Reduced bacterial colony count of anaerobic bacteria is associated with a worsening in lung clearance index and inflammation in cystic fibrosis.

Anaerobic bacteria have been identified in abundance in the airways of cystic fibrosis (CF) subjects. The impact their presence and abundance has on lung function and inflammation is unclear. The aim of this study was to investigate the relationship between the colony count of aerobic and anaerobic bacteria, lung clearance index (LCI), spirometry and C-Reactive Protein (CRP) in patients with CF. Sputum and blood were collected from CF patients at a single cross-sectional visit when clinically stable. Community composition and bacterial colony counts were analysed using extended aerobic and anaerobic culture. Patients completed spirometry and a multiple breath washout (MBW) test to obtain LCI. An inverse correlation between colony count of aerobic bacteria (n = 41, r = -0.35; p = 0.02), anaerobic bacteria (n = 41, r = -0.44, p = 0.004) and LCI was observed. There was an inverse correlation between colony count of anaerobic bacteria and CRP (n = 25, r = -0.44, p = 0.03) only. The results of this study demonstrate that a lower colony count of aerobic and anaerobic bacteria correlated with a worse LCI. A lower colony count of anaerobic bacteria also correlated with higher CRP levels. These results indicate that lower abundance of aerobic and anaerobic bacteria may reflect microbiota disruption and disease progression in the CF lung.

Starved anammox cells are less resistant to NO2⁻ inhibition.

Anaerobic ammonium oxidizing (anammox) bacteria are be inhibited by their terminal electron acceptor, nitrite. Serious nitrite inhibition of the anammox bacteria occurs if the exposure coincides with the absence of the electron donating substrate, ammonium and pH < 7.2. Starvation of biomass occurs during underloading of bioreactors or biomass storage. This work investigated the effect of starvation on the sensitivity of anammox bacteria to nitrite exposure. Batch activity tests were carried out evaluating the response of anammox biomass subjected to different levels of starvation upon exposure to nitrite in the presence and absence of ammonium (active- and resting-cells, respectively). The response of the bacteria was evaluated by measuring the specific anammox activity and the evolution of the ATP content in the biomass over time. The 50% inhibitory concentrations of nitrite in starved- and fresh-resting-cells was 7 mg N L(-1) and 52 mg N L(-1), respectively. By contrast, only moderate nitrite inhibition occurred to starved anammox biomass when exposed to nitrite and ammonium simultaneously. Maximum ATP levels were observed in fresh cells. The ATP content in starved resting cells peaked 2-3 h after addition of NO2(-)(-). The response was hindered in cells starved for long periods. These findings agreed with a bioreactor study in which underloading of anammox biomass (0.10 g N L(-1) d(-1)) decreased its tolerance to a nitrite (only) exposure (101 mg NO2(-)-N L(-1)) and completely disrupted the N removal capacity of the biomass. A similar accumulation of 108 mg NO2(-)-N L(-1) after operation at 0.95 g N L(-1) d(-1) did not cause observable inhibition of the bacteria. The results taken as a whole demonstrate that starved anammox biomass is highly sensitive to nitrite toxicity. An explanation is proposed based on energy requirements to translocate nitrite in the cell.

Iron corrosion by novel anaerobic microorganisms.

Corrosion of iron presents a serious economic problem. Whereas aerobic corrosion is a chemical process, anaerobic corrosion is frequently linked to the activity of sulphate-reducing bacteria (SRB). SRB are supposed to act upon iron primarily by produced hydrogen sulphide as a corrosive agent and by consumption of 'cathodic hydrogen' formed on iron in contact with water. Among SRB, Desulfovibrio species--with their capacity to consume hydrogen effectively--are conventionally regarded as the main culprits of anaerobic corrosion; however, the underlying mechanisms are complex and insufficiently understood. Here we describe novel marine, corrosive types of SRB obtained via an isolation approach with metallic iron as the only electron donor. In particular, a Desulfobacterium-like isolate reduced sulphate with metallic iron much faster than conventional hydrogen-scavenging Desulfovibrio species, suggesting that the novel surface-attached cell type obtained electrons from metallic iron in a more direct manner than via free hydrogen. Similarly, a newly isolated Methanobacterium-like archaeon produced methane with iron faster than do known hydrogen-using methanogens, again suggesting a more direct access to electrons from iron than via hydrogen consumption.

Fusibacter paucivorans gen. nov., sp. nov., an anaerobic, thiosulfate-reducing bacterium from an oil-producing well.

A strictly anaerobic, halotolerant, spindle-shaped rod, designated strain SEBR 4211T, was isolated from an African saline oil-producing well. Cells stain Gram-positive, which was confirmed by electron microscopy observations. Strain SEBR 4211T was motile by means of one to four peritrichous flagella, had a G+C content of 43 mol% and grew optimally at 37 degrees C, pH 7.3, with 0 to 3% (w/v) NaCl. It utilized a limited number of carbohydrates (cellobiose, glucose, fructose, mannitol and ribose) and produced acetate, butyrate, CO2 and H2 as end products from glucose fermentation. It reduced thiosulfate to sulfide. In the presence of thiosulfate, a decrease in butyrate and an increase in acetate production was observed. Phylogenetically, strain SEBR 4211T was related to members of the low G+C Clostridiales order with Clostridium halophilum as the closest relative (16S rDNA sequence similarity of 90%). On the basis of phenotypic, genotypic and phylogenetic characteristics of the isolate, it is proposed to designate it as a new species of a new genus, Fusibacter gen. nov., as Fusibacter paucivorans sp. nov. The type strain is SEBR 4211T (= DSM 12116T).

[An automatic gas scanning device, technical improvement for obtaining a favourable atmosphere for in vitro culture of anaerobic bacteria]. / Balayage gazeux à l'aide d'un automate, une amélioration technique d'obtention d'une atmosphère propice à la culture en jarre des bactéries anaérobies.

All methods for growth of anaerobic bacteria on solid media depend on the elimination of atmospheric O2 through use of a palladium catalyst (Deoxo-Catalyst), active in presence of at least 5% H2 with resultant formation of water. Anaerobic chambers and jars are the two conventional methods employed. Both are based on the elimination of air by means of a pump and its replacement with gas from a cylinder (evacuation-replacement technique). An alternative chemical technique for use in anaerobic jars consists of adding internal gas-generating sachets. The former techniques are more efficient but the trend, particularly in the clinical laboratories, is to use the simpler chemical system that has two inconveniences: a slow establishment of anaerobiosis, and a high cost. We propose a new system that does not require a vacuum pump and consists in flushing anaerobic jars with a convenient gas mixture (H2, CO2, N2: 4.5; 5; 90.5 v/v) by means of an automaton regulating both time and gas flow. Gas-liquid chromatography analysis of the gas inside the jar shows a rapid elimination of gaseous O2, whose residual concentration is low enough to permit growth of all anaerobes of clinical interest, including those which are more O2-sensitive. Comparative qualitative and quantitative data obtained with all available techniques demonstrate the advantages of the new system.

Estocagem de bactérias anaeróbicas / Preservation of anaerobes

A manutençåo da viabilidade das culturas de bactérias anaeróbicas é analisada em três distintos meios para estoque: caldo Gc com redutores, meio para transporte de Cary-Blair (VPI) com 0,2 por cento de agar e meio com leite em pó integral reconstituído a 10 por cento. Os meios para estoque, após a dispersåo das bactérias, foram mantidos em temperatura de congelamento. Para garantir a viabilidade, foram usados crioprotetores e foram controlados os fatores biofísicos do meio para estoque e do meio ambiente. Foram selecionados três gêneros: Bacteroides, Fusobacterium e Propionibacterium. Estes foram repicados de 15 em 15 dias em Tioglicolato suplementado com soro normal de cavalo. A intensidade do crescimento dos três meios testados permaneceu semelhante por 330 dias, considerada uma boa viabilidade da cultura. As vantagens dos meios para estoque e metodologia apresentada såo a sua praticabilidade, eficiência e a dispensa de investimentos altamente onerosos em relaçåo a outras metodologias. O leite integral reconstituído a 10 por cento foi aquele que melhores resultados ofereceu