Robyn Carter

Isolation of Nontuberculous Mycobacteria (NTM) from Household Water and Shower Aerosols in Patients with Pulmonary Disease Caused by NTM

ABSTRACT It has been postulated that susceptible individuals may acquire infection with nontuberculous mycobacteria (NTM) from water and aerosol exposure. This study examined household water and shower aerosols of patients with NTM pulmonary disease. The mycobacteria isolated from clinical samples from 20 patients included M. avium (5 patients), M. intracellulare (12 patients), M. abscessus (7 patients), M. gordonae (1 patient), M. lentiflavum (1 patient), M. fortuitum (1 patient), M. peregrinum (1 patient), M. chelonae (1 patient), M. triplex (1 patient), and M. kansasii (1 patient). One-liter water samples and swabs were collected from all taps, and swimming pools or rainwater tanks. Shower aerosols were sampled using Andersen six-stage cascade impactors. For a subgroup of patients, real-time PCR was performed and high-resolution melt profiles were compared to those of ATCC control strains. Pathogenic mycobacteria were isolated from 19 homes. Species identified in the home matched that found in the patient in seven (35%) cases: M. abscessus (3 cases), M. avium (1 case), M. gordonae (1 case), M. lentiflavum (1 case), and M. kansasii (1 case). In an additional patient with M. abscessus infection, this species was isolated from potable water supplying her home. NTM grown from aerosols included M. abscessus (3 homes), M. gordonae (2 homes), M. kansasii (1 home), M. fortuitum complex (4 homes), M. mucogenicum (1 home), and M. wolinskyi (1 home). NTM causing human disease can be isolated from household water and aerosols. The evidence appears strongest for M. avium, M. kansasii, M. lentiflavum, and M. abscessus. Despite a predominance of disease due to M. intracellulare, we found no evidence for acquisition of infection from household water for this species.

Factors associated with the isolation of Nontuberculous mycobacteria (NTM) from a large municipal water system in Brisbane, Australia

BackgroundNontuberculous mycobacteria (NTM) are normal inhabitants of a variety of environmental reservoirs including natural and municipal water. The aim of this study was to document the variety of species of NTM in potable water in Brisbane, QLD, with a specific interest in the main pathogens responsible for disease in this region and to explore factors associated with the isolation of NTM. One-litre water samples were collected from 189 routine collection sites in summer and 195 sites in winter. Samples were split, with half decontaminated with CPC 0.005%, then concentrated by filtration and cultured on 7H11 plates in MGIT tubes (winter only).ResultsMycobacteria were grown from 40.21% sites in Summer (76/189) and 82.05% sites in winter (160/195). The winter samples yielded the greatest number and variety of mycobacteria as there was a high degree of subculture overgrowth and contamination in summer. Of those samples that did yield mycobacteria in summer, the variety of species differed from those isolated in winter. The inclusion of liquid media increased the yield for some species of NTM. Species that have been documented to cause disease in humans residing in Brisbane that were also found in water include M. gordonae, M. kansasii, M. abscessus, M. chelonae, M. fortuitum complex, M. intracellulare, M. avium complex, M. flavescens, M. interjectum, M. lentiflavum, M. mucogenicum, M. simiae, M. szulgai, M. terrae. M. kansasii was frequently isolated, but M. avium and M. intracellulare (the main pathogens responsible for disease is QLD) were isolated infrequently. Distance of sampling site from treatment plant in summer was associated with isolation of NTM. Pathogenic NTM (defined as those known to cause disease in QLD) were more likely to be identified from sites with narrower diameter pipes, predominantly distribution sample points, and from sites with asbestos cement or modified PVC pipes.ConclusionsNTM responsible for human disease can be found in large urban water distribution systems in Australia. Based on our findings, additional point chlorination, maintenance of more constant pressure gradients in the system, and the utilisation of particular pipe materials should be considered.

Mycobacterium lentiflavum in Drinking Water Supplies, Australia

Humans may acquire infection from potable water.

Drug resistance-conferring mutations in Mycobacterium tuberculosis from Madang, Papua New Guinea

BackgroundMonitoring drug resistance in Mycobacterium tuberculosis is essential to curb the spread of tuberculosis (TB). Unfortunately, drug susceptibility testing is currently not available in Papua New Guinea (PNG) and that impairs TB control in this country. We report for the first time M. tuberculosis mutations associated with resistance to first and second-line anti-TB drugs in Madang, PNG. A molecular cluster analysis was performed to identify M. tuberculosis transmission in that region.ResultsPhenotypic drug susceptibility tests showed 15.7% resistance to at least one drug and 5.2% multidrug resistant (MDR) TB. Rifampicin resistant strains had the rpoB mutations D516F, D516Y or S531L; Isoniazid resistant strains had the mutations katG S315T or inhA promoter C15T; Streptomycin resistant strains had the mutations rpsL K43R, K88Q, K88R), rrs A514C or gidB V77G. The molecular cluster analysis indicated evidence for transmission of resistant strain.ConclusionsWe observed a substantial rate of MDR-TB in the Madang area of PNG associated with mutations in specific genes. A close monitoring of drug resistance is therefore urgently required, particularly in the presence of drug-resistant M. tuberculosis transmission. In the absence of phenotypic drug susceptibility testing in PNG, molecular assays for drug resistance monitoring would be of advantage.

Comparison of Methods for Processing Drinking Water Samples for the Isolation of Mycobacterium avium and Mycobacterium intracellulare

ABSTRACT Several protocols for isolation of mycobacteria from water exist, but there is no established standard method. This study compared methods of processing potable water samples for the isolation of Mycobacterium avium and Mycobacterium intracellulare using spiked sterilized water and tap water decontaminated using 0.005% cetylpyridinium chloride (CPC). Samples were concentrated by centrifugation or filtration and inoculated onto Middlebrook 7H10 and 7H11 plates and Lowenstein-Jensen slants and into mycobacterial growth indicator tubes with or without polymyxin, azlocillin, nalidixic acid, trimethoprim, and amphotericin B. The solid media were incubated at 32°C, at 35°C, and at 35°C with CO2 and read weekly. The results suggest that filtration of water for the isolation of mycobacteria is a more sensitive method for concentration than centrifugation. The addition of sodium thiosulfate may not be necessary and may reduce the yield. Middlebrook M7H10 and 7H11 were equally sensitive culture media. CPC decontamination, while effective for reducing growth of contaminants, also significantly reduces mycobacterial numbers. There was no difference at 3 weeks between the different incubation temperatures.

Clinical Significance of Mycobacterium asiaticum Isolates in Queensland, Australia

ABSTRACT Mycobacterium asiaticum was first reported as a cause of human disease in 1982, with only a few cases in the literature to date. This study aims to review the clinical significance of M. asiaticum isolates in Queensland, Australia. A retrospective review (1989 to 2008) of patients with M. asiaticum isolates was conducted. Data were collected through the Queensland TB Control Centre database. Disease was defined in accordance with the American Thoracic Society criteria. Twenty-four patients (13 female) had a positive culture of M. asiaticum, many residing around the Tropic of Capricorn. M. asiaticum was responsible for pulmonary disease (n = 2), childhood lymphadenitis (n = 1), olecranon bursitis (n = 1), 6 cases of possible pulmonary disease, and 2 possible wound infections. Chronic lung disease was a risk factor for pulmonary infection, and wounds/lacerations were a risk factor for extrapulmonary disease. Extrapulmonary disease responded to local measures. Pulmonary disease responded to ethambutol-isoniazid-rifampin plus pyrazinamide for the first 2 months in one patient, and amikacin-azithromycin-minocycline in another patient. While M. asiaticum is rare in Queensland, there appears to be an environmental niche. Although often a colonizer, it can be a cause of pulmonary and extrapulmonary disease. Treatment of pulmonary disease remains challenging. Extrapulmonary disease does not mandate specific nontuberculous mycobacterium (NTM) treatment.

Diversity of Mycobacterium tuberculosis and drug resistance in different provinces of Papua New Guinea

BackgroundPapua New Guinea (PNG) is a high tuberculosis (TB) burden country of the WHO Western Pacific Region, but so far research on drug resistance (DR) and genotypes of Mycobacterium tuberculosis (M. tuberculosis) was only conducted in few provinces in the country. The aim of the present study was to obtain baseline data on the level of drug resistance and the genotypic diversity of circulating M. tuberculosis in additional provinces and to investigate the differences between three selected sites across PNG.ResultsGenotyping of 147 M. tuberculosis clinical isolates collected in Goroka, Eastern Highlands Province, in Alotau, Milne Bay Province and in Madang, Madang Province revealed three main lineages of M. tuberculosis: Lineage 4 (European-American lineage), Lineage 2 (East-Asian lineage) and Lineage 1 (Indo-Oceanic lineage). All three lineages were detected in all three sites, but the individual lineage compositions varied significantly between sites. In Madang Lineage 4 was the most prevalent lineage (76.6%), whereas in Goroka and Alotau Lineage 2 was dominating (60.5% and 84.4%, respectively) (p < 0.001). Overall, phenotypic drug susceptibility testing showed 10.8% resistance to at least one of the first-line drugs tested. Of all resistant strains (23/212) 30.4% were Streptomycin mono-resistant, 17.4% were Isoniazid mono-resistant and 13% were Rifampicin mono-resistant. Multi-drug resistant (MDR) TB was found in 2.8% of all tested cases (6/212). The highest amount of MDR TB was found in Alotau in Milne Bay Province (4.6%).ConclusionA large number of drug resistant TB infections are present in the country and MDR TB has already been detected in all three surveyed regions of PNG, highlighting the importance of monitoring drug resistance and making it a high priority for the National Control Program. Due to the high prevalence of Lineage 2 in Milne Bay Province and given the frequent association of this lineage with drug resistance, monitoring of the latter should especially be scaled up in that province.

Rapidly growing mycobacteria associated with laparoscopic gastric banding, Australia, 2005-2011.

Device removal seems to be vital to successful therapy.

Non-tuberculous mycobacteria : baseline data from three sites in Papua New Guinea, 2010-2012

OBJECTIVE To determine the proportion of non-tuberculous mycobacteria (NTM) in samples of pulmonary tuberculosis (TB) cases from Papua New Guinea who were diagnosed using acid-fast microscopy. METHODS As part of a case detection study for TB, conducted in three provincial hospitals in Papua New Guinea, sputum samples of suspected tuberculous cases aged 15 years or older were collected from November 2010 to July 2012. Mycobacterial species isolated from sputum and grown in culture were examined to distinguish between NTM and the Mycobacterium tuberculosis complex (MTBC). RESULTS NTM were detected in 4% (9/225) of sputum samples grown in culture. Five (2.2%) of them were identified as NTM only and four (1.8%) were identified as mixed cultures containing both MTBC and NTM. Four different NTM species were identified; M. fortuitum, M. intracellulare, M. terrae and M. avium. DISCUSSION This is the first report from Papua New Guinea identifying NTM in three different locations. As NTM cannot be distinguished from M. tuberculosis through smear microscopy, the presence of NTM can lead to a false-positive diagnosis of tuberculosis. The prevalence of NTM should be determined and a diagnostic algorithm developed to confirm acid-fast bacilli in a smear as M. tuberculosis.

Mycobacterium shimoidei, a Rare Pulmonary Pathogen, Queensland, Australia

Nontuberculous mycobacteria are human pathogens with increasing incidence and prevalence worldwide. Mycobacterium shimoidei is a rare cause of pulmonary disease, with only 15 cases previously reported. This series documents an additional 23 cases of M. shimoidei from Queensland, Australia, and highlights the pathogenicity and clinical role of this species.