Collinsella urealyticum sp. nov., a urease-positive bacterial strain isolated from swine faeces.

A novel actinobacterial strain, designated AGMB00827T, was isolated from swine faeces. Strain AGMB00827T was obligately anaerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped bacterium. Comparative analyses based on the 16S rRNA gene and whole genome sequence revealed that strain AGMB00827T was affiliated to the genus Collinsella, and was most closely related to Collinsella vaginalis Marseille-P2666T (= KCTC 25056T). Biochemical analysis showed strain AGMB00827T was negative for catalase and oxidase. Interestingly, strain AGMB00827T possessed urease activity, which was determined by traditional methods (API test and Christensen's urea medium), unlike related strains. Furthermore, the major cellular fatty acids (> 10%) of the isolate were C18:1 ω9c, C16:0, C16:0 DMA and C18:2 ω9,12c DMA. Based on the whole genome sequence analysis, the DNA G + C content of strain AGMB00827T was 52.3%, and the genome size and numbers of rRNA and tRNA genes were 1,945,251 bp, 3 and 46, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain AGMB00827T and C. vaginalis KCTC 25056 T were 71.0 and 23.2%, respectively. Additionally, the genome analysis revealed that strain AGMB00827T possesses urease gene cluster including ureABC and ureDEFG while the related strains do not have those genes, which is consistent with the urease activity. On the basis of polyphasic taxonomic approach, strain AGMB00827T represents a novel species within the genus Collinsella, for which the name Collinsella urealyticum sp. nov. is proposed. The type strain is AGMB00827T (= KCTC 25287T = GDMCC 1.2724T).

Caproiciproducens faecalis sp. nov., Isolated from Cow Faeces.

The bacterial strain AGMB10547T was isolated from cow faeces deposited by the National Institute of Animal Science in Cheonan, Republic of Korea. The strain AGMB10547T possessed the phenotypic, biochemical and chemotaxonomic characteristics of the bacteria of the family Oscillospiraceae. The isolate was obligately anaerobic, non-motile, Gram-positive and rod-shaped bacteria. The growth of strain AGMB10547T occurred within 35-40 °C (optimum at 37 °C), at pH 6-7 (optimum of 7) and in the presence of 0.5-2.0% (w/v) NaCl. Based on 16S rRNA gene sequence similarity, strain AGMB10547T belonged to the genus Caproiciproducens and was most closely related to Caproiciproducens galactitolivorans BS-1T (96.9%). The DNA G+C content was 49.0 mol%. The major cellular fatty acids (> 10%) of the isolate were C14:0, C14:0 DMA, C16:1 ω9c and C16:0. The average nucleotide identity (ANI) and digital DNA-DNA Hybridization (dDDH) values between strain AGMB10547T and C. galactitolivorans BS-1T were 75.5% and 19.2%. Based on the phenotypic, genotypic, biochemical and chemotaxonomic analyses, strain AGMB10547T represents a novel species of the genus Caproiciproducens, for which the name Caproiciproducens faecalis sp. nov. is proposed. The type strain AGMB10547T (=KCTC 25200T=NBRC 115006T=GDMCC 1.2575T).

Parabacteroides faecalis sp. nov. Isolated from Swine Faeces.

A Gram-negative, obligate anaerobic, non-motile, non-spore-forming, rod-shaped bacterial strain designated AGMB00274T was isolated from swine faeces. An 16S rRNA gene analysis indicated that strain AGMB00274T belonged to the genus Parabacteroides, with the highest similarity to Parabacteroides johnsonii (P. johnsonii) DSM 18315T (sequence similarity of 94.9%). The genome size of strain AGMB00274T was 4,308,683 bp, with a DNA G+C content of 42.5 mol%. The biochemical analysis of strain AGMB00274T showed that it was positive for gelatin hydrolysis and α-fucosidase, but negative for the acid production from D-glucose, D-mannitol, D-maltose, salicin, glycerol, D-cellobiose, D-mannose, D-melezitose, D-sorbitol, D-trehalose, and negative for α-arabinosidase, glutamic acid decarboxylase, and pyroglutamic acid arylamidase. The dominant cellular fatty acids (> 10%) of the isolate were anteiso-C15: 0 (23.2%), iso-C15: 0 (16.6%), C18: 1 ω9c (16.4%), summed feature 11 (iso-C17: 0 3-OH and/or C18: 2 DMA) (12.5%), and C16: 0 (11.3%). The major respiratory quinones of strain AGMB00274T were MK-9 (55.4%) and MK-10 (44.6%). The major polar lipid was phosphatidylethanolamine. Based on phylogenetic, genetic, physiological, and chemotaxonomic analyses, as a novel species of the genus Parabacteroides, strain AGMB00274T was proposed with the name Parabacteroides faecalis sp. nov. The type strain used was AGMB00274T (= KCTC 25286T = GDMCC 1.2742T).

Olsenella intestinalis sp. nov., isolated from cow feces.

A Gram-stain-negative, anaerobic, non-motile, rod-shaped bacterium, designated as BGYT1T, was isolated from the feces of a cow in Andong, Republic of Korea. It was studied using a polyphasic method to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BGYT1T formed a lineage within the genus Olsenella and was most closely related to O. umbonate KCTC 15140T (98.2%). The complete genome sequence of strain BGYT1T was 2,476,083 bp long with a G + C content of 66.9 mol% and contained 1835 genes and 8 contigs. The N50 value was 604,117 bp. There were 50 tRNAs, 6 rRNAs (5S, 16S, 23S), 1778 CDSs and 2 BGCs and 1 tmRNA. The values for ANI (76.8%), AAI (67.3%), and dDDH (22.2%) compared to the closest related species were all below the threshold for bacterial species delineation. In addition, genes encoding the cell wall degrading enzymes such as chitinases, ß-1,3 glucanases, and proteases were also detected. The strain was able to grow at pH 6.0-8.0 (optimum, pH 7.0), in the presence of 0.5-1.5% NaCl (optimum, 0.5%, w/v) and at the temperature range of 35-40 °C (optimum, 35 °C). The predominant fatty acids were C16:0 DMA (20.2%), C16:0 (20.2%), C18:0 (10.5%) and C18:1 cis 9 (17.0%). The polar lipids consisted of an unidentified phospholipid, four unidentified glycolipids and three unidentified lipids. Based on its phenotypic analyses, phylogenetic and physiological characteristics, strain BGYT1T represented a novel species within the genus Olsenella, for which the name Olsenella intestinalis sp. nov. is proposed. The type strain is BGYT1T (= KCTC 25379T = GDMCC 1.3011T).

Succinivibrio faecicola sp. nov., isolated from cow faeces.

A Gram-stain-negative, obligately anaerobic, non-motile, non-spore-forming, helical rod-shaped bacterium, designated AGMB01872T, was isolated from faeces of a cow deposited in the National Institute of Animal Science (Wanju, Republic of Korea). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain AGMB01872T was most closely related to Succinivibrio dextrinosolvens DSM 3072T (= KCTC 25222T, 96.6 %) which belonged to the family Succinivibrionaceae. Growth was occurred at 30-40 °C (optimum, 37 °C), pH 6-7 (optimum, pH 7) and in the presence of 0.5-1.0 % (w/v) NaCl. The genomic DNA G+C content of strain AGMB01872T was 35.9 mol%. The average nucleotide identity value between strain AGMB01872T and S. dextrinosolvens DSM 3072T was 72.1 %. Cells of strain AGMB01872T utilized d-glucose, maltose, d-xylose and l-arabinose. The major fatty acids (>10 %) were C14 : 0 (23.9 %), C16 : 0 (29.4 %), summed feature 5 (10.8 %) and summed feature 10 (30.3 %). The major end-product of glucose fermentation was succinate. Based on the phenotypic, phylogenetic, biochemical, genotypic and chemotaxonomic data, AGMB01872T represents a novel species within the genus Succinivibrio, for which the name Succinivibrio feacicola sp. nov. is proposed. The type strain is AGMB01872T (= KCTC 25201T=NBRC 115007T=GDMCC 1.2573T).

Phocaeicola faecicola sp. nov., isolated from porcine faeces.

An obligately anaerobic, non-motile, Gram-negative and rod-shaped strain (AGMB03916T) was isolated from faeces of a 2-week-old piglet raised at the National Institute of Animal Science in Wanju, Republic of Korea. Growth of strain AGMB03916T occurred at 30-45 °C (optimum, 37 °C), at pH 6-9 (optimum, pH 8) and in the presence of 0.5-1.0 % (w/v) NaCl. Based on the results of 16S rRNA gene sequence analyses, strain AGMB03916T was closely related to two validly published species of the genus Phocaeicola, Phocaeicola plebeius and Phocaeicola coprocola. The 16S rRNA gene sequence similarity of strain AGMB03916T compared to P. plebeius M12T (=KCTC 5793T) and P. coprocola M16T (=KCTC 5443T) were 96.3 and 95.0 %, respectively. The genomic DNA G+C content of strain AGMB03916T was 46.4 mol%. The average nucleotide identity values between strain AGMB03916T and the reference strains were 74.9-78.5 %. Cells were able to utilize d-glucose, lactose, sucrose, maltose, salicin, aesculin hydrolysis, cellobiose and raffinose. The major end product of metabolism was acetate. The major cellular fatty acids (>10 %) of the isolate were iso-C15 : 0, anteiso-C15 : 0, C16 : 0, C16 : 0 3-OH and summed feature 11 (iso-C17 : 0 3-OH and/or C18 : 2 DMA). On the basis of the genotypic, biochemical, chemotaxonomic, phenotypic and phylogenetic data, strain AGMB03916T represents a novel species of the genus Phocaeicola, for which the name Phocaeicola faecicola sp. nov. is proposed. The type strain is AGMB03916T (=KCTC 25014T=GDMCC 1.2574T).

Peptoniphilus faecalis sp. nov., isolated from swine faeces.

An obligately anaerobic, Gram-positive, non-motile, coccus-shaped bacterial strain designated AGMB00490T was isolated from swine faeces. 16S rRNA gene sequence-based phylogenetic analysis indicated that the isolate belongs to the genus Peptoniphilus and that the most closely related species is Peptoniphilus gorbachii WAL 10418T (=KCTC 5947T, 97.22 % 16S rRNA gene sequence similarity). Whole genome sequence analysis determined that the DNA G+C content of strain AGMB00490T was 31.2 mol% and moreover that the genome size and numbers of tRNA and rRNA genes were 2 129 517 bp, 34 and 10, respectively. Strain AGMB00490T was negative for oxidase and urease; positive for catalase, indole production, arginine arylamidase, leucine arylamidase, tyrosine arylamidase and histidine arylamidase; and weakly positive for phenylalanine arylamidase and glycine arylamidase. The major cellular fatty acids (>10 %) of the isolate were determined to be C16 : 0 and C18 : 1 ω9c. Strain AGMB00490T produced acetic acid as a major end product of metabolism. Accordingly, phylogenetic, physiologic and chemotaxonomic analyses revealed that strain AGMB00490T represents a novel species for which the name Peptoniphilus faecalis sp. nov. is proposed. The type strain is AGMB00490T (=KCTC 15944T=NBRC 114159T).

Anaerosporobacter faecicola sp. nov. isolated from faeces of Korean cow.

A novel bacterial isolate designated as strain AGMB01083T was isolated from Korean cow faeces deposited in the National Institute of Animal Science (Wanju, Republic of Korea). The bacterium is obligate anaerobic, Gram-strain-positive, and motile. Cells are straight or curved rod-shaped, flagella and spores are observed. Growth occurs between 20-40 °C (temperature optimum of 35 °C), at pH 7-9 (pH optimum of 7), and in the presence of 0.5-1.0 % (w/v) NaCl. Based on the 16S rRNA gene sequence analysis, the strain belongs to the genus Anaerosporobacter and is most closely related to A. mobilis HY-37-4T (=KCTC5027T, similarity, 95.7 %). The DNA G+C content is 36.2 mol%, determined by the whole-genome sequence. The average nucleotide identity value between strain AGMB01083T and strain A. mobilis HY-37-4T is 75.5 %, below the interspecies identity threshold value. The major cellular fatty acids (>10 %) of strain AGMB01083T are C16 : 0, C16 : 0 dimethyl acetal (DMA), and C16 : 0 3-OH. Based on the phylogenetic, phenotypic, biochemical, chemotaxonomic, and genomic characterization, strain AGMB01083T is proposed to be a novel species, named Anaerosporobacter faecicola, in the genus Anaerosporobacter. The type strain is AGMB01083T (=KCTC 15857T=NBRC 114517T).

Description of Anaerostipes faecalis sp. nov., a new segmented filamentous bacterium isolated from swine faeces.

A novel, strictly anaerobic, gram-negative, segmented filamentous bacterium strain AGMB03513T, was isolated from the faeces of a 5-month-old pig. Phylogenetic analysis based on the 16S rRNA gene indicated that the isolate was a member of the family Lachnospiraceae, and the closest strain was Anaerostipes butyraticus. Strain AGMB03513T formed a lineage within the genus Anaerostipes and was closely related to A. butyraticus DSM 22094 T (= KCTC 15125 T, 95.8%), Anaerostipes hadrus DSM 3319 T (= KCTC 15606 T, 95.5%), Anaerostipes caccae DSM 14662 T (= KCTC 15019 T, 94.0%), and Anaerostipes rhamnosivorans DSM 26241 T (= KCTC 15316 T, 93.4%). Strain AGMB03513T grew at temperatures between 30 and 45 °C, within a pH range of 7.0-9.0, and in medium containing up to 1.5% NaCl. Cells were found to utilise D-glucose, D-mannitol, D-lactose, D-saccharose, D-maltose, D-xylose, L-arabinose, D-mannose, and D-sorbitol, and acetate was identified as the major end product of metabolism. The major components of the cellular fatty acids were C12:0, C16:0, and C18:0. In addition, the bacterium contained meso-diaminopimelic acid in the cell wall. According to the comparative analysis of the whole genome sequence, the DNA G + C content of strain AGMB03513 was 37.0 mol%. In addition, Average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridisation (dDDH) values were obtained in comparisons of strain AGMB03513T with reference strains of species in the genus Anaerostipes. ANI values were found to be between 71.0 and 75.7%, AAI values between 66.6 and 73.2%, and dDDH values between 19.5 and 21.4%. All the data were below the threshold range for species determination. Based on phenotypic, phylogenetic, biochemical, chemotaxonomic, and genomic characteristics, we considered it reasonable to assign a novel species status to strain AGMB03513T, for which we propose the name Anaerostipes faecalis sp. nov. The type strain is AGMB03513T (= KCTC 25020 T = NBRC 114896 T).

Faecalicatena faecalis sp. nov., a moderately alkaliphilic bacterial strain isolated from swine faeces.

An obligately anaerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped strain AGMB00832T was isolated from swine faeces. Phylogenetic analysis based on the 16S rRNA gene, together with the housekeeping genes, gyrB and rpoD, revealed that strain AGMB00832T belonged to the genus Faecalicatena and was most closely related to Faecalicatena orotica KCTC 15331T. In biochemical analysis, strain AGMB00832T was shown to be negative for catalase, oxidase and urease. Furthermore, the isolate was positive for ß-glucosidase, ß-glucuronidase, glutamic acid decarboxylase, proline arylamidase, acid phosphatase and naphthol-AS-BI-phosphohydrolase. The major cellular fatty acids (> 10%) of the isolate were C14:0, C16:0 and C18:1ω11t DMA. Based on the whole genome sequence analysis, the DNA G + C content of strain AGMB00832T was 44.2 mol%, and the genome size and numbers of rRNA and tRNA genes were 5,175,159 bp, 11 and 53, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain AGMB00832T and related strains were ≤ 77.4 and 22.5%, respectively. Furthermore, the genome analysis revealed the presence of genes for alkaline shock protein 23 and cation/proton antiporters, which may facilitate growth of strain AGMB00832T in alkaline culture condition. On the basis of polyphasic taxonomic approach, strain AGMB00832T represents a novel species within the genus Faecalicatena, for which the name Faecalicatena faecalis sp. nov. is proposed. The type strain is AGMB00832T (= KCTC 15946T = NBRC 114613T).

Anaerococcus faecalis sp. nov., Isolated from Swine Faeces.

An obligate anaerobic, Gram-stain-positive, non-spore forming, non-motile, catalase and oxidase-negative, coccoid-shaped bacterium designated AGMB00486T was isolated from swine faeces. The optimal growth of the isolate occurred at pH 8.0 and 37 ℃. Furthermore, the growth was observed in the presence of up to 4% (w/v) NaCl but not at salinity levels higher than 5%. The phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain AGMB00486T was a member of the genus Anaerococcus and that the isolate was most closely related to Anaerococcus vaginalis KCTC 15028T (96.7% 16S rRNA gene sequence similarity) followed by Anaerococcus hydrogenalis KCTC 15014T (96.7%) and Anaerococcus senegalensis KCTC 15435T (96.3%). Whole-genome sequence analysis determined that the DNA G+C content of strain AGMB00486T was 30.1 mol%, and the genome size, numbers of tRNA and rRNA genes were 2,268,866 bp, 47 and 8, respectively. The average nucleotide identity values between strain AGMB00486T and the three related type strains were 77.0, 77.4 and 77.2%, respectively. The major cellular fatty acids (> 10%) of strain AGMB00486T were C14:0, C16:0 and C16:0 DMA. Accordingly, these distinct phenotypic and phylogenetic properties revealed that strain AGMB00486T represents a novel species, for which the name Anaerococcus faecalis sp. nov. is proposed. The type strain is AGMB00486T (= KCTC 15945T = CCTCC AB 202009T).

Characterization of bacteriophage VVP001 and its application for the inhibition of Vibrio vulnificus causing seafood-borne diseases.

Vibrio vulnificus is a major food-borne pathogen that causes septicemia and cellulitis with a mortality rate of >50%. However, there are no efficient natural food preservatives or biocontrol agents to control V. vulnificus in seafood. In this study, we isolated and characterized a novel bacteriophage VVP001. Host range and transmission electron microscopy morphology observations revealed that VVP001 belongs to the family Siphoviridae and specifically infects V. vulnificus. Phage stability tests showed that VVP001 is stable at a broad temperature range of -20 °C to 65 °C and a pH range from 3 to 11, which are conditions for food applications (processing, distribution, and storage). In vitro challenge assays revealed that VVP001 inhibited V. vulnificus MO6-24/O (a clinical isolate) growth up to a 3.87 log reduction. In addition, complete genome analysis revealed that the 76 kb VVP001 contains 102 open reading frames with 49.64% G + C content and no gene encoding toxins or other virulence factors, which is essential for food applications. Application of VVP001 to fresh abalone samples contaminated with V. vulnificus demonstrated its ability to inhibit V. vulnificus growth, and an in vivo mouse survival test showed that VVP001 protects mice against high mortality (survival rate >70% at a multiplicity of infection of 1000 for up to 7 days). Therefore, the bacteriophage VVP001 can be used as a good natural food preservative and biocontrol agent for food applications.

Peribacillus faecalis sp. nov., a moderately halophilic bacterium isolated from the faeces of a cow.

A Gram-stain-positive, facultatively anaerobic, endospore-forming, rod-shaped strain, AGMB 02131T, which grew at 20-40 °C (optimum 30 °C), pH 3.0-11.0 (optimum pH 4.0) and in the presence of 0-18 % (w/v) NaCl (optimum 10 %), was isolated from a cow faecal sample and identified as a novel strain using a polyphasic taxonomic approach. The phylogenetic analysis based on 16S rRNA gene sequences along with the whole genome (92 core gene sets) revealed that AGMB 02131T formed a group within the genus Peribacillus, and showed the highest sequence similarity with Peribacillus endoradicis DSM 28131T (96.9 %), following by Peribacillus butanolivorans DSM 18926T (96.6 %). The genome of AGMB 02131T comprised 70 contigs, the chromosome length was 4 038 965 bp and it had a 38.5 % DNA G+C content. Digital DNA-DNA hybridization revealed that AGMB 02131T displayed 21.4 % genomic DNA relatedness with the most closely related strain, P. butanolivorans DSM 18926T. AGMB 02131T contains all of the conserved signature indels that are specific for members of the genus Peribacillus. The major cellular fatty acids (>10 %) of AGMB 02131T were C18 : 1ω9c, C18:0 and C16 : 0. The major polar lipids present were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. On the basis of the phenotypic, phylogenetic, genomic and chemotaxonomic features, AGMB 02131T represents a novel species of the genus Peribacillus, for which the name Peribacillus faecalis sp. nov. is proposed. The type strain is AGMB 02131T (=KCTC 43221T=CCTCC AB 2020077T).

Effects of corn particle size on nutrient utilization in pigs evaluated under optimal and heat stress conditions.

The effects of corn particle size on nutrient digestibility and energy utilization in pigs were determined under optimal (experiment 1, 25 ± 1 °C) or heat stress (experiment 2, 37 ± 1 °C) conditions. In Exp. 1 and 2, five experimental diets were tested using a 5 × 5 Latin square design involving five barrows (Landrace × Yorkshire × Duroc, average initial body weight of 30 ± 1 kg and 45.0 ± 1.8 kg, respectively, in individual metabolic cages). Dietary treatments were as follows: 200-, 300-, 400-, 600-, 800-µm corn particle sizes obtained by mesh screens. Under optimal thermal conditions, digestibility of dry matter (DM) and crude fiber (CF) from 200-µm diet was higher (P < 0.05) compared to that from the 300-µm and 400-µm diets. The digestibility of crude protein (CP) and ether extract (EE) was the highest (P < 0.05) at the 200-µm particle size. The apparent total tract digestibility of energy was significantly higher (P < 0.05) on the 200-µm diet. Under heat stress, digestibility of CF when corn was ground to 600 µm was higher (P < 0.05) compared to 300 and 400 µm. Digestibility of NDF and ADF was the highest (P < 0.05) at 600-µm corn particle size. In conclusion, grinding corn to 200-µm corn particles had a positive effect on DM, CP, EE, and CF under optimal thermal condition, while the 600-µm corn particle size had positive effects on digestibility of CF, NDF, and ADF than 200-µm corn particle size under heat stress.

Potent O-antigen-deficient (rough) mutants of Salmonella Typhimurium secreting Lawsonia intracellularis antigens enhance immunogenicity and provide single-immunization protection against proliferative enteropathy and salmonellosis in a murine model.

The obligate intracellular pathogen Lawsonia intracellularis (LI), the etiological agent of proliferative enteropathy (PE), poses a substantial economic loss in the swine industry worldwide. In this study, we genetically engineered an O-antigen-deficient (rough) Salmonella strain secreting four selected immunogenic LI antigens, namely OptA, OptB, LfliC, and Lhly. The genes encoding these antigens were individually inserted in the expression vector plasmid pJHL65, and the resultant plasmids were transformed into the ∆asd ∆lon ∆cpxR ∆rfaL Salmonella Typhimurium (ST) strain JOL1800. The individual expression of the selected LI antigens in JOL1800 was validated by an immunoblotting assay. We observed significant (P < 0.05) induction of systemic IgG and mucosal IgA responses against each LI antigen or Salmonella outer membrane protein in mice immunized once orally with a mixture of four JOL1800-derived strains. Further, mRNA of IL-4 and IFN-γ were highly upregulated in splenic T cells re-stimulated in vitro with individual purified antigens. Subsequently, immunized mice showed significant protection against challenge with 106.9 TCID50 LI or 2 × 109 CFU of a virulent ST strain. At day 8 post-challenge, no mice in the immunized groups showed the presence of LI-specific genomic DNA (gDNA) in stool samples, while 50% of non-immunized mice were positive for LI-specific gDNA. Further, all the immunized mice survived the virulent ST challenge, compared to a 20% mortality rate observed in the control mice. Collectively, the constructed rough ST-based LI vaccine candidate efficiently elicited LI and ST-specific humoral and cell-mediated immunity and conferred proper dual protection against PE and salmonellosis.

Update on Antimicrobial Resistance in Clostridium difficile: Resistance Mechanisms and Antimicrobial Susceptibility Testing.

Oral antibiotics such as metronidazole, vancomycin and fidaxomicin are therapies of choice for Clostridium difficile infection. Several important mechanisms for C. difficile antibiotic resistance have been described, including the acquisition of antibiotic resistance genes via the transfer of mobile genetic elements, selective pressure in vivo resulting in gene mutations, altered expression of redox-active proteins, iron metabolism, and DNA repair, as well as via biofilm formation. This update summarizes new information published since 2010 on phenotypic and genotypic resistance mechanisms in C. difficile and addresses susceptibility test methods and other strategies to counter antibiotic resistance of C. difficile.

Comparison of Fecal Microbiota between German Holstein Dairy Cows with and without Left-Sided Displacement of the Abomasum.

One of the most common diseases in high-performance German Holstein dairy cows is left-sided displacement of the abomasum (LDA). Hypomotility of the abomasum is detrimental during the pathogenesis of LDA. It is known that improper interactions between the gut microbiota and the enteric nervous system contribute to dysfunctions of gastrointestinal motility. Therefore, we hypothesized that the gut microbial composition will be different between German Holstein dairy cows with and without LDA. We used 16S rRNA gene analysis to evaluate whether there are any differences in bacterial composition between German Holstein dairy cows with and without LDA. Even though our data are limited to being used to correlate compositional changes with corresponding functional aspects in the pathogenesis of LDA, results from this study show that the fecal microbial compositions of German Holstein dairy cows with LDA shifted and were less diverse than those in normal cows. In particular,Spirochaeteswere absent in cows with LDA.

Hyperimmune bovine colostrum as a novel therapy to combat Clostridium difficile infection.

BACKGROUND: Clostridium difficile is a primary cause of antibiotic-associated diarrhea that typically develops when gut microbiota is altered. Conventional treatment for C. difficile infection (CDI) is additional antimicrobial administration, which further disrupts normal intestinal microbiota, often resulting in poor treatment outcomes. METHODS: A pregnant dairy cow was repeatedly immunized with recombinant mutants of toxins A and B produced by C. difficile, and the resultant hyperimmune bovine colostrum (HBC) was evaluated for therapeutic efficacy in gnotobiotic piglets with diarrhea due to CDI. Control piglets received nonimmune colostrum. To determine the impact of HBC on gut microbiota, 1 of 2 groups of piglets transplanted with normal human gut microbiota was treated with HBC. RESULTS: Nonimmune colostrum-treated piglets developed moderate to severe diarrhea and colitis. In contrast, HBC-treated piglets had mild or no diarrhea and mild or no colitis. Lyophilization had no detectable impact on HBC efficacy. HBC had no discernible effect on the composition of normal human gut microbiota in the porcine intestinal tract. CONCLUSIONS: HBC provides an oral, cost-effective, and safe alternative to antibiotic therapy for CDI. By preserving intestinal microbiota, HBC may be more efficacious than antibiotics. Additional studies are warranted to establish HBC as a viable immunotherapeutic agent for human use against CDI.

Barcoded pyrosequencing-based metagenomic analysis of the faecal microbiome of three purebred pig lines after cohabitation.

The microbial communities in the pig gut perform a variety of beneficial functions. Along with host genetics and diet, farm management practices are an important aspect of agricultural animal production that could influence gut microbial diversity. In this study, we used barcoded pyrosequencing of the V1-V3 regions of the 16S ribosomal RNA (rRNA) genes to characterise the faecal microbiome of three common commercial purebred pig lines (Duroc, Landrace and Yorkshire) before and after cohabitation. The diversity of faecal microbiota was characterised by employing phylogenetic, distance-based and multivariate-clustering approaches. Bacterial diversity tended to become more uniform after mixing of the litters. Age-related shifts were also observed at various taxonomic levels, with an increase in the proportion of the phylum Firmicutes and a decrease in Bacteroidetes over time, regardless of the purebred group. Cohabitation had a detectable effect on the microbial shift among purebred pigs. We identified the bacterial genus Parasutterella as having utility in discriminating pigs according to time. Similarly, Dialister and Bacteroides can be used to differentiate the purebred lines used. The microbial communities of the three purebred pigs became more similar after cohabitation, but retained a certain degree of breed specificity, with the microbiota of Landrace and Yorkshire remaining distinct from that of their distant relative, Duroc.

Microbial shifts in the swine distal gut in response to the treatment with antimicrobial growth promoter, tylosin.

Antimicrobials have been used extensively as growth promoters (AGPs) in agricultural animal production. However, the specific mechanism of action for AGPs has not yet been determined. The work presented here was to determine and characterize the microbiome of pigs receiving one AGP, tylosin, compared with untreated pigs. We hypothesized that AGPs exerted their growth promoting effect by altering gut microbial population composition. We determined the fecal microbiome of pigs receiving tylosin compared with untreated pigs using pyrosequencing of 16S rRNA gene libraries. The data showed microbial population shifts representing both microbial succession and changes in response to the use of tylosin. Quantitative and qualitative analyses of sequences showed that tylosin caused microbial population shifts in both abundant and less abundant species. Our results established a baseline upon which mechanisms of AGPs in regulation of health and growth of animals can be investigated. Furthermore, the data will aid in the identification of alternative strategies to improve animal health and consequently production.