Reclassification of Facklamia ignava, Facklamia sourekii and Facklamia tabacinasalis as Falseniella ignava gen. nov., comb. nov., Hutsoniella sourekii gen. nov., comb. nov., and Ruoffia tabacinasalis gen. nov., comb. nov., and description of Ruoffia halotolerans sp. nov., isolated from hypersaline Inland Sea of Qatar.

A Gram-stain-positive, non-pigmented, coccus-shaped, facultatively anaerobic and α-hemolytic bacterium designated as INB8T was isolated from a hypersaline marine water sample collected at the Inland Sea of Qatar. The isolate was able to grow at 25-40 °C (optimum, 30 °C), at pH 5-11 and with 2-8% NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain INB8T was placed within the family Aerococcaceae with the highest sequence similarity to Facklamia tabacinasalis CCUG 30090T (99.5%), followed by Facklamia hominis CCUG 36813T (93.9%), Facklamia sourekii Y17312T (93.8%), Facklamia ignava CCUG 37419T (93.6%), Facklamia miroungae CCUG 42728T (93.5%), Suicoccus acidiformans ZY16052T (93.5%), Facklamia languida CCUG 37842T (93.2%), Ignavigranum ruoffiae (93.1%), and Dolosicoccus paucivorans DSM 15742T (90.8%). Average nucleotide identity and digital DNA-DNA hybridization values between strain INB8T and F. tabacinasalis CCUG 30090T were determined to be 94.5% and 58.9% respectively, confirming strain INB8T represents a novel species. The major fatty acids were C14:0, C16:0, C18:0 and C18:1 ω9c. The G + C content of strain INB8T determined from the genome was 36.3 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic information, it is proposed that Facklamia tabacinasalis should be reclassified as Ruoffia tabacinasalis, Facklamia ignava be reclassified as Falseniella ignava, and Facklamia sourekii be reclassified Hutsoniella sourekii. It is further proposed that strain INB8T should be classified as a species of the genus Ruoffia for which the name Ruoffia halotolerans sp. nov. is proposed. The type strain is INB8T (= LMG 30291T = CCUG 70701T = QCC/B60/17T).

Ningiella ruwaisensis gen. nov., sp. nov., a member of the family Alteromonadaceae isolated from marine water of the Arabian Gulf.

Strain B66T was isolated from a marine water sample collected at Al Ruwais, located on the northern tip of Qatar. Cells were Gram-stain-negative, strictly aerobic and short- rod-shaped with a polar flagellum. The isolate was able to grow at 15-45 °C (optimum, 30 °C), at pH 5-11 (optimum, pH 6.5-8) and with 0-6 % NaCl. 16S rRNA gene sequence analysis revealed that strain B66T was affiliated with the family Alteromonadaceae, sharing the highest sequence similarities to the genera Alteromonas (93.7-95.4 %), Aestuariibacter (94.0-95.1 %), Agaribacter (93.3-93.7 %), Glaciecola (92.0-93.7 %), Marisendiminitalea (93.2-93.3 %) and Planctobacterium (92.9 %). In the phylogenetic trees, strain B66T demonstrated the novel organism formed a distinct lineage closely associated with Aestuariibacter and Planctobacterium. Major fatty acids were C16 : 0, summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c/iso-C15 : 0 2-OH and iso-C15 : 0 3-OH. The major respiratory quinone was ubiquinone-8 and the major polar lipids are phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content derived from the genome was 43.2 mol%. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic data, strain B66T is considered to represent a novel species and genus for which the name Ningiella ruwaisensis gen. nov., sp. nov., is proposed. The type strain is B66T (=QCC B003/17T=LMG 30288 T=CCUG 70703T).

A Simple In Vitro Gut Model for Studying the Interaction between Escherichia coli and the Intestinal Commensal Microbiota in Cecal Mucus.

A novel in vitro gut model was developed to better understand the interactions between Escherichia coli and the mouse cecal mucus commensal microbiota. The gut model is simple and inexpensive while providing an environment that largely replicates the nonadherent mucus layer of the mouse cecum. 16S rRNA gene profiling of the cecal microbial communities of streptomycin-treated mice colonized with E. coli MG1655 or E. coli Nissle 1917 and the gut model confirmed that the gut model properly reflected the community structure of the mouse intestine. Furthermore, the results from the in vitro gut model mimic the results of published in vivo competitive colonization experiments. The gut model is initiated by the colonization of streptomycin-treated mice, and then the community is serially transferred in microcentrifuge tubes in an anaerobic environment generated in anaerobe jars. The nutritional makeup of the cecum is simulated in the gut model by using a medium consisting of porcine mucin, mouse cecal mucus, HEPES-Hanks buffer (pH 7.2), Cleland's reagent, and agarose. Agarose was found to be essential for maintaining the stability of the microbial community in the gut model. The outcome of competitions between E. coli strains in the in vitro gut model is readily explained by the "restaurant hypothesis" of intestinal colonization. This simple model system potentially can be used to more fully understand how different members of the microbiota interact physically and metabolically during the colonization of the intestinal mucus layer.IMPORTANCE Both commensal and pathogenic strains of Escherichia coli appear to colonize the mammalian intestine by interacting physically and metabolically with other members of the microbiota in the mucus layer that overlays the cecal and colonic epithelium. However, the use of animal models and the complexity of the mammalian gut make it difficult to isolate experimental variables that might dictate the interactions between E. coli and other members of the microbiota, such as those that are critical for successful colonization. Here, we describe a simple and relatively inexpensive in vitro gut model that largely mimics in vivo conditions and therefore can facilitate the manipulation of experimental variables for studying the interactions of E. coli with the intestinal microbiota.

Escherichia coli pathotypes occupy distinct niches in the mouse intestine.

Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we sought to determine if other E. coli pathogens use a similar strategy. We found that uropathogenic E. coli CFT073 and enteropathogenic E. coli E2348/69 occupy intestinal niches that are distinct from that of E. coli EDL933. In contrast, two enterohemorrhagic strains, E. coli EDL933 and E. coli Sakai, occupy the same niche, suggesting that strategies to prevent colonization by a given pathotype should be effective against other strains of the same pathotype. However, we found that a combination of commensal E. coli strains that can prevent colonization by E. coli EDL933 did not prevent colonization by E. coli CFT073 or E. coli E2348/69. Our results indicate that development of probiotics to target multiple E. coli pathotypes will be problematic, as the factors that govern niche occupation and hence stable colonization vary significantly among strains.

Tolumonas osonensis sp. nov., isolated from anoxic freshwater sediment, and emended description of the genus Tolumonas.

A polyphasic taxonomic study was performed on a strain of an unknown Gram-negative, non-motile, saccharolytic, facultatively anaerobic bacterium, strain OCF 7(T), isolated from anoxic freshwater sediment. The strain grew optimally at 22 °C and pH 7.5, and was able to grow under strictly anaerobic conditions. Major fermentation products from glucose metabolism were formate, acetate, ethanol and lactate. Comparative 16S rRNA gene sequence analysis indicated that strain OCF 7(T) was phylogenetically related to the type strain of Tolumonas auensis (97.2 % similarity) within the family Aeromonadaceae of the Gammaproteobacteria. However, OCF 7(T) did not produce toluene from phenylacetate, phenylalanine, phenoxyacetate, phenylsuccinate or phenylbutyrate in the presence of glucose. Phenol was not produced from tyrosine or phenoxyacetate in the presence of glucose. Dominant fatty acids of this micro-organism included C(16 : 0), C(18 : 1)ω7c and C(16 : 1)ω7c (and/or iso-C(15 : 0) 2-OH). Major polar lipids were phosphatidylglycerol and phosphatidylethanolamine, and the respiratory quinone was menaquinone MK-8. The genomic DNA G+C content of strain OCF 7(T) was 52.1 mol%. Based on phylogenetic and phenotypic evidence, strain OCF 7(T) should be classified as a representative of a novel species of Tolumonas, for which the name Tolumonas osonensis sp. nov. is proposed; the type strain is OCF 7(T) ( = DSM 22975(T) = ATCC BAA-1908(T)). An emended description of the genus Tolumonas is also given.

Anaerobes: a piece in the puzzle for alternative biofuels.

Although much newsprint is devoted to the subject of reducing the United States and other major developed countries dependence on their respective foreign energy sources; the most challenging issues for society is to provide long-term, sustainable energy sources to accommodate the global population as a whole. The projected population of planet Earth for the year 2050 is estimated to be in excess of 9 billion. With hydrocarbon-based energy becoming limiting it is unlikely that one type of energy will alone replace our dependence on this source. So-called "green" technologies that include solar, wind and wave powers are now being explored to reduce on traditional hydrocarbon-based fuel sources. The diverse and functional properties of microbes, and in particular anaerobes, are now being utilized in the production of biofuels and may provide one piece of the jigsaw for future energy requirements. Here we present some results of a screening program to identify and characterize a number of carbon monoxide oxidizing, ethanol-producing acetogenic anaerobes phylogenetically located within the Clostridiales.

Alkalibaculum bacchi gen. nov., sp. nov., a CO-oxidizing, ethanol-producing acetogen isolated from livestock-impacted soil.

Phenotypic and phylogenetic studies were performed on three strains of an acetogenic bacterium isolated from livestock-impacted soil. The bacterium stained Gram-negative and was a non-spore-forming rod that was motile by peritrichous flagella. The novel strains had an optimum pH for growth of 8.0-8.5 and utilized H2 : CO2, CO : CO2, glucose, fructose, mannose, turanose, ribose, trimethylamine, pyruvate, methanol, ethanol, n-propanol and n-butanol as growth substrates. Acetate was produced from glucose. Acetate, CO2 and ethanol were produced from CO : CO2. 16S rRNA gene sequence analysis indicated that the novel strains formed a new subline in the family Eubacteriaceae (rRNA cluster XV) of the low G+C-containing Gram-positive bacteria of the class Clostridia. The DNA G+C base composition was 34 mol%. Cell wall analysis revealed the existence of a novel B-type peptidoglycan similar to the B2α-type (B4) configuration with a variation containing aspartic acid. Based on phylogenetic and phenotypic evidence, it is proposed that the new isolates represent a novel genus and species, for which the name Alkalibaculum bacchi gen. nov., sp. nov. is proposed. The type strain of the type species is CP11(T) (=ATCC BAA-1772(T)=DSM 22112(T)).