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

Abstract

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.

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

“…To date this evidence has been largely reported for Mycobacterium avium (6)(7)(8). We recently documented NTM in the Brisbane, Australia, potable water distribution system (9) and have shown that strains of M. lentiflavum (10) and M. abscessus (11) are highly related or identical to those found in patients with disease. Despite frequent identification of Mycobacterium kansasii from water samples, pathogenic strains were found infrequently (unpublished data).…”

“…Water samples were processed as previously described (9,19). After analysis of water sampling revealed an increased yield for rapidly growing mycobacteria using liquid medium (MGIT tubes) (9), these were included for the last 6 houses that were sampled.…”

Species distribution of Non tuberculosis mycobacteria isolates from North of Iran

“…The clinical presentation of NTM is often hard to differentiate from that of MTBC (Mycobacterium tuberculosis complex); therefore, it is important to accurately identify NTM, since the management and treatment of infected patients, as well as the epidemiological control methods implemented, must reflect the specific mycobacterial species encountered [9]. There are many factors that affect recovery of mycobacteria from water.…”

“…Briefly, CPC was added to the sample to give a final concentration of 0.01%. The mixture was shaken for 30 s. After an exposure for 30 min, the samples were immediately filtered through cellulose acetate membrane filter (50 mm, pore size 0.45μm) and rinsed in 100 ml of sterile water to remove residual CPC [8,9]. A strip 10 mm wide was then aseptically cut out from the center of the filter and placed on the medium [10].…”

Nontuberculous mycobacterial lung disease: ecology, microbiology, pathogenesis, and antibiotic resistance mechanisms

“…Previous studies revealed that MABC infections can be acquired in the community or in the hospital environment [75,76]. In the community environment, water supply systems are regarded as likely sources of MABC infection, and in the hospital environment, contamination of medical devices and water are considered to be potential sources of MABC infections [77].…”