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Applied and Environmental Microbiology Jul 2016This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize...
UNLABELLED
This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize decontamination, spiked environmental samples were used to evaluate four decontamination solutions and supplemented media, after which the best decontamination solution and media were used for the actual analysis. The isolates obtained were identified on the basis of specific genetic sequences, including heat shock protein 65, IS2404, IS2606, rpoB, and the ketoreductase gene, as needed. Among the methods evaluated, decontamination with 1 M NaOH followed by 5% oxalic acid gave the highest rate of recovery of mycobacteria (50.0%) and the lowest rate of contamination (15.6%). The cultivation medium that supported the highest rate of recovery of mycobacteria was polymyxin B-amphotericin B-nalidixic acid-trimethoprim-azlocillin-supplemented medium (34.4%), followed by isoniazid-supplemented medium (28.1%). Among the 139 samples cultivated in the main analysis, 58 (41.7%) yielded mycobacterial growth, 70 (50.4%) had no growth, and 11 (7.9%) had all inoculated tubes contaminated. A total of 25 different mycobacterial species were identified. Fifteen species (60%) were slowly growing (e.g., Mycobacterium ulcerans, Mycobacterium avium, Mycobacterium mantenii, and Mycobacterium malmoense), and 10 (40%) were rapidly growing (e.g., Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium abscessus). The occurrence of mycobacterial species in the various environmental samples analyzed was as follows: soil, 16 species (43.2%); vegetation, 14 species (38.0%); water, 3 species (8.0%); moss, 2 species (5.4%); snail, 1 species (2.7%); fungi, 1 species (2.7%). This study is the first to report on the isolation of M. ulcerans and other medically relevant nontuberculous mycobacteria from different environmental sources in Ghana.
IMPORTANCE
Diseases caused by mycobacterial species other than those that cause tuberculosis and leprosy are increasing. Control is difficult because the current understanding of how the organisms are spread and where they live in the environment is limited, although this information is needed to design preventive measures. Growing these organisms from the environment is also difficult, because the culture medium becomes overgrown with other bacteria that also live in the environment, such as in soil and water. We aimed to improve the methods for growing these organisms from environmental sources, such as soil and water samples, for better understanding of important mycobacterial ecology.
Topics: Bacterial Proteins; Bacteriological Techniques; Buruli Ulcer; Culture Media; DNA Transposable Elements; Decontamination; Endemic Diseases; Environmental Microbiology; Ghana; Humans; Nontuberculous Mycobacteria; Specimen Handling
PubMed: 27208141
DOI: 10.1128/AEM.01002-16 -
Journal of Cystic Fibrosis : Official... Jan 2015
Topics: Cystic Fibrosis; Female; Humans; Male; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 25487786
DOI: 10.1016/j.jcf.2014.12.002 -
MBio Aug 2019Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens that colonize household water systems and cause chronic lung infections in susceptible patients....
Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens that colonize household water systems and cause chronic lung infections in susceptible patients. The ability of NTM to form surface-attached biofilms in the nonhost environment and corded aggregates is important to their ability to persist in both contexts. Underlying the development of these multicellular structures is the capacity of mycobacterial cells to adhere to one another. Unlike most other bacteria, NTM spontaneously and constitutively aggregate , hindering our ability to understand the transition between planktonic and aggregated cells. While culturing a model NTM, , in rich medium, we fortuitously discovered that planktonic cells accumulate after ∼3 days of growth. By providing selective pressure for bacteria that disperse earlier, we isolated a strain with two mutations in the oligopeptide permease operon (). A mutant lacking the operon (Δ) disperses earlier than wild type (WT) due to a defect in nutrient uptake. Experiments with WT revealed that growth as aggregates is favored when carbon is replete, but under conditions of low available carbon relative to available nitrogen, grows as planktonic cells. By adjusting carbon and nitrogen sources in defined medium, we tuned the cellular C/N ratio such that grows either as aggregates or as planktonic cells. C/N-mediated aggregation regulation is widespread among NTM with the possible exception of rough-colony isolates. Altogether, we show that NTM aggregation is a controlled process that is governed by the relative availability of carbon and nitrogen for metabolism. Free-living bacteria can assemble into multicellular structures called biofilms. Biofilms help bacteria tolerate multiple stresses, including antibiotics and the host immune system. Nontuberculous mycobacteria are a group of emerging opportunistic pathogens that utilize biofilms to adhere to household plumbing and showerheads and to avoid phagocytosis by host immune cells. Typically, bacteria regulate biofilm formation by controlling expression of adhesive structures to attach to surfaces and other bacterial cells. Mycobacteria harbor a unique cell wall built chiefly of long-chain mycolic acids that confers hydrophobicity and has been thought to cause constitutive aggregation in liquid media. Here we show that aggregation is instead a regulated process dictated by the balance of available carbon and nitrogen. Understanding that mycobacteria utilize metabolic cues to regulate the transition between planktonic and aggregated cells reveals an inroad to controlling biofilm formation through targeted therapeutics.
Topics: Bacterial Adhesion; Bacterial Proteins; Biofilms; Carbon; Culture Media; Membrane Transport Proteins; Mutation; Mycobacterium smegmatis; Nitrogen; Nontuberculous Mycobacteria; Operon
PubMed: 31409683
DOI: 10.1128/mBio.01715-19 -
Revue Scientifique Et Technique... Apr 2001The epidemiology and the natural distribution of Mycobacterium marinum, M. fortuitum, M. chelonae, M. porcinum, M. farcinogenes, M. smegmatis, M. scrofulaceum, M.... (Review)
Review
Mycobacterial infections in domestic and wild animals due to Mycobacterium marinum, M. fortuitum, M. chelonae, M. porcinum, M. farcinogenes, M. smegmatis, M. scrofulaceum, M. xenopi, M. kansasii, M. simiae and M. genavense.
The epidemiology and the natural distribution of Mycobacterium marinum, M. fortuitum, M. chelonae, M. porcinum, M. farcinogenes, M. smegmatis, M. scrofulaceum, M. xenopi, M. kansasii, M. simiae and M. genavense are described. In addition to the bacteriological, biochemical and genetic characteristics, the authors review the pathology of these species, including the natural and experimental diseases and the accompanying lesions, diagnosis, antibiotic sensitivities and treatment of animal infections caused by these mycobacteria.
Topics: Animals; Animals, Domestic; Animals, Wild; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 11288516
DOI: 10.20506/rst.20.1.1269 -
Japanese Journal of Infectious Diseases 2015Nontuberculous mycobacteria (NTM) are associated with a number of clinical diseases and only a few antitubercular agents are active against them. Oxazolidinones comprise... (Comparative Study)
Comparative Study
Nontuberculous mycobacteria (NTM) are associated with a number of clinical diseases and only a few antitubercular agents are active against them. Oxazolidinones comprise a novel class of antimicrobials that inhibit bacterial protein synthesis at the ribosome. Linezolid, the first oxazolidinone antibacterial agent approved for clinical use, has excellent activity against some NTM but is ineffective against others. Sy142 and sy144 are novel oxazolidinones with demonstrated activties against Mycobacterium tuberculosis and Staphylococcus aureus. In this work, we compared the susceptibilities of key NTM species to linezolid, sy142, and sy144. The organisms included 21 isolates of Mycobacterium abscessus, 31 of Mycobacterium avium, 11 of Mycobacterium chelonae, 24 of Mycobacterium fortuitum, 26 of Mycobacterium kansasii, and 17 of Mycobacterium intracellulare. For M. kansasii and M. fortuitum, linezolid showed excellent antimicrobial activity, and an equal MIC range was found in sy142 and sy144. For the species that linezolid was less active against, sy142 and sy144 showed greater antimicrobial activities or exhibited equal compared to linezolid. Particularly, for M. avium and M. intracellulare, the in vitro antimicrobial activity of sy142 was 4-fold higher than that of linezolid. These results demonstrate the potential of these compounds to treat NTM infections.
Topics: Anti-Bacterial Agents; Microbial Sensitivity Tests; Nontuberculous Mycobacteria; Oxazolidinones
PubMed: 25971324
DOI: 10.7883/yoken.JJID.2014.498 -
BMC Microbiology Mar 2019Nontuberculous mycobacteria (NTM) are ubiquitous in nature and recognized agents of opportunistic infection, which is often aggravated by their intrinsic resistance to...
BACKGROUND
Nontuberculous mycobacteria (NTM) are ubiquitous in nature and recognized agents of opportunistic infection, which is often aggravated by their intrinsic resistance to antimicrobials, poorly defined therapeutic strategies and by the lack of new drugs. However, evaluation of their prevalence in anthropogenic environments and the associated antimicrobial resistance profiles have been neglected. In this work, we sought to determine minimal inhibitory concentrations of 25 antimicrobials against 5 NTM isolates recovered from a tertiary-care hospital surfaces. Antimicrobial susceptibilities of 5 other Corynebacterineae isolated from the same hospital were also determined for their potential clinical relevance.
RESULTS
Our phylogenetic study with each of the NTM isolates confirm they belong to Mycobacterium obuense, Mycobacterium mucogenicum and Mycobacterium paragordonae species, the latter initially misidentified as strains of M. gordonae, a species frequently isolated from patients with NTM disease in Portugal. In contrast to other strains, the M. obuense and M. mucogenicum examined here were resistant to several of the CLSI-recommended drugs, suggestive of multidrug-resistant profiles. Surprisingly, M. obuense was susceptible to vancomycin. Their genomes were sequenced allowing detection of gene erm (erythromycin resistance methylase) in M. obuense, explaining its resistance to clarithromycin. Remarkably, and unlike other strains of the genus, the Corynebacterium isolates were highly resistant to penicillin, ciprofloxacin and linezolid.
CONCLUSIONS
This study highlights the importance of implementing effective measures to screen, accurately identify and control viable NTM and closely related bacteria in hospital settings. Our report on the occurrence of rare NTM species with antibiotic susceptibility profiles that are distinct from those of the corresponding Type strains, along with unexpected resistance mechanisms detected seem to suggest that resistance may be more common than previously thought and also a potential threat to frail and otherwise vulnerable inpatients.
Topics: Anti-Bacterial Agents; Corynebacterium; Cross Infection; Drug Resistance, Multiple, Bacterial; Equipment and Supplies, Hospital; Humans; Microbial Sensitivity Tests; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Patients' Rooms; Phylogeny; Portugal; Tertiary Care Centers
PubMed: 30890149
DOI: 10.1186/s12866-019-1428-4 -
BioMed Research International 2015Nontuberculous mycobacteria (NTM) are opportunistic pathogens that are widely distributed in the environment. There is a lack of data on species distribution of these... (Review)
Review
Nontuberculous mycobacteria (NTM) are opportunistic pathogens that are widely distributed in the environment. There is a lack of data on species distribution of these organisms from Iran. This study consists of a review of NTM articles published in Iran between the years 1992 and 2014. In this review, 20 articles and 14 case reports were identified. Among the 20 articles, 13 (65%) studies focused on NTM isolates from clinical specimens, 6 (30%) studies examined NTM isolates from environmental samples, and one (5%) article included both clinical and environmental isolates. M. fortuitum (229/997; 23%) was recorded as the most prevalent and rapid growing mycobacteria (RGM) species in both clinical (28%) and environmental (19%) isolated samples (P < 0.05). Among slow growing mycobacteria (SGM), M. simiae (103/494; 21%) demonstrated a higher frequency in clinical samples whereas in environmental samples it was M. flavescens (44/503; 9%). These data represent information from 14 provinces out of 31 provinces of Iran. No information is available in current published data on clinical or environmental NTM from the remaining 17 provinces in Iran. These results emphasize the potential importance of NTM as well as the underestimation of NTM frequency in Iran. NTM is an important clinical problem associated with significant morbidity and mortality in Iran. Continued research is needed from both clinical and environmental sources to help clinicians and researchers better understand and address NTM treatment and prevention.
Topics: Epidemiological Monitoring; Humans; Iran; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria
PubMed: 26180788
DOI: 10.1155/2015/254285 -
Frontiers in Public Health 2022The increasing worldwide incidence of nontuberculous mycobacterial lung disease (NTM-LD) and the similarity of its manifestations to those of tuberculosis (TB) pose huge... (Review)
Review
BACKGROUND
The increasing worldwide incidence of nontuberculous mycobacterial lung disease (NTM-LD) and the similarity of its manifestations to those of tuberculosis (TB) pose huge challenges in the diagnosis and treatment of NTM-LD, which is commonly misdiagnosed and mistreated as TB. Proper diagnosis and treatment at an early stage can greatly improve patient outcomes.
CASE PRESENTATION
was identified by mNGS in lung tissue of case 1 and bronchioalveolar fluid from case 2 that was not identified using conventional microbiological methods. Multiple NTM species were detected in the blood mNGS samples from case 3 who had disseminated NTM infection. Although NTM was isolated from blood culture, conventional methods failed to identify the organisms to the level of species. All three patients were suffering from and being treated for myelodysplastic syndrome, rheumatoid arthritis, systemic lupus erythematosus, or acute lymphoblastic leukemia, making them immunosuppressed and susceptible to NTM infections. Case 1 and Case 2 significantly improved after anti-NTM treatment, but case 3 succumbed to the infection due to her underlying medical illness despite aggressive treatment.
CONCLUSIONS
The cases in this study demonstrate the effectiveness of mNGS in facilitating and improving the clinical diagnosis of NTM infections. We propose combining mNGS with traditional diagnostic methods to identify pathogens at the early stages of the disease so that targeted treatment can be implemented.
Topics: Humans; Female; Nontuberculous Mycobacteria; High-Throughput Nucleotide Sequencing; Microbiological Techniques; Immunocompromised Host
PubMed: 36452947
DOI: 10.3389/fpubh.2022.972280 -
Antimicrobial Agents and Chemotherapy Feb 2016Multidrug therapy is a standard practice when treating infections by nontuberculous mycobacteria (NTM), but few treatment options exist. We conducted this study to...
Multidrug therapy is a standard practice when treating infections by nontuberculous mycobacteria (NTM), but few treatment options exist. We conducted this study to define the drug-drug interaction between clofazimine and both amikacin and clarithromycin and its contribution to NTM treatment. Mycobacterium abscessus and Mycobacterium avium type strains were used. Time-kill assays for clofazimine alone and combined with amikacin or clarithromycin were performed at concentrations of 0.25× to 2× MIC. Pharmacodynamic interactions were assessed by response surface model of Bliss independence (RSBI) and isobolographic analysis of Loewe additivity (ISLA), calculating the percentage of statistically significant Bliss interactions and interaction indices (I), respectively. Monte Carlo simulations with predicted human lung concentrations were used to calculate target attainment rates for combination and monotherapy regimens. Clofazimine alone was bacteriostatic for both NTM. Clofazimine-amikacin was synergistic against M. abscessus (I = 0.41; 95% confidence interval [CI], 0.29 to 0.55) and M. avium (I = 0.027; 95% CI, 0.007 to 0.048). Based on RSBI analysis, synergistic interactions of 28.4 to 29.0% and 23.2 to 56.7% were observed at 1× to 2× MIC and 0.25× to 2× MIC for M. abscessus and M. avium, respectively. Clofazimine-clarithromycin was also synergistic against M. abscessus (I = 0.53; 95% CI, 0.35 to 0.72) and M. avium (I = 0.16; 95% CI, 0.04 to 0.35), RSBI analysis showed 23.5% and 23.3 to 53.3% at 2× MIC and 0.25× to 0.5× MIC for M. abscessus and M. avium, respectively. Clofazimine prevented the regrowth observed with amikacin or clarithromycin alone. Target attainment rates of combination regimens were >60% higher than those of monotherapy regimens for M. abscessus and M. avium. The combination of clofazimine with amikacin or clarithromycin was synergistic in vitro. This suggests a potential role for clofazimine in treatment regimens that warrants further evaluation.
Topics: Amikacin; Anti-Bacterial Agents; Clarithromycin; Clofazimine; Drug Interactions; Drug Synergism; Drug Therapy, Combination; Microbial Sensitivity Tests; Monte Carlo Method; Mutation; Mycobacterium avium; Nontuberculous Mycobacteria
PubMed: 26643335
DOI: 10.1128/AAC.02615-15 -
Journal of Clinical Microbiology Jul 2014In the Netherlands, clinical isolation of nontuberculous mycobacteria (NTM) has increased over the past decade. Proper identification of isolates is important, as NTM... (Comparative Study)
Comparative Study
In the Netherlands, clinical isolation of nontuberculous mycobacteria (NTM) has increased over the past decade. Proper identification of isolates is important, as NTM species differ strongly in clinical relevance. Most of the currently applied identification methods cannot distinguish between all different Mycobacterium species and complexes within species. rpoB gene sequencing exhibits a promising level of discrimination among rapidly and slowly growing mycobacteria, including the Mycobacterium avium complex. In this study, we prospectively compared rpoB gene sequencing with our routine algorithm of reverse line blot identification combined with partial 16S rRNA gene sequencing of 455 NTM isolates. rpoB gene sequencing identified 403 isolates to species level as 45 different known species and identified 44 isolates to complex level, and eight isolates remained unidentifiable to species level. In contrast, our reference reverse line blot assay with adjunctive 16S rRNA gene sequencing identified 390 isolates to species level (30 distinct species) and identified 56 isolates to complex level, and nine isolates remained unidentified. The higher discriminatory power of rpoB gene sequencing results largely from the distinction of separate species within complexes and subspecies. Also, Mycobacterium gordonae, Mycobacterium kansasii, and Mycobacterium interjectum were separated into multiple groupings with relatively low sequence similarity (98 to 94%), suggesting that these are complexes of closely related species. We conclude that rpoB gene sequencing is a more discriminative identification technique than the combination of reverse line blot and 16S rRNA gene sequencing and could introduce a major improvement in clinical care of NTM disease and the research on the epidemiology and clinical relevance of NTM.
Topics: Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; DNA-Directed RNA Polymerases; Humans; Molecular Sequence Data; Mycobacterium Infections, Nontuberculous; Netherlands; Nontuberculous Mycobacteria; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 24808238
DOI: 10.1128/JCM.00233-14