Environmental sources of rapid growing nontuberculous mycobacteria causing disease in humans

Abstract

Nontuberculous mycobacteria are environmental, opportunistic pathogens whose role in human disease is increasingly recognized, especially regarding the rapid growing mycobacteria (RGM). RGM are recovered from various environmental sources, both natural and man-made. In water systems, RGM can survive by forming biofilms and by interactions with protozoa. The presence and species diversity of RGM in water is influenced by temperature, pH and the chemical quality of the water, as well as the availability of nutrients, although the exact correlations remain controversial. Despite their omnipresence in environmental sources, the actual transmission of RGM to humans, with subsequent clinical disease, has rarely been proven. However, outbreaks as a result of contaminated water sources have been reported, although accidental presence in clinical samples cannot always be excluded. In this setting, the presence of RGM does not necessarily indicate a causal relationship with clinical disease; accidental presence in clinical samples cannot always be excluded. Future studies should focus on the exact environmental sources of infection, aiming to examine possibilities for prevention of infections in patients at risk. Furthermore, studies should focus on the actual sites of the active replication of RGM; their presence may not indicate their natural habitat.

The microbiological quality of water in fish spas with Garra rufa fish, the Netherlands, October to November 2012

“…In the Netherlands, RGM have been isolated from tap and shower water without a direct link to illness [14]. M. chelonae, M. abscessus, and M. fortuitum are frequently found in clinical samples whereas the other species recovered from fish spas are less frequently observed [25]. The three yet unclassified environmental Mycobacterium species have not previously been isolated from human samples in the Netherlands and have not been found in the BLAST database.…”

“…RGM, that have been detected in all examined fish spas, are known environmental opportunistic pathogens that are increasingly recognised as causative agents of human and fish disease, both in sporadic cases and outbreaks [24,25]. Their transmission to humans from an environmental source, with subsequent clinical disease, is however rarely proven, except for cases in hospital settings [24].…”

Mycobacteria in water, soil, plants and air: a review

“…Water and soil are frequent sources of mycobacterial infections either in the form of direct contacts for aquarists or gardeners or by means of aerosols in showers or indoor swimming pools. Water in hospitals and dental units or metal working fluids (Falkinham 1996(Falkinham , 2009aPrimm et al 2004;van Ingen et al 2009) have been a recent focus of attention. A recently published book was devoted to the ecology of mycobacteria and their impact on human and animal health (Kazda et al 2009).…”

Mycobacteria in water, feedstocks and food: analysis of publications

“…paratuberculosis in food Cirone et al, 2007 Mycobacterium avium subsp. paratuberculosis in milk and cheese Grant, 2006 Emerging bacterial pathogens in meat and poultry Mor-Mur and Yuste, 2010 Isolation of mycobacteria from porcine lymph nodes van Ingen et al, 2010 Mycobacterium avium from patients and foods Yoder et al, 1999 Infections due to Mycobacterium avium complex Kasperbauer and Daley, 2008;McGrath et al, 2010 Mycobacterium bovis as a zoonosis Thoen et al, 2006 Tuberculosis: a re-emerging disease in animals and humans Thoen et al, 2009 Nontuberculous mycobacteria causing disease in humans van Ingen et al, 2009 Mycobacteria and HIV-Infected Individuals Yajko et al, 1995 Free-living amoebae -a vector for mycobacteria Salah et al, 2009 Mycobacteria in water and biofilms Falkinham 2009a,b;Falkinham, 2010 …”