Is the bacterial genus name Rhodococcus Zopf 1891 illegitimate? Request for an Opinion.

In 2014, it was reported that the bacterial genus name Rhodococcus Zopf 1891 was illegitimate due to the priority of the cyanobacterial genus name Rhodococcus Hansgirg 1884. Since that time, the consequences of this conclusion have been largely ignored, whilst changes have been made to relevant Rules of the International Code of Nomenclature of Prokaryotes, including significant changes to the way in which the Code treats the names of members of Cyanobacteriota. Given the complexity of the nomenclatural issues, we request the opinion of the Judicial Commission of the International Committee on Systematics of Prokaryotes as to whether the genus name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate.

Proposals to revise the Statutes of the International Committee on Systematics of Prokaryotes.

The International Committee on Systematics of Prokaryotes serves to administer the rules of prokaryotic nomenclature via the International Code of Nomenclature of Prokaryotes, ensures the publication of the International Journal of Systematic and Evolutionary Microbiology, and works to represent the interests of the microbiological disciplines regarding prokaryotic nomenclature. The functions and mechanisms of operation of the International Committee on Systematics of Prokaryotes (ICSP) are defined in its Statutes, which were last revised in 2019. As members of the 2020-2023 and the 2023-2026 ICSP Executive Board and the Judicial Commission, we propose here some further revisions to help improve the clarity and functionality of the Statutes.

A stable home for an equine pathogen: valid publication of the binomial Prescottella equi gen. nov., comb. nov., and reclassification of four rhodococcal species into the genus Prescottella.

Opinion 106 of the Judicial Commission has clarified the nomenclature of the taxon variously named Rhodococcus equi, 'Prescottella equi' and Rhodococcus hoagii. As a consequence, we present here the genus name Prescottella and that of its nomenclatural type species, Prescottella equi comb. nov., for valid publication and propose the reclassification of four rhodococcal species as novel combinations in the genus, namely Prescottella agglutinans Guo et al. 2015 comb. nov., Prescottella defluvii Kämpfer et al. 2014 comb. nov., Prescottella soli Li et al. 2015 comb. nov. and Prescottella subtropica Lee et al. 2019 comb. nov. In addition, we note that a clinical isolate, strain 86-07 (=W8901), likely represents an additional species within the genus Prescottella. Nearly a century after the original description of the type strain of the type species as Corynebacterium equi, we provide a stable home for Prescottella equi and its relatives.

Proposals to emend Rules 8, 15, 22, 25a, 30(3)(b), 30(4), 34a, and Appendix 7 of the International Code of Nomenclature of Prokaryotes.

To complete the ongoing revision of the International Code of Nomenclature of Prokaryotes, we here propose emendation of Rules 8, 15, 22, 25a, 30(3)(b), 30(4), 34a and Appendix 7. These proposed emendations deal with: the nomenclatural type of taxa above genus; the suitability of names published in supplementary material or in papers published on e-print servers for effective publication; the number of culture collection designations to be included in an effective publication of a name of a species or subspecies to qualify for validation of the name; the kinds of restrictions that may be attached to deposits of type strains; and the question whether elevation of a subspecies to the rank of species or lowering of a species to the rank of subspecies establish new combinations. Some of these emendations change the meaning of the Code while others are mere textual clarifications.

Public discussion on a proposed revision of the International Code of Nomenclature of Prokaryotes.

The Editorial Board for the International Code of Nomenclature of Prokaryotes (ICNP) has compiled proposed revisions of the ICNP. As outlined previously (Oren et al., Int J Syst Evol Microbiol 2021;71:004598; https://doi.org/10.1099/ijsem.0.004598) and to comply with Articles 13(b)(4) and 4(d) of the statutes of the International Committee on Systematics of Prokaryotes, a public discussion of the document will start on 1 July 2021, to last for 6 months. Here, we present the procedure for this discussion.

Emendation of Rules 5b, 8, 15 and 22 of the International Code of Nomenclature of Prokaryotes to include the rank of phylum.

Following the International Committee on Systematics of Prokaryotes electronic discussion and vote on proposals to include the rank of phylum in the rules of the International Code of Nomenclature of Prokaryotes, we here announce the results of the ballot. We also present draft versions of the emended Rules 5b, 8, 15 and 22, based on the outcome of the ballot, to be included in the proposal for the preparation of a new revision of the International Code of Nomenclature of Prokaryotes.

Emendation of General Consideration 5 and Rules 18a, 24a and 30 of the International Code of Nomenclature of Prokaryotes to resolve the status of the Cyanobacteria in the prokaryotic nomenclature.

Following the International Committee on Systematics of Prokaryotes electronic discussion and vote on proposals to resolve the status of the Cyanobacteria in the prokaryotic nomenclature, we announce here the results of the ballot. We also present the emended versions of General Consideration 5 and Rules 18a, 24a and 30, based on the outcome of the ballot, to be included in the new revision of the International Code of Nomenclature of Prokaryotes.

The International Journal of Systematic and Evolutionary Microbiology moves to 'true continuous publication' at the beginning of 2021: Proposals to emend Rule 24b (2), Note 1 to Rule 27 and Note 2 to Rule 33b of the International Code of Nomenclature of Prokaryotes.

The International Journal of Systematic and Evolutionary Microbiology (IJSEM) will move to 'true continuous publication' during the first months of 2021 to modernize the workflow and align it with the current online-only nature of the journal. In the new format, articles will be cited using an article number rather than page numbering. The article number will be the Digital Object Identifier (DOI) suffix, i.e., the last six digits of the DOI. Benefits of the new system include streamlining in-house processes, hence, reducing time and costs, and speeding up the publication time of the final 'Version of Record'. Because of the new format of the IJSEM, it is necessary to emend Rule 24b (2) and Note 1 paragraph 3 of Rule 27 of the International Code of Nomenclature of Prokaryotes (ICNP) to regulate matters of priority for papers published after January 2021. We also propose adding another example to Note 2 of Rule 33b to clarify how nomenclatural authorities of names published in the IJSEM from 2021 onward must be cited.

Preparing a revision of the International Code of Nomenclature of Prokaryotes.

The Editorial Board of the International Code of Nomenclature of Prokaryotes here explains the proposed procedure towards the production of the next revision of the Prokaryotic Code, to include public discussion of a draft version, to be prepared by the editors, followed by balloting of the members of the International Committee on Systematics of Prokaryotes.

The van Niel International Prize for Studies in Bacterial Systematics, awarded in 2020 to Tanja Woyke.

The Senate of The University of Queensland, on the recommendation of the Executive Board of the International Committee on Systematics of Prokaryotes, is pleased to present the van Niel International Prize for Studies in Bacterial Systematics for the triennium 2017-2020 to Dr Tanja Woyke in recognition of her contributions made to the field of bacterial systematics. The award, established in 1986 by Professor V. B. D. Skerman of The University of Queensland, honours the contribution of scholarship in the field of microbiology by Professor Cornelis Bernardus van Niel.

Minutes of the International Committee on Systematics of Prokaryotes online discussion on the proposed use of gene sequences as type for naming of prokaryotes, and outcome of vote.

The International Committee on Systematics of Prokaryotes has held an electronic discussion on proposals to amend the International Code of Nomenclature of Prokaryotes in order to allow the use of gene sequence data as type. The scientific discussion is reported. Subsequently members of the International Committee on Systematics of Prokaryotes voted on these proposals, which were rejected.

Genomic analysis of a novel Rhodococcus (Prescottella) equi isolate from a bovine host.

Rhodococcus (Prescottella) equi causes pneumonia-like infections in foals with high mortality rates and can also infect a number of other animals. R. equi is also emerging as an opportunistic human pathogen. In this study, we have sequenced the genome of a novel R. equi isolate, B0269, isolated from the faeces of a bovine host. Comparative genomic analyses with seven other published R. equi genomes, including those from equine or human sources, revealed a pangenome comprising of 6876 genes with 4141 genes in the core genome. Two hundred and 75 genes were specific to the bovine isolate, mostly encoding hypothetical proteins of unknown function. However, these genes include four copies of terA and five copies of terD genes that may be involved in responding to chemical stress. Virulence characteristics in R. equi are associated with the presence of large plasmids carrying a pathogenicity island, including genes from the vap multigene family. A BLAST search of the protein sequences from known virulence-associated plasmids (pVAPA, pVAPB and pVAPN) revealed a similar plasmid backbone on two contigs in bovine isolate B0269; however, no homologues of the main virulence-associated genes, vapA, vapB or vapN, were identified. In summary, this study confirms that R. equi genomes are highly conserved and reports the presence of an apparently novel plasmid in the bovine isolate B0269 that needs further characterisation to understand its potential involvement in virulence properties.

Proposal for changes in the International Code of Nomenclature of Prokaryotes: granting priority to Candidatus names.

Currently, the description of taxa designated Candidatus requires gene sequences and other taxonomically relevant available information in the absence of an isolated pure culture, and Candidatus names are provisional, i.e. without formal standing in nomenclature. If gene sequences are accepted as suitable type material for the description of prokaryotic species, many taxa designated Candidatus would fulfil all the requirements in the International Code of Nomenclature of Prokaryotes for priority. Here we propose that upon acceptance of sequence data as type material, all Candidatus names published before 1 January 2020 which are otherwise in accordance with the rules of the Code will have their priority based upon their date of publication in the International Journal of Systematic and Evolutionary Microbiology, either within a paper, a list of names of Candidatus taxa, or a Validation List, unless a synonymous name already exists based upon deposition of type cultures. We further propose that modifications of the superscript 'T' be used to identify the nomenclatural types. If the type material is a culture, the superscript 'T' will continue to be used. If the type material is a sequence, the superscript 'Ts' will be used. If the type material is some other form of description, the superscript 'Td' will be used.

Blastococcus atacamensis sp. nov., a novel strain adapted to life in the Yungay core region of the Atacama Desert.

A polyphasic study was undertaken to establish the taxonomic status of a Blastococcus strain isolated from an extreme hyper-arid Atacama Desert soil. The isolate, strain P6T, was found to have chemotaxonomic and morphological properties consistent with its classification in the genus Blastococcus. It was shown to form a well-supported branch in the Blastococcus 16S rRNA gene tree together with the type strains of Blastococcus capsensis and Blastococcus saxobsidens and was distinguished from the latter, its close phylogenetic neighbour, by a broad range of phenotypic properties. The draft genome sequence of isolate P6T showed 84.6 % average nucleotide identity, 83.0 % average amino acid identity and a digital DNA-DNA hybridisation value of 27.8 % in comparison with the genome sequence of B. saxobsidens DSM 44509T, values consistent with its assignment to a separate species. Based on these data it is proposed that isolate P6T (NCIMB 15090T=NRRL B-65468T) be assigned to the genus Blastococcus as Blastococcus atacamensis sp. nov. Analysis of the whole genome sequence of B. atacamensis P6T, with 3778 open reading frames and a genome size of 3.9 Mb showed the presence of genes and gene clusters that encode for properties that reflect its adaptation to the extreme environmental conditions that prevail in Atacama Desert soils.

Genomic analysis of endemic clones of toxigenic and non-toxigenic Corynebacterium diphtheriae in Belarus during and after the major epidemic in 1990s.

BACKGROUND: Diphtheria remains a major public health concern with multiple recent outbreaks around the world. Moreover, invasive non-toxigenic strains have emerged globally causing severe infections. A diphtheria epidemic in the former Soviet Union in the 1990s resulted in ~5000 deaths. In this study, we analysed the genome sequences of a collection of 93 C. diphtheriae strains collected during and after this outbreak (1996 - 2014) in a former Soviet State, Belarus to understand the evolutionary dynamics and virulence capacities of these strains. RESULTS: C. diphtheriae strains from Belarus belong to ten sequence types (STs). Two major clones, non-toxigenic ST5 and toxigenic ST8, encompassed 76% of the isolates that are associated with sore throat and diphtheria in patients, respectively. Core genomic diversity is limited within outbreak-associated ST8 with relatively higher mutation rates (8.9 × 10-7 substitutions per strain per year) than ST5 (5.6 × 10-7 substitutions per strain per year) where most of the diversity was introduced by recombination. A variation in the virulence gene repertoire including the presence of tox gene is likely responsible for pathogenic differences between different strains. However, strains with similar virulence potential can cause disease in some individuals and remain asymptomatic in others. Eight synonymous single nucleotide polymorphisms were observed between the tox genes of the vaccine strain PW8 and other toxigenic strains of ST8, ST25, ST28, ST41 and non-toxigenic tox gene-bearing (NTTB) ST40 strains. A single nucleotide deletion at position 52 in the tox gene resulted in the frameshift in ST40 isolates, converting them into NTTB strains. CONCLUSIONS: Non-toxigenic C. diphtheriae ST5 and toxigenic ST8 strains have been endemic in Belarus both during and after the epidemic in 1990s. A high vaccine coverage has effectively controlled diphtheria in Belarus; however, non-toxigenic strains continue to circulate in the population. Recombination is an important evolutionary force in shaping the genomic diversity in C. diphtheriae. However, the relative role of recombination and mutations in diversification varies between different clones.

Adherence and invasive properties of Corynebacterium diphtheriae strains correlates with the predicted membrane-associated and secreted proteome.

BACKGROUND: Non-toxigenic Corynebacterium diphtheriae strains are emerging as a major cause of severe pharyngitis and tonsillitis as well as invasive diseases such as endocarditis, septic arthritis, splenic abscesses and osteomyelitis. C. diphtheriae strains have been reported to vary in their ability to adhere and invade different cell lines. To identify the genetic basis of variation in the degrees of pathogenicity, we sequenced the genomes of four strains of C. diphtheriae (ISS 3319, ISS 4060, ISS 4746 and ISS 4749) that are well characterised in terms of their ability to adhere and invade mammalian cells. RESULTS: Comparative analyses of 20 C. diphtheriae genome sequences, including 16 publicly available genomes, revealed a pan-genome comprising 3,989 protein coding sequences that include 1,625 core genes and 2,364 accessory genes. Most of the genomic variation between these strains relates to uncharacterised genes encoding hypothetical proteins or transposases. Further analyses of protein sequences using an array of bioinformatic tools predicted most of the accessory proteome to be located in the cytoplasm. The membrane-associated and secreted proteins are generally involved in adhesion and virulence characteristics. The genes encoding membrane-associated proteins, especially the number and organisation of the pilus gene clusters (spa) including the number of genes encoding surface proteins with LPXTG motifs differed between different strains. Other variations were among the genes encoding extracellular proteins, especially substrate binding proteins of different functional classes of ABC transport systems and 'non-classical' secreted proteins. CONCLUSIONS: The structure and organisation of the spa gene clusters correlates with differences in the ability of C. diphtheriae strains to adhere and invade the host cells. Furthermore, differences in the number of genes encoding membrane-associated proteins, e.g., additional proteins with LPXTG motifs could also result in variation in the adhesive properties between different strains. The variation in the secreted proteome may be associated with the degree of pathogenesis. While the role of the 'non-classical' secretome in virulence remains unclear, differences in the substrate binding proteins of various ABC transport systems and cytoplasmic proteins potentially suggest strain variation in nutritional requirements or a differential ability to utilize various carbon sources.

Genomic analyses confirm close relatedness between Rhodococcus defluvii and Rhodococcus equi (Rhodococcus hoagii).

Rhodococcus defluvii strain Ca11(T) was isolated from a bioreactor involved in extensive phosphorus removal. We have sequenced the whole genome of this strain, and our comparative genomic and phylogenetic analyses confirm its close relatedness with Rhodococcus equi (Rhodococcus hoagii) strains, which share >80 % of the gene content. The R. equi virulence plasmid is absent though most of the chromosomal R. equi virulence-associated genes are present in R. defluvii Ca11(T). These data suggest that although R. defluvii is an environmental organism, it has the potential to colonize animal hosts.