- Volume 75, Issue 5, 2025

In September 2018, Hurricane Florence resulted in major flooding in North Carolina, USA. Efforts to isolate Listeria monocytogenes and other Listeria spp. from Hurricane Florence floodwaters repeatedly yielded non-haemolytic Listeria-like isolates that could not be readily assigned to known Listeria taxa. Whole-genome sequence analyses against the 28 currently known Listeria species confirmed that the isolates constitute two new taxa within the genus Listeria. Taxon I, with one isolate, showed the highest similarity to Listeria goaensis, with an average nucleotide identity blast of 85.3±4.4% and an in silico DNA–DNA hybridization (isDDH) of 32.4% (range: 30–35%), differing from the latter by its ability to reduce nitrate, ferment d-ribose and sucrose, and by its inability to produce catalase or ferment d-trehalose and d-lactose. Taxon II, represented by 11 isolates, showed the highest similarity to Listeria rocourtiae, with an average nucleotide identity blast of 92.64±3.8% and an isDDH of 49.9% (range: 47.3–52.5%), differing from the latter by its ability to ferment l-arabinose and its inability to ferment l-rhamnose, d-galactose, d-lactose and d-melibiose. The names Listeria tempestatis sp. nov. and Listeria rocourtiae subsp. hofi subsp. nov. are proposed for taxon I and II, respectively, with type strains CLIP 2022/01175T (F6L-1A=CIP 112444T = DSM 117029T) and CLIP 2022/01000T (F66L-1A=CIP 112443T = DSM 117030T), respectively. Both taxa lack known Listeria pathogenic islands, suggesting a lack of pathogenicity for humans.

A recent metagenomic survey has revealed an unknown bacterial clade within the Catenibacterium mitsuokai species to be significantly more prevalent in non-urbanized populations, compared to urbanized ones. We isolated and characterized a strain of this clade from the stool of a healthy adult volunteer. Strain CMD8551T is strictly anaerobic, appears as long chains of Gram-positive rods and produces acetate in the presence of glucose. The lipidomic profile showed a higher proportion of saturated lipid species amongst the detected phospholipids. The whole genome is 2,320,430 bp long and has a G+C content of 33.7 mol% with 2,239 CDSs. A phylogenetic analysis comparing the sequences of the strain CMD8551T with publicly available reference genomes from the Catenibacterium genus revealed that the CMD8551T isolate, together with other isolate genomes, forms a distinct subspecies of C. mitsuokai and has an average nucleotide identity lower than 94% with respect to the previously described C. mitsuokai subsp. mitsuokai. Given the phenotypic, chemotaxonomic and phylogenetic characteristics of the newly isolated CMD8551T (=DSM 118469T=LMG 33725T=CIP 112509T) that clearly differ from those of the C. mitsuokai subsp. mitsuokai type strain RCA14-39T, we propose it as the type strain of a novel subspecies of C. mitsuokai, with the name C. mitsuokai subsp. tridentinum subsp. nov.

Four Gram-stain-negative bacterial strains which can metabolize alkanes and polycyclic aromatic hydrocarbons were isolated. Strains R06ZXJ2T and R09ZXJ6 were isolated from sediments collected in the Arctic Ocean. Strains DY715-9T and DY716-13-1 were isolated from surface sediment samples collected by the deep-sea TV grab in the southwestern Indian Ocean. Phylogenomic analyses based on 16S rRNA gene sequences, average nt identity (ANI) and digital DNA–DNA hybridization (dDDH) revealed that the strains formed two distinct lineages within the genus Vreelandella. Their closest relative was Vreelandella maris QX-1T, with ANI values of 94.35% (R06ZXJ2T) and 95.54% (DY715-9T) and dDDH values of 57.00% and 61.80%, respectively. The pairwise ANI (95.47%) and dDDH (60.70%) between the two novel strains further supported their status as separate species. Phenotypic and chemotaxonomic analyses distinguished them from known Vreelandella species through differences in colony morphology, hydrocarbon degradation profiles and polar lipid compositions. The strains grew optimally at 28 °C and pH 7.0 and can degrade alkanes and polycyclic aromatic hydrocarbons. Based on these results, we propose two novel species: Vreelandella arctica sp. nov. (type strain R06ZXJ2T=MCCC 1A08467T=KCTC 92631T) and Vreelandella indica sp. nov. (type strain DY715-9T=MCCC 1A12469T=KCTC 92628T).

A Gram-stain-negative, strictly aerobic and motile bacterium capable of degrading trifloxystrobin, designated strain J-3T, was isolated from activated sludge from Nanhu Wetland Park in Huaibei City, Anhui Province, PR China. Growth was observed at 0–1.0% NaCl (w/v; optimum: 0.5%) at 15–35 °C (optimum: 30 °C) and pH 5.0–8.0 (optimum: pH 7.5). Strain J-3T could degrade 59.9% of 75.0 µM trifloxystrobin within 3 days of incubation. A novel esterase responsible for hydrolysing trifloxystrobin to trifloxystrobin acid, StrE, was identified in strain J-3T; it exhibited low similarity (<31%) with previously reported trifloxystrobin esterases, indicating its novelty. Phylogenetic analysis based on 16S rRNA gene sequences and genomes indicated that strain J-3T was most closely related to strain Comamonas odontotermitis Dant 3-8T. The 16S rRNA gene similarity between strain J-3T and C. odontotermitis Dant 3-8T was 97.7%. The average nucleotide identity and digital DNA–DNA hybridization values between strain J-3T and strain C. odontotermitis Dant 3-8T were 81.7% and 25.4%, respectively. The major fatty acids were C16:0, summed feature 3 (C16:1  ω7c and/or C16:1  ω6c) and summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The predominant respiratory quinone was Q-8. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic analysis, strain J-3T was considered to represent a novel species within the genus Comamonas, for which the name Comamonas trifloxystrobinivorans sp. nov. is proposed with strain J-3T (=KCTC 8781T=MCCC 1K09559T) as the type strain.

Whole-genome sequencing of cultures at the American Type Culture Collection (ATCC®) is ongoing, with reference-quality genome sequences for our microbial strains added to the ATCC® Genome Portal on a quarterly basis. Following genome assembly, authentication and taxonomy verification are needed for taxonomic updates based on the circumscription of genomic metrics for a species. Moraxella sp. ATCC 23246T was originally identified as an atypical Moraxella catarrhalis; however, an analysis of the complete and closed genome of this strain indicates that it represents a novel species within the Moraxella genus. We propose the name of Moraxella veridica sp. nov. for this long-mischaracterized strain as whole-genome sequencing was used to uncover the truth of this strain’s identity. The type strain is ATCC 23246T (=NCTC 4103T).

A yeast strain isolated from chestnut tree bark collected in Guangshan County, Xinyang, Henan Province, China and a strain isolated from soil collected in Phu Wiang District, Khon Khen Province, Thailand possess identical sequences in the 26S ribosomal RNA gene D1/D2 domain and the internal transcribed spacer (ITS) region. Phylogenetic analysis showed that the two strains belong to the genus Torulaspora and are closely related to T. jiuxiensis but differed from the species by 7 (1.26%, 7 substitutions and 0 gap) and 43 (5.75 %, 31 substitutions and 12 gaps) mismatches in the D1/D2 domain and ITS region, respectively. The result suggests that the Chinese and the Thai strains represent a novel species in the genus Torulaspora, for which the name Torulaspora lindneri sp. nov. (holotype strain CGMCC 2.7783) is proposed. This species forms one or two spherical ascospores in persistent asci, usually with tapered protuberances.