Anaerospora hongkongensis Gen. Nov. Sp. Nov., a Novel Genus and Species with Ribosomal DNA Operon Heterogeneity Isolated from an Intravenous Drug Abuser with Pseudobacteremia

Abstract

Since the discovery of polymerase chain reaction (PCR) and DNA sequencing, comparison of the gene sequences of bacterial species has shown that the 16S rDNA is highly conserved within a species and among species of the same genus, and hence can be used as the new standard for classification of bacteria. Using this new standard, phylogenetic trees, based on base differences between species, are constructed; and bacteria are classified and re-classified into new genera. Recently, the use of this technique for the identification of bacterial strains with ambiguous biochemical profiles and the discovery of novel genera and species have been reported by us and other researchers (5-7, 10, 16, 18-30).Based on the results of 16S rDNA sequencing, major changes in the taxonomy of anaerobic Gram-negative bacteria have been made in recent years (2,4,9,11,15). At the moment, about 50 genera of anaerobic Gram-negative bacteria have been described, three of which were sporulated. In this study, we report the isolation of an anaerobic Gram-negative bacterial strain from the blood culture of an intravenous drug abuser. The strain, named HKU15 T , exhibited phenotypic characteristics that do not fit into patterns of any known genus and species. 16S rDNA sequencing showed that there was only about 90% base identity between the 16S rDNA of HKU15T and that of the most closely related species, Dendrosporobacter quercicolus (15). On the basis of these results we propose a new genus and species, Anaerospora hongkongensis gen. nov. sp. Abstract: A bacterium was isolated from the blood culture of an intravenous drug abuser with pseudobacteremia. The cells were strictly anaerobic, straight or slightly curved, sporulating, Gram-negative rods. It grew on sheep blood agar as non-hemolytic, pinpoint colonies after 48 hr of incubation at 37 C in an anaerobic environment. It was motile but did not produce catalase or cytochrome oxidase. 16S ribosomal DNA (rDNA) sequencing revealed three different copies of 16S rDNA sequences. More than 90% of the differences among them were due to differences in the lengths of the sequences. Phylogenetically, the bacterium is clustered with Dendrosporobacter, Sporomusa, and Propionispora, the other three genera of anaerobic, sporulating, Gram-negative rods. There were 8.6-11.1% differences between the 16S rDNA sequences of the bacterium and that of D. quercicolus, 4.7-15.1% differences between the 16S rDNA sequences of it and those of S. acidovorans, S. aerivorans, S. malonica, S. ovata, S. paucivorans, S. silvacetica, S. spaeroides, and S. termitida, and 7.6-13.1% differences between the 16S rDNA sequences of it and those of P. hippei and P. vibrioides. The G؉C content of the bacterium (mean؎SD) was 46.8؎3.2%. For these reasons, a new genus and species, Anaerospora hongkongensis gen. nov. sp. nov., is proposed, for which HKU15 T is the type strain. Anaerospora hongkongensis

Geobacter pickeringii sp. nov., Geobacter argillaceus sp. nov. and Pelosinus fermentans gen. nov., sp. nov., isolated from subsurface kaolin lenses

“…However, despite their lower potential for Fe(III) reduction, fermentative bacteria can be important to the iron geochemistry of kaolin due to the high organic matter content in kaolin (0.1-5.3 %, w/w). The organic matter of kaolins contains various potential electron donors and fermentable substrates for bacterial metabolism such as formate, acetate, lactate, propionate, butyrate, pyruvate, (Stankewich et al, 1971;Strömpl et al, 2000); 4, Anaerosinus glycerini strain LGS 4 T (Schauder & Schink, 1989;Strömpl et al, 1999); 5, 'Anaerospora hongkongensis' HKU15 (Woo et al, 2005). 'Anaerospora hongkongensis' HKU15 was studied using ANI and ATB ID32A test kits (bioMérieux).…”

Intragenomic heterogeneity of the 16S rRNA gene in strain UFO1 caused by a 100-bp insertion in helix 6

“…The presence of multiple copies of the 16S rRNA gene and heterogeneity among these genes in a single organism has been examined in sequenced microbial genomes (Coenye & Vandamme, 2003; Acinas et al ., 2004). Significant intragenomic heterogeneity between multiple copies of 16S rRNA genes has been reported for Thermobispora bispora (Wang et al ., 1997), Haloarcula marismortui (Mylvaganam & Dennis, 1992; Amann et al ., 2000), Desulfotomaculum kuznetsovii (Tourova et al ., 2001), Anaerospora hongkongensis (Woo et al ., 2005), several Aeromonas strains (Morandi et al ., 2005), and strains of Desulfitobacterium (Villemur et al ., 2007).…”

“…Previous work with Escherichia coli suggested that large variations occurring in one 16S rRNA gene copy can be fixed through recombination events with other 16S rRNA gene copies, thereby homogenizing the sequence among all copies (Hashimoto et al ., 2003). However, insertion sequences 100–200 bp in length have been found in the 5′ region of some bacterial 16S rRNA genes (Patel et al ., 1992; Woo et al ., 2005; Villemur et al ., 2007). Intervening sequences (IVSs) are intron‐like elements that have been found in the rRNA genes of bacteria (Zimmerly, 2005).…”

Internal Transcribed Spacer Region Sequence Heterogeneity in Rhizopus microsporus : Implications for Molecular Diagnosis in Clinical Microbiology Laboratories

“…Recently, we reported rDNA operon heterogeneity in a novel genus and species of bacterium, Anaerospora hongkongensis, isolated from an intravenous drug user (25). When present, such rDNA operon heterogeneity will pose difficulties for direct sequencing of the PCR product for bacterial identification as double or multiple nucleotide peaks will be present in the sequence traces.…”