ABSTRACT
A taxonomic study was carried out on strain 13D2W-2(T), which was isolated from a sulphur-oxidizing bacterial consortium, enriched by the deep-sea sediment of the Atlantic Ocean. The isolate was observed to be Gram-negative, oxidase- and catalase-positive, short rod-shaped and motile by means of a flagellum. Growth was observed at salinities from 0.5 to 12 % and at temperatures from 4 to 41 °C, and the strain found to be able to reduce nitrate but not degrade gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 13D2W-2(T) belongs to the genus Thioclava, with highest sequence similarity of 97.8 % to Thioclava dalianensis DLFJ1-1(T), followed by Thioclava pacifica TL 2(T) (97.7 %), while the sequence similarities to other members of the genus were all below 97.0 %. The digital DNA:DNA hybridization estimated values between strain 13D2W-2(T) and, respectively, T. dalianensis DLFJ1-1(T) and T. pacifica TL 2(T) were 22.6 ± 2.4 and 25.6 ± 2.4 %. The ANI values between strain 13D2W-2(T) and T. dalianensis DLFJ1-1(T) and T. pacifica TL 2(T) were 78.49 and 81.91 % respectively. The principal fatty acid identified was Summed Feature 8 (C18:1 ω7c/ω6c) (74.38 %). The isoprenoid quinone of strain 13D2W-2(T) was identified as Q10 (100 %). The major polar lipids of strain 13D2W-2(T) were found to be comprised of phosphatidylethanolamine, phosphatidylglycerol, an aminophospholipid, a glycolipid and three unknown phospholipids. The G+C content of the chromosomal DNA was determined to be 65.3 mol%. The combined genotypic and phenotypic data show that strain 13D2W-2(T) represents a novel species of the genus Thioclava, for which the name Thioclava atlantica sp. nov. is proposed, with the type strain 13D2W-2(T) ( = MCCC 1A02612(T) = LMG 27145(T)).
Subject(s)
Geologic Sediments/microbiology , Rhodobacteraceae/classification , Rhodobacteraceae/isolation & purification , Atlantic Ocean , Bacterial Typing Techniques , Base Composition , Cluster Analysis , Cytosol/chemistry , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Fatty Acids/analysis , Locomotion , Molecular Sequence Data , Nucleic Acid Hybridization , Phospholipids/analysis , Phylogeny , Quinones/analysis , RNA, Ribosomal, 16S/genetics , Rhodobacteraceae/genetics , Rhodobacteraceae/physiology , Salinity , Sequence Analysis, DNA , Sodium Chloride/metabolism , TemperatureABSTRACT
OBJECTIVES: To test the efficacy of EDP-420, a new ketolide, in experimental pneumococcal meningitis and to determine its penetration into the CSF. METHODS: The experimental rabbit model was used in this study and EDP-420 was tested against a penicillin-resistant and a penicillin- and quinolone-resistant mutant. EDP-420 was also tested against both strains in time-killing assays over 8 h in vitro. RESULTS: In experimental meningitis, EDP-420 produced a bactericidal activity comparable to the standard regimen based on a combination of vancomycin with ceftriaxone against a penicillin-resistant Streptococcus pneumoniae and a penicillin- and quinolone-resistant S. pneumoniae isolate. The penetration of EDP-420 into inflamed meninges was 38% after an i.v. injection of 10 mg/kg. The bactericidal activity of EDP-420 was also confirmed in in vitro time-killing assays. CONCLUSIONS: EDP-420 is an efficacious alternative treatment in pneumococcal meningitis, especially when resistant strains are suspected.
