Syst Evol Microbiol Research Articles

Genome-based reclassification of Kitasatospora niigatensis as a later heterotypic synonym of Kitasatospora cineracea Tajima et al. (2001).

The present study used genome-based approaches to investigate the taxonomic relationship between Kitasatospora cineracea DSM 44780T and Kitasatospora niigatensis DSM 44781T, two species that were previously described by Tajima et al. (Int J Syst Evol Microbiol 51:1765-1771, 2001). The digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI), and average nucleotide identity (ANI) values between the genomes of the two type strains were 90.3, 98.7, and 99.1%, respectively. These values exceeded the established thresholds of 70% (dDDH) and 95-96% (ANI and AAI) for bacterial species delineation, suggesting that K. cineracea and K. niigatensis should share the same taxonomic position. Furthermore, our analysis using the 'Bacterial Pan Genome Analysis' (BPGA) pipeline and the Maximum Likelihood core-genes tree inferred using FastTree2 consistently demonstrated that K. cineracea DSM 44780T and K. niigatensis DSM 44781T are closely related, as indicated by the clustering of these strains in the core-genes phylogenomic tree. Based on these findings, we propose that K. niigatensis should be considered a later heterotypic synonym of K. cineracea.

Description and genomic characterization of Gallaecimonas kandeliae sp. nov., isolated from the sediments of mangrove plant Kandelia obovate.

The genus Gallaecimonas, proposed by Rodríguez-Blanco et al. (Int J Syst Evol Microbiol 60:504-509, 2010), is mainly isolated from marine environments. So far, only three species have been identified and characterized in this genus. In this study, a new Gallaecimonas strain named Q10T was isolated from the sediments of mangrove plant Kandelia obovate taken from Dapeng district, Shenzhen, China. Strain Q10T was a Gram-stain-negative, non-motile, strictly aerobic, rod-shaped bacterium, and grew with 0-8.0% (w/v) NaCl, at 10-45°C and at pH 5.5-8.5. Phylogenetic analysis indicated that strain Q10T and the three Gallaecimonas species formed a clade in the tree, with 16S rRNA gene sequence similarities ranging from 96.0 to 97.0%. The major respiratory quinone is Q8. The polar lipids comprised aminolipid, aminophospholipid, diphosphatidylglycerol, glycolipid, phosphatidylethanolamine, phosphatidylglycerol, glycophospholipid and phospholipid. The predominant fatty acids are C16:0, C17:1ω8c, summed feature 3 (C16:1ω7c/C16:1ω6c), and iso-C16:0. The complete genome of strain Q10T is 3,836,841bp with a G+C content of 62.6mol%. The orthologous proteins analysis revealed 55 unique proteins in strain Q10T related to important biological processes, especially three frataxins related to iron-sulfur cluster assembly, which may play a pivotal role in environmental adaptability of this species. Based on polyphasic taxonomic data, strain Q10T is considered to represent a novel species within the genus Gallaecimonas, for which the name Gallaecimonas kandelia sp. nov. is proposed. The type strain is Q10T (=KCTC 92860T=MCCC 1K08421T). These results contribute to a better understanding of general features and taxonomy of the genus Gallaecimonas.

Serratia silvae sp. nov., Isolated from Forest Soil.

The Gram-negative, oxidase-negative, catalase-positive, rod-shaped strain Arafor3T was isolated from forest soil (France). Comparative 16S rRNA gene analysis and phylogenetic analysis based on (1) multilocus sequence analysis (MLSA) with four housekeeping genes (atpD, gyrB, infB and rpoB) and (2) genomes indicated that strain Arafor3T shared 98.83% 16S rRNA gene sequence similarity with the type strain of Serratia fonticola DSM 4576T and was closely related to this same strain in the MLSA and in the phylogenomic tree reconstruction. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) comparisons of strain Arafor3T with its nearest neighbor S. fonticola DSM 4576T showed 93.5% identity and 55.7% sequence similarity, respectively, and were lower than the 96% and 70% species-level cut-off values relating to these analyses (Logan et al. in Int J Syst Evol Microbiol 59:2114-21, 2009, https://doi.org/10.1099/ijs.0.013649-0 ). The strain differed from S. fonticola in that it was urease and arginine dihydrolase negative. The major fatty acids of strain Arafor3T are C16:0, C16:1 ω7c/C16:1 ω6c, C14:0, C14:0 3-OH/16:1 isoI, and C18:1 ω7c. The major respiratory quinone is Q8. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and 6 unknown lipids. The mol G + C% content of the genomic DNA of strain Arafor3T was 53.49%. Hence, Arafor3T represents a novel species within the genus Serratia, for which the name Serratia silvae sp. nov. is proposed. The type strain is Arafor3T (=LMG 32338T = CIP 111939T).

Microvirgula curvata as a Cause of Ventriculoperitoneal Shunt Infection

Abstract Microvirgula curvata is a small Gram-negative, curved rod first isolated from hydrocarbon-contaminated soil in Kuwait (Subhash et al. Int J Syst Evol Microbiol 2016;66:5309–5313). We describe the first known case of human infection with M. curvata in a 65-year-old man with a ventriculoperitoneal shunt.

Genome-based reclassification of the genus Meiothermus along with the proposal of a new genus Allomeiothermus gen. nov.

Phylogenomic analyses were performed on the nine species of the genus Meiothermus and four species of the genus Calidithermus. Phylogenetic analysis, low values of genomic relatedness indices and functional diversity analysis indicated that Meiothermus silvanus should not be classified within the clades for Meiothermus and Calidithermus but instead be reclassified as a new genus, for which we propose the name Allomeiothermus gen. nov., with Allomeiothermus silvanus comb. nov. as type species. In addition, the species Meiothermus cateniformans Zhang et al. (Int J Syst Evol Microbial 60:840-844, 2010) should also be reclassified as a later heterotypic synonym of Meiothermus taiwanensis Chen et al. (Int J Syst Evol Microbiol 52:1647-1654, 2002) emend. Raposo et al. (2019). This reclassification is based on the high genomic relatedness indices (98.8% ANI; 90.2% dDDH; 99% AAI) that are above the threshold values necessary for defining a new species, as well as on the observation of overlapping functions on Principal Coordinate Analysis plot generated from Clusters of Orthologous Genes.

Duganella aceris sp. nov., isolated from tree sap and proposal to transfer of Rugamonas aquatica and Rugamonas rivuli to the genus Duganella as Duganella aquatica comb. nov., with the emended description of the genus Rugamonas.

A Gram-reaction-negative, strictly aerobic, betaproteobacterial strain, designated SAP-35T, was isolated from sap extracted from Acer pictum in Mt. Halla in Jeju, Republic of Korea, and its taxonomic status was examined by a polyphasic approach. Cells of the organism were non-sporulating, motile rods and grew at 4-30°C, pH 6-7 and in the absence of NaCl. 16S rRNA gene- and whole genome-based phylogenetic analyses showed that strain SAP-35T belonged to the family Oxalobacteraceae and was closely related to Rugamonas rivuli (98.9% 16S rRNA gene sequence similarity) and Rugamonas aquatica (98.4%). The phylogenomic clustering and average amino acid identity values supported that strain SAP-35T belonged to the genus Duganella and two Rugamonas species should be transferred to the genus Duganella. The major isoprenoid quinone of the isolate was Q-8. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The predominant fatty acids were summed feature 3, C16:0 and C17:0 cyclo. The G + C content of genome was 64.9%. The average nucleotide identity and dDDH values between strain SAP-35T and the members of the genera Rugamonas and Duganella were < 85.1% and < 49%, respectively. Based on the combined data presented here, strain SAP-35T (= KCTC 72227T = NBRC 113903T) represents a novel species of the genus Duganella, for which the name Duganella aceris sp. nov. is proposed. Also, Rugamonas aquatica Lu et al. (Int J Syst Evol Microbiol 70: 3328-3334, 2020) and Rugamonas aquatica Lu et al. 2020 are reclassified as Duganella aquatica comb. nov., with the emended description of the genus Rugamonas.

Milk microbiome: evaluation study on the differences among cows with a different health status classified by leukocyte pattern

Milk microbiome: evaluation study on the differences among cows with a different health status classified by leukocyte pattern

Three alternative proposals to emend the Rules of the International Code of Nomenclature of Prokaryotes to resolve the status of the Cyanobacteria in the prokaryotic nomenclature.

Three alternative proposals to emend the Rules of the International Code of Nomenclature of Prokaryotes are presented to resolve the status of the Cyanobacteria in the prokaryotic nomenclature. Two were earlier published (Oren and Garrity, Int J Syst Evol Microbiol 2014;64 : 309-310; Pinevich, Int J Syst Evol Microbiol 2015;65 : 1070-1074). The third proposal is based on reciprocation of Article 45.1 of the International Code of Nomenclature for algae, fungi, and plants. According to Article 13b of the Statutes of the International Committee on Systematics of Prokaryotes, a decision on these proposals must be reached within 11 months from the date of this publication.

The necessity for molecular classification of basidiomycetous biocontrol yeasts

The field of plant protection is steadily reducing the use of chemicals by increasing the use of microbial biocontrol agents. At present, several microorganisms are active ingredients of the so-called biofungicides and some of these are based on yeasts. Molecular techniques applied in microbial taxonomy are leading to extensive revisions of the classification of many microbial groups, including various yeasts used for biocontrol. Recent taxonomic revision of the basidiomycete genus Cryptococcus resulted in C. laurentii (Kufferath) Skinner (Tremellales) being renamed as Papiliotrema laurentii, including strains displaying biocontrol activity, such as strain LS28. In this study, we performed comparisons of ITS, D1D2, TEF1, and RPB1 nucleotide sequences of LS28 with the corresponding genes of the type strains of taxonomically related species. We found that the yeast strain LS28 belongs to the species P. terrestris (Tremellales) (Crestani et al. Int J Syst Evol Microbiol 59:631–636, 2009) rather than P. laurentii. We encourage other groups working on biocontrol to perform molecular characterization of their yeast(s) of interest to identify the species that have the highest potential for practical applications and facilitate possible commercial registration.

Case report: Mycobacterium monacense isolated from the blood culture of a patient with pulmonary infection

BackgroundThe poorly known mycobacterial species Mycobacterium monacense is a rapidly growing non-tuberculous mycobacterium that was first described in 2006 (Reischl et al., Int J Syst Evol Microbiol 56:2575-8, 2006); it has been reported that its isolation is usually associated with skin and lung infections, especially in immunosuppressed patients (Hogardt et al., Jpn J Infect Dis 61:77-8, 2008; Taieb et al., J Hand Surg Am 33:94-6, 2008; Therese et al., Lung India 28:124-6, 2011; Shojaei et al., Ann Lab Med 32:87-90, 2012; Romero et al., New Microbes New Infect 10:112-5, 2016 ). The clinical significance of Mycobacterium monacense is not yet fully understood. Here, we report the first isolation of Mycobacterium monacense from the blood culture of a patient in China with severe pneumonia.Case presentationOn June 26, 2018, a 38-year-old man was admitted to the intensive care unit with breathing difficulty. One day prior, he was discovered with his face immersed in a small pond (non-chlorinated water) and with limb convulsions. He had undergone craniocerebral surgery after trauma 5 years earlier, which left him with epilepsy as a sequela. Bilateral diffuse ground-glass opacity was found in the lungs on chest X ray and chest CT image at admission. The result of the HIV serology test of the patient was negative. The patient was diagnosed with severe pneumonia. Drug-susceptible Klebsiella pneumoniae and Candida glabrata were isolated in the BALF, and yellow-pigmented colonies were isolated from blood cultures of the patient. The strain isolated from blood was identified by 16S rDNA sequencing as Mycobacteria monacense, which is a rapidly growing mycobacterium (RGM). The patient was treated with a combination of cefoperazone sulbactam, linezolid and voriconazole for 10 days, and the symptoms improved. During the one-year follow-up time, the patient did not relapse.ConclusionsWe report the first case of M. monacense isolated from blood cultures in a patient with severe pneumonia, which provided evidence that the environmental microorganism possessed pathogenic characteristics.

A case of Psychrobacter sanguinis bacteremia in a middle-aged man

Psychrobacter sanguinis is a Gram-negative obligate aerobe first identified in 2012. Psychrobacter species are cold-tolerant and often associated with marine environments.1 They are known to cause opportunistic infections. Here, we report the first known case of Psychrobacter sanguinis bacteremia in Singapore in a middle-aged man with no known exposure to seawater or seafood. The organism was initially identified by MALDI-TOF, and confirmed with 16S rRNA sequencing. We also describe further phenotypic studies of this isolate. The patient was admitted with fever, marked hyponatremia, rhabdomyolysis, and altered mental state, and his condition improved with IV ceftriaxone. Reference1.Wirth SE, Ayala-del-Río HL, Cole JA, et al. Psychrobacter sanguinis sp. nov., recovered from four clinical specimens over a 4-year period. Int J Syst Evol Microbiol 2012; 62: 49–54.

Valid publication of the names Caecibacterium and Caecibacterium sporoformans.

Descriptions of the genus Caecibacterium and its proposed type species Caecibacterium sporoformans were published in the IJSEM by Onrust et al. (Int J Syst Evol Microbiol 2017;67:4589-4594). The type strain was deposited as LMG 27730 and DSM 26959. DSM 26959 is a patent strain, and therefore the names were effectively, but not validly, published based on Rule 30(4) of the International Code of Nomenclature of Prokaryotes. The type strain of C. sporoformans is now available from the Deutsche Sammlung von Mikroorganismen und Zellkulturen as DSM 103070 and no restrictions have been placed on its distribution. We here present new descriptions of the genus and its type species so that the names can be validly published.

Request for revision of the Statutes of the International Committee on Systematics of Prokaryotes.

At the Valencia Plenary meeting on 7-9 July, 2017, the Working Group on the organization and structure of the ICSP recommended amendment of the Statutes of the ICSP (Dijkshoorn L. Int J Syst Evol Microbiol 2018; 68: 2104-2110). In October 2017, our Executive-Secretary, Lenie Dijkshoorn, sent out a call for participation in this working group, which began work in December, 2017. The members included William B. Whitman, Carolee Bull, Hans-Jürgen Busse, Pierre-Edouard Fournier, Aharon Oren, and Stefano Ventura. During the Winter and Spring, 2018, a large number of revisions were discussed by the working group. In addition, comments were solicited from Dan Brown [Secretary for Subcommittees on Taxonomy], Iain Sutcliffe [Chair ICSP], Fanus Venter [Member at Large, EB-ICSP], and Martha Trujillo [Editor-in-Chief of IJSEM]. The draft Statutes were then presented to the Executive Board [EB] at its online meeting on May 31, 2018. The EB asked that the working group circulate the draft to the members of the ICSP for comments for 45 days and that comments be returned by July 27, 2018. After that time, the working group incorporated additional suggestions before the final submission to IJSEM for publication. According to our current statutes, there will then be a period of 90 days following publication for further deliberation before a vote by the ICSP members.

Versatile catechol dioxygenases in Sphingobium scionense WP01T.

The objective was to understand the roles of multiple catechol dioxygenases in the type strain Sphingobium scionense WP01T (Liang and Lloyd-Jones in Int J Syst Evol Microbiol 60:413-416, 2010a) that was isolated from severely contaminated sawmill soil. The dioxygenases were identified by sequencing, examined by determining the substrate specificities of the recombinant enzymes, and by quantifying gene expression following exposure to model priority pollutants. Catechol dioxygenase genes encoding an extradiol xylE and two intradiol dioxygenases catA and clcA that are highly similar to sequences described in other sphingomonads are described in S. scionense WP01T. The distinct substrate specificities determined for the recombinant enzymes confirm the annotated gene functions and suggest different catabolic roles for each enzyme. The role of the three enzymes was evaluated by analysis of enzyme activity in crude cell extracts from cells grown on meta-toluate, benzoate, biphenyl, naphthalene and phenanthrene which revealed the co-induction of each enzyme by different substrates. This was corroborated by quantifying gene expression when cells were induced by biphenyl, naphthalene and pentachlorophenol. It is concluded that the ClcA and XylE enzymes are recruited in pathways that are involved in the degradation of chlorinated aromatic compounds such as pentachlorophenol, the XylE and ClcA enzymes will also play a role in degradation pathways that produce alkylcatechols, while the three enzymes ClcA, XylE and CatA will be simultaneously involved in pathways that generate catechol as a degradation pathway intermediate.

Clostridium neonatale sp. nov. linked to necrotizing enterocolitis in neonates and a clarification of species assignable to the genus Clostridium (Prazmowski 1880) emend. Lawson and Rainey 2016.

A description of an outbreak of necrotizing enterocolitis among neonates, linked to the putative novel species Clostridium neonatale and assignable to the genus Clostridium, was previously reported in brief but that name had never been validly published (Alfa et al. Clin Inf Dis 2002;35:S101-S105). Features of this taxon group and its phylogenetic position with respect to contemporary species in the genus Clostridium were recently reviewed and still found to be unique. Therefore, we provide here a description based on biochemical, chemotaxonomic and antimicrobial susceptibility testing (AST), matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS, 16S rRNA gene sequencing as well as information obtained by whole genome sequencing (WGS) for strains 99A005T and 99A006. Those two C. neonatale strains were essentially identical to each other, with genome sizes of 4 658 596-4 705 520 bp and G+C content of 28.4-28.5 mol% (WGS). AST inferred susceptibility to 14 antibiotics. MALDI-TOF spectra were unique and could potentially be used for identification. The type strain is (NML) LCDC 99A005T [=ATCC BAA-265T=CCUG 46077T=St. Boniface Hospital 30686T]. While performing this review, we found that the names of 24 validly published species assignable to the genus Clostridium had been omitted from the emended description of the genus (Lawson and Rainey Int J Syst Evol Microbiol 2016;66 :1009-1016). Those species are listed in brief here. Lastly, based on this review, we also propose that Eubacterium budayi, Eubacterium nitritogenes and Eubacterium combesii be transferred to the emended genus Clostridium, as Clostridium budayi comb. nov., Clostridium nitritogenes comb. nov. and Clostridium combesii comb. nov., respectively.

Plant Microbiome Innovation: M-trophs.

Human population is increasing from 7.6 billion today to an estimated 9.5–10 billion by 2050.1 How can billions more people, with increasing demands for protein and other food sources, be adequately fed without destroying the environment? Utilizing more land for agricultural purposes is not a solution, given that much of the arable land on the planet is already being used for food, fiber, chemical, or fuel production.2 One answer to this complex challenge will lie in the ability to produce more food within the current footprint in sustainable and affordable ways. By one definition, “an agricultural biologicals system is an ecologically, socially, and economically sustainable agricultural production system that promotes safe products by minimizing environmental adverse consequences and reducing the use of non-renewable natural resources.”3 In this article, we discuss opportunities that capitalize on twenty-first century technological innovation and the central role played by the microbial life intimately associated with plants: the plant and soil microbiomes. We examine the potential of Ag biologicals within the agricultural ecosystem. We elucidate their functionality as a means of increasing plant health and crop yields while maintaining environmental sustainability. Finally we illustrate the role that NewLeaf Symbiotics (St. Louis, MO) plays in the introduction of a range of Ag biologicals based on methylobacteria, or M-trophs—bio-complementary products that infuse plants with microbes that are tailored to fit specific crop genetics and environmental conditions.4 Most major agricultural input suppliers and seed companies recognize that biologicals represent a largely untapped opportunity to meet demand for novel and sustainable complements to the existing roster of agricultural chemicals, fertilizers, and genetically modified (GM) traits. Recent government, industrial, and private investments support the belief that significant improvements in crop productivity and environmental sustainability are achievable using complementary biological inputs. Between 2012 and 2015, over $2 billion was invested by Ag multinationals in agreements, mergers, and the acquisition of small biologicals companies.5 These investments are driving the development of the next generation of Ag biologicals. The broad recognition of the agricultural significance of the plant and soil microbiome is supported in large part by the reduced cost, increased speed, and improved accuracy of genomic sequencing. Simultaneous increases in computing power and analytics are driving the rapid evolution of new molecular biology tools directed at solving previously intractable problems. The recognition of the phyto-microbiome as a second genome, with the potential to supplement and interact with the plant genome, offers significant opportunity to improve crop health and yield.6 The persistent evolution of pest resistance to chemical pesticides and traits, combined with consumer demand for sustainable farming and food traceability, have created a strong and growing interest in new Ag biologicals.7 In the US there are 350-plus registered biocontrol agents based on 50-plus species. The market is growing at an average compounded annual growth rate (CAGR) greater than 14%. Every major international and domestic supplier of agronomic inputs is investing in this area. Since most Ag biological products are based on naturally occurring microbes, consumer health and safety concerns about these products are reasonably mitigated. Growers are aware and ready to try new biologicals, in part because biological products like rhizobia and Bacillus thuringiensis (Bt) have been used and accepted for decades. There are, however, significant obstacles to the introduction of novel and efficacious Ag biologicals. Microbes are part of extremely complex soil and plant systems; discovery and delivery of effective products are no simple tasks. Historically, some Ag biological market offerings failed to deliver consistent efficacy equal to conventional inputs, causing the industry to regard Ag biologicals with some caution. Improved strains, advanced formulations, and recognition of the unique value Ag biologicals can provide has led to an increase in their global market share over the past decade from less than 1% to more than 5%. Two of the major strategic challenges to increased use of Ag biologicals are: ▪ Optimization of discovery, screening, and derivation of candidate microbes, and ▪ Alignment of product development with technical and economic drivers of contemporary production farming.

Further characteristics of Arcanobacterium pinnipediorum DSM 28752T and Arcanobacterium wilhelmae DSM 102162T, two novel species of genus Arcanobacterium.

The newly described type strains Arcanobacterium pinnipediorum DSM 28752T and Arcanobacterium wilhelmae DSM 102162T, initially isolated from an anal swab of a harbor seal (Sammra et al. Int J Syst Evol Microbiol 65:4539-4543, 2015) and the genital tract of a rhinoceros (Sammra et al. Int J Syst Evol Microbiol 67:2093-2097, 2017), could be further characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and Fourier transform infrared (FT-IR) spectroscopy and by sequencing the genomic targets 16S-23S rDNA intergenic spacer region (ISR) and the genes rpoB, gap, and tuf. The two strains investigated in the present study were isolated together with several other bacterial species indicating that the pathogenic importance of both species remained unclear. However, the detection of specific spectra by MALDI-TOF MS and by FT-IR spectroscopy and the presented genotypic approaches might help to identify A. pinnipediorum and A. wilhelmae in the future and might elucidate the role these two species play in infections of animals.

Proposal of the suffix -ota to denote phyla. Addendum to 'Proposal to include the rank of phylum in the International Code of Nomenclature of Prokaryotes'.

As an addendum to the earlier proposal to include the rank of phylum in the International Code of Nomenclature of Prokaryotes (Oren et al., Int J Syst Evol Microbiol 2015;65:4284-4287) we propose the suffix -ota to denote phyla, replacing the somewhat awkward -aeota. We therefore present a new draft modified version of Rule 8 of the International Code of Nomenclature of Prokaryotes and a corrected list of names of phyla to be considered for validation after approval of the proposal to include the rank of phylum in the Code.

Reclassification of Thiomicrospira hydrogeniphila (Watsuji et al. 2016) to Thiomicrorhabdus hydrogeniphila comb. nov., with emended description of Thiomicrorhabdus (Boden et al., 2017).

The genus Thiomicrorhabdus (Tmr) in the Piskirickettsiaceae in the Thiotrichales of the Gammaproteobacteria contains four species of sulfur-oxidising obligate chemolithoautotroph with validly published names, all previously classified as Thiomicrospira (Tms) species. Here we demonstrate that Thiomicrospira hydrogeniphila, a recently published hydrogen-utilising chemolithoautotroph closely related to Thiomicrorhabdus frisia (type species of Thiomicrorhabdus) should be classified as a member of the genus Thiomicrorhabdus and not Thiomicrospira, as Thiomicrorhabdus hydrogeniphila comb. nov., on the basis of comparative physiology and morphology as well as 16S rRNA (rrs) gene identity of Tms. hydrogeniphila MAS2T being closer to that of Tmr. frisia JB-A2T (99.1 %) than to Tms. pelophila DSM 1534T (90.5 %) or Hydrogenovibrio marinus MH-110T (94.1 %), and on the basis of the topology of 16S rRNA gene maximum likelihood trees, which clearly place Tms. hydrogeniphila within the genus Thiomicrorhabdus. It was also noted that thiosulfate-grown Thiomicrorhabdus spp. can be distinguished from Thiomicrospira spp. or Hydrogenovibrio spp. on the basis of the 3 dominant fatty acids (C16 : 1, C18 : 1 and C16 : 0), and from other Thiomicrorhabdus spp. on the basis of the fourth dominant fatty acid, which varies between the species of this genus - which could provide a useful diagnostic method. We provide an emended description of Thiomicrorhabdus (Boden R, Scott KM, Williams J, Russel S, Antonen K et al.Int J Syst Evol Microbiol 2017;67:1140-1151) to take into account the properties of Thiomicrorhabdus hydrogeniphila comb. nov.

Reclassification of Sphingopyxis contaminans as Sphingorhabdus contaminans comb. nov. and emended description of the genus Sphingorhabdus.

With the description of the genus Sphingorhabdus, the taxonomic position of Sphingopyxis contaminans was re-evaluated based on analyses of 16S rRNA gene sequences and phenotypic and chemotaxonomic characteristics. The results revealed that Sphingopyxis contaminans is clearly a member of the genus Sphingorhabdus and we proposed that Sphingopyxis contaminans(Subhash Y, Sasikala C, Ramana CV. Int J Syst Evol Microbiol 2014;64:2238-2243) should be reclassified as Sphingorhabduscontaminans comb. nov. An emended description of the genus Sphingorhabdus is also provided.