Olsenella umbonata sp. nov., a microaerotolerant anaerobic lactic acid bacterium from the sheep rumen and pig jejunum, and emended descriptions of Olsenella, Olsenella uli and Olsenella profusa Strain A2 is an anaerobic, variably Gram-stain-positive, non-spore-forming, small and irregularly rod-shaped bacterium from the ruminal fluid of a sheep that has been described informally as a representative of 'Olsenella (basonym Atopobium) oviles'. Three phenotypically similar bacterial strains (lac15, lac16 and lac31 T ) were isolated in concert with Veillonella magna lac18 T from the mucosal jejunum of a pig. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strains A2, lac15, lac16 and lac31 T formed a genetically coherent group (100 % interstrain sequence similarity) within the bigeneric Olsenella-Atopobium branch of the family Coriobacteriaceae, class Actinobacteria. This group was most closely related to the type strains of the two recognized Olsenella species, namely Olsenella uli (sequence similarity of 96.85 %) and Olsenella profusa (sequence similarity of 97.20 %). The sequence similarity to the type strain of Atopobium minutum, the type species of the genus Atopobium, was 92.33 %. Unlike those of O. uli and O. profusa, outgrown colonies of strains A2, lac15, lac16 and lac31 T were opaque and greyish-white with an umbonate elevation on solid culture media. The four novel strains were characterized as being well-adapted and presumably indigenous to the gastrointestinal tract of homoeothermic vertebrates: they were mesophilic, microaerotolerant, neutrophilic and acidotolerant, bile-resistant, mucin-utilizing and markedly peptidolytic lactic acid bacteria. The results of DNA-DNA hybridizations, cellular fatty acid analysis and other differential phenotypic (physiological and biochemical) tests confirmed that strains A2, lac15, lac16 and lac31 T represent a novel species of the genus Olsenella. On the basis of the genotypic and phenotypic results, we therefore describe Olsenella umbonata sp. nov., with lac31 T (5CCUG 58604 T 5DSM 22620 T 5JCM 16156 T ) as the type strain and A2 (5CCUG 58212 5DSM 22619 5JCM 16157) as an additionally available reference strain. Also, based on our data, we propose emended descriptions of the genus Olsenella and the species Olsenella uli and Olsenella profusa.

Veillonella magna sp. nov., isolated from the jejunal mucosa of a healthy pig, and emended description of Veillonella ratti A bacterium, designated strain lac18 T , was isolated in pure culture from the mucosal jejunum of a healthy pig, using a medium selective for anaerobic lactic acid bacteria and containing porcine gastric mucin as the main carbon and nitrogen source. Cells of this strain were coccus-shaped, arranged singly or in pairs and were Gram-stain-negative, oxidase-negative, non-spore-forming, anaerobic and microaerotolerant. An analysis based on 16S rRNA gene sequences indicated that strain lac18 T should be assigned to the genus Veillonella, class Clostridia, phylum Firmicutes. 16S rRNA and dnaK gene sequence-based phylogenetic analyses both indicated that the most closely related species were Veillonella ratti ATCC 17746 T (similarities of 96.6 and 84.5 %, respectively) and Veillonella criceti ATCC 17747 T (similarities of 96.6 and 83.4 %, respectively). The results of DNA-DNA hybridizations between strain lac18 T and these Veillonella species and the type species of the genus, Veillonella parvula DSM 2008 T , confirmed the genotypic distinctness of the novel isolate. Data from phenotypic studies also served to differentiate strain lac18 T from related strains. Therefore strain lac18 T represents a novel species of the genus Veillonella, for which the name Veillonella magna sp. nov. is proposed. The type strain is lac18 T

Two 6-week feeding trials were conducted on a total of 112 newly weaned piglets to examine the recently reported growth promoting effects of dietary rare earth elements (REE) in European pig production. Rare earth element-diets were supplemented with a REE-citrate premix of lanthanum and the light lanthanoides cerium, praseodymium and neodymium at 200 mg/kg for 6 weeks after weaning. Overall for both trials, growth performance of REE-citrate and control fed piglets did not differ significantly (p > 0.05). An early enhancive tendency for REE-citrate in trial 1 (feed conversion ratio, FCR -3%, p = 0.15) proved irreproducible in trial 2. In the late period of trial 1, in-feed addition of REE-citrate significantly impaired piglet performance (FCR + 8%, p = 0.01). A cultivation-independent molecular approach, polymerase chain reaction-denaturing gradient gel electrophoresis was further applied to assess REE induced alterations in the predominant faecal microbiota from weaning pigs. Calculation of various ecological characteristics does not indicate (p > 0.05) an often discussed selective effect on local microbial composition of dietary REE.

Natural plant compounds, such as the chlorophyll a catabolites pheophorbide a (php) and pyropheophorbide a (pyp), are potentially active in the gastrointestinal tracts and manure of livestock as antimicrobial resistance-modifying agents through inhibition of bacterial efflux pumps. To investigate whether php, a known efflux pump inhibitor, and pyp influence bacterial resistance, we determined their long-term effects on the MICs of erythromycin for reference strains of clinically relevant indicator bacteria with macrolide or multidrug resistance efflux pumps. Pyp reduced the final MIC endpoint for Staphylococcus (S.) aureus and Escherichia (E.) coli by up to 1536 and 1024 g erythromycin mL −1 or 1.4-and 1.2-fold, respectively. Estimation of growth parameters of S. aureus revealed that pyp exerted an intrinsic inhibitory effect under anaerobic conditions and was synergistically active, thereby potentiating the effect of erythromycin and partially reversing high-level erythromycin resistance. Anaerobe colony counts of total and erythromycin-resistant bacteria from stored swine manure samples tended to be lower in the presence of pyp. Tylosin, php, and pyp were not detectable by HPLC in the manure or medium. This is the first study showing that pyp affects growth and the level of sensitivity to erythromycin of S. aureus, E. coli, and anaerobic manure bacteria.