RelA-SpoT Homolog toxins pyrophosphorylate the CCA end of tRNA to inhibit protein synthesis.

RelA-SpoT Homolog (RSH) enzymes control bacterial physiology through synthesis and degradation of the nucleotide alarmone (p)ppGpp. We recently discovered multiple families of small alarmone synthetase (SAS) RSH acting as toxins of toxin-antitoxin (TA) modules, with the FaRel subfamily of toxSAS abrogating bacterial growth by producing an analog of (p)ppGpp, (pp)pApp. Here we probe the mechanism of growth arrest used by four experimentally unexplored subfamilies of toxSAS: FaRel2, PhRel, PhRel2, and CapRel. Surprisingly, all these toxins specifically inhibit protein synthesis. To do so, they transfer a pyrophosphate moiety from ATP to the tRNA 3' CCA. The modification inhibits both tRNA aminoacylation and the sensing of cellular amino acid starvation by the ribosome-associated RSH RelA. Conversely, we show that some small alarmone hydrolase (SAH) RSH enzymes can reverse the pyrophosphorylation of tRNA to counter the growth inhibition by toxSAS. Collectively, we establish RSHs as RNA-modifying enzymes.

Microbiological effect of mupirocin and chlorhexidine for Staphylococcus aureus decolonization in community and nursing home based adults.

OBJECTIVE: To compare the presence of Staphylococcus aureus and pathogenic Gram-negative rods (GNR) in the anterior nares, posterior pharynx and three skin sites in community-based adults and nursing home-based adults before and after treatment with nasal mupirocin and topical chlorhexidine. METHODS: S. aureus-colonized adults were recruited from the community (n=26) and from nursing homes (n=8). Eligible participants were cultured for S. aureus and GNR during two study visits and then received intranasal mupirocin and topical chlorhexidine for 5days, with a 2-month follow-up period. RESULTS: After decolonization, we found sustained decreases of S. aureus colonization in nose, throat and skin sites over 4-8weeks in both populations. Intranasal mupirocin did not increase GNR colonization in nose or throat. Chlorhexidine did not decrease GNR colonization in skin sites. CONCLUSIONS: Decolonization with mupirocin and chlorhexidine leads to a sustained effect on S. aureus colonization without affecting GNR colonization.

Description of Auricoccus indicus gen. nov., sp. nov., isolated from skin of human ear.

A Gram-stain-positive, non-motile, non-spore-forming, small spherical bacterium, strain S31T, was isolated from skin surface (external ear lobe) of a healthy human subject and characterized using a polyphasic approach. On the basis of 1507 bp 16S rRNA gene sequence comparison, S31T showed highest (92.8 %, AY119686) sequence similarity with Macrococcus brunensis CCUG 47200T followed by Macrococcus caseolyticus DSM 20597T (92.7 % AP009484) and formed a separate clade with 65 % bootstrap support. The DNA G+C content was found to be 34 mol%. Anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0 are the predominant fatty acids in fatty acid methyl ester (FAME) profile of strain S31T. It contained A3α type peptidoglycan with l-Lys-Gly3-l-Ala peptide. Comparative study of morphological and physiological traits indicated that S31T has phenetically diverged from its closest relatives. On the basis of morphological, chemotaxonomic and genotypic data, S31T showed marked distinctions from its closest relatives of the family Staphylococcaceae and is proposed to represent a novel genus Auricoccus with Auricoccus indicus as type species of the genus. S31T (CCUG 69858T=KCTC 33611T=MCC 3027T) is the type strain of the species.

Multicenter Study on Incubation Conditions for Environmental Monitoring and Aseptic Process Simulation.

Environmental monitoring and aseptic process simulations represent an integral part of the microbiological quality control system of sterile pharmaceutical products manufacturing operations. However, guidance documents and manufacturers practices differ regarding recommendations for incubation time and incubation temperature, and, consequently, the environmental monitoring and aseptic process simulation incubation strategy should be supported by validation data. To avoid any bias coming from in vitro studies or from single-site manufacturing in situ studies, we performed a collaborative study at four manufacturing sites with four samples at each location. The environmental monitoring study was performed with tryptic soy agar settle plates and contact plates, and the aseptic process simulation study was performed with tryptic soy broth and thioglycolate broth. The highest recovery rate was obtained with settle plates (97.7%) followed by contact plates (65.4%) and was less than 20% for liquid media (tryptic soy broth 19% and thioglycolate broth 17%). Gram-positive cocci and non-spore-forming Gram-positive rods were largely predominant with more than 95% of growth and recovered best at 32.5 °C. The highest recovery of molds was obtained at 22.5 °C alone or as the first incubation temperature. Strict anaerobes were not recovered. At the end of the five days of incubation no significant statistical difference was obtained between the four conditions. Based on these data a single incubation temperature at 32.5 °C could be recommended for these four manufacturing sites for both environmental monitoring and aseptic process simulation, and a second plate could be used, periodically incubated at 22.5 °C. Similar studies should be considered for all manufacturing facilities in order to determine the optimal incubation temperature regime for both viable environmental monitoring and aseptic process simulation. LAY ABSTRACT: Microbiological environmental monitoring and aseptic process simulation confirm that pharmaceutical cleanrooms are in an appropriate hygienic condition for manufacturing of sterile drug products. Guidance documents from different health authorities or expert groups differ regarding recommendation of the applied incubation time and incubation temperature, leading to variable manufacturers practices. Some recent publications have demonstrated that laboratory studies are not relevant to determine the best incubation regime and that in situ manufacturing site studies should be used. To solve any possible bias coming from laboratory studies or single-site in situ studies, we conducted a multicenter study at four manufacturing sites with a significant amount of real environmental monitoring samples collected directly from the environment in pharmaceutical production during manufacturing operations with four solid and liquid nutrient media. These samples were then incubated under four different conditions suggested in the guidance documents. We believe that the results of our multicenter study confirming recent other single-site in situ studies could be the basis of the strategy to determine the best incubation regime for both viable environmental monitoring and aseptic process simulation in any manufacturing facility.

Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology.

Gelatiniphilus marinus gen. nov., sp. nov., a bacterium from the culture broth of a microalga, Picochlorum sp. 122, and emended description of the genus Hwangdonia.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped bacterium, designated strain GYP-24T, was isolated from the culture broth of a marine microalga, Picochlorum sp. 122. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain GYP-24T forms a robust cluster with H.wangdoniaseohaensis KCTC 32177T (95.8 % sequence similarity) in the family Flavobacteriaceae. Growth of strain GYP-24T was observed at 15, 22, 28, 30, 33 and 37 °C (optimal 30-33 °C), pH 6.0-10.0 (optimal pH 7.0-8.0) and in the presence of 0.5-4 % (w/v) NaCl (optimal 2-3 %). The only menaquinone of strain GYP-24T was MK-6, and the G+C content of the genomic DNA was 36.9 mol%. The major fatty acid profile comprised iso-C17 : 0 3-OH, summed feature 3 (C16 : 1 ω7c/ω6c), iso-C15 : 1 G and iso-C15 : 0. The major polar lipids of strain GYP-24T were phosphatidylethanolamine, one unidentified phospholipid, three unidentified aminolipids and three unidentified lipids. Comprehensive analyses based on polyphasic characterization of GYP-24T indicated that it represents a novel species of a new genus, for which the name Gelatiniphilus marinus gen. nov., sp. nov. is proposed. The type strain is GYP-24T (=KCTC 42903T=MCCC 1K01730T). An emended description of the genus Hwangdonia is also given.

Extracellular secretion of noncatalytic plant cell wall-binding proteins by the cellulolytic thermophile Caldicellulosiruptor bescii.

Caldicellulosiruptor bescii efficiently degrades cellulose, xylan, and native grasses at high temperatures above 70°C under anaerobic conditions. C. bescii extracellularly secretes multidomain glycoside hydrolases along with proteins of unknown function. In this study, we analyzed the C. bescii proteins that bind to the cell walls of timothy grass by using mass spectrometry, and we identified four noncatalytic plant cell wall-binding proteins (PWBPs) with high pI values (9.2 to 9.6). A search of a conserved domain database showed that these proteins possess a common domain related to solute-binding proteins. In addition, 12 genes encoding PWBP-like proteins were detected in the C. bescii genomic sequence. To analyze the binding properties of PWBPs, recombinant PWBP57 and PWBP65, expressed in Escherichia coli, were prepared. The PWBPs displayed a wide range of binding specificities: they bound to cellulose, lichenan, xylan, arabinoxylan, glucuronoxylan, mannan, glucomannan, pectin, oligosaccharides, and the cell walls of timothy grass. The proteins showed the highest binding affinity for the plant cell wall, with association constant (Ka) values of 5.2 × 10(6) to 44 × 10(6) M(-1) among the insoluble polysaccharides tested, as measured using depletion binding isotherms. Affinity gel electrophoresis demonstrated that the proteins bound to the acidic polymer pectin most strongly among the soluble polysaccharides tested. Fluorescence microscopic analysis showed that the proteins bound preferentially to the cell wall in a section of grass leaf. Binding of noncatalytic PWBPs with high pI values might be necessary for efficient utilization of polysaccharides by C. bescii at high temperatures.

Oribacterium parvum sp. nov. and Oribacterium asaccharolyticum sp. nov., obligately anaerobic bacteria from the human oral cavity, and emended description of the genus Oribacterium.

Three strictly anaerobic, Gram-positive, non-spore-forming, rod-shaped, motile bacteria, designated strains ACB1(T), ACB7(T) and ACB8, were isolated from human subgingival dental plaque. All strains required yeast extract for growth. Strains ACB1(T) and ACB8 were able to grow on glucose, lactose, maltose, maltodextrin and raffinose; strain ACB7(T) grew weakly on sucrose only. The growth temperature range was 30-42 °C with optimum growth at 37 °C. Major metabolic fermentation end products of strain ACB1(T) were acetate and lactate; the only product of strains ACB7(T) and ACB8 was acetate. Major fatty acids of strain ACB1(T) were C(14 : 0), C(16 : 0), C(16 : 1)ω7c dimethyl aldehyde (DMA) and C(18 : 1)ω7c DMA. Major fatty acids of strain ACB7(T) were C(12 : 0), C(14 : 0), C(16 : 0), C(16 : 1)ω7c and C(16 : 1)ω7c DMA. The hydrolysate of the peptidoglycan contained meso-diaminopimelic acid, indicating peptidoglycan type A1γ. Genomic DNA G+C content varied from 42 to 43.3% between strains. According to 16S rRNA gene sequence phylogeny, strains ACB1(T), ACB8 and ACB7(T) formed two separate branches within the genus Oribacterium, with 98.1-98.6% sequence similarity to the type strain of the type species, Oribacterium sinus. Predicted DNA-DNA hybridization values between strains ACB1(T), ACB8, ACB7(T) and O. sinus F0268 were <70%. Based on distinct genotypic and phenotypic characteristics, strains ACB1(T) and ACB8, and strain ACB7(T) are considered to represent two distinct species of the genus Oribacterium, for which the names Oribacterium parvum sp. nov. and Oribacterium asaccharolyticum sp. nov. are proposed. The type strains are ACB1(T) ( = DSM 24637(T) = HM-481(T) = ATCC BAA-2638(T)) and ACB7(T) ( = DSM 24638(T) = HM-482(T) = ATCC BAA-2639(T)), respectively.

Description of Anaerobacterium chartisolvens gen. nov., sp. nov., an obligately anaerobic bacterium from Clostridium rRNA cluster III isolated from soil of a Japanese rice field, and reclassification of Bacteroides cellulosolvens Murray et al. 1984 as Pseudobacteroides cellulosolvens gen. nov., comb. nov.

An obligately anaerobic bacterial strain designated T-1-35(T) was isolated as a dominant cultivable cellulose-degrading bacterium from soil of a Japanese rice field as an anaerobic filter-paper degrader. Cells of strain T-1-35(T) stained Gram-positive and were non-spore-forming rods with rounded ends, 0.8-1.0×3.5-15.0 µm, and motile by means of two to four polar flagella. Cells of strain T-1-35(T) exhibited pleomorphism: in aged cultures (over 90 days of incubation), almost all cells were irregularly shaped. Although no spore formation was observed, cells tolerated high temperatures, up to 90 °C for 10 min. The temperature range for growth was 15-40 °C, with an optimum at 35 °C. The pH range for growth was 5.5-9.0, with an optimum at pH 8.0-8.5 (slightly alkaliphilic). Strain T-1-35(T) fermented some carbohydrates to produce ethanol and lactate as the major products. Major cellular fatty acids were iso-C16 : 0 and iso-C13 : 0 3-OH. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain T-1-35(T) belonged to Clostridium rRNA cluster III. The closest relative of strain T-1-35(T) was Bacteroides cellulosolvens WM2(T), with 16S rRNA gene sequence similarity of 93.4 %. Phenotypic, physiological and molecular genetic methods demonstrated that strain T-1-35(T) was distinct from its phylogenetic relatives (members of Clostridium rRNA cluster III) because it predominantly produced ethanol, iso-C13 : 0 3-OH was a major cellular fatty acid and it always exhibited pleomorphism. On the basis of the results of a polyphasic taxonomic study, strain T-1-35(T) is considered to represent a novel genus and species, Anaerobacterium chartisolvens gen. nov., sp. nov. The type strain of Anaerobacterium chartisolvens is T-1-35(T) ( = DSM 27016(T) = NBRC 109520(T)). In addition, from the results of our phylogenetic analysis and its phenotypic features, the species Bacteroides cellulosolvens Murray et al. 1984 is proposed to be reclassified in the new genus Pseudobacteroides as Pseudobacteroides cellulosolvens gen. nov., comb. nov., with the type strain WM2(T) ( = ATCC 35603(T) = DSM 2933(T) = NRCC 2944(T)).

Fusicatenibacter saccharivorans gen. nov., sp. nov., isolated from human faeces.

Three Gram-stain-positive, obligately anaerobic, non-motile, non-spore-forming, spindle-shaped bacterial strains (HT03-11(T), KO-38 and TT-111), isolated from human faeces were characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing showed that the strains were highly related to each other genetically (displaying >99 % sequence similarity) and represented a previously unknown subline within the Blautia coccoides rRNA group of organisms (cluster XIVa). The closest phylogenetic neighbours of strain HT03-11(T) were Clostridium bolteae WAL 16351(T) (93.7 % 16S rRNA gene sequence similarity) and Clostridium saccharolyticum WM1(T) (93.7 % similarity). All isolates produced lactic acid, formic acid, acetic acid and succinic acid as fermentation end products from glucose. Their chemotaxonomic properties included lysine as the cell wall diamino acid and C16 : 0, C18 : 1ω7c DMA and C16 : 0 DMA as the major fatty acids. The G+C contents of the genomic DNA were 46.9-47.2 mol% (HPLC). Several phenotypic and chemotaxonomic characteristics could be readily used to differentiate the isolates from phylogenetically related clostridia. Therefore, strains HT03-11(T), KO-38 and TT-111 represent a novel species in a new genus of the family Lachnospiraceae, for which the name Fusicatenibacter saccharivorans gen. nov., sp. nov. is proposed. The type strain of the type species is HT03-11(T) ( = YIT 12554(T) = JCM 18507(T) = DSM 26062(T)).

Fonticella tunisiensis gen. nov., sp. nov., isolated from a hot spring.

A strictly anaerobic, moderately thermophilic, halotolerant rod, designated BELH25(T), was isolated from a water sample of a Tunisian hot spring. Cells were non-motile, 2-6 µm long and 0.4-0.6 µm wide, appearing singly or in pairs. The isolate grew at 45-70 °C (optimum 55 °C), at pH 6.2-8.0 (optimum pH 7.0) and with 0-4% NaCl (optimum 0-2.0%). Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain BELH25(T) used cellobiose, fructose, galactose, glucose, maltose, mannose, sucrose, starch and yeast extract as electron donors. The main fermentation products from glucose metabolism were formate, acetate, ethanol and CO2. The predominant cellular fatty acids were iso-C15:0, iso-C17:0 and anteiso-C15:0. The DNA G+C content was 37.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain BELH25(T) was most closely related to Caloramator viterbiensis JW/MS-VS5(T) and Fervidicella metallireducens AeB(T) (92.2 and 92.1% sequence similarity, respectively), and the isolate was positioned approximately equidistantly between these genera. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain BELH25(T) is proposed to be a member of a novel species of a novel genus within the order Clostridiales, family Clostridiaceae, for which the name Fonticella tunisiensis gen. nov., sp. nov. is proposed. The type strain of the type species is BELH25(T) (=DSM 24455(T)=JCM 17559(T)).

Salisediminibacterium halotolerans gen. nov., sp. nov., a halophilic bacterium from soda lake sediment.

An orange-pigmented, Gram-reaction-positive, non-spore-forming, halophilic, alkali-tolerant rod, designated strain halo-2(T), was isolated from sediment of Xiarinaoer soda lake, in China's Inner Mongolia Autonomous Region. Strain halo-2(T) grew in a complex medium with 3-30 % (w/v) NaCl and at pH 5-10. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the major respiratory isoprenoid quinone was MK-7. The predominant cellular fatty acids were anteiso-C(15 : 0) (43.6 %), anteiso-C(17 : 0) (14.8 %) and iso-C(15 : 0) (6.8 %) and the polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA G+C content of the novel strain was 48.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain halo-2(T) was most closely related to Bacillus agaradhaerens DSM 8721(T) (93.9 % sequence similarity). However, strain halo-2(T) could be clearly differentiated from its closest phylogenetic relatives on the basis of several phenotypic, genotypic and chemotaxonomic characteristics. Strain halo-2(T) therefore represents a novel species in a new genus for which the name Salisediminibacterium halotolerans gen. nov., sp. nov. is proposed. The type strain of the type species is halo-2(T) (= CGMCC 1.7654(T) = NBRC 104935(T)).

Tinción de Gram de tejido: alcances y limitaciones / Gram stain of tissue biopsy: scope and pitfalls

La identificación de microorganismos en tejido es esencial para reconocer un proceso infeccioso. Inicialmente, mediante la coloración de hematoxilina-eosina, se puede identificar el patrón de inflamación asociado y luego, a través de tinciones basadas en plata y la tinción de Gramde tejido se visualizan los microorganismos. La tinción de Gram no solo sirve para bacterias, sino también para algunos hongos y parásitos; no obstante, esta técnica tiene algunos inconvenientes, como la contaminación con otros microorganismos y la imposibilidad de visualizar algunas bacterias, entre ellas Legionella pneumophila, Leptospira spp y Bartonella spp. En este artículode revisión se describirán los fundamentos del Gram de tejido, su contribución en el diagnóstico de infecciones como herramienta adicional para el reconocimiento de microorganismos, y sus limitaciones.

The identification of microorganisms in tissue is pivotal to recognize infectious processes.At first, the hematoxylin-eosin stain is used to identify the pattern of inflammation associated; after that, microorganisms are seen through Gram or silver stains. Gram Stain of tissue biopsy not only stains bacteria, but also a number of fungus and parasites. However, this technique has some disadvantages, such as contamination with other microorganisms, and lack of stain of some bacteria, including Legionella pneumophila, Leptospira spp and Bartonella spp. This review articleaims to describe the fundamentals of Gram stain of tissue biopsy and its assistance in infectious diagnosis as an additional tool for recognition of microorganisms, as well as its limitations.

Effect of supplementation of micronutrients and phytochemicals to fructooligosaccharides on growth response of probiotics and E. coli.

Probiotics and prebiotics, which can change the colonic microenvironment, are the areas of current interest. Unutilizable fractions of the foods and fortificants, which reach the colon can affect the profile of probiotics. Effects of eight such factors viz. zinc sulphate, zinc carbonate, ferrous sulphate, ferric citrate, quercetin, gallic acid, phytic acid, and oxalic acid were, therefore, investigated on 24 H growth of Lactobacillus acidophilus (L1) and Lactobacillus plantarum (L2), two isolates of bifidobacteria (longum (L3) and bifidum (L4)) and a marketed consortium (L5) of eight probiotic cultures. MRS medium with marketed fructooligosaccharide as the only source of carbon was used for study of dose response curves. Quercetin and zinc sulphate showed significant positive effect for L1 and L5 (P < 0.01), whereas there was slight positive effect or no effect on growth of other probiotics. Phytic acid showed a significant inhibitory effect for L2 and a slight inhibitory effect on L3 and L4 whereas L5 were able to tolerate phytic acid. Oxalic acid had slight positive effect for L1 (P < 0.05) and L5 and no effect on growth of other probiotics (P > 0.05). Further, zinc sulphate, ferrous sulphate, quercetin, and oxalic acid significantly inhibited growth of E. coli (P < 0.05)

Characterization of an O-desmethylangolensin-producing bacterium isolated from human feces.

A bacterium that converted daidzein to O-desmethylangolensin was isolated from the feces of healthy humans. It was an obligately anaerobic, nonsporeforming, nonmotile and Gram-positive rod. The isolate used glucose, sucrose, raffinose, maltose, and fructose as carbon sources. It did not hydrolyze gelatin, esculin, or starch. The strain was urease, acid phosphatase, and arginine dihydrolase positive. It was catalase, oxidase, H(2)S, and indole negative. The major products of glucose fermentation were butyrate and lactate. Its mol% G+C was 51.2. The major cellular fatty acids were C(16:0) DMA, C(16:0), and C(16:0) aldehyde. The structural type of cell wall peptidoglycan was suggested to be A1gamma. The isolate was susceptible to beta-lactam, cefem, and macrolide antibiotics and resistant to aminoglycoside and quinolone antibiotics. The bacterium was related to Eubacterium ramulus ATCC29099(T), Eubacterium rectale ATCC33656(T), and species of the genus Roseburia, but the highest 16S rRNA gene similarity to these described species was only 94.4%, consistent with its being classified as a novel genus. Based on the above, the isolate, named strain SY8519, was identified as belonging to a novel genus in the Clostridium rRNA cluster XIVa.

Anaerostipes butyraticus sp. nov., an anaerobic, butyrate-producing bacterium from Clostridium cluster XIVa isolated from broiler chicken caecal content, and emended description of the genus Anaerostipes.

Four butyrate-producing isolates were obtained from the caecal content of a 4-week-old broiler chicken. The 16S rRNA gene sequences were determined and confirmed the close relatedness of the four isolates, which suggested that they were derived from a single bacterial clone. Phylogenetic analysis based on 16S rRNA gene sequences showed that its closest relatives were members of cluster XIVa of the Clostridium subphylum of Gram-positive bacteria and that the closest related type strain was Anaerostipes caccae L1-92(T) (94.5 % similarity). Similarity levels of 96-98 % with sequences from uncultured bacteria from human stool samples were observed. On the basis of morphological, biochemical and phylogenetic characteristics, this strain is assigned to a novel species in the genus Anaerostipes, for which the name Anaerostipes butyraticus sp. nov. is proposed. The type strain is 35-7(T) (=LMG 24724(T) =DSM 22094(T)). An emended description of the genus Anaerostipes is also provided.

Comparison of in vitro models to study bacterial adhesion to the intestinal epithelium.

AIMS: To evaluate the adhesion ability of intestinal bacteria to different in vitro models of intestinal epithelia, and to estimate the suitability of these models and the type of interactions involved. METHODS AND RESULTS: The adhesion of probiotic (Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis Bb12), commensal (B. animalis IATA-A2 and B. bifidum IATA-ES2) and potentially pathogenic bacteria (E. coli and L. monocytogenes) was determined. The adhesion models used were polycarbonate-well plates, with or without mucin, and different configurations of Caco-2 and/or HT29-MTX cell cultures. All bacteria adhered to wells without mucin (2.6-27.3%), the values being highly variable depending on the bacterial strain. Adhesion percentages of potentially probiotic bacteria to Caco-2 cultures were remarkably lower (P < 0.05) than those to mucin, and more similar to those of pathogenic strains. The lowest adhesion of different bacterial strains was detected on HT29-MTX (0.5-2.3%) cultures and Caco-2/HT29-MTX (0.6-3.2%) cocultures, while these values were increased in Caco-2 cultures plus mucin. CONCLUSIONS: The results suggested that bacterial strains exhibit different capacities to adhere to cellular components and several types of mucin present in different models, showing preferences for intestinal MUC2. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of Caco-2 cells monolayer plus mucin (type II) better approaches the physiological characteristics of in vivo situation, providing a reliable and suitable in vitro model to evaluate bacterial adhesion.

Bacteriological quality and risk assessment of the imported and domestic bottled mineral water sold in Fiji.

Considering the popularity of bottled mineral water among indigenous Fijians and tourists alike, a study was carried out to determine the bacteriological quality of different bottled waters. A risk assessment was also carried out. Seventy-five samples of bottled mineral water belonging to three domestic brands and 25 samples of one imported brand were analysed for heterotrophic plate count (HPC) bacteria and faecal coliforms. HPC counts were determined at 22 degrees C and 37 degrees C using R2A medium and a membrane filtration technique was used to determine the faecal coliform (FC) load in 100 ml of water on mFC agar. Between 28 and 68% of the samples of the various domestic brands failed to meet the WHO standard of 100 colony forming units (cfu) per 100 ml at 22 degrees C and 7% of these also tested positive for faecal coliforms. All imported bottled mineral water samples were within WHO standards. A risk assessment of the HPC bacteria was carried out in terms of beta haemolytic activity and antibiotic resistance. More than 50% of the isolates showed beta haemolytic activity and were multi-drug resistant. While the overall quality of the product was generally good, there is a need to enforce stringent quality standards for the domestic bottlers to ensure the safety of consumers.

Lysinibacillus parviboronicapiens sp. nov., a low-boron-containing bacterium isolated from soil.

A spore-forming, Gram-positive-staining, motile, rod-shaped and low-boron-containing bacterium was isolated from soil. The strain, designated BAM-582(T), can tolerate 6 % (w/v) NaCl and 50 mM boron, but optimal growth was observed without addition of boron or NaCl. The optimum temperature and pH for growth were 30 degrees C (range 10-37 degrees C) and pH 7 (range pH 6-8). A comparative analysis of the 16S rRNA gene sequence demonstrated that the isolated strain was closely related to Lysinibacillus fusiformis DSM 2898(T) (97.7 % similarity) and Lysinibacillus sphaericus IAM 13420(T) (98.2 %). Levels of DNA-DNA relatedness were 33.9 % with L. fusiformis DSM 2898(T) and 29.5 % with L. sphaericus DSM 28(T). The genomic DNA G+C content of the novel strain was 38.7 mol%. The major respiratory quinone was MK-7 and the major fatty acids were iso-C(15 : 0) (37.4 %) and anteiso-C(15 : 0) (19.0 %). Analysis of cell-wall amino acids revealed that the strain contained peptidoglycan with lysine, aspartic acid, alanine and glutamic acid, as is the case with other species of the genus Lysinibacillus. Based upon its distinctive peptidoglycan composition, phylogenetic and genotypic analyses and physiological characteristics, the strain BAM-582(T) is concluded to represent a novel species in the genus Lysinibacillus, for which the name Lysinibacillus parviboronicapiens sp. nov. is proposed (type strain BAM-582(T) =NBRC 103144(T) =KCTC 13154(T)).