- Volume 54, Issue 6, 2004

The prevalence and diversity of bartonellae infecting the blood of 10 small mammal species inhabiting nine Nature Reserves of the Free State province, South Africa, was assessed using phenotypic, genotypic and phylogenetic methods. Of 86 small mammals sampled, 38 animals belonging to five different species yielded putative bartonellae. Thirty-two isolates were confirmed as bartonellae and were characterized by comparison of partial citrate synthase gene (gltA) sequences. Phylogenetic reconstructions derived from alignment of these sequences with those available for other bartonellae indicated that the South African rodent-associated isolates formed two distinct clades within the radius of the genus Bartonella. One of these clades also included recognized Bartonella species associated with rodents native to Eurasia but not to the New World, whereas the second clade contained exclusively isolates associated with South African rodents. Comparison of gltA sequences delineated the isolates into a number of ecologically distinct populations and provided an indication that a combination of phylogenetics and the identification of sequence clusters in housekeeping protein-encoding genes could be developed as a key criterion in the classification of bartonellae. This study is the first to investigate wildlife-associated bartonellae in Africa, adding support to their ubiquity and broad diversity and to the paradigm that the phylogenetic positions of the Bartonella species encountered today have been influenced by the geographical distribution of their hosts.

The current classification of non-pigmented and late-pigmenting rapidly growing mycobacteria (RGM) capable of producing disease in humans and animals consists primarily of three groups, the Mycobacterium fortuitum group, the Mycobacterium chelonae–abscessus group and the Mycobacterium smegmatis group. Since 1995, eight emerging species have been tentatively assigned to these groups on the basis of their phenotypic characters and 16S rRNA gene sequence, resulting in confusing taxonomy. In order to assess further taxonomic relationships among RGM, complete sequences of the 16S rRNA gene (1483–1489 bp), rpoB (3486–3495 bp) and recA (1041–1056 bp) and partial sequences of hsp65 (420 bp) and sodA (441 bp) were determined in 19 species of RGM. Phylogenetic trees based upon each gene sequence, those based on the combined dataset of the five gene sequences and one based on the combined dataset of the rpoB and recA gene sequences were then compared using the neighbour-joining, maximum-parsimony and maximum-likelihood methods after using the incongruence length difference test. Combined datasets of the five gene sequences comprising nearly 7000 bp and of the rpoB+recA gene sequences comprising nearly 4600 bp distinguished six phylogenetic groups, the M. chelonae–abscessus group, the Mycobacterium mucogenicum group, the M. fortuitum group, the Mycobacterium mageritense group, the Mycobacterium wolinskyi group and the M. smegmatis group, respectively comprising four, three, eight, one, one and two species. The two protein-encoding genes rpoB and recA improved meaningfully the bootstrap values at the nodes of the different groups. The species M. mucogenicum, M. mageritense and M. wolinskyi formed new groups separated from the M. chelonae–abscessus, M. fortuitum and M. smegmatis groups, respectively. The M. mucogenicum group was well delineated, in contrast to the M. mageritense and M. wolinskyi groups. For phylogenetic organizations derived from the hsp65 and sodA gene sequences, the bootstrap values at the nodes of a few clusters were <70 %. In contrast, phylogenetic organizations obtained from the 16S rRNA, rpoB and recA genes were globally similar to that inferred from combined datasets, indicating that the rpoB and recA genes appeared to be useful tools in addition to the 16S rRNA gene for the investigation of evolutionary relationships among RGM species. Moreover, rpoB gene sequence analysis yielded bootstrap values higher than those observed with recA and 16S rRNA genes. Also, molecular signatures in the rpoB and 16S rRNA genes of the M. mucogenicum group showed that it was a sister group of the M. chelonae–abscessus group. In this group, M. mucogenicum ATCC 49650T was clearly distinguished from M. mucogenicum ATCC 49649 with regard to analysis of the five gene sequences. This was in agreement with phenotypic and biochemical characteristics and suggested that these strains are representatives of two closely related, albeit distinct species.

ATCC 23581T has been cited as the type strain of Leptospira interrogans since 1980. In 1986, the Centers for Disease Control informed the ATCC that this strain was Leptospira interrogans serovar budapest, not serovar icterohaemorrhagiae as deposited originally. An authentic culture of the Leptospira interrogans serovar icterohaemorrhagiae RGAT strain was then submitted and assigned ATCC 43642, which was designated as the type strain of Leptospira interrogans in an article by Yasuda et al. [ Yasuda et al. (1987) . Int J Syst Bacteriol 37, 407–415]. In this Request for an Opinion to the Judicial Commission, it is proposed that a correction be made in the Approved Lists of Bacterial Names to acknowledge ATCC 43642 as the type strain of Leptospira interrogans.