Mycobacteria in Runoff Waters from Natural and Drained Peatlands

Abstract

To assess the effect of peatland type and of forest‐drainage performed 30 yr earlier on the occurrence of mycobacteria in runoff‐waters, the counts of culturable mycobacteria were followed during a snow‐free season. Runoff‐waters were from a natural and a drained peatland and each had a different nutrient status. Samples were collected in May, June, August, and October of 1992. Mycobacteria were isolated from all waters. The highest culturable counts were detected in August (up to 7.3 × 103 CFU/L). The runoff‐waters from the two natural peatlands had similar median counts, whereas lowering of the water table by drainage slightly increased the mycobacterial counts in most cases. Changes in vegetation, such as a decrease in the coverage of Sphagnum species, or soil characteristics following drainage had little effect on the occurrence of mycobacteria in the runoff‐waters, even though Sphagnum vegetation has been regarded as important for the growth of these bacteria. The counts of mycobacteria in the runoff‐waters correlated with precipitation but not with air temperature. This indicates that the mycobacterial growth took place mainly in vegetation and soil, not in the runoff‐waters. When total runoff during May to October was taken into account, the leaching rates of mycobacteria from all catchments were about 4 to 5 × 1011 CPU km−2. Thus drainage had a negligible effect on the leaching of mycobacteria from peatlands.

Comparative Genetic Analysis of Mycobacterium ulcerans and Mycobacterium marinum Reveals Evidence of Recent Divergence

“…It also suggests that slow growth may be of selective advantage to M. ulcerans. These advantages may include facilitation of growth as an endosymbiont (9,28) and survival under nutrientpoor conditions (27). The presence of two copies of the rRNA operon in M. marinum also has taxonomic implications for its current classification as a slow-growing species (67).…”

Mycobacterium xenopi and related organisms isolated from stream waters in Finland and description of Mycobacterium botniense sp. nov.

“…The same water also harboured isolates of the M. avium complex and M. malmoense (Iivanainen et al, 1994 ;Katila et al, 1995). Peatlands and high organic matter content are apparently important to many potentially pathogenic mycobacteria in the natural environment (Iivanainen et al, 1993(Iivanainen et al, , 1999 (2,4,6,x-tetramethyl-20 : 0 and 2,4,6,x,x-pentamethyl-22 : 0) can be used marker substances. The most reliable identification is achieved by 16S rDNA sequencing.…”

Mutants of Mycobacterium smegmatis unable to grow at acidic pH in the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone

“…Mycobacteria are likely to encounter both acidic and mildly acidic pH in the environments they inhabit (Iivanainen et al, 1999;Oh & Straubinger, 1996;Sturgill-Koszycki et al, 1994). For example, acidic conditions (pH 3?5-4?3) often prevail in soil and aquatic habitats where saprophytic mycobacteria are found (Iivanainen et al, 1999).…”

“…For example, acidic conditions (pH 3?5-4?3) often prevail in soil and aquatic habitats where saprophytic mycobacteria are found (Iivanainen et al, 1999). In the host environment, Mycobacterium tuberculosis resides in the phagocytic vacuole of host macrophages where the intraphagosomal pH is mildly acidic (pH 6?1-6?5) (Oh & Straubinger, 1996;Sturgill-Koszycki et al, 1994).…”