Mycobacterium palustre sp. nov., a potentially pathogenic, slowly growing mycobacterium isolated from clinical and veterinary specimens and from Finnish stream waters.

Abstract

Taxonomic studies were performed on a phenotypically homogeneous group of 13 mycobacteria isolated from clinical, veterinary and stream-water samples. The methods applied included chromatographic analyses of bacterial lipids, biochemical tests and sequencing of the 16S rDNA and the internal transcribed spacer 1 (ITS1) region. Positive results in urease, Tween 80 hydrolysis and pyrazinamidase tests and a negative result in a semi-quantitative catalase test, combined with the ability to grow at 42 degrees C, distinguished this group among the yellow-pigmented, slowly growing mycobacteria. Unique fatty acid and mycolic acid profiles in chromatographic analyses and the results of gene sequencing indicated that the novel isolates represent a previously undescribed species, for which the name Mycobacterium palustre sp. nov. is proposed. The fatty acid profile obtained by GLC was characterized by the presence of several methyl-branched fatty acid markers. The most prominent markers were 2-methyleicosanoic, tetracosanoic and hexacosanoic acids. According to 16S rDNA sequencing, M. palustre is phylogenetically closest to Mycobacterium kubicae, a recently described species. M. palustre gives a false-positive result in a hybridization test with the AccuProbe Mycobacterium avium complex. One of the strains was isolated from a lymph-node biopsy from a child with cervical lymphadenitis. Thus, M. palustre should be listed among potential inducers of paediatric lymphadenitis. The veterinary isolates originated from the lymph nodes of slaughter pigs. The majority of the strains were recovered from natural waters, which highlights the role of the environment as a source of potentially pathogenic mycobacteria. The type strain of M. palustre is strain E846T (= DSM 44572T = ATCC BAA-377T).

The new mycobacteria: an update

“…All but one of the strains investigated gave a positive result with the commercial DNA probe AccuProbe (Gen‐Probe) specific for MAC but not with the probes specific for Mycobacterium avium and Mycobacterium intracellulare . An identical anomalous reaction had been reported for another newly described species, M. palustre (Torkko et al , 2002).…”

Mycobacterium saskatchewanense sp. nov., a novel slowly growing scotochromogenic species from human clinical isolates related to Mycobacterium interjectum and Accuprobe-positive for Mycobacterium avium complex

“…1), but with more and better-developed late peaks. It is almost indistinguishable from that of the newly described Mycobacterium palustre, also an MAC AccuProbe-positive species (Torkko et al, 2002). With its central double peak and higher end peaks, it is very similar to some published profiles of strains as well as of a Québec clinical single cluster pattern identified as M. interjectum (Lumb et al, 1997), distinct from the double-cluster pattern of the type strain of M. interjectum (Butler & Guthertz, 2001).…”

“…Phenotypic characteristics of the study strains in comparison with other slowly growing Mycobacterium species Strains/species: 1, study strains (n=15); 2, strain MB54784; 3, strain MCRO 8 (Springer et al, 1996); 4. M. palustre (Torkko et al, 2002); 5. M. interjectum 4185/92 T (Springer et al, 1993;Tortoli et al, 1996); 6, M. avium complex; 7, M. gordonae (Kent & Kubica, 1985).…”

Environmental Presence ofMycobacterium tuberculosisComplex in Aggregation Points at the Wildlife/Livestock Interface

“…This statement could also be generalized to other mycobacteria that do not belong to the MTC, such as non‐tuberculous mycobacteria (NTM) including members of the M. avium complex. NTM are widely distributed in natural and man‐made environments, and there is an increasing awareness of their pathogenic potential in humans and animals (Torkko et al., ).…”