Species Of Environmental Mycobacteria Research Articles

Environmental reservoirs of pathogenic mycobacteria across the Ethiopian biogeographical landscape.

The Mycobacterium genus comprises over one-hundred-and-fifty recognised species, the majority of which reside in the environment and many of which can be pathogenic to mammals. Some species of environmental mycobacteria may interfere with BCG vaccination efficacy and in tuberculin test interpretation. Examining biogeographic trends in the distribution of members of the mycobacteria across a number of physicochemical and spatial gradients in soil and water environments across Ethiopia using oligotyping identified differential distributions of pathogenic and significant species. The tuberculosis complex was identified in more than 90% of water samples and taxonomic groups implicated in lower BCG vaccine efficiency were core in both soil and water Mycobacterium communities. A reservoir of Mycobacterium bovis was identified in water, with up to 7.3×102 genome equivalents per ml. Elevation, temperature, habitat and vegetation type were important predictors of both soil and water Mycobacterium communities. These results represent the first step in understanding the potential risk of exposure to environmental mycobacteria that may undermine efforts to reduce disease incidence.

Clinical Significance of Environmental Mycobacteria Isolated From Respiratory Specimens of Patients With and Without Silicosis

ObjectiveTo describe the clinical, functional and radiographic differences of respiratory disease caused by environmental mycobacteria in patients with and without silicosis. MethodRetrospective, observational study in patients with nontuberculous mycobacteria isolated in the Hospital Meixoeiro (University Hospital of Vigo) microbiology laboratory between January 2007 and December 2013. Patients were grouped according to the presence or absence of silicosis and mycobacterial lung disease, using American Thoracic Society criteria. ResultsIn 156 cases, at least one species of environmental mycobacteria had been isolated from the respiratory culture. A total of 71% were identified in men, 40 (25.6%) of whom had silicosis. Sixty patients (38.5%) met American Thoracic Society microbiological criteria: 62.5% of the silicosis group and 30.2% of the non-silicosis group. The most common species were Mycobacterium avium complex, Mycobacterium genavense and Mycobacterium chelonae. American Thoracic Society criteria for environmental mycobacterial disease were met in 34 (22.7%) patients: 14 in the silicosis group and 20 in the non-silicosis group. Treatment was administered in 24 cases, with better bacteriological eradication levels in the non-silicosis group. ConclusionsIn our series, a history of silicosis was related with a higher incidence of environmental mycobacterial disease. The causative species in the majority of cases in our setting was Mycobacterium avium complex, followed by Mycobacterium genavense. Patients with silicosis showed lower cure rates after treatment.

Composición lipídica de la pared celular de tres especies de micobacterias ambientales y su posible correlación con la formación de biofilms y movilidad por sliding

Composición lipídica de la pared celular de tres especies de micobacterias ambientales y su posible correlación con la formación de biofilms y movilidad por sliding

Isolated Strains of Nontuberculous Mycobacterium Interfere with Immune Responses Associated with Mycobacterium Bovis BCG Vaccination

Prior exposure of a vaccine to certain species of environmental mycobacteria can prime the immune system against common mycobacterial antigens, which can in turn reduce the subsequent efficacy of live attenuated mycobacterial vaccines (such as Mycobacterium bovis BCG), in both human and livestock vaccination programs. In this study, five strains of nontubeculous mycobacterium, all isolated from lymphonodi mandibulares and lymphonodi mesenterici samples of swine and cattle, were investigated to determine their growth characteristics and effects on the immune system in murine models. Markedly, different effects on the immune system were observed. The different results may be linked to the inherent growth characteristics of the five strains, The implications of these findings for BCG vaccination protocols are discussed.

A Case of Disseminated Skin and Soft Tissue Infection due toMycobacterium abscessuswith Metastatic Breast Cancer

Mycobacterium abscessus is a rapidly growing species of environmental mycobacteria commonly found in soil, dust, and water throughout the world. In immunocompetent patients, M. abscessus usually causes localized infection of skin and soft tissue in association with a traumatic or surgical wound. Although rare, it may cause disseminated systemic infection in patients with HIV, diabetes, or medically induced immunosuppression. Here we report a case of a 53-year-old female patient with disseminated skin and soft tissue infection due to M. abscessus who presented with multiple skin lesions on the trunk, back and four extremities. The patient had undergone salvage chemotherapy, modified radical mastectomy, and palliative chemotherapy for metastatic breast cancer. Granulomatous inflam mation and acid-fast bacilli were found on skin biopsy. M. abscessus was identified via mycobacterial culture and PCR-restriction fragment length polymorphism analysis. The patient responded well to clarithromycin, cefoxitin and amikacin therapy, and was subsequently discharged on oral antimicrobial therapy. Non-tuberculous mycobacterial (NTM) infection is a rare cause of skin and soft tissue infection, and a very high index of suspicion is required to initiate an evaluation for NTM. In metastatic cancer patients with multiple skin lesions, skin infection due to NTM must be differentiated not only from cutaneous metastasis but also from bacterial or fungal infection.

Environmental Strains of Mycobacterium avium Interfere with Immune Responses Associated with Mycobacterium bovis BCG Vaccination

Prior exposure of a vaccinee to certain species of environmental mycobacteria can prime the immune system against common mycobacterial antigens, which can in turn reduce the subsequent efficacy of live attenuated mycobacterial vaccines (such as Mycobacterium bovis BCG), in both human and livestock vaccination programs. In this study, two strains of Mycobacterium avium, both isolated from New Zealand livestock, were investigated to determine their growth characteristics and effects on the immune system in murine models. Markedly different effects on the immune system were observed; an IS901-negative strain (WAg 207) induced significant up-regulation of cell surface activation markers (major histocompatibility complex II, CD80, and CD86) on in vitro-derived dendritic cells and induced the release of proinflammatory monokines (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor alpha) in dendritic cell-macrophage cocultures following direct in vitro contact of cells with bacteria. In contrast, an IS901-positive strain (WAg 206) had none of these effects. When mice were exposed to M. avium via oral infection prior to BCG parenteral immunization, both strains were shown to be capable of decreasing subsequent antigen-stimulated gamma interferon secretion by splenic lymphocytes, although this effect was more significant for strain WAg 206. Both strains also induced a mycobacterial antigen-specific serological response in M. avium-sensitized and BCG-immunized mice; this response was greater in WAg 206-sensitized mice, and there was a predominance of immunoglobulin G1 antibody. The down-regulation of IFN-gamma responses and the up-regulation of antibody responses are characteristic of a switch to a type 2 immune response. The different results may be linked to the inherent growth characteristics of the two strains, since WAg 206 was shown to grow slowly in murine macrophages in vitro and to cause a persistent systemic infection following infection in vivo, while WAg 207 grew fast and did not persist in mice. The implications of these findings for BCG vaccination protocols are discussed.

Mycobacterial Ecology of the Rio Grande

This is the first study to characterize the environmental conditions which contribute to the presence and proliferation of environmental mycobacteria in a major freshwater river. Over 20 different species of environmental mycobacteria were isolated, including the pathogenic M. avium and M. kansasii. Species of the rapidly growing M. fortuitum complex were the most commonly isolated mycobacteria, and one-third of all isolates were not identified at the species level, even by 16S sequencing. PCR restriction analysis of the hsp65 gene was more accurate and rapid than biochemical tests and as accurate as yet less expensive than 16S sequencing, showing great promise as a new tool for species identification of environmentally isolated mycobacteria. Total environmental mycobacteria counts positively correlated with coliform and Escherichia coli counts and negatively correlated with chemical toxicity and water temperature. Environmental mycobacteria can survive in the alkaline conditions of the river despite previous reports that especially acidic conditions favor their presence. A representative river isolate (M. fortuitum) survived better than E. coli O157:H7 at pHs below 7 and above 8 in nutrient broth. The river strain also retained viability at 8 ppm of free chlorine, while E. coli was eliminated at 2 ppm and above. Thus, in vitro studies support environmental observations that a variety of extreme conditions favor the hardy environmental mycobacteria.

Environmental mycobacteria in northern Malawi: implications for the epidemiology of tuberculosis and leprosy.

More than 36000 individuals living in rural Malawi were skin tested with antigens derived from 12 different species of environmental mycobacteria. Most were simultaneously tested with RT23 tuberculin, and all were followed up for both tuberculosis and leprosy incidence. Skin test results indicated widespread sensitivity to the environmental antigens, in particular to Mycobacterium scrofulaceum, M. intracellulare and one strain of M. fortuitum. Individuals with evidence of exposure to 'fast growers' (i.e. with induration to antigens from fast growers which exceeded their sensitivity to tuberculin), but not those exposed to 'slow growers', were at reduced risk of contracting both tuberculosis and leprosy, compared to individuals whose indurations to the environmental antigen were less than that to tuberculin. This evidence for cross protection from natural exposure to certain environmental mycobacteria may explain geographic distributions of mycobacterial disease and has important implications for the mechanisms and measurement of protection by mycobacterial vaccines.

Evolutionary bottlenecks in the agents of tuberculosis, leprosy, and paratuberculosis

Parasitic mycobacteria cause important human and animal diseases including tuberculosis, leprosy, and paratuberculosis. Several methods demonstrate a high degree of sequence conservation in three parasitic mycobacterial species (Mycobacterium tuberculosis, M. Ieprae, andM. aviumsubspeciesparatuberculosis). Each of these species has completely conserved deoxyribonucleic acid (DNA) sequence in an internal transcribed spacer. In contrast, several species of environmental mycobacteria (M. intracellulare, M. kansasii, M. gordonae, andM. scrofulaceum) have substantial strain-to-strain variation in this region. These data suggest that each of the parasitic species has gone through a recent evolutionary bottleneck. Comparisons of tandem-repeat DNA from ancient and modern mycobacterial strains may allow this hypothesis to be tested directly.

Antibodies to Mycobacterium paratuberculosis and nine species of environmental mycobacteria in Crohn's disease and control subjects.

Cultural and serological studies have provided limited, often conflicting, evidence of a role for mycobacteria in the pathogenesis of Crohn's disease. Interest has focussed on Mycobacterium paratuberculosis, previously considered to be common in the environment with no major role as a human pathogen. Whether a specific serum antibody response to mycobacteria occurs in Crohn's disease or ulcerative colitis was investigated. Sera from patients with Crohn's disease (n = 38), ulcerative colitis (n = 15), and a healthy control population (n = 30) were assayed in an enzyme linked immunosorbent assay (ELISA) using eight filtered sonicate mycobacterial preparations and a purified protein derivative made from the bovine tubercle bacillus. In addition, IgG, IgM, and IgA levels to M paratuberculosis were determined in sera from patients with active (n = 24) or inactive (n = 29) Crohn's disease and the control populations. There was strong evidence of contact with environmental mycobacteria in all patients and control populations, with the greatest responses to preparations of M avium, M tuberculosis, and M kansasii. A large proportion of patients with Crohn's disease had antibodies that bound most antigens tested but there were no statistical differences between these values and those of the control population. Similarly, there were no differences in antibody levels to M paratuberculosis in patient and control groups. Although a subset of patients with active Crohn's disease (25%) had IgG concentrations that exceeded the control mean by more than 2 SD, this phenomenon may not be specific to Crohn's disease: 20% of a small group of patients with coeliac disease had similarly raised IgG levels to M paratuberculosis. These findings do not provide serological evidence of a role for this organism in the pathogenesis of Crohn's disease.

Survey of mycobacteria isolated from urine and the genitourinary tract in south-east England from 1980 to 1989.

Between 1980 and 1989, the Public Health Laboratory Service Regional Tuberculosis Centre, Dulwich, received cultures of mycobacteria isolated from urine and the genitourinary tract of 1392 new patients: 803 isolates were members of the tuberculosis complex (753 M. tuberculosis, 45 M. bovis, 4 M. africanum) and 589 were various species of environmental mycobacteria. The incidence of the latter isolations varied by region and by year and, with 17 exceptions (13 from endometrial curettings, 2 from hydrocele fluid, 1 from a scrotal abscess and 1 from a kidney), all isolations of environmental mycobacteria were from urine; very few of them appeared to be clinically significant. Those that could be significant included 1 isolate from a kidney, 1 from a post-renal transplant patient and 4 from patients with AIDS, 3 of whom had disseminated mycobacterial disease. Reports of clinically significant isolations of environmental mycobacteria from the genitourinary tract are reviewed.