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Canadian Respiratory Journal 2011
Topics: Humans; Lung Diseases; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 21369543
DOI: 10.1155/2011/235614 -
International Journal of Molecular... Jun 2020Over the last years, nontuberculous mycobacteria (NTM) have emerged as important human pathogens. Infections caused by NTM are often difficult to treat due to an... (Review)
Review
Over the last years, nontuberculous mycobacteria (NTM) have emerged as important human pathogens. Infections caused by NTM are often difficult to treat due to an intrinsic multidrug resistance for the presence of a lipid-rich outer membrane, thus encouraging an urgent need for the development of new drugs for the treatment of mycobacterial infections. Efflux pumps (EPs) are important elements that are involved in drug resistance by preventing intracellular accumulation of antibiotics. A promising strategy to decrease drug resistance is the inhibition of EP activity by EP inhibitors (EPIs), compounds that are able to increase the intracellular concentration of antimicrobials. Recently, attention has been focused on identifying EPIs in mycobacteria that could be used in combination with drugs. The aim of the present review is to provide an overview of the current knowledge on EPs and EPIs in NTM and also, the effect of potential EPIs as well as their combined use with antimycobacterial drugs in various NTM species are described.
Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Drug Synergism; Humans; Membrane Transport Proteins; Microbial Sensitivity Tests; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Small Molecule Libraries
PubMed: 32545436
DOI: 10.3390/ijms21124191 -
BMC Veterinary Research Jan 2021Mycobacterium avium complex (MAC) causes a chronic infectious in the birds known as avian mycobacteriosis. Almost all species of the birds are susceptible to MAC which...
BACKGROUND
Mycobacterium avium complex (MAC) causes a chronic infectious in the birds known as avian mycobacteriosis. Almost all species of the birds are susceptible to MAC which consists of two closely related species of mycobacteria, that is, M. avium and M. intracellulare. This study aimed to determine the occurrence of Mycobacterium avium subsp. avium (MAA) in chickens and captive birds in selected states of Peninsular Malaysia.
RESULTS
A 300 fecal samples were collected from village chickens (n = 100), layer chickens (n = 100) and captive birds (n = 100). Fecal samples were split into two aliquots for microbiological and molecular detection of MAA. Microbiology detection consisted of microscopy (Ziehl-Neelsen staining) and culture of samples decontaminated with 1% Cetylperidinium chloride and vancomycin, nalidixic acid and amphotericin B (VNA) antibiotic cocktail [vancomycin (VAN) 100 μg/ml, nalidixic acid (NAL) 100 μg/ml and amphotericin B (AMB) 50 μg/ml] onto Löwenstein-Jensen (L-J). Molecular detection (PCR-IS901) was performed to detect MAA DNA from the feces and PCR-16S rRNA and IS901 for identification of genus Mycobacterium and Mycobacterium avium sub species avium isolated onto L-J. All samples (296) were AFB negative smear. M. avium was isolated in 0.3% (1/296) samples by culture and detected in 2.5% (6/242) samples by PCR (IS901). Other mycobacteria were found in 1.7% (5/296) chickens. Of five isolates, two were identified as Mycobacterium terrae and M. engbaekii and remaining isolates were not sequenced. Birds positive for M. avium included White Pelican (n = 1) Black Hornbill (n = 1), Macaw (n = 2), Cockatoo (n = 2) and village chicken (n = 1).
CONCLUSION
It is concluded that chickens and birds were infected with M. avium in selected areas of Peninsular Malaysia. Although, PCR is rapid, reliable and cost effective method for detection of M. avium in a subclinical stage, the culture of the avian feces should still be used as a reference test for the diagnosis of avian tuberculosis.
Topics: Animals; Birds; Chickens; DNA, Bacterial; Feces; Malaysia; Mycobacterium; Nontuberculous Mycobacteria; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Tuberculosis, Avian
PubMed: 33413380
DOI: 10.1186/s12917-020-02695-8 -
Frontiers in Immunology 2021Autophagy is critically involved in host defense pathways through targeting and elimination of numerous pathogens autophagic machinery. Nontuberculous mycobacteria... (Review)
Review
Autophagy is critically involved in host defense pathways through targeting and elimination of numerous pathogens autophagic machinery. Nontuberculous mycobacteria (NTMs) are ubiquitous microbes, have become increasingly prevalent, and are emerging as clinically important strains due to drug-resistant issues. Compared to (Mtb), the causal pathogen for human tuberculosis, the roles of autophagy remain largely uncharacterized in the context of a variety of NTM infections. Compelling evidence suggests that host autophagy activation plays an essential role in the enhancement of antimicrobial immune responses and controlling pathological inflammation against various NTM infections. As similar to Mtb, it is believed that NTM bacteria evolve multiple strategies to manipulate and hijack host autophagy pathways. Despite this, we are just beginning to understand the molecular mechanisms underlying the crosstalk between pathogen and the host autophagy system in a battle with NTM bacteria. In this review, we will explore the function of autophagy, which is involved in shaping host-pathogen interaction and disease outcomes during NTM infections. These efforts will lead to the development of autophagy-based host-directed therapeutics against NTM infection.
Topics: Animals; Anti-Bacterial Agents; Autophagy; Biological Evolution; Drug Resistance, Bacterial; Host-Pathogen Interactions; Humans; Immunity, Innate; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 34552591
DOI: 10.3389/fimmu.2021.728742 -
Scientific Reports Aug 2019A 59-year-old tobacco smoker male with chronic bronchitis living in Taravao, French Polynesia, Pacific, presented with a two-year growing nodule in the middle lobe of...
A 59-year-old tobacco smoker male with chronic bronchitis living in Taravao, French Polynesia, Pacific, presented with a two-year growing nodule in the middle lobe of the right lung. A guided bronchoalveolar lavage inoculated onto Löwenstein-Jensen medium yielded colonies of a rapidly-growing non-chromogenic mycobacterium designed as isolate P7213. The isolate could not be identified using routine matrix-assisted laser desorption ionization-time of flight-mass spectrometry and phenotypic and probe-hybridization techniques and yielded 100% and 97% sequence similarity with the respective 16S rRNA and rpoB gene sequences of Mycobacterium virginiense in the Mycobacterium terrae complex. Electron microscopy showed a 1.15 µm long and 0.38 µm large bacillus which was in vitro susceptible to rifampicin, rifabutin, ethambutol, isoniazid, doxycycline and kanamycin. Its 4,511,948-bp draft genome exhibited a 67.6% G + C content with 4,153 coding-protein genes and 87 predicted RNA genes. Genome sequence-derived DNA-DNA hybridization, OrthoANI and pangenome analysis confirmed isolate P7213 was representative of a new species in the M. terrae complex. We named this species "Mycobacterium mephinesia".
Topics: Bronchoalveolar Lavage; Genome, Bacterial; Humans; Lung; Male; Middle Aged; Mycobacterium; Nontuberculous Mycobacteria; Polynesia; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 31371776
DOI: 10.1038/s41598-019-47674-8 -
Drug Discovery Today Aug 2018Incidence of pulmonary diseases caused by non-tuberculous mycobacteria (NTM), relatives of Mycobacterium tuberculosis, is increasing at an alarming rate, surpassing... (Review)
Review
Incidence of pulmonary diseases caused by non-tuberculous mycobacteria (NTM), relatives of Mycobacterium tuberculosis, is increasing at an alarming rate, surpassing tuberculosis in many countries. Current chemotherapies require long treatment times and the clinical outcomes are often disappointing. There is an urgent medical need to discover and develop new, more-efficacious anti-NTM drugs. In this review, we summarize the current status of NTM drug development, and highlight knowledge gaps and scientific obstacles in NTM drug discovery. We propose strategies to reduce biological uncertainties and to begin to populate a NTM drug pipeline with attractive leads and drug candidates.
Topics: Animals; Anti-Bacterial Agents; Drug Discovery; Drug Resistance, Bacterial; Humans; Molecular Structure; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Structure-Activity Relationship
PubMed: 29635026
DOI: 10.1016/j.drudis.2018.04.001 -
Journal of Clinical Microbiology May 2019This minireview provides an update on recent taxonomic changes for the genus with an emphasis on newly identified species isolated from humans or associated with human... (Review)
Review
This minireview provides an update on recent taxonomic changes for the genus with an emphasis on newly identified species isolated from humans or associated with human disease.
Topics: Humans; Mycobacterium; Mycobacterium Infections; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Phylogeny
PubMed: 30602442
DOI: 10.1128/JCM.01408-18 -
Journal of Applied Microbiology Nov 2006Ultraviolet (UV) irradiation for drinking water treatment was examined for inactivation and subsequent dark and photo-repair of Mycobacterium terrae.
AIM
Ultraviolet (UV) irradiation for drinking water treatment was examined for inactivation and subsequent dark and photo-repair of Mycobacterium terrae.
METHODS AND RESULTS
UV sources tested were low pressure (monochromatic, 254 nm) and medium pressure (polychromatic UV output) Hg lamps. UV exposure resulted in inactivation, and was followed by dark or photo-repair experiments. Inactivation and repair were quantified utilizing a molecular-based endonuclease sensitive site (ESS) assay and conventional colony forming unit (CFU) viability assay. Mycobacterium terrae was more resistant to UV disinfection compared to many other bacteria, with approximately 2-log reduction at a UV fluence of 10 mJ cm(-2) ; similar to UV inactivation of M. tuberculosis. There was no difference in inactivation between monochromatic or polychromatic UV lamps. Mycobacterium terrae did not undergo detectable dark repair. Photo-repair resulted in recovery from inactivation by approximately 0.5-log in less than 30 min for both UV lamp systems.
CONCLUSIONS
Mycobacterium terrae is able to photo-repair DNA damage within a short timeframe. The number of pyrimidine dimers induced by UV light were similar for Escherichia coli and M. terrae, however, this similarity did not hold true for viability results.
SIGNIFICANCE AND IMPACT OF THE STUDY
There is no practical difference between UV sources for disinfection or prevention of DNA repair for M. terrae. The capability of M. terrae to photo-repair UV damage fairly quickly is important for wastewater treatment applications where disinfected effluent is exposed to sunlight. Finally, molecular based assay results should be evaluated with respect to differences in the nucleic acid content of the test micro-organism.
Topics: Colony Count, Microbial; DNA Damage; DNA Repair; DNA, Bacterial; Disinfection; Dose-Response Relationship, Radiation; Nontuberculous Mycobacteria; Ultraviolet Rays; Water Microbiology
PubMed: 17040222
DOI: 10.1111/j.1365-2672.2006.03023.x -
Acta Medica Portuguesa Dec 1999The isolation of nontuberculous mycobacteria was considered for many years as a result of contamination or transient colonization. The role of these bacteria in human... (Review)
Review
The isolation of nontuberculous mycobacteria was considered for many years as a result of contamination or transient colonization. The role of these bacteria in human disease was recognized only after 1950. They were present almost exclusively in patients with underlying pulmonary pathology and were rare. The prevalence of disease caused by nontuberculous mycobacteria was dramatically increased with the AIDS epidemic. Disseminated infection with MAC and other atypical mycobacteria is nowadays a frequent complication of AIDS. The authors describe some epidemiological and clinical features of these nontuberculous mycobacteria emphasizing the role of MAC and make some considerations about the diagnosis, prophylaxis and treatment of these diseases. The authors end by presenting their own clinical experience.
Topics: Humans; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 10892440
DOI: No ID Found -
Clinical Microbiology Reviews Jan 2004Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are... (Review)
Review
Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are complex and likely much broader than currently recognized. Environmental mycobacteria preferentially survive chlorination in municipal water, using it as a vector to infect humans. Widespread chlorination of water has likely selected more resistant environmental mycobacteria species and potentially explains the shift from M. scrofulaceum to M. avium as a cause of cervical lymphadenitis in children. Thus, human activities have affected mycobacterial ecology. While the slow growth and hydrophobicity of environmental mycobacteria appear to be disadvantages, the unique cell wall architecture also grants high biocide and antibiotic resistance, while hydrophobicity facilitates nutrient acquisition, biofilm formation, and spread by aerosolization. The remarkable stress tolerance of environmental mycobacteria is the major reason they are human pathogens. Environmental mycobacteria invade protozoans, exhibiting parasitic and symbiotic relationships. The molecular mechanisms of mycobacterial intracellular pathogenesis in animals likely evolved from similar mechanisms facilitating survival in protozoans. In addition to outright infection, environmental mycobacteria may also play a role in chronic bowl diseases, allergies, immunity to other pulmonary infections, and the efficacy of bacillus Calmette-Guerin vaccination.
Topics: Animals; Environmental Microbiology; Eukaryota; Humans; Incidence; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Tuberculosis
PubMed: 14726457
DOI: 10.1128/CMR.17.1.98-106.2004