Mycobacterium canettii

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Michel Drancourt - One of the best experts on this subject based on the ideXlab platform.

  • Culturomics Discloses Anti-Tubercular Enterococci Exclusive of Pulmonary Tuberculosis: A Preliminary Report.
    Microorganisms, 2020
    Co-Authors: Mustapha Fellag, Nina Gouba, Marielle Bedotto, Moussa Sakana, Dezemon Zingue, Zekiba Tarnagda, Matthieu Million, Michel Drancourt
    Abstract:

    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.

  • Translocation of Mycobacterium tuberculosis after experimental ingestion
    PLoS ONE, 2019
    Co-Authors: Mustapha Fellag, Feriel Bouzid, Fabienne Bregeon, Hubert Lepidi, Ahmed Loukil, Jamal Saad, Michel Drancourt
    Abstract:

    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 10 6 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.
    PloS one, 2019
    Co-Authors: Ahmed Loukil, Feriel Bouzid, Djaltou Aboubaker Osman, Michel Drancourt
    Abstract:

    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.

  • Extended spectrum of antibiotic susceptibility for tuberculosis, Djibouti
    International Journal of Antimicrobial Agents, 2018
    Co-Authors: Feriel Bouzid, Eric Garnotel, Djaltou Aboubaker Osman, Mohamed Osman Hassan, Emilie Javelle, Hélène Astier, Fabrice Simon, Michel Drancourt
    Abstract:

    In the Horn of Africa, there is a high prevalence of tuberculosis that is reported to be partly driven by multidrug-resistant (MDR) Mycobacterium tuberculosis strictu sensu strains. We conducted a prospective study to investigate M. tuberculosis complex species causing tuberculosis in Djibouti, and their in vitro susceptibility to standard anti-tuberculous antibiotics in addition to clofazimine, minocycline, chloramphenicol and sulfadiazine. Among the 118mycobacteria isolates from 118 successive patients with suspected pulmonary tuberculosis, 111 strains of M. tuberculosis, five Mycobacterium canettii, one `Mycobacterium simulans' and one Mycobacterium kansasii were identified. Drug-susceptibility tests performed on the first 78 isolates yielded nine MDR M. tuberculosis isolates. All isolates were fully susceptible to clofazimine, minocycline and chloramphenicol, and 75 of 78 isolates were susceptible to sulfadiazine. In the Horn of Africa, patients with confirmed pulmonary tuberculosis caused by an in vitro susceptible strain may benefit from anti-leprosy drugs, sulfamides and phenicol antibiotics. (c) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  • Ready experimental translocation of Mycobacterium canettii yields pulmonary tuberculosis
    Infection and immunity, 2017
    Co-Authors: Feriel Bouzid, F. Bregeon, Hubert Lepidi, Helen D. Donoghue, David E. Minnikin, Michel Drancourt
    Abstract:

    ABSTRACT Mycobacterium canettii, which has a smooth colony morphology, is the tuberculous organism retaining the most genetic traits from the putative last common ancestor of the rough-morphology Mycobacterium tuberculosis complex. To explore whether M. canettii can infect individuals by the oral route, mice were fed phosphate-buffered saline or 106M. canettii mycobacteria and sacrificed over a 28-day experiment. While no M. canettii was detected in negative controls, M. canettii-infected mice yielded granuloma-like lesions for 4/4 lungs at days 14 and 28 postinoculation (p.i.) and positive PCR detection of M. canettii for 5/8 mesenteric lymph nodes at days 1 and 3 p.i. and 5/6 pooled stools collected from day 1 to day 28 p.i. Smooth M. canettii colonies grew from 68% of lungs and 36% of spleens and cervical lymph nodes but fewer than 20% of axillary lymph nodes, livers, brown fat samples, kidneys, or blood samples throughout the 28-day experiment. Ready translocation in mice after digestive tract challenge demonstrates the potential of ingested M. canettii organisms to relocate to distant organs and lungs. The demonstration of this relocation supports the possibility that populations may be infected by environmental M. canettii.

Roland Brosch - One of the best experts on this subject based on the ideXlab platform.

  • From environmental bacteria to obligate pathogen: the study of adaptations enhancing the persistence of tuberculosis bacilli
    Tuberculosis, 2019
    Co-Authors: Aideen C. Allen, Roland Brosch, Wladimir Malaga, Céline Berrone, Flavie Moreau, Catherine Astarie-dequeker, Philip Supply, Ali Hassan, Christophe Guilhot
    Abstract:

    The highly contagious human pathogen Mycobacterium tuberculosis is responsible for an estimated 1.5 million deaths each year. A major feature of M. tuberculosis is its unique capacity to survive within the host for decades. In contrast, the evolutionary early-branching rare tubercle bacilli Mycobacterium canettii, which is thought to have originated from the same pool of ancestors as M. tuberculosis, rarely causes tuberculosis (TB) in humans and has a reduced capacity to persist and cause disease in the mouse model. Our objectives are to identify the genetic adaptations which allow persistence of TB bacilli within the host, and to characterise their functional consequences. Using an experimental evolution strategy, we have shown that recurrent in vivo passaging of a M. canettii strain (for more than 2 years) allows clones to emerge as “persistent mutants” that have a greater ability to survive in the host, and gain the characteristics of classical M. tuberculosis strains. Several “persistent mutants” were selected and the persistence phenotype was confirmed in several mouse genetic backgrounds. Next, these mutants were subjected to extensive phenotypic characterisation and were found to have enhanced resistance to stress encountered during infection, and increased virulence in human monocyte-derived macrophages. Currently, the mutations responsible for these phenotypes are being characterised. Comparing the genetic differences between the parental M. canettii strain, the “persistent” M. canettii clones and M. tuberculosis will help identify the molecular mechanisms driving evolution from putative generalist mycobacteria, towards professional human pathogen.

  • From environmental bacteria to obligate human pathogen: adaptations associated with the emergence of tuberculosis bacilli
    2019
    Co-Authors: Delphine Payros, Roland Brosch, Wladimir Malaga, Alexandre Pawlik, Serge Mazères, Céline Berrone, Flavie Moreau, Catherine Astarie-dequeker, Christophe Guilhot
    Abstract:

    The current hypothesis is that tuberculosis (TB) bacilli, Mycobacterium tuberculosis, have emerged from an environmental ancestor by adaptation of existing functions and acquisition of specific genes. The closest relations to this ancestor are the Mycobacterium canettii strains, which rarely cause TB and are unable to transmit in humans. Here, we aim to depict the molecular events that contributed to the emergence of a highly efficient human pathogen. Genomic sequence comparison of M. canettii and M. tuberculosis strains reveals polymorphisms in the genes phoPR, which encode a two component regulatory system required for virulence. RNA-Seq analyses showed that most genes controlled by the PhoPR regulon are underexpressed in M. canettii when compared with M. tuberculosis. Consistently, most M. canettii strains display reduced capacity to produce and secrete several major virulence factors controlled by PhoPR. Genetic transfer of the phoPR allele from M. tuberculosis to a M. canettii strain deficient for phoPR resulted in a higher capacity to infect human macrophages and mice, and to induce inflammatory responses. These results shed light on the transition from opportunistic to obligatory human pathogen, and indicate that this transition selected a highly active phoPR allele that confers an advantage for colonization of mammalian hosts.

  • Evolution of virulence in the Mycobacterium tuberculosis complex
    Current Opinion in Microbiology, 2018
    Co-Authors: Mickael Orgeur, Roland Brosch
    Abstract:

    Mycobacterium tuberculosis, the causative agent of human tuberculosis is one of the most widely spread human pathogens. It has succeeded to infect a quarter of the global human population by developing most sophisticated ways to circumvent innate and adaptive immune defences. This highly specialized, major human pathogen has evolved from a pool of ancestral environmental mycobacteria, whose extant representatives are known under the name of Mycobacterium canettii. Recent whole genome analyses in combination with different phenotypic screens have provided key insights into the evolution of M. tuberculosis and closely related members regrouped in the M. tuberculosis complex (MTBC). They have also elucidated novel virulence determinants that are essential for these obligate pathogens. In this review, we present the most recent evolutionary models of the MTBC and various factors that have contributed to the outstanding evolutionary success of the tuberculosis agent.

  • The Biology and Epidemiology of Mycobacterium canettii
    2017
    Co-Authors: Philip Supply, Roland Brosch
    Abstract:

    Genome-based insights into the evolution of Mycobacterium tuberculosis and other tuberculosis-causing mycobacteria are constantly increasing. In particular, the recent genomic and functional characterization of several Myocbacterium canettii strains, which are thought to resemble in many aspects the putative common ancestor of the members of the M. tuberculosis complex (MTBC), has consolidated a plausible scenario of the early evolution of tuberculosis-causing mycobacteria, in which the clonal MTBC, comprising numerous key pathogens of mammalian hosts, has evolved from a generalist Mycobacterium living in the environment. These studies also have considerably enriched our knowledge on selected molecular events that likely have contributed to the incursion, maintenance and spread of the MTBC members in diverse mammalian hosts. Here, we summarize and discuss recently revealed molecular and evolutionary aspects and emphasize the vast utility of M. canettii strains for identifying the mechanisms that contributed to the global emergence of M. tuberculosis as one of the most important human pathogens.

  • key experimental evidence of chromosomal dna transfer among selected tuberculosis causing mycobacteria
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Eva C. Boritsch, Alexandre Pawlik, Philip Supply, Christiane Bouchier, Varun Khanna, Nadine Honore, Victor H Navas, Torsten Seemann, Timothy P Stinear, Roland Brosch
    Abstract:

    Abstract Horizontal gene transfer (HGT) is a major driving force of bacterial diversification and evolution. For tuberculosis-causing mycobacteria, the impact of HGT in the emergence and distribution of dominant lineages remains a matter of debate. Here, by using fluorescence-assisted mating assays and whole genome sequencing, we present unique experimental evidence of chromosomal DNA transfer between tubercle bacilli of the early-branching Mycobacterium canettii clade. We found that the obtained recombinants had received multiple donor-derived DNA fragments in the size range of 100 bp to 118 kbp, fragments large enough to contain whole operons. Although the transfer frequency between M. canettii strains was low and no transfer could be observed among classical Mycobacterium tuberculosis complex (MTBC) strains, our study provides the proof of concept for genetic exchange in tubercle bacilli. This outstanding, now experimentally validated phenomenon presumably played a key role in the early evolution of the MTBC toward pathogenicity. Moreover, our findings also provide important information for the risk evaluation of potential transfer of drug resistance and fitness mutations among clinically relevant mycobacterial strains.

Feriel Bouzid - One of the best experts on this subject based on the ideXlab platform.

  • Translocation of Mycobacterium tuberculosis after experimental ingestion
    PLoS ONE, 2019
    Co-Authors: Mustapha Fellag, Feriel Bouzid, Fabienne Bregeon, Hubert Lepidi, Ahmed Loukil, Jamal Saad, Michel Drancourt
    Abstract:

    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 10 6 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.
    PloS one, 2019
    Co-Authors: Ahmed Loukil, Feriel Bouzid, Djaltou Aboubaker Osman, Michel Drancourt
    Abstract:

    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.

  • Extended spectrum of antibiotic susceptibility for tuberculosis, Djibouti
    International Journal of Antimicrobial Agents, 2018
    Co-Authors: Feriel Bouzid, Eric Garnotel, Djaltou Aboubaker Osman, Mohamed Osman Hassan, Emilie Javelle, Hélène Astier, Fabrice Simon, Michel Drancourt
    Abstract:

    In the Horn of Africa, there is a high prevalence of tuberculosis that is reported to be partly driven by multidrug-resistant (MDR) Mycobacterium tuberculosis strictu sensu strains. We conducted a prospective study to investigate M. tuberculosis complex species causing tuberculosis in Djibouti, and their in vitro susceptibility to standard anti-tuberculous antibiotics in addition to clofazimine, minocycline, chloramphenicol and sulfadiazine. Among the 118mycobacteria isolates from 118 successive patients with suspected pulmonary tuberculosis, 111 strains of M. tuberculosis, five Mycobacterium canettii, one `Mycobacterium simulans' and one Mycobacterium kansasii were identified. Drug-susceptibility tests performed on the first 78 isolates yielded nine MDR M. tuberculosis isolates. All isolates were fully susceptible to clofazimine, minocycline and chloramphenicol, and 75 of 78 isolates were susceptible to sulfadiazine. In the Horn of Africa, patients with confirmed pulmonary tuberculosis caused by an in vitro susceptible strain may benefit from anti-leprosy drugs, sulfamides and phenicol antibiotics. (c) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  • Ready experimental translocation of Mycobacterium canettii yields pulmonary tuberculosis
    Infection and immunity, 2017
    Co-Authors: Feriel Bouzid, F. Bregeon, Hubert Lepidi, Helen D. Donoghue, David E. Minnikin, Michel Drancourt
    Abstract:

    ABSTRACT Mycobacterium canettii, which has a smooth colony morphology, is the tuberculous organism retaining the most genetic traits from the putative last common ancestor of the rough-morphology Mycobacterium tuberculosis complex. To explore whether M. canettii can infect individuals by the oral route, mice were fed phosphate-buffered saline or 106M. canettii mycobacteria and sacrificed over a 28-day experiment. While no M. canettii was detected in negative controls, M. canettii-infected mice yielded granuloma-like lesions for 4/4 lungs at days 14 and 28 postinoculation (p.i.) and positive PCR detection of M. canettii for 5/8 mesenteric lymph nodes at days 1 and 3 p.i. and 5/6 pooled stools collected from day 1 to day 28 p.i. Smooth M. canettii colonies grew from 68% of lungs and 36% of spleens and cervical lymph nodes but fewer than 20% of axillary lymph nodes, livers, brown fat samples, kidneys, or blood samples throughout the 28-day experiment. Ready translocation in mice after digestive tract challenge demonstrates the potential of ingested M. canettii organisms to relocate to distant organs and lungs. The demonstration of this relocation supports the possibility that populations may be infected by environmental M. canettii.

  • Extended spectrum of antibiotic susceptibility for tuberculosis, Djibouti
    International journal of antimicrobial agents, 2017
    Co-Authors: Feriel Bouzid, Eric Garnotel, Djaltou Aboubaker Osman, Mohamed Osman Hassan, Emilie Javelle, Hélène Astier, Fabrice Simon, Michel Drancourt
    Abstract:

    In the Horn of Africa, there is a high prevalence of tuberculosis that is reported to be partly driven by multidrug-resistant (MDR) Mycobacterium tuberculosis strictu sensu strains. We conducted a prospective study to investigate M. tuberculosis complex species causing tuberculosis in Djibouti, and their in vitro susceptibility to standard anti-tuberculous antibiotics in addition to clofazimine, minocycline, chloramphenicol and sulfadiazine. Among the 118 mycobacteria isolates from 118 successive patients with suspected pulmonary tuberculosis, 111 strains of M. tuberculosis, five Mycobacterium canettii, one 'Mycobacterium simulans' and one Mycobacterium kansasii were identified. Drug-susceptibility tests performed on the first 78 isolates yielded nine MDR M. tuberculosis isolates. All isolates were fully susceptible to clofazimine, minocycline and chloramphenicol, and 75 of 78 isolates were susceptible to sulfadiazine. In the Horn of Africa, patients with confirmed pulmonary tuberculosis caused by an in vitro susceptible strain may benefit from anti-leprosy drugs, sulfamides and phenicol antibiotics.

Nalin Rastogi - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenomic analysis of the species of the Mycobacterium tuberculosis complex demonstrates that Mycobacterium africanum, Mycobacterium bovis, Mycobacterium caprae, Mycobacterium microti and Mycobacterium pinnipedii are later heterotypic synonyms of
    International Journal of Systematic and Evolutionary Microbiology, 2018
    Co-Authors: Marco A. Riojas, Katya J. Mcgough, Cristin J. Rider-riojas, Nalin Rastogi, Manzour Hernando Hazbón
    Abstract:

    The species within the Mycobacterium tuberculosis Complex (MTBC) have undergone numerous taxonomic and nomenclatural changes, leaving the true structure of the MTBC in doubt. We used next-generation sequencing (NGS), digital DNA–DNA hybridization (dDDH), and average nucleotide identity (ANI) to investigate the relationship between these species. The type strains of Mycobacterium africanum , Mycobacterium bovis , Mycobacterium caprae , Mycobacterium microti and Mycobacterium pinnipedii were sequenced via NGS. Pairwise dDDH and ANI comparisons between these, previously sequenced MTBC type strain genomes (including ‘Mycobacterium canettii’, ‘Mycobacterium mungi’ and ‘Mycobacterium orygis’) and M. tuberculosis H37RvT were performed. Further, all available genome sequences in GenBank for species in or putatively in the MTBC were compared to H37RvT. Pairwise results indicated that all of the type strains of the species are extremely closely related to each other (dDDH: 91.2–99.2 %, ANI: 99.21–99.92 %), greatly exceeding the respective species delineation thresholds, thus indicating that they belong to the same species. Results from the GenBank genomes indicate that all the strains examined are within the circumscription of H37RvT (dDDH: 83.5–100 %). We, therefore, formally propose a union of the species of the MTBC as M. tuberculosis . M. africanum , M. bovis , M. caprae , M. microti and M. pinnipedii are reclassified as later heterotypic synonyms of M. tuberculosis . ‘M. canettii’, ‘M. mungi’, and ‘M. orygis’ are classified as strains of the species M. tuberculosis . We further recommend use of the infrasubspecific term ‘variant’ (‘var.’) and infrasubspecific designations that generally retain the historical nomenclature associated with the groups or otherwise convey such characteristics, e.g. M. tuberculosis var. bovis.

  • Simple and rapid method for detection of nitrate reductase activity of Mycobacterium tuberculosis and Mycobacterium canettii grown in the Bactec MGIT960 system.
    Journal of Microbiological Methods, 2010
    Co-Authors: Khye Seng Goh, Nalin Rastogi
    Abstract:

    Mycobacterium tuberculosis reduces nitrate very strongly as compared to Mycobacterium bovis and M. bovis BCG. Nitrate reductase, in conjunction with niacin accumulation, constitutes one of the major biochemical tests used in clinical microbiology laboratories to differentiate M. tuberculosis from other members of the M. tuberculosis complex, as well as nontuberculous Mycobacteria. Determination of nitrate reductase activity is currently performed using cultures grown on solid media with a slow detection time and the need for large quantities of bacilli, as otherwise the test is not reliable. Hereby, we propose a nitrate reduction test coupled to Bactec MGIT960 system as a simple, rapid and economic method with a total gain of time of about 3 to 4weeks over the conventional solid medium. In our study, almost all the M. tuberculosis and Mycobacterium canettii strains gave a strongly positive nitrate reductase result within 1day of positive detection by the MGIT960 system. In contrast, M. bovis, M. bovis BCG and M. africanum strains remained negative even after 14days of incubation. The possibility to detect nitrate reductase within 1 to 3days of a positive culture using MGIT960 opens new perspectives with the possibility of confirming M. tuberculosis - starting directly from pathological specimens.

  • Sequencing of the pncA Gene in Members of the Mycobacterium tuberculosis Complex Has Important Diagnostic Applications: Identification of a Species-Specific pncA Mutation in “Mycobacterium canettii” and the Reliable and Rapid Predictor of Pyrazinamid
    Journal of clinical microbiology, 2006
    Co-Authors: Akos Somoskovi, Nalin Rastogi, Jillian Dormandy, Khye Seng Goh, Linda M. Parsons, Michel Kaswa, Max Salfinger
    Abstract:

    Testing for susceptibility to pyrazinamide (PZA) and analysis of the pncA gene sequences of 423 Mycobacterium tuberculosis complex isolates have revealed a unique silent nucleotide substitution that enables the rapid identification of “M. canettii” (proposed name). Moreover, the lack of a defined mutation within the pncA gene strongly suggests that an alternative mechanism is responsible for PZA resistance. Our results indicate that DNA sequencing of the pncA gene has the potential to shorten the turnaround time and increase the accuracy of PZA susceptibility testing of the M. tuberculosis complex.

  • Study of the gyrB gene polymorphism as a tool to differentiate among Mycobacterium tuberculosis complex subspecies further underlines the older evolutionary age of 'Mycobacterium canettii'.
    Molecular and cellular probes, 2006
    Co-Authors: Khye Seng Goh, Michel Fabre, Richard C Huard, Solveig Schmid, Christophe Sola, Nalin Rastogi
    Abstract:

    The present investigation evaluated the PCR-restriction fragment length polymorphism (RFLP) analysis of hsp65 and gyrB targets for differentiation of the species within the Mycobacterium tuberculosis complex (MTC) both by including new restriction enzymes and previously unstudied species. The hsp65 restriction analysis using HhaI resulted in a characteristic 'Mycobacterium canettii' pattern. A study of the gyrB gene polymorphism using TaqIalpha and HinfI allowed the initial division of MTC into two major groups, one consisting of M. tuberculosis and 'M. canettii' as opposed to another single group with other species. Three different patterns were observed with RsaI, the first characteristic of Mycobacterium microti, the second with Mycobacterium bovis, M. bovis BCG and Mycobacterium caprae (M. caprae was easily separated from M. bovis, and M. bovis BCG by SacII digestion), and the third with M. tuberculosis, 'M. canettii', Mycobacterium africanum, Mycobacterium pinnipedii, and the dassie bacillus. Although further discrimination within the last group was not obtained using additional restriction enzymes, the HaeIII and RsaI digestions highlighted an important gyrB polymorphism among 'M. canettii' strains. A study of the single nucleotide polymorphisms (SNP) within the gyrB by sequence analysis not only confirmed the results of the restriction analysis, but showed further differences among 'M. canettii' isolates that were not picked up using the existing battery of restriction enzymes. As many as 11 different SNPs were identified in the collection of eight 'M. canettii' isolates studied. Considering that gyrB variability among MTC member species other than 'M. canettii' is as restricted as hsp65 variability among MTC, our data corroborate a recent proposition that the 'M. canettii' group is evolutionary much older than the other MTC members. In conclusion, gyrB PCR-RFLP is a simple and rapid low-cost method that combined with phenotypic characteristics, may be helpful to differentiate most of the subspecies within the MTC.

  • Molecular Evolutionary History of Tubercle Bacilli Assessed by Study of the Polymorphic Nucleotide within the Nitrate Reductase (narGHJI) Operon Promoter
    Journal of clinical microbiology, 2005
    Co-Authors: Khye Seng Goh, Nalin Rastogi, Richard C Huard, Mylène Berchel, Christophe Sola
    Abstract:

    A well-characterized collection of Mycobacterium tuberculosis complex (MTC) isolates, representing all known subspecies as well as some relevant genotypic families of M. tuberculosis, was analyzed for the newly discovered narGHJI −215 C-to-T promoter single-nucleotide polymorphism (SNP). This point mutation has been shown in earlier studies to be responsible for the differential nitrate reductase activity of M. tuberculosis versus M. bovis. As previously defined by the presence or the absence of the TbD1 genetic locus, the group included both the “modern” W-Beijing, Haarlem, and Central-Asian1 (CAS1) families as well as the “ancestral” East-African-Indian (EAI) clade. Interestingly, among “modern” M. tuberculosis isolates, those previously classified as Principal Genetic Group 1 (PGG1) organisms by katG463-gyrA95 polymorphism analysis did not present the two-banded narGHJI restriction fragment length polymorphism analysis of PCR products pattern common to the other PGG1 MTC members, including the “ancestral” M. tuberculosis isolates. Instead, they showed a one-banded pattern, aligning them with other evolutionarily recent M. tuberculosis isolates of the PGG2 and PGG3 groups, such as Haarlem, Latin-American and Mediterranean (LAM), and X families. The presence of a nitrate reductase producer phenotype in “Mycobacterium canettii” and some “ancestral” M. tuberculosis isolates, despite a two-band −215C genotype, argues in favor of an alternate mechanism to explain the differential nitrate reductase activity of certain PGG1 subspecies of the MTC. Overall, these findings may help to establish the precise evolutionary history of important genotype families such as W-Beijing and suggest that the −215T genotype may have contributed the virulence, spread, and evolutionary success of “modern” M. tuberculosis strains compared to the remaining MTC organisms.

Philip Supply - One of the best experts on this subject based on the ideXlab platform.

  • From environmental bacteria to obligate pathogen: the study of adaptations enhancing the persistence of tuberculosis bacilli
    Tuberculosis, 2019
    Co-Authors: Aideen C. Allen, Roland Brosch, Wladimir Malaga, Céline Berrone, Flavie Moreau, Catherine Astarie-dequeker, Philip Supply, Ali Hassan, Christophe Guilhot
    Abstract:

    The highly contagious human pathogen Mycobacterium tuberculosis is responsible for an estimated 1.5 million deaths each year. A major feature of M. tuberculosis is its unique capacity to survive within the host for decades. In contrast, the evolutionary early-branching rare tubercle bacilli Mycobacterium canettii, which is thought to have originated from the same pool of ancestors as M. tuberculosis, rarely causes tuberculosis (TB) in humans and has a reduced capacity to persist and cause disease in the mouse model. Our objectives are to identify the genetic adaptations which allow persistence of TB bacilli within the host, and to characterise their functional consequences. Using an experimental evolution strategy, we have shown that recurrent in vivo passaging of a M. canettii strain (for more than 2 years) allows clones to emerge as “persistent mutants” that have a greater ability to survive in the host, and gain the characteristics of classical M. tuberculosis strains. Several “persistent mutants” were selected and the persistence phenotype was confirmed in several mouse genetic backgrounds. Next, these mutants were subjected to extensive phenotypic characterisation and were found to have enhanced resistance to stress encountered during infection, and increased virulence in human monocyte-derived macrophages. Currently, the mutations responsible for these phenotypes are being characterised. Comparing the genetic differences between the parental M. canettii strain, the “persistent” M. canettii clones and M. tuberculosis will help identify the molecular mechanisms driving evolution from putative generalist mycobacteria, towards professional human pathogen.

  • The Biology and Epidemiology of Mycobacterium canettii
    2017
    Co-Authors: Philip Supply, Roland Brosch
    Abstract:

    Genome-based insights into the evolution of Mycobacterium tuberculosis and other tuberculosis-causing mycobacteria are constantly increasing. In particular, the recent genomic and functional characterization of several Myocbacterium canettii strains, which are thought to resemble in many aspects the putative common ancestor of the members of the M. tuberculosis complex (MTBC), has consolidated a plausible scenario of the early evolution of tuberculosis-causing mycobacteria, in which the clonal MTBC, comprising numerous key pathogens of mammalian hosts, has evolved from a generalist Mycobacterium living in the environment. These studies also have considerably enriched our knowledge on selected molecular events that likely have contributed to the incursion, maintenance and spread of the MTBC members in diverse mammalian hosts. Here, we summarize and discuss recently revealed molecular and evolutionary aspects and emphasize the vast utility of M. canettii strains for identifying the mechanisms that contributed to the global emergence of M. tuberculosis as one of the most important human pathogens.

  • key experimental evidence of chromosomal dna transfer among selected tuberculosis causing mycobacteria
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Eva C. Boritsch, Alexandre Pawlik, Philip Supply, Christiane Bouchier, Varun Khanna, Nadine Honore, Victor H Navas, Torsten Seemann, Timothy P Stinear, Roland Brosch
    Abstract:

    Abstract Horizontal gene transfer (HGT) is a major driving force of bacterial diversification and evolution. For tuberculosis-causing mycobacteria, the impact of HGT in the emergence and distribution of dominant lineages remains a matter of debate. Here, by using fluorescence-assisted mating assays and whole genome sequencing, we present unique experimental evidence of chromosomal DNA transfer between tubercle bacilli of the early-branching Mycobacterium canettii clade. We found that the obtained recombinants had received multiple donor-derived DNA fragments in the size range of 100 bp to 118 kbp, fragments large enough to contain whole operons. Although the transfer frequency between M. canettii strains was low and no transfer could be observed among classical Mycobacterium tuberculosis complex (MTBC) strains, our study provides the proof of concept for genetic exchange in tubercle bacilli. This outstanding, now experimentally validated phenomenon presumably played a key role in the early evolution of the MTBC toward pathogenicity. Moreover, our findings also provide important information for the risk evaluation of potential transfer of drug resistance and fitness mutations among clinically relevant mycobacterial strains.

  • A glimpse into the past and predictions for the future: the molecular evolution of the tuberculosis agent
    Molecular microbiology, 2014
    Co-Authors: Eva C. Boritsch, Philip Supply, Nadine Honore, Timothy P Stinear, Torsten Seeman, Roland Brosch
    Abstract:

    Recent advances in genomics and molecular biology are providing an excellent opportunity to get a glimpse into the past, to examine the present, and to predict the future evolution of pathogenic mycobacteria, and in particular that of Mycobacterium tuberculosis, the agent of human tuberculosis. The recent availability of genome sequences of several Mycobacterium canettii strains, representing evolutionary early-branching tubercle bacilli, has allowed the genomic and molecular features of the putative ancestor of the M. tuberculosis complex (MTBC) to be reconstituted. Analyses have identified extensive lateral gene transfer and recombination events in M. canettii and/or the MTBC, leading to suggestions of a past environmental reservoir where the ancestor(s) of the tubercle bacilli might have adapted to an intracellular lifestyle. The daily increases in M. tuberculosis genome data and the remaining urgent Public Health problem of tuberculosis make it more important than ever to try and understand the origins and the future evolution of the MTBC. Here we critically discuss a series of questions on gene-loss, acquisition, recombination, mutation and conservation that have recently arisen and which are key to better understand the outstanding evolutionary success of one of the most widespread and most deadly bacterial pathogens in the history of humankind.

  • Mycobacterial Pathogenomics and Evolution.
    Microbiology spectrum, 2014
    Co-Authors: Daria Bottai, Timothy P Stinear, Philip Supply, Roland Brosch
    Abstract:

    Most mycobacterial species are harmless saprophytes, often found in aquatic environments. A few species seem to have evolved from this pool of environmental mycobacteria into major human pathogens, such as Mycobacterium tuberculosis, the agent of tuberculosis, Mycobacterium leprae, the leprosy bacillus, and Mycobacterium ulcerans, the agent of Buruli ulcer. While the pathogenicity of M. ulcerans relates to the acquisition of a large plasmid encoding a polyketide-derived toxin, the molecular mechanisms by which M. leprae or M. tuberculosis have evolved to cause disease are complex and involve the interaction between the pathogen and the host. Here we focus on M. tuberculosis and closely related mycobacteria and discuss insights gained from recent genomic and functional studies. Comparison of M. tuberculosis genome data with sequences from nontuberculous mycobacteria, such as Mycobacterium marinum or Mycobacterium kansasii, provides a perception of the more distant evolution of M. tuberculosis, while the recently accomplished genome sequences of multiple tubercle bacilli with smooth colony morphology, named Mycobacterium canettii, have allowed the ancestral gene pool of tubercle bacilli to be estimated. The resulting findings are instrumental for our understanding of the pathogenomic evolution of tuberculosis-causing mycobacteria. Comparison of virulent and attenuated members of the M. tuberculosis complex has further contributed to identification of a specific secretion pathway, named ESX or Type VII secretion. The molecular machines involved are key elements for mycobacterial pathogenicity, strongly influencing the ability of M. tuberculosis to cope with the immune defense mounted by the host.

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