Croceicoccus gelatinilyticus sp. nov., isolated from a tidal flat sediment

Exploring Nocardia's ecological spectrum and novel therapeutic frontiers through whole-genome sequencing: unraveling drug resistance and virulence factors

Nocardia farcinica is the leading pathogen responsible for nocardiosis, a life-threatening infection primarily affecting immunocompromised patients. In this study, the genomic sequence of a clinically isolated N. farcinica sample was sequenced. Subsequently, the assembled genome was annotated to identify antimicrobial resistance and virulence genes, as well as plasmid and prophages. The analysis of the entire genome size was 6,021,225 bp, with a GC content of 70.78% and consists of 103 contigs and N50 values of 292,531 bp. The genome analysis revealed the presence of several antimicrobial resistance genes, including RbpA, mtrA, FAR-1, blaFAR-1, blaFAR-1_1, and rox. In addition, virulence genes such as relA, icl, and mbtH were also detected. The present study signifies that N. farcinica genome is pivotal for the understanding of antimicrobial resistance and virulence genes is crucial for comprehending resistance mechanism, and developing effective strategies to combat bacterial infections effectively, especially adhesins and toxins. This study aids in identifying crucial drug targets for combating multidrug-resistant N. farcinica in the future.

Croceicoccus hydrothermalis sp. nov., isolated from shallow-sea hydrothermal system off Kueishantao Island

A Gram-stain-negative, strictly aerobic, non-motile, ovoid or short-rod shaped, orange-pigmented bacterial strain, designated as strain JLT1T, was isolated from seawater of the shallow-sea hydrothermal system, near Kueishantao Islet. Growth was observed at 5–45°C (optimum, 30 °C) and pH 5.0–11.0 (optimum, pH 7.0). The salinity range for growth was 0–12 % (optimum, 2–4 %) (w/v) NaCl. JLT1T contained ubiquinone-10 as the main respiratory quinone. Iso-C12 : 0, summed feature 3 (C16 : 1ω7c/ω6c) and summed feature 8 (C18 : 1ω6c/ω7c) were identified as the major cellular fatty acids. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unidentified phospholipids, eight unidentified glycolipids and an unidentified lipid. The 16S rRNA gene of JLT1T shared the greatest similarity (96.31 %) with those of Croceicoccus pelagius Ery9T and Croceicoccus ponticola GM-16T. The draft genome size of JLT1T is 3.56 Mb, with 3578 potential genes and a genomic DNA G+C content of 63.24 mol %. Average nucleotide identity and digital DNA–DNA hybridization values of JLT1T compared with C. pelagius Ery9T, C. ponticola GM-16T, Croceicoccus sediminis S2-4-2T, Croceicoccus mobilis Ery22T and Croceicoccus marinus E4A9T were 74.5, 73.9, 74.4, 74.3 and 74.8 % and 20.6, 19.2, 20.0, 20.5 and 19.8%, respectively. On the basis of these phylogenetic, chemotaxonomic and phenotypic features, JLT1T is concluded to represent a novel species of the genus Croceicoccus , for which the name Croceicoccus hydrothermalis sp. nov. is proposed. The type strain is JLT1T (=CGMCC 1.15786T =JCM 31508T).

Ruegeria alba sp. nov., Isolated from a Tidal Flat Sediment

A novel Gram-staining-negative, aerobic, rod-shaped, and white-colored bacterium designated as 1NDH52C^T was isolated from a tidal flat sediment and its taxonomic position was determined using a polyphasic taxonomic approach. The microorganism was found to grow at 10-37 °C, pH 6.0-9.0, and in the presence of 0-2% (w/v) NaCl, and to hydrolyze gelatin and aesculin. The major cellular fatty acid of strain 1NDH52C^T was summed feature 8 (C_19:1 ω7c and/or C_18:1 ω6c); the polar lipids comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, and a lipid; the respiratory quinone was ubiquinone-10. The 16S rRNA gene-based phylogenetic analysis showed that strain 1NDH52C^T was closely related to members of the genus Ruegeria with the identity of 98.2% to the type strain Ruegeria pomeroyi DSM 15711^T. The genome DNA G + C content of strain 1NDH52C^T was 63.6%. The phylogenomic analysis indicated that strain 1NDH52C^T formed an independent branch distinct from reference type strains of species within this genus. Digital DNA-DNA hybridization and average nucleotide identity values between strain 1NDH52C^T and reference strains were, respectively, 19.1-41.5% and 78.3-91.3%, which are far below the thresholds of 70% and 95-96% for species definition, respectively, indicating that strain 1NDH52C^T represents a novel genospecies of the genus Ruegeria. Based on phenotypic and genotypic data, strain 1NDH52C^T is concluded to represent a novel species of the genus Ruegeria, for which the name Ruegeria alba sp. nov., is proposed. The type strain of the species is 1NDH52C^T (= GDMCC 1.2382^T = KCTC 82664^T).