Nontuberculous mycobacteria in drinking water systems – the challenges of characterization and risk mitigation

Abstract

Nontuberculous mycobacteria (NTM) pulmonary infections are a growing concern worldwide, with a disproportionate incidence in persons with pre-existing health conditions. NTM have frequently been found in municipally-treated drinking water and building plumbing, leading to the hypothesis that an important source of NTM exposure is drinking water. The identification and quantification of NTM in environmental samples are complicated by genetic variability among NTM species, making it challenging to determine if clinically-relevant NTM are present. Additionally, their unique cellular features and lifestyles make NTM and their nucleic acids difficult to recover. This review highlights recent work focused on quantification and characterization of NTM and on understanding the influence of source water, treatment plants, distribution systems, and building plumbing on the abundance of NTM in drinking water.

Evaluation of a new culture medium for isolation of nontuberculous mycobacteria from environmental water samples

“…RGM medium alone had the highest concentration (102.6 CFU/mL) of 102.6 CFU/mL (± 11.9 CFU/ mL) 1 Percentages out of 223 samples 2 Percentages out of 100 total positives by any method 3 Combined results of each sample processed on both 7H10 and 7H11 resulting in the same initial sample inoculum volume as RGM medium. 4 Average concentration of NTM in 100 positive samples plus or minus the standard error of the mean. PLOS ONE mycobacteria, which was significantly higher than 7H11 alone (65.5 CFU/mL) (p < 0.01) and the combination of 7H10 and 7H11 (72.3 CFU/mL) (p < 0.01) but not 7H10 alone (79.0 CFU/ mL).…”

“…In the United States the annual incidence of NTM disease is thought to be 3.2–9.8 per 100,000 population [ 2 ] and the associated economic burden of hospitalization has been estimated to be $435 million per year [ 3 ]. There are over 150 known species of NTM and infection from pathogenic strains is increasing in frequency with the potential to cause severe infection in those most vulnerable [ 4 , 5 ]. Mycobacterium species have characteristics that make them difficult to control in building water systems even with on-site secondary disinfection.…”

Genome Sequence of Mycobacterium abscessus Phage phiT46-1

“… Mycobacterium abscessus is a nontuberculous mycobacterium (NTM) that is ubiquitous in the environment and is common in water and soil ( 1 ). M. abscessus is a common cause of pulmonary and disseminated infections in immunocompromised individuals, particularly those with cystic fibrosis ( 2 , 3 ).…”

Identification Mycobacterium spp. in the Natural Water of Two Austrian Rivers

“…NTM are found in a wide range of geographical locations and they have been isolated from a variety of samples originating from many different environmental conditions, including low organic matter concentrations and low oxygen level concentrations [ 9 ]. These mycobacteria have been reported from water, biofilm and soil and have been found in association with infections in a wide range of hosts, such as mammals, including humans, and birds as well as aquatic animals [ 3 , 10 , 11 , 12 , 13 ]. The most common species identified in water samples include M. marinum , M. gordonae , M. flavescens , M. fortuitum , and M. chelonae (isolated from aquariums and swimming pools).…”