scholarly journals Reconstituting the genus Mycobacterium

Author(s):  
Conor J. Meehan ◽  
Roman A. Barco ◽  
Yong-Hwee E. Loh ◽  
Sari Cogneau ◽  
Leen Rigouts

The definition of a genus has wide-ranging implications both in terms of binomial species names and also evolutionary relationships. In recent years, the definition of the genus Mycobacterium has been debated due to the proposed split of this genus into five new genera ( Mycolicibacterium , Mycolicibacter , Mycolicibacillus , Mycobacteroides and an emended Mycobacterium ). Since this group of species contains many important obligate and opportunistic pathogens, it is important that any renaming of species does not cause confusion in clinical treatment as outlined by the nomen periculosum rule (56a) of the Prokaryotic Code. In this study, we evaluated the proposed and original genus boundaries for the mycobacteria, to determine if the split into five genera was warranted. By combining multiple approaches for defining genus boundaries (16S rRNA gene similarity, amino acid identity index, average nucleotide identity, alignment fraction and percentage of conserved proteins) we show that the original genus Mycobacterium is strongly supported over the proposed five-way split. Thus, we propose that the original genus label be reapplied to all species within this group, with the proposed five genera potentially used as sub-genus complex names.

2021 ◽  
Author(s):  
Conor J Meehan ◽  
Roman A. Barco ◽  
Yong-Hwee E Loh ◽  
Sari Cogneau ◽  
Leen Rigouts

AbstractThe definition of a genus has wide ranging implications both in terms of binomial species names and also evolutionary relationships. In recent years, the definition of the genus Mycobacterium has been debated due to the proposed split of this genus into five new genera (Mycolicibacterium, Mycolicibacter, Mycolicibacillus, Mycobacteroides and an emended Mycobacterium). Since this group of species contains many important obligate and opportunistic pathogens, it is important that any renaming of species is does not cause confusion in clinical treatment as outlined by the nomen periculosum rule (56a) of the Prokaryotic Code.In this study, we evaluated the proposed and original genus boundaries for the mycobacteria, to determine if the split into five genera was warranted. By combining multiple approaches for defining genus boundaries (16S rRNA gene similarity, amino acid identity index, average nucleotide identity, alignment fraction and percentage of conserved proteins) we show that the original genus Mycobacterium is strongly supported over the proposed five-way split. Thus, we propose that the original genus label be reapplied to all species within this group, with the proposed five genera used as sub-genus complex names.


Author(s):  
Min Yang ◽  
Jiang Li ◽  
Xiao-meng Lv ◽  
Li-rong Dai ◽  
Ke-jia Wu ◽  
...  

A strictly anaerobic, thermophilic, Gram-stain-negative bacterium, named as strain S15T, was isolated from oily sludge of Shengli oilfield in PR China. Cells of strain S15T were straight or slightly curved rods with 0.4–0.8 µm width × 1.4–3 µm length and occurred mostly in pairs or short chains. Endospore-formation was not observed. The strain grew optimally at 55 °C (range from 30–65 °C), pH 6.5 (pH 6.0–8.5) and 0–30 g l−1 NaCl (optimum with 10 g l−1 NaCl). Yeast extract was an essential growth factor for strain S15T. The major cellular fatty acid was iso-C15 : 0 (58.2 %), and the main polar lipids were amino phospholipid (APL), glycolipids (GLs) and phosphatidylethanolamine (PE). The G+C content of DNA of strain S15T was 52.2 mol%. Strain S15T shared 89.8 % 16S rRNA gene similarity with the most related organism Acetomicrobium hydrogeniformans DSM 22491T in the phylum Synergistetes . The paired genomic average amino acid identity (AAI) and percentage of conserved proteins (POCP) values showed relatedness of less than 58.0 and 39.7 % with type strains of the species in the phylum Synergistetes . On the basis of phenotypic, phylogenetic and phylogenomic evidences, strain S15T constitutes a novel species in a novel genus, for the name Thermosynergistes pyruvativorans gen. nov., sp. nov. is proposed. The type strain is S15T (=CCAM 583T=JCM 33159T). Thermosynergistaceae fam. nov. is also proposed.


2020 ◽  
Vol 70 (11) ◽  
pp. 5734-5739 ◽  
Author(s):  
Kristin Mühldorfer ◽  
Claudia A. Szentiks ◽  
Gudrun Wibbelt ◽  
Mark van der Linden ◽  
Christa Ewers ◽  
...  

Novel catalase-negative, Gram-stain-positive, beta-haemolytic, coccus-shaped organisms were isolated from Chacoan peccaries that died from respiratory disease. The initial API 20 Strep profiles suggested Streptococcus agalactiae with acceptable identification scores, but the 16S rRNA gene similarity (1548 bp) to available sequences of streptococci was below 98 %. Next taxa of the genus Streptococcus , displaying highest similarities to the strains from this study, were S. bovimastitidis NZ1587T (97.5 %), S. iniae ATCC 29178T (97.5 %), S. hongkongensis HKU30T (97.4 %), S. parauberis DSM 6631T (97.1 %), S. penaeicida CAIM 1838T (97.1 %), S. pseudoporcinus DSM 18513T (97.0 %), S. didelphis DSM 15616T (96.6 %), S. ictaluri 707-05T (96.6 %), S. uberis JCM 5709T (96.5 %) and S. porcinus NCTC 10999T (96.4 %). All other Streptococcus species had sequence similarities of below 96.4 %. A sodA gene as well as whole genome-based core genome phylogeny of three representative strains and 145 available Streptococcus genomes confirmed the unique taxonomic position. Interstrain average nucleotide identity (ANI) and amino acid identity (AAI) values were high (ANI >96 %; AAI 100%), but for other streptococci clearly below the proposed species boundary of 95–96 % (ANI <75 %; AAI <83 %). Results were confirmed by genome-to-genome distance calculations. Pairwise digital DNA–DNA hybridization estimates were high (>90 %) between the novel strains, but well below the species boundary of 70 % for closely related Streptococcus type strains (23.5–19.7 %). Phenotypic properties as obtained from extended biochemical profiles and MALDI-TOF mass spectrometry supported the outstanding rank. Based on the presented molecular and physiological data of the six strains, we propose a novel taxon for which we suggest the name Streptococcus catagoni sp. nov. with the type strain 99-1/2017T (=DSM 110457T=CCUG 74072T) and five reference strains.


2020 ◽  
Vol 70 (4) ◽  
pp. 2879-2887 ◽  
Author(s):  
Dong Han ◽  
Heng-Lin Cui

A novel Gram-stain-negative, aerobic and rod-shaped halophilic archaeon, designated HD8-45T, was isolated from the red brine of salted brown alga Laminaria produced at Dalian, PR China. According to the results of 16S rRNA gene and rpoB′ gene sequence comparisons, strain HD8-45T showed the highest sequence similarity to the corresponding genes of Salinirussus salinus YGH44T (95.1 and 85.2 % similarities, respectively), Halovenus aranensis EB27T (91.2 and 86.0 % similarities, respectively). The low sequence similarity and the phylogeny implied the novel generic status of strain HD8-45T. Genomic relatedness analyses showed that strain HD8-45T were clearly distinguished from other species in the order Halobacteriales , with average nucleotide identity, amino acid identity and in silico DNA–DNA hybridization values not more than 75.1, 65.6 and 21.5 %. The polar lipid pattern contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, two major glycolipids and two minor glycolipids. The two major glycolipids and a minor glycolipid were chromatographically identical to disulfated mannosyl glucosyl diether, sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. The major respiratory quinones were menaquinone MK-8 and MK-8(H2). The DNA G+C content was 62.0 mol% (Tm ) and 61.9 mol% (genome). All these results showed that strain HD8-45T represents a novel species of a new genus in the order Halobacteriales , for which the name Salinibaculum litoreum gen. nov., sp. nov. is proposed. The type strain of Salinibaculum litoreum is HD8-45T (=CGMCC 1.15328T=JCM 31107T).


Author(s):  
Soon Dong Lee ◽  
In Seop Kim ◽  
Hanna Choe ◽  
Ji-Sun Kim

A Gram-negative, facultatively anaerobic bacterium, designated SAP-6T, was isolated from sap extracted from Acer pictum in Mt. Halla in Jeju, Republic of Korea and its precise taxonomic status was determined by a polyphasic approach. Cells were non-sporulating, motile, short rods and showed growth at 4–37 °C, pH 6.0–8.0 and 0–4% NaCl. Phylogenomic analysis based on 92 core gene sequences showed that strain SAP-6T belonged to the family Pectobacteriaceae and formed a distinct clade between members of the genera Sodalis and Biostraticola with gene support index of 89. The closest phylogenetic neighbours were Biostraticola tofi DSM 19580T (97.3% 16S rRNA gene sequence similarity) and Sodalis praecaptivus HS1T (96.8%), with the average amino acid identity values of 75.3% and 74.0%, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The major isoprenoid quinones were Q-7 and Q-8. The predominant fatty acids were C16:0, C17:0 cyclo and summed feature 3. The DNA G+C content was 57.0%. On the basis of data presented here, strain SAP-6T (=KCTC 52622T=DSM 104038T) represents a novel species of a new genus in the family Pectobacteriaceae , for which the name Acerihabitans arboris gen. nov., sp. nov. is proposed.


Author(s):  
Zhe Li ◽  
Wenjin Hu ◽  
Shushi Huang ◽  
Yuanlin Huang ◽  
Fei Li ◽  
...  

A Gram-stain-negative, aerobic, milky white bacterium, designated B2012T, was isolated from mangrove sediment collected at Beibu Gulf, South China Sea. Antimicrobial activity assay revealed that the isolate possesses the capability of producing antibacterial compounds. Strain B2012T shared the highest 16S rRNA gene sequence relatedness (96.9–95.5 %) with members of the genus Acuticoccus . The isolate and all known Acuticoccus species contain Q-10 as the main respiratory quinone and have the same polar lipid components (phosphatidylcholine, unidentified glycolipid, unidentified lipid, unidentified amino lipid and phosphatidylglycerol). However, genomic relatedness referred by values of average nucleotide identity, digital DNA–DNA hybridization, average amino acid identity and the percentage of conserved proteins between strain B2012T and other type strains of the genus Acuticoccus were below the proposed thresholds for species discrimination. The genome of strain B2012T was assembled into 65 scaffolds with an N50 size of 244239 bp, resulting in a 5.5 Mb genome size. Eight secondary metabolite biosynthetic gene clusters were detected in this genome, including three non-ribosomal peptide biosynthetic loci encoding yet unknown natural products. Strain B2012T displayed moderately halophilic and alkaliphilic properties, growing optimally at 2–3 % (w/v) NaCl concentration and at pH 8–9. The major cellular fatty acids (>10 %) were anteiso-C15 : 0, C16 : 0 dimethyl aldehyde (DMA) and C16 : 0. Combined data from phenotypic, genotypic and chemotaxonomic analyses suggested that strain B2012T represents a novel species of the genus Acuticoccus , for which the name Acuticoccus mangrovi sp. nov. is proposed. The type strain of the type species is B2012T (=MCCC 1K04418T=KCTC 72962T).


Author(s):  
Kyung June Yim ◽  
Dong-Hyun Jung ◽  
Seok Won Jang ◽  
Sanghwa Park

A cream-coloured, Gram-stain-negative, rod-shaped bacterium, designated strain KSC-6T, was isolated from soil sampled at the Gapcheon River watershed in Daejeon, Republic of Korea. The organism does not require NaCl for growth and grows at pH 6.0–8.0 (optimum, pH 7.0) and 10–37 °C (optimum, 25 °C). Phylogenetic trees based on the 16S rRNA gene sequences reveal that strain KSC-6T belongs to the family Chitinophagaceae within the order Chitinophagales and is most closely related to Panacibacter ginsenosidivorans Gsoil 1550T (95.9% similarity). The genomic DNA G+C content was 38.9 mol%. The major cellular fatty acids (>8 %) of strain KCS-6T were iso-C15:0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The predominant respiratory quinone was menaquinone 7 and the predominant polar lipids were phosphatidylethanolamine, five unidentified aminolipids and two unidentified lipids. Based on genome analyses, low digital DNA–DNA hybridization, average nucleotide identity and average amino acid identity values with closely related genera, and differential chemotaxonomic and physiological properties, we suggest that strain KCS-6T represents a novel species in a new genus in the family Chitinophagaceae , for which the name Limnovirga soli gen. nov., sp. nov. (type strain KCS-6T=KCCM 43337T=NBRC 114336T) is proposed.


2013 ◽  
Vol 63 (Pt_9) ◽  
pp. 3287-3292 ◽  
Author(s):  
Akio Tani ◽  
Nurettin Sahin

Pink-pigmented, facultatively methylotrophic bacteria, strains 87eT and 99bT, were isolated from the bryophytes Haplocladium microphyllum and Brachythecium plumosum, respectively. The cells of both strains were Gram-reaction-negative, motile, non-spore-forming rods. On the basis of 16S rRNA gene sequence similarity, strains 87eT and 99bT were found to be related to Methylobacterium organophilum ATCC 27886T (97.1 % and 97.7 %, respectively). Strains 87eT and 99bT showed highest 16S rRNA gene similarity to Methylobacterium gnaphalii 23eT (98.3 and 99.0 %, respectively). The phylogenetic similarities to all other species of the genus Methylobacterium with validly published names were less than 97 %. Major cellular fatty acids of both strains were C18 : 1ω7c and C18 : 0. The results of DNA–DNA hybridization, phylogenetic analyses based on 16S rRNA and cpn60 gene sequences, fatty acid profiles, whole-cell matrix-assisted, laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis, and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strains 87eT and 99bT from their phylogenetically closest relatives. We propose that strains 87eT and 99bT represent novel species within the genus Methylobacterium , for which the names Methylobacterium haplocladii sp. nov. (type strain 87eT = DSM 24195T = NBRC 107714T) and Methylobacterium brachythecii sp. nov. (type strain 99bT = DSM 24105T = NBRC 107710T) are proposed.


2020 ◽  
Vol 70 (5) ◽  
pp. 3335-3339 ◽  
Author(s):  
Guanghua Wang ◽  
Dahao Tang ◽  
Guangyu Li ◽  
Shuailiang Xu ◽  
Ge Dang ◽  
...  

A Gram-stain-negative, non-spore-forming, aerobic, motile, curved rod-shaped bacterium, designed strain R148T was isolated from a coralline algae Tricleocarpa sp. collected from Weizhou island, PR China. The optimal growth of R148T occurred at 25 °C, pH 8–9 in the presence of 0.5 % (w/v) NaCl on the basis of amended marine broth 2216. The genomic DNA G+C content was 59.5 mol%. The only detected respiratory quinone was Q-10. The major polar lipids were phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and three unidentified ninhydrin-positive lipids. The major cellular fatty acids were C18 : 1ω7c, C16 : 1ω7c, C19 : 0cyclo 9, 10 DMA and C18 : 0. The results of 16S rRNA gene-based global alignment indicated that the closest neighbour of strain R148T was Pelagibius litoralis DSM 21314T (93.1 % similarity), the second is Limibacillus halophilus KCTC 42420T (92.2 %). The results of phylogenetic analysis indicated that R148T forms a distinct branch in the robust clade of R148T and P. litoralis DSM 21314T, while the taxonomic position of this clade in the family Rhodospirillaceae is ambiguous among phylogenetic approaches. The low 16S rRNA gene similarity and distinct polar lipid and cellular fatty acid profile could readily distinguish R148T from closely related type strains. So R148T is suggested to represent a novel species in a novel genus, for which the name Denitrobaculum tricleocarpae gen. nov., sp. nov. is proposed. The type strain is R148T (=MCCC 1K03781T=KCTC 72137T).


2020 ◽  
Vol 70 (4) ◽  
pp. 2204-2210 ◽  
Author(s):  
Zhi Tian ◽  
Shan Lu ◽  
Dong Jin ◽  
Jing Yang ◽  
Ji Pu ◽  
...  

Two Gram-stain-positive, catalase-positive and oxidase-negative, aerobic, non-motile, cellobiose-utilizing, short-rod-shaped strains (Z28T and Z29) were isolated from faeces of Tibetan antelope (Pantholops hodgsonii) collected on the Qinghai–Tibet Plateau. Strain Z28T shared 98.1, 98.0, 97.8 and 97.4 % 16S rRNA gene similarity, 24.1, 22.8, 23.2 and 26.3 % digital DNA–DNA hybridization relatedness and 80.8, 80.0, 80.7 and 80.9 % average nucleotide identity values with Cellulomonas oligotrophica DSM 24482T, Cellulomonas flavigena DSM 20109T, Cellulomonas iranensis DSM 14785T and Cellulomonas terrae JCM 14899T, respectively. Results from further phylogenetic analyses based on the 16S rRNA gene and 148 core genes indicated that strains Z28T and Z29 were closest to C. oligotrophica DSM 24482T and C. flavigena DSM 20109T, but clearly separated from the currently recognized species of the genus Cellulomonas . The genomic DNA G+C content of strain Z28T was 75.3 mol%. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C15 : 1 A, C16 : 0 and anteiso-C17 : 0. Ribose and mannose were detected as the whole-cell sugars. The major respiratory quinone was MK-9(H4) and ornithine was the diamino acid of the cell wall. The polar lipids present in strain Z28T were phosphatidylethanolamine, five phospholipids, two aminophospholipids, aminolipid and three unidentified lipids. Comparison of phenotypic and phylogenetic features between the two strains and the related organisms revealed that Z28T and Z29 represent a novel species of the genus Cellulomonas , for which the name Cellulomonas shaoxiangyii sp. nov. is proposed. The type strain is Z28T (=CGMCC 1.16477T=DSM 106200T).


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