated with the results of the culture detection of four intestinal bacteria. These observations indicate that ingested M. tuberculosis mycobacteria can translocate, notably provoking lymphatic tuberculosis.

Decrypting the environmental sources of Mycobacterium canettii by high-throughput biochemical profiling.

Mycobacterium canettii is a smooth bacillus related to the Mycobacterium tuberculosis complex. It causes lymph nodes and pulmonary tuberculosis in patients living in countries of the Horn of Africa, including Djibouti. The environmental reservoirs of M. canettii are still unknown. We aimed to further decrypt these potential reservoirs by using an original approach of High-Throughput Carbon and Azote Substrate Profiling. The Biolog Phenotype profiling was performed on six clinical strains of M. canettii and one M. tuberculosis strain was used as a positive control. The experiments were duplicated and authenticated by negative controls. While M. tuberculosis metabolized 22/190 (11%) carbon substrates and 3/95 (3%) nitrogen substrates, 17/190 (8.9%) carbon substrates and three nitrogen substrates were metabolized by the six M. canettii strains forming the so-called corebiologome. A total at 16 carbon substrates and three nitrogen substrates were metabolized in common by M. tuberculosis and the six M. canettii strains. Moreover, at least one M. canettii strain metabolized 36/190 (19%) carbon substrates and 3/95 (3%) nitrogen substrates for a total of 39/285 (13%) substrates. Classifying these carbon and nitrogen substrates into ten potential environmental sources (plants, fruits and vegetables, bacteria, algae, fungi, nematodes, mollusks, mammals, insects and inanimate environment) significantly associated carbon and nitrogen substrates metabolized by at least one M. canettii strain with plants (p = 0.006). These results suggest that some plants endemic in the Horn of Africa may serve as ecological niches for M. canettii. Further ethnobotanical studies will indicate plant usages by local populations, then guiding field microbiological investigations in order to prove the definite environmental reservoirs of this opportunistic tuberculous pathogen.

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

Using 894 phylogenetically diverse genomes of the Mycobacterium tuberculosis complex (MTBC), we simulated in silico the ability of the Hain Lifescience GenoType MTBC assay to differentiate the causative agents of tuberculosis. Here, we propose a revised interpretation of this assay to reflect its strengths (e.g., it can distinguish some strains of Mycobacterium canettii and variants of Mycobacterium bovis that are not intrinsically resistant to pyrazinamide) and limitations (e.g., Mycobacterium orygis cannot be differentiated from Mycobacterium africanum).

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

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. 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. 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. 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.