Breznakia blatticola gen. nov. sp. nov. and Breznakia pachnodae sp. nov., two fermenting bacteria isolated from insect guts, and emended description of the family Erysipelotrichaceae.
Two novel, obligately anaerobic Firmicutes from the family Erysipelotrichaceae were isolated from the intestinal tracts of a cockroach (strain ErySL, Shelfordella lateralis) and a scarab beetle larva (strain Pei061, Pachnoda ephippiata). Phylogenetic analysis indicated that the strains belong to a monophyletic group of hitherto uncultured bacteria from insect guts that are only distantly related to any described species (<90% 16S rRNA gene sequence similarity). Ultrastructural analysis revealed a Gram-positive cell envelope and, in the case of strain ErySL, a wide electron-lucent space between the cytoplasmic membrane and cell wall. In older cultures, cells formed pleomorphic rods with a thicker peptidoglycan layer. Both strains were obligately anaerobic and fermented glucose to formate, ethanol, and acetate as major products, but strain Pei061 tolerated up to 1% oxygen in the headspace. The same type of metabolism was observed with Erysipelothrix inopinata, except that the latter grew, albeit poorly, even under air. However, previous claims of a microaerophilic or facultatively anaerobic metabolism in the genus Erysipelothrix could not be substantiated. Based on phenotypic and phylogenetic evidence, we propose to classify the isolates as members of a new genus, Breznakia blatticola gen. nov. sp. nov. and Breznakia pachnodae sp. nov., with strain ErySL(T) (=DSM 28867(T)=JCM 30190(T)) and strain Pei061(T) (=DSM 16784(T)=JCM 30191(T)) as type strains, and provide an emended description of the family Erysipelotrichaceae.
Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043 Marburg, Germany.
Dorothee
D
Tegtmeier
Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043 Marburg, Germany.
Cornelius
C
Riese
Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043 Marburg, Germany.
Oliver
O
Geissinger
Institute of Biology/Zoology, Free University of Berlin, Königin-Luise-Strasse 1-3, 14195 Berlin, Germany.
Renate
R
Radek
Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043 Marburg, Germany. Electronic address: brune@mpi-marburg.mpg.de.
Andreas
A
Brune
D000818:Animals; D015373:Bacterial Typing Techniques; D001482:Base Composition / Q000235:genetics; D001483:Base Sequence; D001517:Coleoptera / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D005285:Fermentation / Q000502:physiology*; D000068536:Bacillota / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D000069196:Gastrointestinal Microbiome / Q000235:genetics*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S
Emended family description; Erysipelotrichaceae; Insect gut bacteria; Mixed-acid fermentation; Novel genus; Obligately anaerobic