Characterization of Mycobacterium bohemicum Isolated from Human, Veterinary, and Environmental Sources

Abstract

Chemotaxonomic and genetic properties were determined for 14 mycobacterial isolates identified as members of a newly described species Mycobacterium bohemicum. The isolates recovered from clinical, veterinary, and environmental sources were compared for lipid composition, biochemical test results, and sequencing of the 16S ribosomal DNA (rDNA) and the 16S-23S rDNA internal transcribed spacer (ITS) regions. The isolates had a lipid composition that was different from those of other known species. Though the isolates formed a distinct entity, some variations were detected in the features analyzed. Combined results of the phenotypic and genotypic analyses were used to group the isolates into three clusters. The major cluster (cluster A), very homogenous in all respects, comprised the M. bohemicum type strain, nine clinical and veterinary isolates, and two of the five environmental isolates. Three other environmental isolates displayed an insertion of 14 nucleotides in the ITS region; they also differed from cluster A in fatty alcohol composition and produced a positive result in the Tween 80 hydrolysis test. Among these three, two isolates were identical (cluster B), but one isolate (cluster C) had a unique high-performance liquid chromatography profile, and its gas liquid chromatography profile lacked 2-octadecanol, which was present in all other isolates analyzed. Thus, sequence variation in the 16S-23S ITS region was associated with interesting variations in lipid composition. Two of the isolates analyzed were regarded as potential inducers of human or veterinary infections. Each of the environmental isolates, all of which were unrelated to the cases presented, was cultured from the water of a different stream. Hence, natural waters are potential reservoirs of M. bohemicum.In the past few years, species descriptions of several unclassified mycobacteria have been published, and more new species will certainly be identified in the future. In 1998, a novel species, Mycobacterium bohemicum, isolated from a patient with Down's syndrome and tuberculosis, was described by Reischl and coworkers (11). Only one additional report on this species has been presented so far (17). Despite its recent discovery, M. bohemicum seems to be more common than many of the other newly classified species. From 1989 through 1996, we isolated unidentifiable mycobacteria from specimens taken from four human patients and one goat. Isolates shown to be similar by means of gas liquid chromatography (GLC) analyses of cellular fatty acid and alcohol composition and biochemical testing (12) were also detected among environmental isolates grown from water taken from Finnish streams in 1990 (4). These isolates have recently been verified as M. bohemicum by partial sequencing of the 16S rRNA gene. In 1999, an additional three clinical isolates were identified as M. bohemicum.We describe here the characteristics of Finnish M. bohemicum isolates originating from clinical, veterinary, and environmental sources, together with some descriptions of the so...

Mycobacterium mantenii sp. nov., a pathogenic, slowly growing, scotochromogenic species

“…4). A divergent HPLC profile in environmental isolates compared with clinical isolates has also been noted for Mycobacterium bohemicum (Torkko et al, 2001). …”

The HPLC-double-cluster pattern of some Mycobacterium gordonae strains is due to their dicarboxy-mycolate content

“…The mycolic acid pattern exhibited by these clinical isolates is also uncommon in members of the genus Mycobacterium, as the presence of α-, methoxy-, keto-and dicarboxy-mycolates has only been reported in two additional species of the genus, Mycobacterium komossense and Mycobacterium bohemicum (Minnikin et al, 1985a ;Torkko et al, 2001). We conclude that the variability in the mycolic acid patterns of strains of M. gordonae, as detected by HPLC and TLC, exists because of the presence of additional components (dicarboxy-mycolates) in some strains of this species.…”

Mycobacterium bohemicumand Cervical Lymphadenitis in Children

“…A cyclic disease pattern was observed; peaks were noted for 1993, 1997, 2000, and 2005. However, the last peak had a low amplitude; since then a diminution in the proportion of siblings who transmitted the infection to young infants was observed (2). These results could have been caused…”

“…M. bohemicum was fi rst described in 1998 in a patient with Down syndrome (1). The organism is characterized by a unique 16S rRNA gene sequence (1) and has been isolated from humans, animals, and the environment (2). Published data on M. bohemicum are limited to the original species description and 5 additional case reports (3)(4)(5)(6).…”

“…Immunization of children with a highly effi cacious pertussis whole-cell (Pw) vaccine (Sanofi Pasteur MSD, Lyon, France) for 40 years (since 1966) has reduced the incidence of pertussis. It has been demonstrated that infectious or vaccinal immunity to pertussis wanes with time and that pertussis is no longer a pediatric disease (1)(2)(3)(4)(5). Transmission now occurs predominantly from adolescents and adults to unvaccinated newborns.…”