Importance of Local and Regional Scales in Shaping Mycobacterial Abundance in Freshwater Lakes

Abstract

Biogeographical studies considering the entire bacterial community may underestimate mechanisms of bacterial assemblages at lower taxonomic levels. In this context, the study aimed to identify factors affecting the spatial and temporal dynamic of the Mycobacterium, a genus widespread in aquatic ecosystems. Nontuberculous mycobacteria (NTM) density variations were quantified in the water column of freshwater lakes at the regional scale (annual monitoring of 49 lakes in the Paris area) and at the local scale (2-year monthly monitoring in Créteil Lake) by real-time quantitative PCR targeting the atpE gene. At the regional scale, mycobacteria densities in water samples ranged from 6.7 × 10 to 1.9 × 10 genome units per liter. Density variations were primarily explained by water pH, labile iron, and dispersal processes through the connection of the lakes to a river. In Créteil Lake, no spatial variation of mycobacterial densities was noticed over the 2-year monthly survey, except after large rainfall events. Indeed, storm sewer effluents locally and temporarily increased NTM densities in the water column. The temporal dynamic of the NTM densities in Créteil Lake was associated with suspended solid concentrations. No clear seasonal variation was noticed despite a shift in NTM densities observed over the 2012-2013 winter. Temporal NTM densities fluctuations were well predicted by the neutral community model, suggesting a random balance between loss and gain of mycobacterial taxa within Créteil Lake. This study highlights the importance of considering multiple spatial scales for understanding the spatio-temporal dynamic of bacterial populations in natural environments.

Impact of Escherichia coli from stormwater drainage on recreational water quality: an integrated monitoring and modelling of urban catchment, pipes and lake

“…The detection limit of <0.075 MPN ml -1 water sample is estimated. Moreover, a monthly E. coli monitoring program of Lake Créteil is performed from January 2012 to December 2013 (Roguet et al, 2018), which covers the lake monitoring period.…”

A multi-omics study on quantifying antimicrobial resistance in European freshwater lakes

“…Representatives of the genus Mycobacterium can be observed in large quantities in almost all samples since it is widespread in aquatic ecosystems and is likely dominated by nontuberculous mycobacteria (NTM) ( Roguet et al, 2018 ). Roguet and the coworkers pointed out that the flowing of rivers into lakes appeared to strongly increase NTM densities, as opposed to lakes without connected rivers ( Roguet et al, 2018 ). Acinetobacter species were also present in many samples, albeit in smaller quantities.…”

River Sediments Downstream of Villages in a Karstic Watershed Exhibited Increased Numbers and Higher Diversity of Nontuberculous Mycobacteria

“…Humane doctors are often asked by sick patients and parents of child patients with mycobacteriosis, what are the risks of their possible reinfection. Very often, various components of the environment are cited as sources of clinically relevant NTM [ 2 , 11 ], including drinking water [ 9 ], water used for personal hygiene in heavy industry and collieries [ 40 ], water used for recreation [ 8 , 13 , 14 ], soil [ 3 ], indoor environment [ 7 ], and other environmental components. The results of this study point to the fact that even the immediate surroundings of the water stream in villages and below the villages can also be risky for these adult and child patients, including some other predisposed persons.…”