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FEMS Microbiology Ecology Jun 2013Within intertidal sediments, much of the dissolved organic carbon (DOC) consists of carbohydrate-rich extracellular polymeric substances (EPS) produced by...
Within intertidal sediments, much of the dissolved organic carbon (DOC) consists of carbohydrate-rich extracellular polymeric substances (EPS) produced by microphytobenthic biofilms. EPS are an important source of carbon and energy for aerobic and anaerobic microorganisms owing to burial of microphytobenthos and downward transport of their exudates. We established slurries of estuarine biofilms to determine the fate of organic carbon and EPS fractions, differing in size and complexity, under oxic and anoxic conditions. DOC and hot-water-extracted organic matter (predominately diatom chrysolaminarin) were utilised rapidly at similar rates in both conditions. Concentrations of insoluble, high-molecular-weight EPS were unchanged in oxic microcosms, but were significantly degraded under anoxic conditions (39% degradation by day 25). Methanogenesis and sulphate reduction were major anaerobic processes in the anoxic slurries, and 16S rRNA gene pyrosequencing revealed that Desulfobacteraceae (relative sequence abundance increased from 1.9% to 12.2%) and Desulfobulbaceae (increased from 1.5% to 4.3%) were the main sulphate reducers, whilst Clostridia and Bacteroidetes were likely responsible for anaerobic hydrolysis and fermentation of EPS. We conclude that a diverse consortium of anaerobic microorganisms (including coexisting sulphate reducers and methanogens) degrade both labile and refractory microphytobenthic-derived carbon and that anaerobic degradation may be the primary fate of more structurally complex components of microphytobenthic EPS.
Topics: Aerobiosis; Anaerobiosis; Bacteria, Aerobic; Bacteria, Anaerobic; Biofilms; Carbohydrate Metabolism; Carbon; Diatoms; Estuaries; Fermentation; Geologic Sediments; Hydrolysis; Microbial Consortia; Polymers
PubMed: 23346920
DOI: 10.1111/1574-6941.12077 -
Scientific Reports Feb 2022As oral or intestinal bacteria have been found in pancreatic cystic fluid and tumors, understanding bacterial migration from the duodenum into the pancreas via...
As oral or intestinal bacteria have been found in pancreatic cystic fluid and tumors, understanding bacterial migration from the duodenum into the pancreas via hepato-pancreatic duct is critical. Mathematical models of migration of aerobic bacteria from the duodenum to the pancreas with tumors were developed. Additionally, the bacterial distributions under the pH gradient and those under flow were measured in double-layer flow based microfluidic device and T-shaped cylinders. Migration of aerobic bacteria from the duodenum into pancreas is counteracted by bile and pancreatic juice flow but facilitated by pH-taxis from acidic duodenum fluid toward more favorable slightly alkaline pH in pancreatic juice. Additionally, the reduced flow velocity in cancer patients, due to compressed pancreatic duct by solid tumor, facilitates migration. Moreover, measured distribution of GFP E. coli under the pH gradient in a microfluidic device validated pH-tactic behaviors. Furthermore, Pseudomonas fluorescens in hydrochloride solution, but not in bicarbonate solution, migrated upstream against bicarbonate flow of > 20 μm/s, with an advancement at approximately 50 μm/s.
Topics: Bacteria, Aerobic; Cell Movement; Duodenum; Humans; Hydrogen-Ion Concentration; Pancreas; Pancreatic Juice; Pancreatic Neoplasms
PubMed: 35110595
DOI: 10.1038/s41598-022-05554-8 -
Antimicrobial Agents and Chemotherapy May 2012The in vitro activities of LFF571, a novel analog of GE2270A that inhibits bacterial growth by binding with high affinity for protein synthesis elongation factor Tu,... (Comparative Study)
Comparative Study
The in vitro activities of LFF571, a novel analog of GE2270A that inhibits bacterial growth by binding with high affinity for protein synthesis elongation factor Tu, fidaxomicin, and 10 other antimicrobial agents were determined against 50 strains of Clostridium difficile and 630 other anaerobic and aerobic organisms of intestinal origin. LFF571 possesses potent activity against C. difficile and most other Gram-positive anaerobes (MIC(90), ≤ 0.25 μg/ml), with the exception of bifidobacteria and lactobacilli. The MIC(90)s for aerobes, including enterococci, Staphylococcus aureus (as well as methicillin-resistant S. aureus [MRSA] isolates), Streptococcus pyogenes, and other streptococci were 0.06, 0.125, 2, and 8 μg/ml, respectively. Comparatively, fidaxomicin showed variable activity against Gram-positive organisms: MIC(90)s against C. difficile, Clostridium perfringens, and Bifidobacterium spp. were 0.5, ≤ 0.015, and 0.125 μg/ml, respectively, but >32 μg/ml against Clostridium ramosum and Clostridium innocuum. MIC(90) for S. pyogenes and other streptococci was 16 and >32 μg/ml, respectively. LFF571 and fidaxomicin were generally less active against Gram-negative anaerobes.
Topics: Aminoglycosides; Anti-Bacterial Agents; Bacteria, Aerobic; Bacteria, Anaerobic; Clostridioides difficile; Enterocolitis, Pseudomembranous; Fidaxomicin; Humans; Intestines; Microbial Sensitivity Tests; Microbial Viability; Peptide Elongation Factor Tu; Protein Biosynthesis; Species Specificity; Thiazoles
PubMed: 22290948
DOI: 10.1128/AAC.06305-11 -
PloS One 2022Organic fertilizers and especially microbial biomass, also known as microbial fertilizer, can enable a paradigm shift to the conventional fertilizer-to-food chain,...
Organic fertilizers and especially microbial biomass, also known as microbial fertilizer, can enable a paradigm shift to the conventional fertilizer-to-food chain, particularly when produced on secondary resources. Microbial fertilizers are already common practice (e.g. Bloom® and Synagro); yet microbial fertilizer blends to align the nutrient release profile to the plant's needs are, thus far, unexplored. Moreover, most research only focuses on direct fertilization effects without considering added value properties, such as disease prevention. This study has explored three promising types of microbial fertilizers, namely dried biomass from a consortium of aerobic heterotrophic bacteria, a microalga (Arthrospira platensis) and a purple non-sulfur bacterium (Rhodobacter sphaeroides). Mineralization and nitrification experiments showed that the nitrogen mineralization profile can be tuned to the plant's needs by blending microbial fertilizers, without having toxic ammonium peaks. In a pot trial with perennial ryegrass (Lolium perenne L.), the performance of microbial fertilizers was similar to the reference organic fertilizer, with cumulative dry matter yields of 5.6-6.7 g per pot. This was confirmed in a pot trial with tomato (Solanum lycopersicum L.), showing an average total plant length of 90-99 cm after a growing period of 62 days for the reference organic fertilizer and the microbial fertilizers. Moreover, tomato plants artificially infected with powdery mildew (Oidium neolycopersici), a devastating disease for the horticultural industry, showed reduced disease symptoms when A. platensis was present in the growing medium. These findings strengthen the application potential of this novel class of organic fertilizers in the bioeconomy, with a promising match between nutrient mineralization and plant requirements as well as added value in crop protection.
Topics: Bacteria, Aerobic; Biomass; Fertilizers; Hydrogen-Ion Concentration; Lolium; Solanum lycopersicum; Nitrification; Nitrogen; Nutrients
PubMed: 35108295
DOI: 10.1371/journal.pone.0262497 -
Journal of Applied Microbiology Dec 2016Determination of the diversities and antibiotic resistances of the most abundant aerobic culturable bacteria and their survival in 15 German biogas plants (BGPs).
AIM
Determination of the diversities and antibiotic resistances of the most abundant aerobic culturable bacteria and their survival in 15 German biogas plants (BGPs).
METHODS AND RESULTS
Microbiological standard media (complex and selective media) were applied to enumerate mesophilic and oligotrophic bacteria (Enterobacteriaceae, Salmonella, staphylococci and enterococci) in input and output samples of BGPs. Concentrations of aerobic culturable bacteria in outputs were mostly one to two orders of magnitude lower than in input samples. In total, 852 isolates from input and 902 from output samples were identified either by partial 16S rRNA gene sequencing or Matrix-assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) analysis. Antibiotic resistance screening of target families against veterinary relevant antibiotics resulted in similar resistance pattern in input and output samples.
CONCLUSIONS
Potentially pathogenic bacteria were detected in output samples of BGPs, but in decreased abundance. The selectivity of the most applied clinical standard media was insufficient.
SIGNIFICANCE AND IMPACT OF THE STUDY
Only little is known about the release of antibiotic resistant and potentially pathogenic bacteria from BGPs. However, this study indicates the detection of several potentially pathogenic bacteria in output samples, which showed several antibiotic resistances.
Topics: Anti-Bacterial Agents; Bacteria, Aerobic; Biodiversity; Biofuels; Drug Resistance, Bacterial; Germany; Microbial Viability; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 27552433
DOI: 10.1111/jam.13277 -
Antimicrobial Agents and Chemotherapy May 1998The comparative in vitro activity of the ketolide HMR 3647 (RU 66647) and those of structurally related macrolide-lincosamide-streptogramin compounds (erythromycin,...
The comparative in vitro activity of the ketolide HMR 3647 (RU 66647) and those of structurally related macrolide-lincosamide-streptogramin compounds (erythromycin, roxithromycin, azithromycin, clarithromycin, josamycin, lincomycin, pristinamycin, and quinupristin-dalfopristin) as well as those of benzylpenicillin, doxycycline, vancomycin, teicoplanin, levofloxacin, and rifapentine against 247 aerobic and facultative non-spore-forming gram-positive bacilli were determined by an agar dilution method. The ketolide was active against most organisms tested except Corynebacterium striatum, coryneform CDC group 12, and Oerskovia spp. The frequency of resistance to erythromycin and other macrolides as well as that to lincomycin was high. Pristinamycin and, to a lesser extent, quinupristin-dalfopristin were very active, but resistance to these agents was present in some strains of Rhodococcus equi, Listeria spp., C. striatum, Erysipelothrix rhusiopathiae, and Oerskovia spp. HMR 3647 was very active against all erythromycin-sensitive and many erythromycin-nonsusceptible strains, especially Corynebacterium minutissimum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum, and Corynebacterium jeikeium. In vitro resistance to benzylpenicillin was common, but doxycycline, vancomycin, and teicoplanin were very active against most organisms tested except E. rhusiopathiae, against which glycopeptide antibiotics were not active. The in vitro activity of levofloxacin was remarkable, but resistance to this agent was common for C. amycolatum, Corynebacterium urealyticum, C. jeikeium, and Oerskovia spp. strains. Rifapentine was also very active in vitro against many organisms, but resistance to this agent was always present in E. rhusiopathiae and was very common in C. striatum and C. urealyticum.
Topics: Anti-Bacterial Agents; Bacteria, Aerobic; Corynebacterium; Gram-Positive Asporogenous Rods; Humans; Ketolides; Macrolides; Microbial Sensitivity Tests
PubMed: 9593121
DOI: 10.1128/AAC.42.5.1028 -
Antimicrobial Agents and Chemotherapy Oct 2013The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174...
Comparative in vitro activities of SMT19969, a new antimicrobial agent, against Clostridium difficile and 350 gram-positive and gram-negative aerobic and anaerobic intestinal flora isolates.
The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active against C. difficile isolates (MIC range, 0.125 to 0.5 μg/ml; MIC90, 0.25 μg/ml), including ribotype 027 strains, than fidaxomicin (range, 0.06 to 1 μg/ml; MIC90, 0.5 μg/ml) and two to six dilutions lower than either vancomycin or metronidazole. SMT19969 and fidaxomicin were generally less active against Gram-negative anaerobes, especially the Bacteroides fragilis group species, than vancomycin and metronidazole, suggesting that SMT19969 has a lesser impact on the normal intestinal microbiota that maintain colonization resistance. SMT19969 showed limited activity against other Gram-positive anaerobes, including Bifidobacteria species, Eggerthella lenta, Finegoldia magna, and Peptostreptococcus anaerobius, with MIC90s of >512, >512, 64, and 64 μg/ml, respectively. Clostridium species showed various levels of susceptibility, with C. innocuum being susceptible (MIC90, 1 μg/ml) and C. ramosum and C. perfringens being nonsusceptible (MIC90, >512 μg/ml). Activity against Lactobacillus spp. (range, 0.06 to >512 μg/ml; MIC90, >512 μg/ml) was comparable to that of fidaxomicin and varied by species and strain. Gram-positive aerobic cocci (Staphylococcus aureus, Enterococcus faecalis, E. faecium, and streptococci) showed high SMT19969 MIC90 values (128 to >512 μg/ml).
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Bacillus; Bacteria, Aerobic; Bacteria, Anaerobic; Bifidobacterium; Clostridioides difficile; Enterococcus faecalis; Gram-Positive Bacteria; Intestines; Microbial Sensitivity Tests; Peptostreptococcus; Staphylococcus aureus
PubMed: 23877700
DOI: 10.1128/AAC.01136-13 -
World Journal of Microbiology &... Jun 2016This paper investigates the effect of temperature on nitrogen and carbon removal by aerobic granules from landfill leachate with a high ammonium concentration and low...
This paper investigates the effect of temperature on nitrogen and carbon removal by aerobic granules from landfill leachate with a high ammonium concentration and low concentration of biodegradable organics. The study was conducted in three stages; firstly the operating temperature of the batch reactor with aerobic granules was maintained at 29 °C, then at 25 °C, and finally at 20 °C. It was found that a gradual decrease in operational temperature allowed the nitrogen-converting community in the granules to acclimate, ensuring efficient nitrification even at ambient temperature (20 °C). Ammonium was fully removed from leachate regardless of the temperature, but higher operational temperatures resulted in higher ammonium removal rates [up to 44.2 mg/(L h) at 29 °C]. Lowering the operational temperature from 29 to 20 °C decreased nitrite accumulation in the GSBR cycle. The highest efficiency of total nitrogen removal was achieved at 25 °C (36.8 ± 10.9 %). The COD removal efficiency did not exceed 50 %. Granules constituted 77, 80 and 83 % of the biomass at 29, 25 and 20 °C, respectively. Ammonium was oxidized by both aerobic and anaerobic ammonium-oxidizing bacteria. Accumulibacter sp., Thauera sp., cultured Tetrasphaera PAO and Azoarcus-Thauera cluster occurred in granules independent of the temperature. Lower temperatures favored the occurrence of denitrifiers of Zooglea lineage (not Z. resiniphila), bacteria related to Comamonadaceae, Curvibacter sp., Azoarcus cluster, Rhodobacter sp., Roseobacter sp. and Acidovorax spp. At lower temperatures, the increased abundance of denitrifiers compensated for the lowered enzymatic activity of the biomass and ensured that nitrogen removal at 20 °C was similar to that at 25 °C and significantly higher than removal at 29 °C.
Topics: Aerobiosis; Ammonium Compounds; Bacteria, Aerobic; Biodegradation, Environmental; Biomass; Carbon; Enzyme Activation; In Situ Hybridization, Fluorescence; Nitrification; Nitrites; Nitrogen; Sewage; Temperature; Wastewater; Water Pollutants, Chemical
PubMed: 27116957
DOI: 10.1007/s11274-016-2046-z -
BMC Infectious Diseases Apr 2019Cleaning and disinfection processes must be improved so that there is a reduction in environmental contamination of frequent-contact surfaces. The objective of this...
BACKGROUND
Cleaning and disinfection processes must be improved so that there is a reduction in environmental contamination of frequent-contact surfaces. The objective of this study was to evaluate cleaning and disinfection of surfaces at a specialized healthcare unit after an intervention program.
METHODS
Exploratory, longitudinal, and correlational study carried out in a medium-complexity clinic. Two hundred and forty samples from five surfaces were collected during three phases: diagnosis; implementation of an intervention program; and evaluation of immediate and long-term effects. In total, 720 evaluations were made, performed through three monitoring methods: visual inspection; adenosine triphosphate bioluminescence assay (ATP); and aerobic colony count (ACC). The Wilcoxon, Mann-Whitney, and Fisher's Exact tests were run to analyze data statistically.
RESULTS
Cleaning and disinfection of surfaces were not being performed properly in most cases. Failure rates of surfaces reached 37.5 and 100% when the ATP and ACC procedures were used, respectively. However, after an intervention program, an improvement occurred. Success rates increased by 43.96% (ATP) and 12.46% (ACC) in phase I, by 70.6% (ATP) and 82.3% (ACC) immediately after interventions, and by 76.52% (ATP) and 85.76% (ACC) two months after the changes, showing that the program was effective.
CONCLUSION
The present study reveals that implementing intervention actions with a cleaning and healthcare team brings benefits to prevent the spread of pathogenic agents through frequently touched hospital surfaces.
Topics: Bacteria, Aerobic; Disinfection; Housekeeping, Hospital; Longitudinal Studies; Luminescent Measurements; Outpatients; Statistics, Nonparametric
PubMed: 31035961
DOI: 10.1186/s12879-019-3977-4 -
Scientific Reports Jul 2015Thousands of net-heterotrophic and strongly stratifying lakes dominate the boreal landscape. Besides their central role as emitters of greenhouse gases, we have only...
Thousands of net-heterotrophic and strongly stratifying lakes dominate the boreal landscape. Besides their central role as emitters of greenhouse gases, we have only recently begun to understand the microbial systems driving the metabolic processes and elemental cycles in these lakes. Using shotgun metagenomics, we show that the functional potential differs among lake types, with humic lakes being particularly enriched in carbon degradation genes. Most of the metabolic pathways exhibit oxygen- and temperature-dependent stratification over depth, coinciding with shifts in bacterial community composition, implying that stratification is a major factor controlling lake metabolism. In the bottom waters, rare and poorly characterized taxa, such as ε-Proteobacteria, but also autotrophs, such as photolithotrophic Chlorobia were abundant. These oxygen-depleted layers exhibited high genetic potential for mineralization, but also for fixation of carbon and nitrogen, and genetic markers for both methane production and oxidation were present. Our study provides a first glimpse of the genetic versatility of freshwater anoxic zones, and demonstrates the potential for complete turnover of carbon compounds within the water column.
Topics: Bacteria, Aerobic; Bacteria, Anaerobic; Carbon; Lakes; Metagenomics; Nitrogen; Oxygen; Water; Water Microbiology
PubMed: 26159227
DOI: 10.1038/srep12102