Can Humidifier Reservoir Bacteria Colonize the Circuit During Mechanical Ventilation?

Background:Although the circuit condensate, an ideal bacterial reservoir, may flow into the humidifier reservoir (HR), no study has investigated if HR-colonized bacteria colonize other circuit locations with airflow. Therefore, the objective of this study was to explore if bacterial growth in the HR leads to bacterial colonization in the ventilator circuit. Methods: A randomized controlled experiment was performed in a public tertiary hospital in Guangdong Province, China. In vitro mechanical ventilation models (n = 60), divided into sterile water samples (n = 30) and broth samples (n = 30), were established. Sterile water was used for humidification in the ventilation models. The sterile water group contained either Acinetobacter baumannii (n = 15) or Pseudomonas aeruginosa (n = 15) in humidifier water. The broth group was similar to the sterile water group, but brain heart infusion broth was added to the HR. After 24, 72, and 168 h of continuous ventilation, bacteria in the humidifier water and at different circuit locations were sampled and cultured, and the results were analyzed by the Chi-square test. The difference in bacterial concentration at the HR outlet was analyzed by the F test, and P < 0.05 was considered statistically significant.Results:Bacterial culture results of the sterile water samples were negative. Bacteria in the humidifier water continued to proliferate in the broth group, and the bacterial concentration at different times was not significantly different (P > 0.05). With prolonged ventilation, the bacterial concentration at the HR outlet increased (P < 0.05). During continuous ventilation, no bacterial growth occurred at 10 cm from the HR outlet and the Y-piece of the ventilator circuit. The bacterial concentration at the HR outlet was higher in the P. aeruginosa group than in the A. baumannii group (P < 0.05).Conclusions:Sterile water in the HR was not conducive to bacterial growth. Although bacteria grew in the HR and could reach the HR outlet, colonization of other circuit locations was unlikely.

Spatial and Seasonal Structure of Bacterial Communities Within Alpine Vineyards: Trentino as a Case Study

Bacteria have a fundamental role in determining the fitness of grapevine, the composition of grapes and the features of wines but at present, little information is available. In this work, the bacteria colonizing the different portions of grapevine (bark, leaves and grapes) were explored in the vineyards of the Alpine region of Trentino, considering the impact of different environmental and agronomical variables. The vineyards included in the work were selected based on their different geographical positions (altitude) and grapevine training systems in order to explore the whole variability of the grapevine ecosystem. Moreover, the surface amount of copper was measured on grapes and leaves during the vegetative growth. Bacterial analysis, performed using plate counts and Illumina MiSeq, revealed an increase in the concentration of grape bacteria proportional to the progress of the ripening stage. Conversely, the peak of bacterial concentration onto leaf and bark samples occurred in August, probably due to the more favourable environmental conditions. In bark samples, the bacterial microbiota reached the 7 log CFU/cm2, while 6 log UFC/g were measured in grape samples. A remarkable biodiversity was observed, with 13 phyla, 35 classes, 55 orders, 78 families and 95 genera of bacteria present. The presence of some taxa (Alphaproteobacteria, Desulfovibrionaceae, Clostriadiales, Oscillospira, Lachnospiraceae and Bacteroidales) was ubiquitous in all vineyards, but differences in terms of relative abundance were observed according to the vegetative stage, altitude of the vineyard and training system. Bacteria having oenological implication (Lactobacillus, Pediococcus and Oenococcus) were detected in grape samples collected in August, in low abundance. The data revealed a complex bacterial ecosystem inside the vineyard that, while maintaining common traits, evolves according to environmental and agronomical inputs. This study contributes to define the role of bacteria in the complex balance established in each vineyard between human actions and agricultural environment, known as terroir.

Bacterial Detection and Recovery From Poultry Litter

The level of pathogens in poultry litter used for raising broiler chickens is critical to the overall health of a broiler chicken flock and food safety. Therefore, it is imperative that methods used for determining bacterial concentration in litter are accurate and reproducible across studies. In this perspective, we discuss the shortcomings associated with current methods used for bacterial quantification and detection from litter and assess the efficacy of one method for pathogen and commensal (Campylobacter, Salmonella, Escherichia coli, and Enterococcus spp.) recovery. The limit of quantitation and detection for this method differed between pathogens, and the recovery rate (∼138–208%) was higher for Salmonella, E. coli, and Enterococcus compared to Campylobacter (24%). Our results suggest that pathogen recovery from litter is highly variable and pathogen concentrations need to be reported in dry weight before comparisons can be made between studies.

Does the freshwater mussel Anodonta anatina remove the fish pathogen Flavobacterium columnare from water?

Global decline of freshwater mussels (Unionoida) is threatening biodiversity and the essential ecosystem services that mussels provide. As filter-feeding organisms, freshwater mussels remove phytoplankton and suspended particles from the water. By filtering bacteria, freshwater mussels also decrease pathogen loads in the water. The objective of this study was to evaluate whether the common freshwater bivalve Anodonta anatina (duck mussel) could remove the bacterial fish pathogen Flavobacterium columnare from the water. Mussels reduced bacteria in both of the two experiments performed, so that the bacterial concentration at the end of the 96-h monitoring in mussel treatments was only 0.3–0.5 times that of the controls. Surprisingly, mussels did not reduce algal cell concentration statistically significantly. Mussel behavior (shell openness, foot position, and movement) was not affected by the presence of bacteria or algae, except for biodeposition formation, which was greatest in algal-fed treatments, followed by bacterial-fed treatments and controls, respectively. The intestines of bacteria-incubated A. anatina harbored F. columnare, suggesting that mussels ingested the bacteria. Present results suggest that freshwater mussels may also have a potential to mitigate aquaculture pathogen problems, as well as play a role in water quality management.

Nematicidal Activity of the Endophyte Serratia ureilytica against Nacobbus aberrans in Chili Plants (Capsicum annuum L.) and Identification of Genes Related to Biological Control

The genus Serratia is widely distributed in soil, water, plants, animals, invertebrates, and humans. Some species of this genus have antifungal, antibacterial, and nematicidal activity. In this work, the nematicidal activity of the endophytic strain of Serratia sp. in chili, Capsicum annuum L., is reported, where at a bacterial concentration of 4 × 109 cel/mL, the penetration of nematodes into the roots significantly decreased by 91 and 55% at 7 and 21 days after inoculation. This bacterial concentration also significantly decreased the number of galls, eggs, egg masses and reproduction factor produced by Nacobbus aberrans in Chili plants, with respect to the control where this bacterial strain was not applied. In the analysis of the genome of the strain, based on average nucleotide identity (ANI), the isolate could be affiliated to the species Serratia ureilytica. The size of the genome is 5.4 Mb, with a 59.3% content of GC. Genes related to the synthesis of chitinases, siderophores, proteases C, serralisins, hemolysin, and serrawettin W2 that have been reported for biocontrol of nematodes were identified in the genome. It is the first report of Serratia ureilytica with nematicidal activity. Based on these results of nematicidal activity, this strain can be evaluated in the field as an alternative in the biocontrol of Nacobbus aberrans in chili cultivation.

Phytochemicals and Bioactivities of Syzygium filiformevar. filiforme

Syzygium filiforme var. filiforme is a plant variety from dicotyledonous plant family (Myrtaceae). Phytochemical studies on S. filiforme var. filiforme stem bark have successfully isolated and characterized arjunolic acid (1), alphitolic acid (2), betulinic acid (3), ursolic acid (4), ursolic acid 3-methyl ester (5), β-sitosterol (6) and stigmasterol (7). The inhibitory activities against free radical, starch, and bacteria for major compounds were tested by using DPPH, α-glucosidase and minimum inhibitory and bacterial concentration assays, respectively. No promising antioxidant activity was shown on tested samples except methanolic crude extract. For antidiabetic activity, methanolic and dichloromethane crude extracts displayed potent activity compared to 1-deoxynojirimycin. Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) assays for antibacterial activity were evaluated on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. All crude extracts and major compounds displayed weak and no promising activities for MIC method, respectively. Meanwhile, for MBC method, hexane crude extract and compound 1 showed inhibition against B. subtilis.

DEVELOPMENT OF COMPRESSIVE STRENGTH AND ULTRASONIC PULSE VELOCITY RELATIONSHIP OF MICROBIAL CONCRETE USING BACILLUS SUBTILIS BACTERIA

Concrete,a multiscale composite in its natural state, is an absolutely essential element of infrastructure throughout the world. Concrete is able to carry high compressive load but very weak in case of tensile forces, for which steel bars are embedded in the concrete.Again, cracks in concrete are unavoidable. Corrosive elements can go into cracks once theyve formed and consequently deterioration of the structural concrete starts with the corrosion of embedded steel. This leads to the strength reductionand durability curtailment of concrete. So, crack minimization in reinforced concrete is a must for both strength and durability aspect as well as for economic reasons as crack repair is a costly process. The goal of this study is to compare the performance of traditional and bacterial concrete and to find a link between compressive strength and bacterial culture concentration, as well as to determine the optimal bacterial concentration in concrete. 100 mm cubical sizeconcrete specimens were cast and cured for different ages in plain water to study the strength aspect and ultrasonic pulse velocity (UPV) analysis of concrete using Bacillus subtilis bacteria.With different bacterial concentrations of 2.12 x 108 cells/ml, 2.12 x 107 cells/ml, 3.25 x 108 cells/ml, 3.25 x 107 cells/ml, 6.39 x 108 cells/ml, 6.39 x 107 cells/ml, 7.91 x 108 cells/ml and 7.91 x 107 cells/mlconcrete specimens have been studied. From the investigation it is found that concrete specimens containing bacterial species shows better performance than conventional concrete due to calcite precipitation. Among them, concrete specimens of bacterial concentration 6.39 x 108 cells/ml of bacterial water shows better result against strength deterioration and UPV analysis.

Effects of Biofilm Burkholderia Pyrrocinia JK-SH007 On The Colonization And Growth Promotion of Poplar

Burkholderia pyrrocinia JK-SH007 is a high-potential biological control strain. We changed the composition of medium during the fermentation of JK-SH007 cells and induced these cells to form a biofilm. In this experiment, we deeply studied the biofilm physical and chemical properties. The new fermentation process improves the colonization ability of JK-SH007 and promotes poplar growth. In addition, the biofilm bacterial concentration reached 1010 CFU/mL, the cell dry weight increased over that of a control by 3-10-fold, there was increased environmental stress resistance and IAA secretion, and progeny cells retained resistance to adverse environments. The new biofilm cells were applied to poplar. The JK-SH007 colonization ability was improved in the biofilm, and some bacteria existed as biofilms (cell clusters) in poplar, which would promote forming a dominant niche. Biofilm JK-SH007 has an increased affinity for poplar during colonization and promotes poplar growth under hydroponic conditions, proving the reliability of the new morphology for treating poplar ulcer disease. This work further provides a theoretical basis for commercially producing JK-SH007.

Galvanic current dosage and bacterial concentration are determinants of the bactericidal effect of percutaneous needle electrolysis: an in vitro study

Percutaneous needle electrolysis (PNE) is a physiotherapy technique that has been shown to be effective in different pathologies such as tendinopathies or mammary fistula. For many years, theoretical bactericidal and germicidal effects have been attributed to this type of galvanic currents, partly explained by the changes in pH that it generates. However, these effects have not yet been demonstrated. The aim of this study was to evaluate the bactericidal effect and the changes in pH caused by PNE. S. aureus were prepared in two different solutions (TSB and saline solution) and in different concentrations (from 9 to 6 Log10 CFU/mL). Bacteria were treated with three experimental PNE doses to assess bacterial death levels and the changes caused to the pH of the medium. The viable cell count showed that all experimental PNE doses had a bactericidal effect against a high concentration (9 Log10 CFU/mL) of S. aureus in saline solution (p < 0.001). Furthermore, we found that when the concentration of bacteria decreased, a lower dose of galvanic current generated the same effect as a higher dose. Changes in pH were registered only in experiments performed with saline solution. PNE had a bactericidal effect against S. aureus and the level of this effect was mainly modulated by the solution, the bacterial concentration and the dose. Changes affecting pH were modulated by the type of solution and there was no relationship between this and bacterial death.