Corynebacterium fournierii sp. nov., isolated from the female genital tract of a patient with bacterial vaginosis

Corynebacterium guaraldiae sp. nov.: a new species of Corynebacterium from human infections

Non-diphtheria Corynebacterium species (NDC) belonging to the human skin and mucosa microbiota are frequently neglected as contaminants. However, reports of human infections by Corynebacterium spp. have increased considerably in recent years. In this study, a group of six NDC isolates of urine (n = 5) and sebaceous cyst (n = 1) from two South American countries were identified at genus level or misidentified based on API® Coryne and genetic/molecular analyses. The 16S rRNA (99.09-99.56%) and rpoB (96.18-97.14%) gene sequence similarities of the isolates were higher when compared with Corynebacterium aurimucosum DSM 44532 T. Multilocus sequence analysis (MLSA) indicated that these six NDC isolates compose a distinctive phylogenetic clade. Genome-based taxonomic analysis with the whole-genome sequences was able to separate these six isolates from other known Corynebacterium type strains. Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between closely related type strains and the six isolates were considerably lower than the currently recommended threshold values for species circumscription. Phylogenetic and genomic taxonomy analyses indicated these microorganisms as a novel Corynebacterium species, for which we formally propose the name Corynebacterium guaraldiae sp. nov. with isolate 13T (= CBAS 827T = CCBH 35012T) as type strain.

Genome Characterization and Probiotic Potential of Corynebacterium amycolatum Human Vaginal Isolates

The vaginal microbiome of healthy women contains nondiphtheria corynebacteria. The role and functions of nondiphtheria corynebacteria in the vaginal biotope are still under study. We sequenced and analysed the genomes of three vaginal C. amycolatum strains isolated from healthy women. Previous studies have shown that these strains produced metabolites that significantly increased the antagonistic activity of peroxide-producing lactic acid bacteria against pathogenic and opportunistic microorganisms and had strong antimicrobial activity against opportunistic pathogens. Analysis of the C. amycolatum genomes revealed the genes responsible for adaptation and survival in the vaginal environment, including acid and oxidative stress resistance genes. The genes responsible for the production of H₂O₂ and the synthesis of secondary metabolites, essential amino acids and vitamins were identified. A cluster of genes encoding the synthesis of bacteriocin was revealed in one of the annotated genomes. The obtained results allow us to consider the studied strains as potential probiotics that are capable of preventing the growth of pathogenic microorganisms and supporting colonisation resistance in the vaginal biotope.

Phylogenomic Reappraisal of Fatty Acid Biosynthesis, Mycolic Acid Biosynthesis and Clinical Relevance Among Members of the Genus Corynebacterium

The genus Corynebacterium encompasses many species of biotechnological, medical or veterinary significance. An important characteristic of this genus is the presence of mycolic acids in their cell envelopes, which form the basis of a protective outer membrane (mycomembrane). Mycolic acids in the cell envelope of Mycobacterium tuberculosis have been associated with virulence. In this study, we have analysed the genomes of 140 corynebacterial strains, including representatives of 126 different species. More than 50% of these strains were isolated from clinical material from humans or animals, highlighting the true scale of pathogenic potential within the genus. Phylogenomically, these species are very diverse and have been organised into 19 groups and 30 singleton strains. We find that a substantial number of corynebacteria lack FAS-I, i.e., have no capability for de novo fatty acid biosynthesis and must obtain fatty acids from their habitat; this appears to explain the well-known lipophilic phenotype of some species. In most species, key genes associated with the condensation and maturation of mycolic acids are present, consistent with the reports of mycolic acids in their species descriptions. Conversely, species reported to lack mycolic acids lacked these key genes. Interestingly, Corynebacterium ciconiae, which is reported to lack mycolic acids, appears to possess all genes required for mycolic acid biosynthesis. We suggest that although a mycolic acid-based mycomembrane is widely considered to be the target for interventions by the immune system and chemotherapeutics, the structure is not essential in corynebacteria and is not a prerequisite for pathogenicity or colonisation of animal hosts.

Corynebacterium zhongnanshanii sp. nov. isolated from trachea of Marmota himalayana, Corynebacterium lujinxingii sp. nov. and Corynebacterium wankanglinii sp. nov. from human faeces

Six novel facultatively anaerobic, Gram-stain-positive, rod-shaped, non-haemolytic bacteria (zg-320^T/zg-336, zg-917^T/zg-910 and zg-913^T/zg-915) isolated from animal tissues and human faeces were found to belong to the genus Corynebacterium based on the phylogenetic analyses of 16S rRNA gene and 262 core genes set. Based on the greatest degree of 16S rRNA similarity, zg-320^T/zg-336 had the highest 16S rRNA gene similarity to Corynebacterium falsenii DSM 44353^T (97.51 %), zg-917^T/zg-910 to Corynebacterium coyleae DSM 44184^T (98.68 %), and zg-913^T/zg-915 to Corynebacterium afermentans subsp. lipophilum CIP 103500^T (98.79 %). The three novel type strains had a relatively high DNA G+C content (61.2-64.4 mol%), low DNA relatedness and ANI values with their respective neighbours: 23.5/72.7 %, 25.0/72.3%and 22.6/73.1 % (zg-320^T vs. Corynebacterium auriscanis CIP 106629^T, Corynebacterium resistens DSM 45100^T and Corynebacterium suicordis DSM 45110^T); 24.4/82.3% and 23.7/81.3 % (zg-917^T vs. C. coyleae DSM 44184^T and Corynebacterium jeddahense JCB^T); 26.8/83.7% and 27.7/84.4 % (zg-913^T vs. Corynebacterium mucifaciens ATCC 700355^T and C. afermentans subsp. lipophilum CCUG 32105^T). The three novel species had C_16 : 0, C_18 : 0, C_18 : 1  ω9c and C_18 : 0 ante/C_18 : 2  ω6,9c as the major cellular fatty acids; MK-8(H₂) in strain zg-917^T and MK-9(H₂) in strains zg-320^T and zg-913^T were found to be the major respiratory quinones. For the three novel species, the detected major polar lipids included diphosphatidylglycerol, phosphatidyl inositol mannoside, phosphatidylglycerol and phosphatidylinositol, the cell-wall peptidoglycan was based on meso-DAP, and the whole-cell sugars mainly included ribose, arabinose and galactose. The three novel species grew optimally at 35-37 °C, 0.5 % (w/v) NaCl and pH 7.0-8.0; notably, they were tolerant of 10.5 % (w/v) NaCl. Based on the results of these comprehensive analyses, three novel species in the genus Corynebacterium are proposed, aptly named Corynebacterium zhongnanshanii sp. nov. (zg-320^T = GDMCC 1.1719^T = JCM 34106^T), Corynebacterium lujinxingii sp. nov. (zg-917^T = GDMCC 1.1707^T = JCM 34094^T) and Corynebacterium wankanglinii sp. nov. (zg-913^T = GDMCC 1.1706^T = JCM 34398^T).

Taxonogenomics description of Arcanobacterium urinimassiliense sp. nov., a new bacterial species isolated from urine sample

Strain Marseille-P3248т is a new species from the order Actinomycetales that was isolated from the urine sample of a girl aged 20 months with rotavirus gastroenteritis. It is a facultative anaerobic Gram-positive rod-shaped bacterium. Strain Marseille-P3248т exhibits 94.73% sequence similarity with Arcanobacterium pluranimalium strain M430/94/2, a phylogenetically related species with standing in nomenclature. Its genome size is 1 667 964 bp with 49.1% G + C content. Strain Marseille-P3248т (= CSURP3248) is the type strain of the new species Arcanobacterium urinimassiliense sp. nov.

Summary of Novel Bacterial Isolates Derived from Human Clinical Specimens and Nomenclature Revisions Published in 2018 and 2019

Knowledge of novel prokaryotic taxon discovery and nomenclature revisions is of importance to clinical microbiology laboratory practice, infectious disease epidemiology, and studies of microbial pathogenesis. Relative to bacterial isolates derived from human clinical specimens, we present an in-depth summary of novel taxonomic designations and revisions to prokaryotic taxonomy that were published in 2018 and 2019. Included are several changes pertinent to former designations of or within Propionibacterium spp., Corynebacterium spp., Clostridium spp., Mycoplasma spp., Methylobacterium spp., and Enterobacteriaceae Future efforts to ascertain clinical relevance for many of these changes may be augmented by a document development committee that has been appointed by the Clinical and Laboratory Standards Institute.

Corynebacterium urinapleomorphum sp. nov., a new bacterial species isolated from human urine sample

Corynebacterium urinapleomorphum sp. nov. stain Marseille-P2799T (= CSURP2799; = DSM103272) is a new species from the order Corynebacteriales that was isolated from urine of a 2-month-old child with gastroenteritis.