Mycobacterium Chelonae Abscessus Research Articles

Current significance of the Mycobacterium chelonae-abscessus group

Organisms of the Mycobacterium chelonae-abscessus group can be significant pathogens in humans. They produce a number of diseases including acute, invasive and chronic infections, which may be difficult to diagnose correctly. Identification among members of this group is complicated by differentiating at least eleven (11) known species and subspecies and complexity of identification methodologies. Treatment of their infections may be problematic due to their correct species identification, antibiotic resistance, their differential susceptibility to the limited number of drugs available, and scarcity of susceptibility testing.

Cyclophostin and Cyclipostins analogues, new promising molecules to treat mycobacterial-related diseases

The progression of mycobacterial diseases requires the development of new therapeutics. This study evaluated the efficacy and selectivity of a panel of Cyclophostin and Cyclipostins analogues (CyCs) against various bacteria and mycobacteria. The activity 26 CyCs was first assayed by the agar plate method. Compounds exhibiting 50–100% growth inhibition were then selected to determine their minimum inhibitory concentrations (MICs) by the resazurin microtiter assay (REMA). The best drug candidate was further tested against clinical mycobacterial isolates and bacteria responsible for nosocomial infections, including 6 Gram-negative bacteria, 5 Gram-positive bacteria, 29 rapid-growing mycobacteria belonging to the Mycobacterium chelonae–abscessus clade and 3 slow-growing mycobacteria (Mycobacterium marinum, Mycobacterium bovis BCG and Mycobacterium tuberculosis). Among the 26 CyCs tested, 10 were active and their inhibitory activity was exclusively restricted to mycobacteria. The best candidate (CyC17) was further tested against 26 clinical strains and showed high selectivity for mycobacteria, with MICs (<2–40 µg/mL) comparable with those of most classical antimicrobials used to treat M. abscessus infections. Together, these results support the fact that such CyCs represent a new family of potent and selective inhibitors against mycobacteria. This is of particular interest for future chemotherapeutic developments against mycobacterial-associated infections, especially against M. abscessus, the most drug-resistant mycobacterial species.

Prokaryotic Taxonomy Rules and Nomenclature Changes in the Mycobacterium Chelonae–Abscessus Group: Author Reply

Future MicrobiologyVol. 5, No. 10 Letter to the EditorFree AccessProkaryotic taxonomy rules and nomenclature changes in the Mycobacterium chelonae–abscessus group: author replySylvia Cardoso Leão, Rafael Silva Duarte & Erica ChimaraSylvia Cardoso Leão† Author for correspondenceDepartamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu 862 3° andar, São Paulo-SP, Brazil. Search for more papers by this authorEmail the corresponding author at sylvia.leao@unifesp.br, Rafael Silva DuarteInstituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BrazilSearch for more papers by this author & Erica ChimaraSetor de Micobactérias, Instituto Adolfo Lutz, São Paulo, SP, BrazilSearch for more papers by this authorPublished Online:12 Nov 2010https://doi.org/10.2217/fmb.10.121AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInReddit We thank Jorge Sampaio for his interest in our paper and appreciate his suggestions regarding the taxonomy of rapidly growing mycobacteria. His concern about the nomenclature of members of the Mycobacterium chelonae–abscessus group is justifiable. After an extensive phenotypic and genotypic characterization of members of the M. chelonae–abscessus group, Leao et al. proposed the union of M. abscessus, M. bolletii and M. massiliense and the recognition of two subspecies within M. abscessus: M. abscessus subsp. abscessus and M. abscessus subsp. massiliense [1]. The name ‘massiliense’ was chosen as it appeared first in the literature. A note has been submitted and is under evaluation in the International Journal of Systematic and Evolutionary Microbiology (ITSEM) to provide a complete and strict systematic description of M. abscessus and its subspecies in accordance with the Rules of the Bacteriological Code (1990 Revision) [2,3]. In this note, the name M. abscessus subsp. massiliense is corrected to M. abscessus subsp. bolletii because according to Rule 24b (2) the name M. bolletii has priority over the name M. massiliense; these taxa are heterotypic synonyms and, according to Rule 38, must be united under the name M. bolletii; and finally, according to Rule 50b, the name of the subspecies must be M. abscessus subsp. bolletii. However, we disagree with publishing an erratum because at the time our paper was published in Future Microbiology [4] the nomenclature of the proposed M. abscessus subspecies was not validated and there was only one reference available for citation, that of Leao et al. [1]. Moreover, a detailed description of the cited species and subspecies is required and a possible change in the nomenclature of these taxa in the future is still under consideration by the IJSEM.Financial & competing interests disclosureThe authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript.Bibliography1 Leao SC, Tortoli E, Viana-Niero C et al.: Characterization of mycobacteria from a major Brazilian outbreak suggests that revision of the taxonomic status of members of the Mycobacterium chelonae–M. abscessus group is needed. J. Clin. Microbiol.47(9),2691–2698 (2009).Crossref, Medline, CAS, Google Scholar2 De Vos P, Trüper HG: Judicial commission of the International Committee on Systematic Bacteriology. IXth International (IUMS) Congress of Bacteriology and Applied Microbiology. Minutes of the meetings, 14, 15 and 18 August 1999, Sydney, Australia. Int. J. Syst. Evol. Microbiol.50,2239–2244 (2000).Crossref, Google Scholar3 Lapage SP, Sneath PHA, Lessel EF, Skerman VBD, Seeliger HPR, Clark WA: International Code of Nomenclature of Bacteria (1990 Revision). American Society for Microbiology, Washington, DC, USA (1992).Google Scholar4 Leao SC, Viana-Niero C, Matsumoto CK et al.: Epidemic of surgical-site infections by a single clone of rapidly growing mycobacteria in Brazil. Future Microbiol.5(6),971–980 (2010).Link, Google ScholarFiguresReferencesRelatedDetails Vol. 5, No. 10 Follow us on social media for the latest updates Metrics History Published online 12 November 2010 Published in print October 2010 Information© Future Medicine LtdFinancial & competing interests disclosureThe authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript.PDF download

Clinical relevance of Mycobacterium chelonae–abscessus group isolation in 95 patients

To determine the clinical relevance of Mycobacterium chelonae-abscessus group isolation from clinical samples. We retrospectively reviewed medical files of all patients from whom these mycobacteria were isolated between January 1999 and January 2005 and re-identified the isolates by rpoB sequencing. We applied the American Thoracic Society (ATS) diagnostic criteria to establish clinical relevance. Ninety-five patients were traced (56 M. chelonae, 25 Mycobacterium abscessus, 8 Mycobacterium massiliense, 6 Mycobacterium bolletii). Most isolates were cultured from pulmonary samples in patients with pre-existing pulmonary disease. Among patients with pulmonary isolates, 27% (20/74) meets ATS criteria; M. abscessus is most relevant (50%; 9/18), followed by M. massiliense (29%; 2/7), M. bolletii (20%; 1/5) and M. chelonae (18%; 8/44). Extrapulmonary disease presented as disseminated skin disease, eye disease specific for M. chelonae and otomastoiditis for M. abscessus. Treatment, especially for pulmonary M. abscessus disease, yielded limited results. One-fourth of the patients with pulmonary M. chelonae-abscessus group isolates met the ATS criteria; this percentage differs by species. Species distribution and clinical relevance differ from other regions. M. abscessus isolation in cystic fibrosis patients warrants special attention. Current ATS criteria might be too lenient to diagnose M. chelonae-abscessus group disease.

RpoB gene sequence-based characterization of emerging non-tuberculous mycobacteria with descriptions of Mycobacterium bolletii sp. nov., Mycobacterium phocaicum sp. nov. and Mycobacterium aubagnense sp. nov.

Over the past 10 years, 16S rRNA gene sequencing has contributed to the establishment of more than 45 novel species of non-tuberculous mycobacteria and to the description of emerging mycobacterial infections. Cumulative experience has indicated that this molecular tool underestimates the diversity of this group and does not distinguish between all recognized mycobacterial taxa. In order to improve the recognition of emerging rapidly growing mycobacteria (RGM), rpoB gene sequencing has been developed. Our previous studies have shown that an RGM isolate is a member of a novel species if it exhibits >3 % sequence divergence in the rpoB gene from the type strains of established species. When applied to a collection of 59 clinical RGM isolates, rpoB gene sequencing revealed nine novel isolates (15.3 %) whereas only two isolates (3.4 %) were deemed to be novel by conventional 16S rRNA gene sequence analysis. A polyphasic approach, including biochemical tests, antimicrobial susceptibility analyses, hsp65, sodA and recA gene sequence analysis, DNA G+C content determination and cell-wall fatty acid composition analysis, supported the evidence that these nine isolates represent three novel species. Whereas Mycobacterium phocaicum sp. nov. (type strain N4T = CIP 108542T = CCUG 50185T) and Mycobacterium aubagnense sp. nov. (type strain U8T = CIP 108543T = CCUG 50186T; Mycobacterium mucogenicum group) were susceptible to most antibiotics, Mycobacterium bolletii sp. nov. (type strain BD(T) = CIP 108541T = CCUG 50184T; Mycobacterium chelonae-abscessus group) was resistant to the quinolones, tetracycline, macrolides and imipenem. Only M. bolletii was resistant to clarithromycin. These data illustrate that rpoB gene sequence-based identification is a powerful tool to characterize emerging RGM and mycobacterial infections and provides valuable help in differentiating RGM at both the intra- and interspecies level, thus contributing to a faster and more efficient diagnosis and epidemiological follow-up.

Rapid Species Identification Within the Mycobacterium chelonae-abscessus Group by High-Resolution Melting Analysis of hsp65 PCR Products

Rapid Species Identification Within the Mycobacterium chelonae-abscessus Group by High-Resolution Melting Analysis of hsp65 PCR Products

Dissection of phylogenetic relationships among 19 rapidly growing Mycobacterium species by 16S rRNA, hsp65, sodA, recA and rpoB gene sequencing

The current classification of non-pigmented and late-pigmenting rapidly growing mycobacteria (RGM) capable of producing disease in humans and animals consists primarily of three groups, the Mycobacterium fortuitum group, the Mycobacterium chelonae-abscessus group and the Mycobacterium smegmatis group. Since 1995, eight emerging species have been tentatively assigned to these groups on the basis of their phenotypic characters and 16S rRNA gene sequence, resulting in confusing taxonomy. In order to assess further taxonomic relationships among RGM, complete sequences of the 16S rRNA gene (1483-1489 bp), rpoB (3486-3495 bp) and recA (1041-1056 bp) and partial sequences of hsp65 (420 bp) and sodA (441 bp) were determined in 19 species of RGM. Phylogenetic trees based upon each gene sequence, those based on the combined dataset of the five gene sequences and one based on the combined dataset of the rpoB and recA gene sequences were then compared using the neighbour-joining, maximum-parsimony and maximum-likelihood methods after using the incongruence length difference test. Combined datasets of the five gene sequences comprising nearly 7000 bp and of the rpoB+recA gene sequences comprising nearly 4600 bp distinguished six phylogenetic groups, the M. chelonae-abscessus group, the Mycobacterium mucogenicum group, the M. fortuitum group, the Mycobacterium mageritense group, the Mycobacterium wolinskyi group and the M. smegmatis group, respectively comprising four, three, eight, one, one and two species. The two protein-encoding genes rpoB and recA improved meaningfully the bootstrap values at the nodes of the different groups. The species M. mucogenicum, M. mageritense and M. wolinskyi formed new groups separated from the M. chelonae-abscessus, M. fortuitum and M. smegmatis groups, respectively. The M. mucogenicum group was well delineated, in contrast to the M. mageritense and M. wolinskyi groups. For phylogenetic organizations derived from the hsp65 and sodA gene sequences, the bootstrap values at the nodes of a few clusters were <70 %. In contrast, phylogenetic organizations obtained from the 16S rRNA, rpoB and recA genes were globally similar to that inferred from combined datasets, indicating that the rpoB and recA genes appeared to be useful tools in addition to the 16S rRNA gene for the investigation of evolutionary relationships among RGM species. Moreover, rpoB gene sequence analysis yielded bootstrap values higher than those observed with recA and 16S rRNA genes. Also, molecular signatures in the rpoB and 16S rRNA genes of the M. mucogenicum group showed that it was a sister group of the M. chelonae-abscessus group. In this group, M. mucogenicum ATCC 49650(T) was clearly distinguished from M. mucogenicum ATCC 49649 with regard to analysis of the five gene sequences. This was in agreement with phenotypic and biochemical characteristics and suggested that these strains are representatives of two closely related, albeit distinct species.

Recurrent therapy resistant mastoiditis by Mycobacterium cheilonae abscessus, a nontuberculous mycobacterium

A rare case of recurrent mastoiditis is described with abscess formation caused by a nontuberculous mycobacterium (NTM) Mycobacterium chelonae abscessus. The exceptionally slow wound healing after repeated surgical debridement was striking. A literature study showed that in contrast with NTM infections of other parts of the body, infections of the middle ear were most commonly seen in immunocompetent children. If a case of chronic unilateral otitis media shows insufficient response to antibiotic therapy and surgical debridement, mycobacterial infection should be considered. The case described below illustrates the importance of histopathological and microbiological investigations.

Mycobactériose pulmonaire à Mycobacterium chelonae chez une enfant atteinte de mucoviscidose

Summary The role of rapidly growing mycobacteria (RGM) in pulmonary disease is unclear. We report one case of lung disease caused by RGM in a 6-year-old child with cystic fibrosis. Mycobacterium chelonae was identified and was susceptible only to kanamycin and clarithromycin. The child, who clinically improved with clarithromycin, received treatment for 12 months and negativity of cultures was obtained. Diagnosis of lung disease caused by RGM is based on microbiologic, histologic, radiographic and clinical criteria. The majority of cases are caused by Mycobacterium chelonae abscessus . This organism is uniformly resistant to standard antituberculosis drugs and many other antibiotics, but clarithromycin has excellent activity against it; clinical trials of this newer macrolide are ongoing to evaluate the role of this agent for treatment of M. chelonae abscessus lung disease.

Mycobacterium chelonae Infection among Patients Receiving High-Flux Dialysis in a Hemodialysis Clinic in California

Between July 1987 and January 1988, five patients dialyzed at a hemodialysis outpatient clinic developed systemic Mycobacterium chelonae abscessus (MCA) infections. Four of the five patients had arteriovenous graft infections, and two died during antimicrobial therapy. Case-patients were more likely than control-patients to have received high-flux dialysis during the 6 mo before their infection (100% vs. 30%, P = .009). MCA was cultured from the hose connected to a water spray device used for manual reprocessing of high-flux but not regular dialyzers. Renalin was the germicide used to manually disinfect dialyzers for reuse and was prepared at a concentration of 2.5%. Laboratory studies documented survival of MCA from two high-flux dialyzers that were reprocessed in a manner similar to that used in the clinic. Early diagnosis with complete rather than partial graft removal in combination with antimicrobial therapy is recommended for MCA graft infections. In addition, 2.5% Renalin did not appear to ensure complete killing of MCA in high-flux dialyzers that were manually reprocessed at this hemodialysis clinic.