1
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Jin W, Wang J, Yang X. Analysis of three cases with false positive PCR results of non tuberculosis mycobacterium. Respir Med Case Rep 2023; 47:101973. [PMID: 38260180 PMCID: PMC10801299 DOI: 10.1016/j.rmcr.2023.101973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024] Open
Abstract
Background Real-time fluorescent quantitative PCR (RT-PCR) can effectively distinguish between Mycobacterium tuberculosis (MTB) and Non-tuberculosis mycobacterium (NTM), but when there are overlapping sequences between other pathogens (such as Nocardia otidiscaviarum, Mycobacterium parantracellulare, Mycolicibacterium fluoranthenivorans) and NTM, abnormal amplification curves may appear. Case presentation The clinical manifestations of the three patients were fever and respiratory symptoms. Chest CT showed "multiple lung infections". The acid-fast bacilli were negative by microscopic examination. The results of RT-PCR detection of Mycobacterium tuberculosis DNA showed that they are all NTM, while the results of DNA microarray method showed that there were no non-Mycobacterium tuberculosis. Identified by MALDI-TOF mass spectrometry, they are Nocardia otidiscaviarum, Mycobacterium parantracellale, Mycolicibacterium fluoranthenivorans. We found that the sequences of the above three bacteria can be combined with the primers and probes used for NTM PCR detection, resulting in false positive. Conclusions In the RT-PCR detection of mycobacteria, if there's abnormal amplification, and the mycobacterial species cannot be identified, the amplified products sequencing or MALDI- TOF mass spectrometry identification will help avoid the omission of rare pathogens.
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Affiliation(s)
| | | | - Xin Yang
- The clinical Laboratory, Yantai Yuhuangding Hospital, 20 Yuhuangding East Road, Yantai 264000, Shandong, China
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2
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Nguyen MVH, Daley CL. Treatment of Mycobacterium avium Complex Pulmonary Disease: When Should I Treat and What Therapy Should I Start? Clin Chest Med 2023; 44:771-783. [PMID: 37890915 DOI: 10.1016/j.ccm.2023.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Abstract
Treatment of M avium pulmonary disease requires a three-drug, macrolide-based regimen that is administered for 12 months beyond culture conversion. The regimen can be administered 3 days a week in non-cavitary, nodular bronchiectatic disease but should be given daily when cavitary disease is present. For treatment refractory disease, amikacin liposome inhalation suspension is added to the regimen. Parenteral amikacin or streptomycin should be administered in the setting of extensive radiographic involvement or macrolide resistance. Recurrence of disease is common and often due to reinfection. Novel and repurposed agents are being evaluated in clinical trials.
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Affiliation(s)
- Minh-Vu H Nguyen
- Division of Mycobacterial and Respiratory Infections, National Jewish Health, Denver, CO 80206, USA
| | - Charles L Daley
- Division of Mycobacterial and Respiratory Infections, National Jewish Health, Denver, CO 80206, USA.
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3
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Han HS, Gunn-Moore D. First report of Mycobacteria avium complex ( Mycobacteria intracellulare) in a cat from Southeast Asia. JFMS Open Rep 2023; 9:20551169231194311. [PMID: 37810578 PMCID: PMC10559717 DOI: 10.1177/20551169231194311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023] Open
Abstract
Case summary A 3-year-old castrated male domestic shorthaired cat, with indoor-outdoor access, was presented for chronic, progressive multinodular to generalised subcutaneous nodules covering much of its body. Previous medical treatment with doxycycline had been unhelpful. Fine-needle aspiration of the nodules revealed intra- and extracellular multibacillary negative staining rods in pyogranulomatous inflammation. Bacterial culture and susceptibility studies isolated Mycobacterium intracellulare, with zimine as the drug of choice for treatment. Initial triple therapy with rifampicin, azithromycin and pradofloxacin was ineffective, and was changed to triple therapy with clofazimine, clarithromycin and doxycycline once drug susceptibility was known, which was given for 3 months, after which long-term therapy with clofazimine and clarithromycin was continued. Relevance and novel information Slow growing M intracellulare, a member of the Mycobacterium avium complex (MAC), has never been reported to cause disease in cats from Singapore and, by extension, Southeast Asia. The infection in this patient resulted in subcutaneous nodules, which started on the face, then spread to the feet and much of the rest of its body. This is in contrast to that commonly reported for infection with M avium, which is also a member of MAC, and may not only present with similar signs in cats, but also progress to systemic spread. Susceptibility studies suggest clofazimine as the drug of choice when treating this infection, and this case supports its use as empirical therapy for veterinarians treating this disease in this region while awaiting culture and sensitivity results.
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Affiliation(s)
- Hock Siew Han
- Veterinary Emergency and Specialty Hospital, Singapore
| | - Danièlle Gunn-Moore
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Edinburgh, Midlothian, UK
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Mizzi R, Plain KM, Whittington R, Timms VJ. Global Phylogeny of Mycobacterium avium and Identification of Mutation Hotspots During Niche Adaptation. Front Microbiol 2022; 13:892333. [PMID: 35602010 PMCID: PMC9121174 DOI: 10.3389/fmicb.2022.892333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/06/2022] [Indexed: 12/27/2022] Open
Abstract
Mycobacterium avium is separated into four subspecies: M. avium subspecies avium (MAA), M. avium subspecies silvaticum (MAS), M. avium subspecies hominissuis (MAH), and M. avium subspecies paratuberculosis (MAP). Understanding the mechanisms of host and tissue adaptation leading to their clinical significance is vital to reduce the economic, welfare, and public health concerns associated with diseases they may cause in humans and animals. Despite substantial phenotypic diversity, the subspecies nomenclature is controversial due to high genetic similarity. Consequently, a set of 1,230 M. avium genomes was used to generate a phylogeny, investigate SNP hotspots, and identify subspecies-specific genes. Phylogeny reiterated the findings from previous work and established that Mycobacterium avium is a species made up of one highly diverse subspecies, known as MAH, and at least two clonal pathogens, named MAA and MAP. Pan-genomes identified coding sequences unique to each subspecies, and in conjunction with a mapping approach, mutation hotspot regions were revealed compared to the reference genomes for MAA, MAH, and MAP. These subspecies-specific genes may serve as valuable biomarkers, providing a deeper understanding of genetic differences between M. avium subspecies and the virulence mechanisms of mycobacteria. Furthermore, SNP analysis demonstrated common regions between subspecies that have undergone extensive mutations during niche adaptation. The findings provide insights into host and tissue specificity of this genetically conserved but phenotypically diverse species, with the potential to provide new diagnostic targets and epidemiological and therapeutic advances.
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Affiliation(s)
- Rachel Mizzi
- Farm Animal Health, School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW, Australia
| | - Karren M Plain
- Farm Animal Health, School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW, Australia.,Microbiology and Parasitology Research, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | - Richard Whittington
- Farm Animal Health, School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW, Australia
| | - Verlaine J Timms
- Neilan Laboratory of Microbial and Molecular Diversity, College of Engineering, Science and Environment, The University of Newcastle, Newcastle, NSW, Australia
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5
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Tateishi Y, Ozeki Y, Nishiyama A, Miki M, Maekura R, Fukushima Y, Nakajima C, Suzuki Y, Matsumoto S. Comparative genomic analysis of Mycobacterium intracellulare: implications for clinical taxonomic classification in pulmonary Mycobacterium avium-intracellulare complex disease. BMC Microbiol 2021; 21:103. [PMID: 33823816 PMCID: PMC8025370 DOI: 10.1186/s12866-021-02163-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/18/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Mycobacterium intracellulare is a representative etiological agent of emerging pulmonary M. avium-intracellulare complex disease in the industrialized countries worldwide. The recent genome sequencing of clinical strains isolated from pulmonary M. avium-intracellulare complex disease has provided insight into the genomic characteristics of pathogenic mycobacteria, especially for M. avium; however, the genomic characteristics of M. intracellulare remain to be elucidated. RESULTS In this study, we performed comparative genomic analysis of 55 M. intracellulare and related strains such as M. paraintracellulare (MP), M. indicus pranii (MIP) and M. yonogonense. Based on the average nucleotide identity, the clinical M. intracellulare strains were phylogenetically grouped in two clusters: (1) the typical M. intracellulare (TMI) group, including ATCC13950 and virulent M.i.27 and M.i.198 that we previously reported, and (2) the MP-MIP group. The alignment of the genomic regions was mostly preserved between groups. Plasmids were identified between groups and subgroups, including a plasmid common among some strains of the M.i.27 subgroup. Several genomic regions including those encoding factors involved in lipid metabolism (e.g., fadE3, fadE33), transporters (e.g., mce3), and type VII secretion system (genes of ESX-2 system) were shown to be hypermutated in the clinical strains. M. intracellulare was shown to be pan-genomic at the species and subspecies levels. The mce genes were specific to particular subspecies, suggesting that these genes may be helpful in discriminating virulence phenotypes between subspecies. CONCLUSIONS Our data suggest that genomic diversity among M. intracellulare, M. paraintracellulare, M. indicus pranii and M. yonogonense remains at the subspecies or genovar levels and does not reach the species level. Genetic components such as mce genes revealed by the comparative genomic analysis could be the novel focus for further insight into the mechanism of human pathogenesis for M. intracellulare and related strains.
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Affiliation(s)
- Yoshitaka Tateishi
- Department of Bacteriology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
| | - Yuriko Ozeki
- Department of Bacteriology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Akihito Nishiyama
- Department of Bacteriology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Mari Miki
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Osaka, Japan
| | - Ryoji Maekura
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, Toyonaka, Osaka, Japan
- Graduate School of Health Care Sciences, Jikei Institute, Osaka, Japan
| | - Yukari Fukushima
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
| | - Chie Nakajima
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
- International Collaboration Unit, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Yasuhiko Suzuki
- Division of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
- International Collaboration Unit, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Sohkichi Matsumoto
- Department of Bacteriology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
- Laboratory of Tuberculosis, Institute of Tropical Disease, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya, Indonesia
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6
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Shin MK, Shin SJ. Genetic Involvement of Mycobacterium avium Complex in the Regulation and Manipulation of Innate Immune Functions of Host Cells. Int J Mol Sci 2021; 22:ijms22063011. [PMID: 33809463 PMCID: PMC8000623 DOI: 10.3390/ijms22063011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium avium complex (MAC), a collection of mycobacterial species representing nontuberculous mycobacteria, are characterized as ubiquitous and opportunistic pathogens. The incidence and prevalence of infectious diseases caused by MAC have been emerging globally due to complications in the treatment of MAC-pulmonary disease (PD) in humans and the lack of understating individual differences in genetic traits and pathogenesis of MAC species or subspecies. Despite genetically close one to another, mycobacteria species belonging to the MAC cause diseases to different host range along with a distinct spectrum of disease. In addition, unlike Mycobacterium tuberculosis, the underlying mechanisms for the pathogenesis of MAC infection from environmental sources of infection to their survival strategies within host cells have not been fully elucidated. In this review, we highlight unique genetic and genotypic differences in MAC species and the virulence factors conferring the ability to MAC for the tactics evading innate immune attacks of host cells based on the recent advances in genetic analysis by exemplifying M. avium subsp. hominissuis, a major representative pathogen causing MAC-PD in humans. Further understanding of the genetic link between host and MAC may contribute to enhance host anti-MAC immunity, but also provide novel therapeutic approaches targeting the pangenesis-associated genes of MAC.
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Affiliation(s)
- Min-Kyoung Shin
- Department of Microbiology and Convergence Medical Sciences, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju 52727, Korea;
| | - Sung Jae Shin
- Department of Microbiology and Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
- Correspondence: ; Tel.: +82-2-2228-1813
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7
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Differential Genotyping of Mycobacterium avium Complex and Its Implications in Clinical and Environmental Epidemiology. Microorganisms 2020; 8:microorganisms8010098. [PMID: 31936743 PMCID: PMC7022546 DOI: 10.3390/microorganisms8010098] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 11/16/2022] Open
Abstract
In recent decades, the incidence and prevalence of nontuberculous mycobacteria (NTM) have greatly increased, becoming a major worldwide public health problem. Among numerous NTM species, the Mycobacterium avium complex (MAC) is the most predominant species, causing disease in humans. MAC is recognized as a ubiquitous microorganism, with contaminated water and soil being established sources of infection. However, the reason for the recent increase in MAC-associated disease has not yet been fully elucidated. Furthermore, human MAC infections are associated with a variety of infection sources. To improve the determination of infection sources and epidemiology of MAC, feasible and reliable genotyping methods are required to allow for the characterization of the epidemiology and biology of MAC. In this review, we discuss genotyping methods, such as pulsed-field gel electrophoresis, a variable number of tandem repeats, mycobacterial interspersed repetitive-unit-variable number of tandem repeats, and repetitive element sequence-based PCR that have been applied to elucidate the association between the MAC genotypes and epidemiological dominance, clinical phenotypes, evolutionary process, and control measures of infection. Characterizing the association between infection sources and the epidemiology of MAC will allow for the development of novel preventive strategies for the effective control of MAC infection.
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8
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Tortoli E, Meehan CJ, Grottola A, Fregni Serpini G, Fabio A, Trovato A, Pecorari M, Cirillo DM. Genome-based taxonomic revision detects a number of synonymous taxa in the genus Mycobacterium. INFECTION GENETICS AND EVOLUTION 2019; 75:103983. [PMID: 31352146 DOI: 10.1016/j.meegid.2019.103983] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/21/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022]
Abstract
The aim of this study was to clarify the taxonomic status of named species within the genus Mycobacterium. The analysis of genomes belonging to 174 taxa (species or subspecies) of the genus Mycobacterium was conducted using both the Average Nucleotide Identity and the Genome to Genome Distance. A number of synonymous taxa were detected. The list of synonyms includes: two subspecies of M. chelonae (M. chelonae subsp. bovis and M. chelonae subsp. gwanakae), two subspecies of M. fortuitum (M. fortuitum subsp. fortuitum and M. fortuitum subsp. acetamidolyticum), four subspecies of M. avium (M. avium subsp. avium, M. avium subsp. silvaticum, M. avium subsp. paratuberculosis and "M. avium subsp. hominissuis"), two couples of subspecies of M. intracellulare (M. intracellulare subsp. intracellulare/M. intracellulare subsp. paraintracellulare and M. intracellulare subsp. chimaera/M. intracellulare subsp. yongonense), the species M. austroafricanum and M. vanbaalenii, the species M. senegalense and M. conceptionense, the species M. talmoniae and M. eburneum and the species M. marinum, M. ulcerans and M. pseudoshottsii. Furthermore one species were reclassified as subspecies of another mycobacterium: M. lepraemurium was reclassified as a subspecies of M. avium (M. avium subsp. lepraemurium). The updates to nomenclature are proposed basing on the priority of names according the Code of nomenclature of prokaryotes. For two species (M. bouchedurhonense and M. marseillense) the loss of standing in nomenclature is proposed because of unavailability of respective type strains in culture collections.
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Affiliation(s)
- Enrico Tortoli
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy.
| | - Conor J Meehan
- BCCM/ITM Mycobacterial Culture Collection, Department of Biomedical Science, Institute of Tropical Medicine, Antwerp, Belgium
| | - Antonella Grottola
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy
| | | | - Anna Fabio
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy
| | - Alberto Trovato
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Monica Pecorari
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy
| | - Daniela M Cirillo
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
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GenoType NTM-DR Performance Evaluation for Identification of Mycobacterium avium Complex and Mycobacterium abscessus and Determination of Clarithromycin and Amikacin Resistance. J Clin Microbiol 2019; 57:JCM.00516-19. [PMID: 31167842 DOI: 10.1128/jcm.00516-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/28/2019] [Indexed: 12/22/2022] Open
Abstract
We evaluated the GenoType NTM-DR (NTM-DR) line probe assay for identifying Mycobacterium avium complex (MAC) species and Mycobacterium abscessus subspecies and for determining clarithromycin and amikacin resistance. Thirty-eight reference strains and 145 clinical isolates (58 MAC and 87 M. abscessus isolates), including 54 clarithromycin- and/or amikacin-resistant strains, were involved. The performance of the NTM-DR assay in rapid identification was evaluated by comparison with results of multigene sequence-based typing, whereas performance in rapid detection of clarithromycin and amikacin resistance was evaluated by comparison with sequencing of the erm(41), rrl, and rrs genes and drug susceptibility testing (DST). The accuracies of MAC and M. abscessus (sub)species identification were 92.1% (35/38) and 100% (145/145) for the 38 reference strains and 145 clinical isolates, respectively. Three MAC strains other than M. intracellulare were found to cross-react with the M. intracellulare probe in the assay. Regarding clarithromycin resistance, NTM-DR detected rrl mutations in 52 isolates and yielded 99.3% (144/145) and 98.6% (143/145) concordant results with sequencing and DST, respectively. NTM-DR sensitivity and specificity in the detection of clarithromycin resistance were 96.3% (52/54) and 100% (91/91), respectively. The NTM-DR yielded accurate erm(41) genotype results for all 87 M. abscessus isolates. Regarding amikacin resistance, NTM-DR detected rrs mutations in five isolates and yielded 99.3% (144/145) and 97.9% (142/145) concordant results with sequencing and DST, respectively. Our results indicate that the NTM-DR assay is a straightforward and accurate approach for discriminating MAC and M. abscessus (sub)species and for detecting clarithromycin and amikacin resistance mutations and that it is a useful tool in the clinical setting.
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10
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Abstract
This minireview provides an update on recent taxonomic changes for the genus Mycobacterium with an emphasis on newly identified species isolated from humans or associated with human disease.
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11
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Kim BJ, Kim BR, Jeong J, Lim JH, Park SH, Lee SH, Kim CK, Kook YH, Kim BJ. A description of Mycobacterium chelonae subsp. gwanakae subsp. nov., a rapidly growing mycobacterium with a smooth colony phenotype due to glycopeptidolipids. Int J Syst Evol Microbiol 2018; 68:3772-3780. [PMID: 30311876 DOI: 10.1099/ijsem.0.003056] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Three rapidly growing mycobacterial strains, MOTTH4W, MOTT36WT and MOTT68W, were isolated from the sputa of three independent Korean patients co-infected with Mycobacterium yongonense Type II strains. The 16S rRNA gene sequences of all three strains were unique, which were closest to that of Mycobacterium chelonae subsp. bovis KCTC 39630T (99.9 % similarity). Multilocus sequence typing analysis targeting 10 housekeeping genes including hsp65 and rpoB revealed the distinct phylogenetic location of these strains, which were clustered with M. chelonae subsp. chelonae ATCC 35752T and M. chelonae subsp. bovis KCTC 39630T. Phylogenetic analysis based on whole genome sequences revealed a 95.89 % average nucleotide identity (ANI) value with M. chelonae subsp. chelonae, slightly higher than the 95.0 % ANI criterion for determining a novel species. In addition, phenotypic characteristics such as a smooth colony morphology and growth inhibition at 37 °C, distinct MALDI-TOF MS profiles of extracted total lipids due to surface glycopeptidolipids, and distinct drug susceptibility profiles further supported the taxonomic characterization of these strains as representing a novel subspecies of Mycobacterium chelonae. Mycobacterium chelonae subsp. gwanakae subsp. nov. is proposed and the type strain is MOTT36WT (=KCTC 29127T=JCM 32454T).
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Affiliation(s)
- Byoung-Jun Kim
- 1Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bo-Ram Kim
- 1Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Joseph Jeong
- 2Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Ji-Hun Lim
- 2Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Sang Hyuk Park
- 2Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Seung-Heon Lee
- 3Korean Institute of Tubercuosis, Chungbuk, Republic of Korea
| | - Chang Ki Kim
- 3Korean Institute of Tubercuosis, Chungbuk, Republic of Korea
| | - Yoon-Hoh Kook
- 1Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bum-Joon Kim
- 1Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
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12
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van Ingen J, Turenne CY, Tortoli E, Wallace RJ, Brown-Elliott BA. A definition of the Mycobacterium avium complex for taxonomical and clinical purposes, a review. Int J Syst Evol Microbiol 2018; 68:3666-3677. [PMID: 30231956 DOI: 10.1099/ijsem.0.003026] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nontuberculous mycobacteria, particularly the Mycobacterium avium complex (MAC) bacteria, are increasingly recognized as opportunistic pathogens of humans. As a result, studies on antibiotic treatment and taxonomy of the MAC are intensifying, but an updated definition of what constitutes the MAC, either for taxonomical studies or for clinical purposes, is lacking. On the basis of literature review and phylogenetic analyses, we propose to define the MAC as a grouping of slow-growing mycobacteria that show corresponding values in at least two of the following targets against either M. avium ATCC 25291T or Mycobacterium intracellulare ATCC 13950T: >99.4 % sequence identity for the full 16S rRNA gene, >98.7 % for the partial (5') 16S rRNA gene, >97.3 % for hsp65 and >94.4 % for rpoB region V. A >97.5 % value in concatenated analyses of >2500 bp that includes 16S rRNA, hsp65 and rpoB gene sequence data or ≥85 % average nucleotide identity to M. avium ATCC 25291T or M. intracellulare ATCC 13950T on basis of whole genome sequencing data is recommended. This molecular definition is based on the distances observed between the classical members of the MAC, M. avium and M. intracellulare. Applying this definition, the complex currently consists of 12 validly published species: Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera, Mycobacterium colombiense, Mycobacterium arosiense, Mycobacterium vulneris, Mycobacterium bouchedurhonense, Mycobacterium timonense, Mycobacterium marseillense, Mycobacterium yongonense, Mycobacterium paraintracellulare and Mycobacterium lepraemurium.
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Affiliation(s)
- Jakko van Ingen
- 1Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Enrico Tortoli
- 3Emerging Bacterial Pathogens Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Richard J Wallace
- 4Mycobacteria/Nocardia Laboratory, University of Texas Health Science Center at Tyler, Tyler, Texas, USA
| | - Barbara A Brown-Elliott
- 4Mycobacteria/Nocardia Laboratory, University of Texas Health Science Center at Tyler, Tyler, Texas, USA
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Nouioui I, Carro L, García-López M, Meier-Kolthoff JP, Woyke T, Kyrpides NC, Pukall R, Klenk HP, Goodfellow M, Göker M. Genome-Based Taxonomic Classification of the Phylum Actinobacteria. Front Microbiol 2018; 9:2007. [PMID: 30186281 PMCID: PMC6113628 DOI: 10.3389/fmicb.2018.02007] [Citation(s) in RCA: 405] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/09/2018] [Indexed: 11/29/2022] Open
Abstract
The application of phylogenetic taxonomic procedures led to improvements in the classification of bacteria assigned to the phylum Actinobacteria but even so there remains a need to further clarify relationships within a taxon that encompasses organisms of agricultural, biotechnological, clinical, and ecological importance. Classification of the morphologically diverse bacteria belonging to this large phylum based on a limited number of features has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees. Here, draft genome sequences of a large collection of actinobacterial type strains were used to infer phylogenetic trees from genome-scale data using principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families, and genera, as well as many species and a few subspecies were shown to be in need of revision leading to proposals for the recognition of 2 orders, 10 families, and 17 genera, as well as the transfer of over 100 species to other genera. In addition, emended descriptions are given for many species mainly involving the addition of data on genome size and DNA G+C content, the former can be considered to be a valuable taxonomic marker in actinobacterial systematics. Many of the incongruities detected when the results of the present study were compared with existing classifications had been recognized from 16S rRNA gene trees though whole-genome phylogenies proved to be much better resolved. The few significant incongruities found between 16S/23S rRNA and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences. Similarly good congruence was found between the discontinuous distribution of phenotypic properties and taxa delineated in the phylogenetic trees though diverse non-monophyletic taxa appeared to be based on the use of plesiomorphic character states as diagnostic features.
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Affiliation(s)
- Imen Nouioui
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lorena Carro
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Marina García-López
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jan P. Meier-Kolthoff
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Tanja Woyke
- Department of Energy, Joint Genome Institute, Walnut Creek, CA, United States
| | - Nikos C. Kyrpides
- Department of Energy, Joint Genome Institute, Walnut Creek, CA, United States
| | - Rüdiger Pukall
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Hans-Peter Klenk
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael Goodfellow
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Markus Göker
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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14
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Practice Guidelines for Clinical Microbiology Laboratories: Mycobacteria. Clin Microbiol Rev 2018; 31:31/2/e00038-17. [PMID: 29386234 DOI: 10.1128/cmr.00038-17] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacteria are the causative organisms for diseases such as tuberculosis (TB), leprosy, Buruli ulcer, and pulmonary nontuberculous mycobacterial disease, to name the most important ones. In 2015, globally, almost 10 million people developed TB, and almost half a million patients suffered from its multidrug-resistant form. In 2016, a total of 9,287 new TB cases were reported in the United States. In 2015, there were 174,608 new case of leprosy worldwide. India, Brazil, and Indonesia reported the most leprosy cases. In 2015, the World Health Organization reported 2,037 new cases of Buruli ulcer, with most cases being reported in Africa. Pulmonary nontuberculous mycobacterial disease is an emerging public health challenge. The U.S. National Institutes of Health reported an increase from 20 to 47 cases/100,000 persons (or 8.2% per year) of pulmonary nontuberculous mycobacterial disease among adults aged 65 years or older throughout the United States, with 181,037 national annual cases estimated in 2014. This review describes contemporary methods for the laboratory diagnosis of mycobacterial diseases. Furthermore, the review considers the ever-changing health care delivery system and stresses the laboratory's need to adjust and embrace molecular technologies to provide shorter turnaround times and a higher quality of care for the patients who we serve.
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15
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Nouioui I, Sangal V, Carro L, Teramoto K, Jando M, Montero-Calasanz MDC, Igual JM, Sutcliffe I, Goodfellow M, Klenk HP. Two novel species of rapidly growing mycobacteria: Mycobacterium lehmannii sp. nov. and Mycobacterium neumannii sp. nov. Int J Syst Evol Microbiol 2017; 67:4948-4955. [PMID: 29058645 DOI: 10.1099/ijsem.0.002350] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two rapidly growing mycobacteria with identical 16S rRNA gene sequences were the subject of a polyphasic taxonomic study. The strains formed a well-supported subclade in the mycobacterial 16S rRNA gene tree and were most closely associated with the type strain of Mycobacterium novocastrense. Single and multilocus sequence analyses based on hsp65, rpoB and 16S rRNA gene sequences showed that strains SN 1900T and SN 1904T are phylogenetically distinct but share several chemotaxonomic and phenotypic features that are are consistent with their classification in the genus Mycobacterium. The two strains were distinguished by their different fatty acid and mycolic acid profiles, and by a combination of phenotypic features. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values for strains SN 1900T and SN 1904T were 61.0 % and 94.7 %, respectively; in turn, the corresponding dDDH and ANI values with M. novocastrense DSM 44203T were 41.4 % and 42.8 % and 89.3 % and 89.5 %, respectively. These results show that strains SN1900T and SN 1904T form new centres of taxonomic variation within the genus Mycobacterium. Consequently, strains SN 1900T (40T=CECT 8763T=DSM 43219T) and SN 1904T (2409T=CECT 8766T=DSM 43532T) are considered to represent novel species, for which the names Mycobacteriumlehmannii sp. nov. and Mycobacteriumneumannii sp. nov. are proposed. A strain designated as 'Mycobacteriumacapulsensis' was shown to be a bona fide member of the putative novel species, M. lehmannii.
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Affiliation(s)
- Imen Nouioui
- School of Biology, Ridley Building 2, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Vartul Sangal
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Lorena Carro
- School of Biology, Ridley Building 2, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Kanae Teramoto
- Advanced and Fundamental Technology Center, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
| | - Marlen Jando
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | | | - José Mariano Igual
- Instituto de Recursos Naturales y Agrobiología de Salamanca, Consejo Superior de Investigaciones Científicas (IRNASA-CSIC), c/Cordel de Merinas 40-52, 37008 Salamanca, Spain
| | - Iain Sutcliffe
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Michael Goodfellow
- School of Biology, Ridley Building 2, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Hans-Peter Klenk
- School of Biology, Ridley Building 2, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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16
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Tortoli E, Fedrizzi T, Meehan CJ, Trovato A, Grottola A, Giacobazzi E, Serpini GF, Tagliazucchi S, Fabio A, Bettua C, Bertorelli R, Frascaro F, De Sanctis V, Pecorari M, Jousson O, Segata N, Cirillo DM. The new phylogeny of the genus Mycobacterium: The old and the news. INFECTION GENETICS AND EVOLUTION 2017; 56:19-25. [PMID: 29030295 DOI: 10.1016/j.meegid.2017.10.013] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Phylogenetic studies of bacteria have been based so far either on a single gene (usually the 16S rRNA) or on concatenated housekeeping genes. For what concerns the genus Mycobacterium these approaches support the separation of rapidly and slowly growing species and the clustering of most species in well-defined phylogenetic groups. The advent of high-throughput shotgun sequencing leads us to revise conventional taxonomy of mycobacteria on the light of genomic data. For this purpose we investigated 88 newly sequenced species in addition to 60 retrieved from GenBank and used the Average Nucleotide Identity pairwise scores to reconstruct phylogenetic relationships within this genus. RESULTS Our analysis confirmed the separation of slow and rapid growers and the intermediate position occupied by the M. terrae complex. Among the rapid growers, the species of the M. chelonae-abscessus complex belonged to the most ancestral cluster. Other major clades of rapid growers included the species related to M. fortuitum and M. smegmatis and a large grouping containing mostly environmental species rarely isolated from humans. The members of the M. terrae complex appeared as the most ancestral slow growers. Among slow growers two deep branches led to the clusters of species related to M. celatum and M. xenopi and to a large group harboring most of the species more frequently responsible of disease in humans, including the major pathogenic mycobacteria (M. tuberculosis, M. leprae, M. ulcerans). The species previously grouped in the M. simiae complex were allocated in a number of sub-clades; of them, only the one including the species M. simiae identified the real members of this complex. The other clades included also species previously not considered related to M. simiae. The ANI analysis, in most cases supported by Genome to Genome Distance and by Genomic Signature-Delta Difference, showed that a number of species with standing in literature were indeed synonymous. CONCLUSIONS Genomic data revealed to be much more informative in comparison with phenotype. We believe that the genomic revolution enabled by high-throughput shotgun sequencing should now be considered in order to revise the conservative approaches still informing taxonomic sciences.
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Affiliation(s)
- Enrico Tortoli
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy.
| | - Tarcisio Fedrizzi
- Centre for Integrative Biology, University of Trento, Trento, Italy.
| | - Conor J Meehan
- Mycobacteriology unit, Department of Biomedical Science, Institute of Tropical Medicine, Antwerp, Belgium.
| | - Alberto Trovato
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy.
| | - Antonella Grottola
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy.
| | | | | | - Sara Tagliazucchi
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy.
| | - Anna Fabio
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy.
| | - Clotilde Bettua
- Centre for Integrative Biology, University of Trento, Trento, Italy.
| | - Roberto Bertorelli
- NGS Facility, Laboratory of Biomolecular Sequence and Structure Analysis for Health, Centre for Integrative Biology, University of Trento, Italy.
| | - Francesca Frascaro
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy.
| | - Veronica De Sanctis
- NGS Facility, Laboratory of Biomolecular Sequence and Structure Analysis for Health, Centre for Integrative Biology, University of Trento, Italy.
| | - Monica Pecorari
- Microbiology and Virology Unit, University Hospital Polyclinic, Modena, Italy.
| | - Olivier Jousson
- Centre for Integrative Biology, University of Trento, Trento, Italy.
| | - Nicola Segata
- Centre for Integrative Biology, University of Trento, Trento, Italy.
| | - Daniela M Cirillo
- Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy.
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17
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Kim BJ, Kim GN, Kim BR, Jeon CO, Jeong J, Lee SH, Lim JH, Lee SH, Kim CK, Kook YH, Kim BJ. Description of Mycobacterium chelonae subsp. bovis subsp. nov., isolated from cattle (Bos taurus coreanae), emended description of Mycobacterium chelonae and creation of Mycobacterium chelonae subsp. chelonae subsp. nov. Int J Syst Evol Microbiol 2017; 67:3882-3887. [PMID: 28895525 DOI: 10.1099/ijsem.0.002217] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023] Open
Abstract
Three rapidly growing mycobacterial strains, QIA-37T, QIA-40 and QIA-41, were isolated from the lymph nodes of three separate Korean native cattle, Hanwoo (Bos taurus coreanae). These strains were previously shown to be phylogenetically distinct but closely related to Mycobacterium chelonae ATCC 35752T by taxonomic approaches targeting three genes (16S rRNA, hsp6 and rpoB) and were further characterized using a polyphasic approach in this study. The 16S rRNA gene sequences of all three strains showed 99.7 % sequence similarity with that of the M. chelonae type strain. A multilocus sequence typing analysis targeting 10 housekeeping genes, including hsp65 and rpoB, revealed a phylogenetic cluster of these strains with M. chelonae. DNA-DNA hybridization values of 78.2 % between QIA-37T and M. chelonae indicated that it belongs to M. chelonae but is a novel subspecies distinct from M. chelonae. Phylogenetic analysis based on whole-genome sequences revealed a 95.44±0.06 % average nucleotide identity (ANI) value with M. chelonae, slightly higher than the 95.0 % ANI criterion for determining a novel species. In addition, distinct phenotypic characteristics such as positive growth at 37 °C, at which temperature M. chelonae does not grow, further support the taxonomic status of these strains as representatives of a novel subspecies of M. chelonae. Therefore, we propose an emended description of Mycobacterium chelonae, and descriptions of M. chelonae subsp. chelonae subsp. nov. and M. chelonae subsp. bovis subsp. nov. are presented; strains ATCC 35752T(=CCUG 47445T=CIP 104535T=DSM 43804T=JCM 6388T=NCTC 946T) and QIA-37T (=KCTC 39630T=JCM 30986T) are the type strains of the two novel subspecies.
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Affiliation(s)
- Byoung-Jun Kim
- Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ga-Na Kim
- Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bo-Ram Kim
- Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Che Ok Jeon
- School of Biological Sciences, Chung-Ang University, Seoul, Republic of Korea
| | - Joseph Jeong
- Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Seon Ho Lee
- Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Ji-Hun Lim
- Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Seung-Heon Lee
- Korean Institute of Tubercuosis, Chungbuk, Republic of Korea
| | - Chang Ki Kim
- Korean Institute of Tubercuosis, Chungbuk, Republic of Korea
| | - Yoon-Hoh Kook
- Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bum-Joon Kim
- Department of Biomedical Sciences, Microbiology and Immunology, Cancer Research Institute, Institute of Endemic Diseases, and Liver Research Institute, Seoul National University Medical Research Center (SNUMRC), Seoul National University College of Medicine, Seoul, Republic of Korea
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18
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Janda JM. Taxonomic update on proposed nomenclature and classification changes for bacteria of medical importance, 2016. Diagn Microbiol Infect Dis 2017; 88:100-105. [PMID: 28238386 DOI: 10.1016/j.diagmicrobio.2017.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/06/2017] [Indexed: 12/22/2022]
Abstract
A key aspect of medical, public health, and diagnostic microbiology laboratories is the accurate identification and rapid reporting and communication to medical staff regarding patients with infectious agents of clinical importance. Microbial taxonomy in the age of molecular diagnostics and phylogenetics creates changes in taxonomy at a logarithmic rate further complicating this process. This update focuses on the description of new species and classification changes proposed in 2016.
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Affiliation(s)
- J Michael Janda
- Public Health Laboratory, Public Health Services Department, Kern County, Bakersfield, CA, 93306-3302.
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19
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Emergence of mmpT5 Variants during Bedaquiline Treatment of Mycobacterium intracellulare Lung Disease. J Clin Microbiol 2016; 55:574-584. [PMID: 27927925 DOI: 10.1128/jcm.02087-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/01/2016] [Indexed: 11/20/2022] Open
Abstract
Bedaquiline (BDQ), a diarylquinoline antibiotic that targets ATP synthase, is effective for the treatment of Mycobacterium tuberculosis infections that no longer respond to conventional drugs. While investigating the off-label use of BDQ as salvage therapy, seven of 13 patients with Mycobacterium intracellulare lung disease had an initial microbiological response and then relapsed. Whole-genome comparison of pretreatment and relapse isolates of M. intracellulare uncovered mutations in a previously uncharacterized locus, mmpT5 Preliminary analysis suggested similarities between mmpT5 and the mmpR5 locus, which is associated with low-level BDQ resistance in M. tuberculosis Both genes encode transcriptional regulators and are adjacent to orthologs of the mmpS5-mmpL5 drug efflux operon. However, MmpT5 belongs to the TetR superfamily, whereas MmpR5 is a MarR family protein. Targeted sequencing uncovered nonsynonymous mmpT5 mutations in isolates from all seven relapse cases, including two pretreatment isolates. In contrast, only two relapse patient isolates had nonsynonymous changes in ATP synthase subunit c (atpE), the primary target of BDQ. Susceptibility testing indicated that mmpT5 mutations are associated with modest 2- to 8-fold increases in MICs for BDQ and clofazimine, whereas one atpE mutant exhibited a 50-fold increase in MIC for BDQ. Bedaquiline shows potential for the treatment of M. intracellulare lung disease, but optimization of treatment regimens is required to prevent the emergence of mmpT5 variants and microbiological relapse.
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