Non-tuberculosis Mycobacterial Species Research Articles

Nontuberculous Mycobacterial Infection in Wisconsin Adults and Its Relationship to Race and Social Disadvantage.

Rationale: Population-based data on the epidemiology of nontuberculosis mycobacterial (NTM) infections are limited, particularly with respect to variation in NTM infection among racial groups and socioeconomic strata. Wisconsin is one of a handful of states where mycobacterial disease is notifiable, allowing large, population-based analyses of the epidemiology of NTM infection in this state. Objectives: To estimate the incidence of NTM infection in Wisconsin adults, describe the geographic distribution of NTM infection across the state, identify the frequency and type of infection caused by different NTM species, and investigate associations between NTM infection and demographics and socioeconomic status. Methods: We conducted a retrospective cohort study using laboratory reports of all NTM isolates from Wisconsin residents submitted to the Wisconsin Electronic Disease Surveillance System from 2011 to 2018. For the analyses of NTM frequency, multiple reports from the same individual were enumerated as separate isolates when nonidentical, collected from different sites or collected more than one year apart. Results: A total of 8,135 NTM isolates from 6,811 adults were analyzed. Mycobacterium avium complex accounted for 76.4% of respiratory isolates. The M. chelonae-abscessus group was the most common species isolated from skin and soft tissue. The annual incidence of NTM infection was stable over the study period (from 22.1 per 100,000 to 22.4 per 100,000). The cumulative incidence of NTM infection among Black (224 per 100,000) and Asian (244 per 100,000) individuals was significantly higher compared with that among their White counterparts (97 per 100,000). Total NTM infections were significantly more frequent (P < 0.001) in individuals from disadvantaged neighborhoods, and racial disparities in the incidence of NTM infection generally remained consistent when stratified by measures of neighborhood disadvantage. Conclusions: More than 90% of NTM infections were from respiratory sites, with the vast majority caused by M. avium complex. Rapidly growing mycobacteria predominated as skin and soft tissue pathogens and were important minor respiratory pathogens. We found a stable annual incidence of NTM infection in Wisconsin between 2011 and 2018. NTM infection occurred more frequently in non-White racial groups and in individuals experiencing social disadvantage, suggesting that NTM disease may be more frequent in these groups as well.

In vitro activity of SPR719 against Mycobacterium ulcerans, Mycobacterium marinum and Mycobacterium chimaera.

Nontuberculosis mycobacterial (NTM) infections are increasing in prevalence across the world. In many cases, treatment options for these infections are limited. However, there has been progress in recent years in the development of new antimycobacterial drugs. Here, we investigate the in vitro activity of SPR719, a novel aminobenzimidazole antibiotic and the active form of the clinical-stage compound, SPR720, against several isolates of Mycobacterium ulcerans, Mycobacterium marinum and Mycobacterium chimaera. We show that SPR719 is active against these NTM species with a MIC range of 0.125–4 μg/ml and that this compares favorably with the commonly utilized antimycobacterial antibiotics, rifampicin and clarithromycin. Our findings suggest that SPR720 should be further evaluated for the treatment of NTM infections.

Animal Models of Mycobacteria Infection.

This manuscript describes the infection of mice and guinea pigs with mycobacteria via various routes, as well as necropsy methods for the determination of mycobacterial loads within target organs. Additionally, methods for cultivating mycobacteria and preparing stocks are described. The protocols outlined are primarily used for M. tuberculosis, but can also be used for the study of other non-tuberculosis mycobacterial species. A wide variety of animal models have been used to test new vaccines, drugs, and the impact of cigarette exposure. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Aerosol infection of mice with mycobacteria Basic Protocol 2: Aerosol infection of guinea pig with mycobacteria using a Madison chamber Alternate Protocol 1: Cigarette exposure prior to infection of mice with mycobacteria Alternate Protocol 2: Intravenous infection of mice with mycobacteria Basic Protocol 3: Necropsy methods for animals experimentally infected with mycobacteria Basic Protocol 4: Following the course of infection Basic Protocol 5: Measuring the animal immune response to infection Support Protocol: Cultivation of mycobacteria for use in animal experiments.

Clinical and microbiological characteristics of non-tuberculous mycobacteria diseases in Singapore with a focus on pulmonary disease, 2012-2016

BackgroundInformation on non-tuberculosis mycobacterial (NTM) diseases remains limited in Singapore and other Southeast Asian countries. This study aimed to delineate epidemiological and clinical features of pulmonary NTM disease.MethodsA retrospective review was performed on all NTM isolates identified in Singapore General Hospital from 2012 to 2016 using the 2007 ATS/IDSA diagnostic criteria.ResultsA total of 2026 NTM isolates from 852 patients were identified. M. abscessus-chelonae group (1010, 49.9%) was the most commonly isolated and implicated in pulmonary NTM disease. Pulmonary cases (352, 76%) had the highest prevalence among patients diagnosed with NTM diseases (465/852, 54.6%) with no gender difference. Male patients were older (68.5 years, P = 0.014) with a higher incidence of chronic obstructive pulmonary disease (COPD) (23.6%, P < 0.001) and recurrent cough with phlegm production (51.6%, P = 0.035). In contrast, more female patients had bronchiectasis (50%, P < 0.001) and haemoptysis (37.6%, P = 0.042). Age and COPD were associated with multiple NTM species isolation per patient.ConclusionsM. abscessus-chelonae group was the commonest NTM species isolated in Singapore. Pulmonary NTM infection has the highest frequency with male and female patients associated with a higher incidence of COPD and bronchiectasis respectively. Age and COPD were associated with multiple NTM species isolation per patient.

The Mycobacterium phlei Genome: Expectations and Surprises.

Mycobacterium phlei, a nontuberculosis mycobacterial species, was first described in 1898–1899. We present the complete genome sequence for the M. phlei CCUG21000T type strain and the draft genomes for four additional strains. The genome size for all fiveis 5.3 Mb with 69.4% Guanine-Cytosine content. This is ≈0.35 Mbp smaller than the previously reported M. phlei RIVM draft genome. The size difference is attributed partly to large bacteriophage sequence fragments in the M. phlei RIVM genome. Comparative analysis revealed the following: 1) A CRISPR system similar to Type 1E (cas3) in M. phlei RIVM; 2) genes involved in polyamine metabolism and transport (potAD, potF) that are absent in other mycobacteria, and 3) strain-specific variations in the number of σ-factor genes. Moreover, M. phlei has as many as 82 mce (mammalian cell entry) homologs and many of the horizontally acquired genes in M. phlei are present in other environmental bacteria including mycobacteria that share similar habitat. Phylogenetic analysis based on 693 Mycobacterium core genes present in all complete mycobacterial genomes suggested that its closest neighbor is Mycobacterium smegmatis JS623 and Mycobacterium rhodesiae NBB3, while it is more distant to M. smegmatis mc2 155.

Animal Models of Mycobacteria Infection

This unit describes the infection of mice and guinea pigs with mycobacteria via various routes, as well as necropsy methods for the determination of mycobacterial loads within target organs. Additionally, methods for cultivating mycobacteria and preparing stocks are described. The protocols outlined are primarily used for M. tuberculosis, but can also be used for the study of other non-tuberculosis mycobacterial species.

Mycobacterium conceptionense infection complicating face rejuvenation with fat grafting

We report a third case of Mycobacterium conceptionense infection, which was found in a 50-year-old female following face rejuvenation surgery with fat grafting. The pathogen was identified using 16S rRNA gene and rpoB gene sequences. The growing diversity of non-tuberculosis mycobacterial species causing human infections emphasizes that early and precise identification is imperative for successful treatment.

Electrospray ionization-tandem mass spectrometry analysis of the mycolic acid profiles for the identification of common clinical isolates of mycobacterial species

Mycolic acids are unique and complex molecular structures found in mycobacterial species. In the present study, we investigated whether electrospray ionization-tandem mass spectrometry (ESI-MS/MS) can be used to identify mycobacterial species based on their mycolic acid profiles. Clinical isolates of Mycobacterium tuberculosis complex and 18 nontuberculosis mycobacterial (NTM) species identified by PCR-restriction fragment length polymorphism (RFLP) or real-time PCR were used for this analysis. Crude lipid extracts were prepared by saponifying 1–2 colonies of individual isolates of mycobacterial species and by chloroform and methanol (2:1, v/v) extraction. ESI-MS/MS in negative ion mode with high cone voltage and collision energy was used for mycolic acid profiling analysis. Combinatorial precursor ion scans of m/ z 395, 367, and 339 in the range of m/ z 1000–1400 resulted in spectra specific to individual mycobacteria. M. tuberculosis complex and M. pulveris showed major ions by performing precursor ion scans on m/ z 395 and 367, while other NTM species showed major ions by performing scans on m/ z 367 and 339. The different NTM species examined showed different species dependent mycolic acid profiles. In conclusion, we describe a rapid, reliable, and informative ESI-MS/MS protocol for mycolic acid profiling in mycobacterial species, which allows mycobacterial species to be easily identified in clinical laboratories.

Chronic Mycobacterium marinum infection acts as a tumor promoter in Japanese Medaka ( Oryzias latipes)

An accumulating body of research indicates there is an increased cancer risk associated with chronic infections. The genus Mycobacterium contains a number of species, including M. tuberculosis, which mount chronic infections and have been implicated in higher cancer risk. Several non-tuberculosis mycobacterial species, including M. marinum, are known to cause chronic infections in fish and like human tuberculosis, often go undetected. The elevated carcinogenic potential for fish colonies infected with Mycobacterium spp. could have far reaching implications because fish models are widely used to study human diseases. Japanese medaka ( Oryzias latipes) is an established laboratory fish model for toxicology, mutagenesis, and carcinogenesis; and produces a chronic tuberculosis-like disease when infected by M. marinum. We examined the role that chronic mycobacterial infections play in cancer risk for medaka. Experimental M. marinum infections of medaka alone did not increase the mutational loads or proliferative lesion incidence in all tissues examined. However, we showed that chronic M. marinum infections increased hepatocellular proliferative lesions in fish also exposed to low doses of the mutagen benzo[a]pyrene. These results indicate that chronic mycobacterial infections of medaka are acting as tumor promoters and thereby suggest increased human risks for cancer promotion in human populations burdened with chronic tuberculosis infections.

Susceptibilities of nontuberculosis mycobacterial species to amoxicillin-clavulanic acid alone and in combination with antimycobacterial agents.

Neither amoxicillin nor clavulanic acid used alone was active at the highest level tested, i.e., 256.0 micrograms/ml, in vitro against 24 isolates of Mycobacterium fortuitum, Mycobacterium kansasii, and Mycobacterium marinum. However, the MIC of an amoxicillin-clavulanic acid combination of 2:1 was < or = 8.0/4.0 micrograms/ml for 50 percent of the isolates tested, with all isolates being inhibited in the range of 4.0/2.0 to 32.0/16.0 micrograms/ml, respectively. Titration of amoxicillin-clavulanic acid with a fixed 2-micrograms/ml concentration of ethambutol resulted in synergistic activity against 3 of 9 isolates of M. fortuitum, 10 of 10 isolates of M. kansasii, and 5 of 5 isolates of M. marinum. This observation was confirmed in a checkerboard analysis in which fractional inhibitory concentrations were < or = 0.5 for 20 of the 24 isolates. Synergistic activity was observed against the other four isolates in one of two trials. On the other hand, titration of amoxicillin-clavulanic acid in the presence of either one or two fixed concentrations of isoniazid, rifampin, cycloserine, tetracycline, or amikacin failed to result in synergism.