Anaerobic Medium Research Articles

Blautia hominis sp. nov., isolated from human faeces.

A strictly anaerobic, Gram-stain-positive, non-motile and coccoid- or oval-shaped bacterium, designated strain KB1T, was isolated from a faecal sample of a patient with diverticulitis in South Korea. Degeneracies in the 16S rRNA gene sequence of strain KB1T were resolved by cloning, which yielded five different sequences with heterogeneity. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain KB1T formed a monophyletic branch with species in the genus Blautia, with highest sequence similarity to the type strain of Blautia producta (97.7-98.9 %), followed by Blautia coccoides (97.5-98.1 %). Strain KB1T was able to grow at temperatures of between 15 and 42 °C, with optimal growth at 37 °C, and in the presence of 20 % dehydrated bile. Acetic acid, succinic acid, lactic acid and fumaric acid were produced by strain KB1T from Gifu anaerobic medium broth as metabolic fermentation end-products. The major cellular fatty acids of strain KB1T were C14 : 0, C16 : 0 and C16 : 0 dimethyl aldehyde. The DNA G+C content was 46.3 mol%. The average nucleotide identity value between strain KB1T and the type strain of B. producta was 84.1 %. On the basis of polyphasic analysis, strain KB1T represents a novel species in the genus Blautia, for which the name Blautia hominis sp. nov. is proposed. The type strain is KB1T (=KCTC 15618T=JCM 32276T).

Biogas Improvement by Adding Australian Zeolite During the Anaerobic Digestion of C:N Ratio Adjusted Swine Manure

Maintenance of the ideal carbon: nitrogen (C:N) ratio with a minimum level of TAN is a key challenge for achieving maximum potential CH4 production through the anaerobic digestion process of agricultural waste such as swine manure. Biogas production can be enhanced by adding zeolite into the anaerobic digestion medium. However, the effects of zeolite addition to C:N ratio adjusted feedstock, on the digester performance is unknown. The objectives of this study were to investigate the effect of Australian zeolite on anaerobic digestion of swine manure with a C:N ratio adjusted to 30 and to determine the optimal zeolite application rate to achieve the best performance. The Australian zeolite significantly enhanced CH4 production and reduced the lag phase of anaerobic digestion in batch production. The optimal addition rate of zeolite was appeared to be around 40 g/L. The better digester performance was attributed by the reduction of dissolved ammonium from the digestate. This study indicates that Australian zeolite is an effective treatment to address problems associated with co-digestion of swine manure with different carbon sources.

Enhanced biohydrogen production from nutrient-free anaerobic fermentation medium with edible fungal pretreated rice straw.

An edible fungal pretreatment of rice straw was proposed for enhanced hydrogen production while reducing the chemical cost for traditional biological hydrogen production from lignocellulose. In this research, rice straw was pretreated by edible fungus Gymnopus contrarius J2 at room temperature under static conditions for 15 d at first. The highest hydrogen yield of 5.71 mmol g−1-pretreated rice straw was obtained, 74% higher than the counterpart without pretreatment. Chemical composition analysis demonstrated that lignin removal was up to 22.4% with a little cellulose and hemicellulose loss of 13.3% and 17.1%, respectively, which is in favor of hydrogen production. Additionally, microscopic structure observation combined with FT-IR and XRD analysis illustrated the structural disruption of pretreated rice straw, and the crystalline index of rice straw can be decreased by 46.2% after pretreatment, which might account for the hydrogen production enhancement. The results also indicated that the hydrogen yield from pretreated rice straw was not affected without the addition of yeast extract and vitamins to the culture medium, which is substantial evidence that edible fungal pretreated rice straw could provide prerequisite nutrients for hydrogen-producing bacteria. Overall, edible fungal pretreatment has great potential under the mild conditions for high hydrogen yields and thus leads to a new direction to realize a highly efficient and economically competitive biological hydrogen production process from lignocellulosic biomass.

Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry analysis of In vitro metabolites of lignans from fructus forsythiae by Human Fecal Flora

Background: Phillyrin and (+)-pinoresinol 4-O-β-D-glucoside are the major active furofuran-type lignans in Fructus Forsythiae. The metabolic routes and metabolites of these two lignans are not well understood yet. Objective: In this study, we attempted to identify the human-intestine bacterial metabolites of lignans from Fructus Forsythiae. Materials and Methods: Two natural compounds, phillyrin and (+)-pinoresinol 4-O-β-D-glucoside were incubated with human fecal microflora in an anaerobic incubator for 72 h and the metabolites with highly sensitive ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) were analyzed. Results: As a result, nine metabolites were determined using a Syncronis™ C18column (particle size 1.7 mm) in a gradient elution system. These metabolites were then identified according to the mass fragmental mechanism, MS/MS fragment ions, and previous publications. The results of this study indicated that the major metabolites of furofuran-type lignans are through the processes of hydrolysis, demethylation, reduction, dehydroxylation, and oxidation. Conclusions: Lignans can be metabolized by intestinal microbiota and the intestinal bacteria play a critical role in the metabolism of components administered orally. Abbreviations used: GAM: General anaerobic medium; UPLC/Q-TOF-MS: Ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry; ESI: Negative ion electrospray; RT: Retention time; TCM: Traditional Chinese Medicine.

Inclusion of Bacillus amyloliquefaciens strain TOA5001 in the diet of broilers suppresses the symptoms of coccidiosis by modulating intestinal microbiota.

Coccidiosis is an intestinal parasitic infection and one of the most prevalent and economically damaging diseases of chickens. Furthermore, coccidia-induced mucogenesis promotes secondary colonization by Clostridium perfringens, a major pathogen of chickens that causes necrotic enteritis. Our previous work found that supernatant of a culture of Bacillus amyloliquefaciens strain TOA5001 (BA) inhibited the growth of C. perfringens on Gifu anaerobic broth medium. Accordingly, we evaluated the effectiveness of dietary BA administration in inhibiting C. perfringens colonization of the intestine in broilers that were experimentally infected with coccidia. Ten healthy broilers from a BA-supplemented (2×105 colony-forming units/g of feed) broiler group and 10 from a non-treated group were challenged with Eimeria tenella and E. maxima (5000 oocysts of each species/chick) at 28 days old. At 36 days old, five chicks from each group were slaughtered, whereas the remaining five in each group were killed at 49 days old. Dietary BA administration into Eimeria-challenged birds reduced coccidial symptoms such as intestinal lesions. It also modified the cecal microbiota through suppressing C. perfringens and E.coli colonization, and inducing domination of Faecalibacterium prausnitzii, the Lactobacillus group and unknown Lachnospiraceae genera by bacterial DNA-based metagenome analyses. B. amyloliquefaciens TOA5001 supplementation suppressed the symptoms of coccidiosis by modulating cecal microbiota in Eimeria-challenged broilers.

Characterization of a xylanolytic bacterial strain C10 isolated from the rumen of a red deer (Cervus elaphus) closely related of the recently described species Actinomyces succiniciruminis, A. glycerinitolerans, and A. ruminicola.

Gram-stain-positive, catalase and oxidase-negative and short rod-shaped bacterium C10 with occasional branching was isolated under strictly anaerobic conditions from the rumen fluid of a red deer (Cervus elaphus) in the course of study attempting to uncover new xylanolytic and cellulolytic rumen bacteria inhabiting the digestive tract of wild ruminants in the Czech Republic. The anaerobic M10 medium containing bovine rumen fluid and carboxymethylcellulose as a defined source of organic carbon was used in the process of bacterial isolation. The 16S rRNA gene similarity revealed recently characterized new species Actinomyces succiniciruminis Am4T (GenBank accession number of the gene retrieved from the complete genome: LK995506) and Actinomyces glycerinitolerans G10T (GenBank accession number from the complete genome: NZFQTT01000017) as the closest relatives (99.7 and 99.6% gene pairwise identity, respectively), followed by the Actinomyces ruminicola DSM 27982T (97.2%, in all compared fragment of 41468pb). Due to the taxonomic affinity of the examined strain to both species A. succiniciruminis and A. glycerinitolerans, its taxonomic status towards these species was evaluated using variable regions of rpsA (length of 519bp) and rplB (597bp) gene sequences amplified based on specific primers designed so as to be applicable in differentiation, classification, and phylogeny of Actinomyces species/strains. Comparative analyses using rpsA and rplB showed 98.5 and 97.9% similarities of C10 to A. succiniciruminis, respectively, and 97.5 and 97.6% similarities to A. glycerinitolerans, respectively. Thus, gene identities revealed that the evaluated isolate C10 (=DSM 100236 = LMG 28777) is a little more related to the species A. succiniciruminis isolated from the rumen of a Holstein-Friesian cow than A. glycerinitolerans. Phylogenetic analyses confirmed affinity of strain C10 to both recently characterized species. Unfortunately, they did not allow the bacterial strain to be classified into a particular species. Phenotypic characterization suggested similar conclusions. This brief contribution is aimed at classification and detailed phenotypic characterization of bacterial strain C10 isolated from the rumen of a wild red deer exhibiting, from the point of view of Actinomyces species, noteworthy cellulolytic and xylanolytic activities.

In-situ prevention of hydrogen sulfide formation during anaerobic digestion using zinc oxide nanowires

The utilization of Anaerobic Digestion (AD) technology for biogas and energy generation is often hindered by high concentration of sulfur-containing compounds in wastewater and consequential hydrogen sulfide (H2S) in biogas. In this work, we demonstrated a process, where independent mechanisms of anaerobic microorganisms and an inorganic reactive adsorbent (zinc oxide nanowires) worked synergistically to remove soluble sulfide (HS−) and prevent H2S formation during AD. Using a model aqueous sodium sulfide (Na2S) system, the nanowires (dosage 1g/L) effectively removed sulfides from the Na2S solution to a maximum of 625mg S2−/L per gram of ZnO. During 24h and 3-day long (involving three consecutive sulfate feeding cycles) AD studies using anaerobic microbial medium (2g/L SO42− and 1g/L ZnO), no decrease in methanogenic activity and biogas production were observed using the ZnO nanowires, indicating that the nanowires can reduce the sulfide toxicity during AD. The post-process analysis of the recovered nanomaterial using energy-dispersive X-ray spectroscopy and X-ray diffraction showed the presence of sulfur and zinc sulfide (ZnS), respectively, validating HS− removal by the nanowires. This process intensification approach of combining AD and H2S removal into a single process step will help extend AD technology to high sulfate containing wastewaters.

In Vitro Fermentation Patterns of Rice Bran Components by Human Gut Microbiota.

Whole grain rice is a rich source of fiber, nutrients, and phytochemicals that may promote gastrointestinal health, but such beneficial components are typically removed with the bran during polishing. Soluble feruloylated arabinoxylan oligosaccharides (FAXO) and polyphenols (RBPP) isolated from rice bran are hypothesized to have positive impacts on human gut microbiota through a prebiotic function. Using an in vitro human fecal fermentation bioassay, FAXO and RBPP treatments were assessed for short-chain fatty acids (SCFA) production patterns and by evaluating their impacts on the phylogentic composition of human gut microbiota by 16S rRNA gene sequencing. Fresh fecal samples collected from healthy adults (n = 10, 5 males, 5 females) were diluted with anaerobic medium. Each sample received five treatments: CTRL (no substrates), FOS (fructooligosaccharides), FAXO, RBPP, and MIX (FAXO with RBPP). Samples were incubated at 37 °C and an aliquot was withdrawn at 0, 4, 8, 12, and 24 h Results showed that SCFA production was significantly increased with FAXO and was comparable to fermentation with FOS, a well-established prebiotic. RBPP did not increase SCFA productions, and no significant differences in total SCFA production were observed between FAXO and MIX, indicating that RBPP does not modify FAXO fermentation. Changes in microbiota population were found in FAXO treatment, especially in Bacteroides, Prevotella, and Dorea populations, indicating that FAXO might modulate microbiota profiles. RBPP and MIX increased Faecalibacterium, specifically F. prausnitzii. Combined FAXO and RBPP fermentation increased abundance of butyrogenic bacteria, Coprococcus and Roseburia, suggesting some interactive activity. Results from this study support the potential for FAXO and RBPP from rice bran to promote colon health through a prebiotic function.

The effect of nitrate and monensin on in vitro ruminal fermentation.

Two experiments evaluated the effect of calcium ammonium nitrate decahydrate (calcium nitrate [NIT]) and monensin sodium (MON) on in vitro fermentation parameters of 2 contrasting diets (100:0 and 10:90 forage-to-concentrate ratios). Diet addition of NIT (0, 1.25, and 2.5 g/100 g DM) and MON (0, 3, and 6 mg/L) were tested alone and combined (9 treatments total; 5 bottles per treatment). Mixed ruminal microorganisms were incubated in anaerobic media containing 0.5 g of substrate diet, 1 of 9 treatments, and 40 mL buffer solution. Incubations were performed in batch cultures for 48 h at 39°C. Headspace gas volume was measured and sampled at 4, 8, 12, 24, and 48 h, and the VFA profile was assessed at the end of the experiment. Total gas production was reduced by NIT (87.9 vs. 94.6 mL; < 0.01) and MON (78.6 vs. 94.6 mL; < 0.01) and, in Exp. 2, further reduced by NIT+MON when the additives were combined (161.1 vs. 196.9 mL; < 0.01). Methane production from control in Exp. 1 and Exp. 2 averaged 9.1 and 15.3 mL, respectively, and was decreased by NIT (3.4 and 8.3 mL in Exp. 1 and Exp. 2, respectively; P < 0.01), MON (4.1 and 7.7 mL; in Exp. 1 and Exp. 2, respectively; < 0.01) and NIT+MON (1.1 and 1.5 mL; in Exp. 1 and Exp. 2, respectively; < 0.01). Both experiments demonstrated a significant increase in nitrous oxide (NO; < 0.01) when NIT was added. Compared to the control treatment, IVDMD was reduced when NIT+MON was added at the higher doses in EXP1 (31.7 vs. 37.4%; < 0.01) and EXP2 (76.6 vs. 79.9 %; < 0.01). Net VFA production was not affected by treatments ( > 0.10), but molar proportions of acetate and butyrate were reduced by MON ( < 0.01). Propionate molar proportion was increased in both experiments by MON ( < 0.01) and further increased in Exp. 2 when the additives were combined at lower doses ( < 0.01). Compared to the control treatment, the acetate:propionate (A:P) ratio was reduced by MON in Exp. 1(1.2 vs. 2.8; < 0.01) and Exp. 2 (1.0 vs. 2.3; < 0.01). Fermentation efficiency (%) was increased by MON (81.7 vs. 73.7%; < 0.01) and further increased in Exp. 2 when the additives were combined at lower doses (87.2 vs. 76.6%; < 0.01). The combination of NIT and MON in 2 contrasting diets proved beneficial by altering fermentation products toward lower CH and more propionate; however, the addition of NIT consistently increased NO production. Negative effects of the additives on IVDMD were found only when the additives were combined at higher doses.

Discovery and Biochemical Characterization of UDP-Glucose Dehydrogenase from Akkermansia muciniphila.

The biocatalytic oxidation of UDP-glucose in the presence of NAD+ is catalyzed by UDP-glucose dehydrogenases. The main objective of this study was the characterization of a UDP-glucose dehydrogenase (AmUGD) from Akkermansia muciniphila, a bacterium originally isolated from human faeces in an anaerobic medium containing gastric mucin as the sole carbon source. The biochemical analysis of AmUGD was performed using a plate reader-based assay measuring the reaction by-product NADH. Furthermore, HPLC- and MALDI-ToF-MS- based methods were used for the enzyme characterization. The recombinant form of the protein was expressed in E. coli and the purified enzyme exhibited optimum levels of activity at 37°C and pH 9.0. While the enzyme is active in the absence of metal ions, the presence of Zn2+ ions results in markedly enhanced levels of catalysis. This study describes the first characterization of a nucleotide-processing enzyme from A. muciniphila. The ease of expression and purification of this enzyme make it ideal for biotechnological applications such as the enzymatic synthesis of nucleotide sugars, which may in turn be used for the synthesis of complex carbohydrates or glycoconjugates.

Diagnostic accuracy of the LightCycler® SeptiFast assay in the childhood febrile neutropenia

Infection is the main problem among the patients receiving cancer therapy. The mortality rate can be reduced by the appropriate treatment in the right time. Although blood culture is the gold standard for the diagnoses of sepsis, many factors influence the results of blood culture in children. For this reason, real time polymerase chain reaction (Rt-PCR) has gained importance for the diagnoses of microbiological agents as it is faster than the conventional methods. In this study, we aimed to compare the efficacy of SeptiFast (SF) test with blood culture among children with neutropenic fever. Between January 2013 and December 2014, 62 children (34 boys, 38 girls) mean age 7.56 ± 4.8 (0-18) years with cancer were included in this study during their 94 febrile attacks of neutropenia (NA). Blood samples for blood culture and Septifast test were taken before the initiation of antibiotic therapy. Blood cultures were routinely collected in aerobic and anaerobic media and incubated using the BACTEC 9120 system (Becton-Dickinson Diagnostic Systems, USA). Identification and antimicrobial susceptibility testing of the isolates were performed using the Vitek2® system (bioMérieux, France) according to the recommendations of the Clinical and Laboratory Standards Institute. The LightCycler SF test was used according to the manufacturer instructions. Of 94 attacks 34 (36.1%) were positive for blood culture and 33 (35.1%) for SF test. The positivity ratio is found as 29.7% (28/94) by blood culture when the analysis of five coagulase negative staphylococci were excluded due to contamination. Positivity was detected in 25 (26.6%) of the 94 NA both with blood culture and SF test.The difference between these two tests was statistically significant (p< 0.05). There was discordance with a rate of 28.7% between these two methods. Polymicrobial infections were detected only with SF test. The detection of fungal infection rate was higher with SF test than blood culture. When SF test was compared with blood culture the results were as follows; sensitivity 91%, specificity 98.3%, positive predictive value 97%, negative predictive value 96.7%, diagnostic performance was 96.2%, respectively. As a result, PCR based tests can be used in children with NA attacks even though blood culture is still needed to perform the antibiotic sensitivity tests. SF test seems to be a sensitive test for the early diagnosis of the pathogens and the initiation of the appropriate therapy according to the etiological agent.

Use of Gifu Anaerobic Medium for culturing 32 dominant species of human gut microbes and its evaluation based on short-chain fatty acids fermentation profiles.

Recently, a "human gut microbial gene catalogue," which ranks the dominance of microbe genus/species in human fecal samples, was published. Most of the bacteria ranked in the catalog are currently publicly available; however, the growth media recommended by the distributors vary among species, hampering physiological comparisons among the bacteria. To address this problem, we evaluated Gifu anaerobic medium (GAM) as a standard medium. Forty-four publicly available species of the top 56 species listed in the "human gut microbial gene catalogue" were cultured in GAM, and out of these, 32 (72%) were successfully cultured. Short-chain fatty acids from the bacterial culture supernatants were then quantified, and bacterial metabolic pathways were predicted based on in silico genomic sequence analysis. Our system provides a useful platform for assessing growth properties and analyzing metabolites of dominant human gut bacteria grown in GAM and supplemented with compounds of interest.

Degradation of the fungal cell wall by clostridial strains isolated from soil subjected to biological soil disinfestation and biocontrol of Fusarium wilt disease of spinach.

Biological soil disinfestation (BSD) involves elimination of soil-borne plant pathogens in an environmentally friendly manner. Two anaerobic bacterial strains (H110 and TB8) isolated from BSD-treated soil samples were analyzed for their roles in elimination of pathogenic fungi. The two strains were identified as Clostridium beijerinckii based on 16S rRNA gene sequences and phenotypic properties. The strains fermented various carbohydrates and produced acetate, butyrate, and n-butanol as major products as well as abundant gases (H2 and CO2). For evaluation of the antifungal potential of these strains, cells of a pathogen (spinach wilt disease, Fusarium oxysporum f. sp. spinaciae) were co-inoculated into anaerobic media with each anaerobic strain. After incubation for ~3weeks at 30°C, 10-30% of the cells of the pathogen survived when incubated without the anaerobic isolates, whereas the pathogen was eliminated when co-incubated with each anaerobe because of the growth of the anaerobic bacterium. It was found by microscopic examination that mycelial cells of the fungal pathogen were severely degraded during the first 3-7days of the co-incubation. The two strains utilized major cell wall polysaccharides of ascomycetous fungi-chitosan and ß-1,3-glucan (curdlan and laminarin)-as fermentative substrates added to the medium. Furthermore, both isolates degraded a cell wall preparation isolated from the mycelium of the Fusarium pathogen of spinach wilt disease. We concluded that the two anaerobic strains kill the pathogen of spinach wilt disease by degrading major fungal cell wall components as antifungal activities.

Impact of β2-1 fructan on faecal community change: results from a placebo-controlled, randomised, double-blinded, cross-over study in healthy adults.

Healthy adults (n 30) participated in a placebo-controlled, randomised, double-blinded, cross-over study consisting of two 28 d treatments (β2-1 fructan or maltodextrin; 3×5 g/d) separated by a 14-d washout. Subjects provided 1 d faecal collections at days 0 and 28 of each treatment. The ability of faecal bacteria to metabolise β2-1 fructan was common; eighty-seven species (thirty genera, and four phyla) were isolated using anaerobic medium containing β2-1 fructan as the sole carbohydrate source. β2-1 fructan altered the faecal community as determined through analysis of terminal restriction fragment length polymorphisms and 16S rRNA genes. Supplementation with β2-1 fructan reduced faecal community richness, and two patterns of community change were observed. In most subjects, β2-1 fructan reduced the content of phylotypes aligning within the Bacteroides, whereas increasing those aligning within bifidobacteria, Faecalibacterium and the family Lachnospiraceae. In the remaining subjects, supplementation increased the abundance of Bacteroidetes and to a lesser extent bifidobacteria, accompanied by decreases within the Faecalibacterium and family Lachnospiraceae. β2-1 Fructan had no impact on the metagenome or glycoside hydrolase profiles in faeces from four subjects. Few relationships were found between the faecal bacterial community and various host parameters; Bacteroidetes content correlated with faecal propionate, subjects whose faecal community contained higher Bacteroidetes produced more caproic acid independent of treatment, and subjects having lower faecal Bacteroidetes exhibited increased concentrations of serum lipopolysaccharide and lipopolysaccharide binding protein independent of treatment. We found no evidence to support a defined health benefit for the use of β2-1 fructans in healthy subjects.

Selection for novel, acid-tolerant Desulfovibrio spp. from a closed Transbaikal mine site in a temporal pH-gradient bioreactor.

Almost all the known isolates of acidophilic or acid-tolerant sulphate-reducing bacteria (SRB) belong to the spore-forming genus Desulfosporosinus in the Firmicutes. The objective of this study was to isolate acidophilic/acid-tolerant members of the genus Desulfovibrio belonging to deltaproteobacterial SRB. The sample material originated from microbial mat biomass submerged in mine water and was enriched for sulphate reducers by cultivation in anaerobic medium with lactate as an electron donor. A stirred tank bioreactor with the same medium composition was inoculated with the sulphidogenic enrichment. The bioreactor was operated with a temporal pH gradient, changing daily, from an initial pH of 7.3 to a final pH of 3.7. Among the bacteria in the bioreactor culture, Desulfovibrio was the only SRB group retrieved from the bioreactor consortium as observed by 16S rRNA-targeted denaturing gradient gel electrophoresis. Moderately acidophilic/acid-tolerant isolates belonged to Desulfovibrio aerotolerans-Desulfovibrio carbinophilus-Desulfovibrio magneticus and Desulfovibrio idahonensis-Desulfovibrio mexicanus clades within the genus Desulfovibrio. A moderately acidophilic strain, Desulfovibrio sp. VK (pH optimum 5.7) and acid-tolerant Desulfovibrio sp. ED (pH optimum 6.6) dominated in the bioreactor consortium at different time points and were isolated in pure culture.

Preoperative doxycycline does not decolonize Propionibacterium acnes from the skin of the shoulder: a randomized controlled trial

Propionibacterium acnes is frequently cultured in patients undergoing both primary and revision shoulder surgery. The purpose of this study was to evaluate the efficacy and safety of preoperative oral administration of doxycycline in decreasing the colonization of skin around the shoulder by P. acnes. This was a single-institution, prospective, randomized controlled trial of male patients undergoing shoulder arthroscopy. Patients were randomized to receive oral doxycycline (100 mg twice a day) for 7 days or to the standard of care (no drug). Before skin incision, 2 separate 3-mm punch biopsy specimens were obtained from the sites of the anterior and posterior arthroscopic portals and were sent for culture in anaerobic and aerobic medium held for 13 days. There were 22 of 37 (59.5%) patients in the no-drug group and 16 of 37 (43.2%) patients in the doxycycline group who had at least 1 dermal culture positive for P. acnes (P = .245). In the no-drug group, 10 patients (45.5%) had 1 positive culture and 12 (54.5%) had 2 positive cultures (34 total positive cultures [45.9%]). In the doxycycline group, 6 (37.5%) patients had 1 positive culture and 10 (62.5%) had 2 positive cultures (26 total positive cultures [35.1%]; P = .774). Administration of oral doxycycline for 7 days before surgery did not reduce colonization of P. acnes significantly. Given the potential risk for emergence of bacterial resistance and the adverse effects associated with administration of antibiotics, we do not recommend routine use of oral doxycycline for preoperative decolonization of the shoulder.

The human jejunum has an endogenous microbiota that differs from those in the oral cavity and colon

BackgroundThe upper half of the human small intestine, known as the jejunum, is the primary site for absorption of nutrient-derived carbohydrates, amino acids, small peptides, and vitamins. In contrast to the colon, which contains 1011–1012 colony forming units of bacteria per ml (CFU/ml), the normal jejunum generally ranges from 103 to 105 CFU per ml. Because invasive procedures are required to access the jejunum, much less is known about its bacterial microbiota. Bacteria inhabiting the jejunal lumen have been investigated by classical culture techniques, but not by culture-independent metagenomics.ResultsThe lumen of the upper jejunum was sampled during enteroscopy of 20 research subjects. Culture on aerobic and anaerobic media gave live bacterial counts ranging from 5.8 × 103 CFU/ml to 8.0 × 106 CFU/ml. DNA from the same samples was analyzed by 16S rRNA gene-specific quantitative PCR, yielding values from 1.5 × 105 to 3.1 × 107 bacterial genomes per ml. When calculated for each sample, estimated bacterial viability ranged from effectively 100% to a low of 0.3%. 16S rRNA metagenomic analysis of uncultured bacteria by Illumina MiSeq sequencing gave detailed microbial composition by phylum, genus and species. The genera Streptococcus, Prevotella, Veillonella and Fusobacterium, were especially abundant, as well as non-oral genera including Escherichia, Klebsiella, and Citrobacter. The jejunum was devoid of the genera Alistipes, Ruminococcus, Faecalibacterium, and other extreme anaerobes abundant in the colon. In patients with higher bacterial loads, there was no significant change in microbial species composition.ConclusionsThe jejunal lumen contains a distinctive bacterial population consisting primarily of facultative anaerobes and oxygen-tolerant obligate anaerobes similar to those found in the oral cavity. However, the frequent abundance of Enterobacteriaceae represents a major difference from oral microbiota. Although a few genera are shared with the colon, we found no evidence for retrograde movement of the most abundant colonic microbes to the jejunum. Some individuals had much higher bacterial loads, but this was not correlated with decreases in bacterial species diversity or other evidence of dysbiosis.

Corrosion of bare and silane-coated mild steel in chloride medium with and without sulphate reducing bacteria

Abstract Influence of Bis[triethoxysilyl]ethane (BTSE) silane coating on the corrosion resistance of a mild steel in an aerobic chloride medium and an anaerobic microbial medium containing sulphate reducing bacteria (SRB) was analysed using a comprehensive electrochemical and chemical analyses. The Silane coating acted as a physical barrier and significantly improved the corrosion resistance of mild steel in an aerobic chloride medium. However, the improvement was limited in the anaerobic microbial medium. Surface morphology examination and chemical analysis using Fourier transformed infrared spectroscopy confirm the formation of a dense biofilm on BTSE-coated surface after pre-exposure to biotic media, which can be attributed to the absence of any antimicrobial functional group in this silane. This study is first of its kind to indicate the limitations of established coating systems in retarding microbial corrosion and emphasizes the importance of the modification of current coating systems with anti-microbial functional groups to impede the formation of biofilms and effectively hinder microbial corrosion.

A retrospective evaluation of the performance of 2 blood culture media in detection of bloodstream infection: clinical comparison of BACTEC and BacT/Alert systems

Objective To evaluate the clinical performance of the BACTEC Plus aerobic, BACTEC Lytic anaerobic, BacT/Alert aerobic and anaerobic blood culture media in detection of bloodstream infections. Methods Retrospective study was conducted. A total of four blood culture bottles from each inpatient with suspected bloodstream infections were collected and analyzed from June 2013 to September 2015 in Peking University People′s Hospital. The four bottles, including BACTEC Plus aerobic, BACTEC Lytic anaerobic, BacT/Alert FA aerobic and BacT/Alert FN anaerobic media, and was incubated for 5 days in the BacT/Alert 3D and BACTEC FX instruments, respectively. Time to detection (TTD) and positive rate in detecting bacteria of the two systems were evaluated by Wilcoxon test and Chi-square test. Results Among 2 189 total cultures collected, 20 were excluded because of blood shortage and 201 (9.27%) were positive for pathogens. The positive rates of BACTEC Plus aerobic media and BacT/Alert FA aerobic media were 75.3% (140/186) and 69.4% (129/186) (χ2=1.625, P=0.202), respectively. While, the positive rates of BacT/Alert FN anaerobic media and BACTEC Lytic anaerobic media were 81.8% (99/121) and 63.6% (77/121) for total organisms, respectively (χ2=10.083, P=0.001). A significant difference in TTD was detected in BACTEC Plus aerobic media[11.0 (8.0-16.0) h]and BacT/Alert FA aerobic media[13.9 (10.4-18.7) h](Z=-5.240, P<0.001). BACTEC Lytic anaerobic media[8.0 (7.0-10.0) h]had a shorter TTD (Z=-4.299, P<0.001) than BacT/Alert FN anaerobic media[11.3 (9.3-12.7) h]. The positive rates of BACTEC and BacT/Alert system were 74.13% (149/201) and 74.63% (150/201), respectively, compared with taking one set from each system. Conclusions BACTEC media has a shorter TTD and almost the same bacterial recovery, and lower false positive rate than the BacT/Alert media.(Chin J Lab Med, 2017, 40: 303-308) Key words: Bacteremia; Blood culture; Bacteria; Culture medias; Evaluation studies

Exogenous lactobacilli mitigate microbial changes associated with grain fermentation (corn, oats, and wheat) by equine fecal microflora ex vivo.

Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, wheat, or oats at 1.6% (w/v) starch and one of five treatments: Control (substrate only), L. acidophilus, L. buchneri, L. reuteri, or an equal mixture of all three (107 cells/mL, final concentration). After 24 h of incubation (37°C, 160 rpm), samples were collected for pH and enumerations of total amylolytics, Group D Gram-positive cocci (GPC; Enterococci, Streptococci), lactobacilli, and lactate-utilizing bacteria. Enumeration data were log transformed prior to ANOVA (SAS, v. 9.3). Lactobacilli inhibited pH decline in corn and wheat fermentations (P < 0.0001). Specifically, addition of either L. reuteri or L. acidophilus was most effective at mitigating pH decline with both corn and wheat fermentation, in which the greatest acidification occurred (P < 0.05). Exogenous lactobacilli decreased amylolytics, while increasing lactate-utilizers in corn and wheat fermentations (P < 0.0001). In oat fermentations, L. acidophilus and L. reuteri inhibited pH decline and increased lactate-utilizers while decreasing amylolytics (P < 0.0001). For all substrates, L. reuteri additions (regardless of viability) had the lowest number of GPC and the highest number of lactobacilli and lactate-utilizers (P < 0.05). There were no additive effects when lactobacilli were mixed. Exogenous lactobacilli decreased the initial (first 8 h) rate of starch catalysis when wheat was the substrate, but did not decrease total (24 h) starch utilization in any case. These results indicate that exogenous lactobacilli can impact the microbial community and pH of cereal grain fermentations by equine fecal microflora ex vivo. Additionally, dead (autoclaved) exogenous lactobacilli had similar effects as live lactobacilli on fermentation. This latter result indicates that the mechanism by which lactobacilli impact other amylolytic bacteria is not simple resource competition.