Rapid intrapartum test for maternal group B streptococcal colonisation and its effect on antibiotic use in labouring women with risk factors for early-onset neonatal infection (GBS2): cluster randomised trial with nested test accuracy study

Background Mother-to-baby transmission of group B Streptococcus (GBS) is the main cause of early-onset infection. We evaluated whether, in women with clinical risk factors for early neonatal infection, the use of point-of-care rapid intrapartum test to detect maternal GBS colonisation reduces maternal antibiotic exposure compared with usual care, where antibiotics are administered due to those risk factors. We assessed the accuracy of the rapid test in diagnosing maternal GBS colonisation, against the reference standard of selective enrichment culture. Methods We undertook a parallel-group cluster randomised trial, with nested test accuracy study and microbiological sub-study. UK maternity units were randomised to a strategy of rapid test (GeneXpert GBS system, Cepheid) or usual care. Within units assigned to rapid testing, vaginal-rectal swabs were taken from women with risk factors for vertical GBS transmission in established term labour. The trial primary outcome was the proportion of women receiving intrapartum antibiotics to prevent neonatal early-onset GBS infection. The accuracy of the rapid test was compared against the standard of selective enrichment culture in diagnosing maternal GBS colonisation. Antibiotic resistance profiles were determined in paired maternal and infant samples. Results Twenty-two maternity units were randomised and 20 were recruited. A total of 722 mothers (749 babies) participated in rapid test units; 906 mothers (951 babies) were in usual care units. There was no evidence of a difference in the rates of intrapartum antibiotic prophylaxis (relative risk 1.16, 95% CI 0.83 to 1.64) between the rapid test (41%, 297/716) and usual care (36%, 328/906) units. No serious adverse events were reported. The sensitivity and specificity measures of the rapid test were 86% (95% CI 81 to 91%) and 89% (95% CI 85 to 92%), respectively. Babies born to mothers who carried antibiotic-resistant Escherichia coli were more likely to be colonised with antibiotic-resistant strains than those born to mothers with antibiotic-susceptible E. coli. Conclusion The use of intrapartum rapid test to diagnose maternal GBS colonisation did not reduce the rates of antibiotics administered for preventing neonatal early-onset GBS infection than usual care, although with considerable uncertainty. The accuracy of the rapid test is within acceptable limits. Trial registration ISRCTN74746075. Prospectively registered on 16 April 2015

The Effect of Gibberellic Acid on the Production Characteristics and Biochemical Parameters of Tetraselmis Suecica in an Enrichment Culture

The use of gibberellic acid as a stimulator of microalgae growth has beensubstantiatedexperimentally.This research aimed to assess the effect of exposure to a wide range of gibberellic acid concentrations on the growth dynamics ofthe microalgaTetraselmissuecicain an enrichment culture. The duration of the experiments was 14 days. It has been shown that gibberellic acid,atconcentrations of 0.39–3.20× 10−8M, stimulates algaegrowth. In this research, the exposure to gibberellic acid at concentrations of 0.39–3.20 × 10−8M was accompanied by a variation in the pattern of growth curves: the maximum number of cells was recorded on day seven of the experiment. A higher concentration of the phytohormone (3.84 × 10−8М) inhibited the increase inculture density. The growth of theT. suecicaculture in the control group was 332%;the growth of the culture exposed to gibberellic acid at a concentration of 0.39 × 10−8M was1136%. The values of the specific growth rate ofT. suecicawere estimated for different periods of cultivation. On day14 of the experiment, the biochemical composition of microalgae biomass was analyzed.According to the results, gibberellic acid stimulated the accumulation of carbohydrates, proteins, and chlorophyll. Nevertheless, the phytohormone had no effect on lipidaccumulation. An assumption was made thatexposure to low concentrations of phytohormone stimulates the growth of microalgae by reducing the lag phase of growth. Keywords: gibberellic acid, microalga, cultivation, lipids, carbohydrates, proteins

Activity-Based Protein Profiling for the Identification of Novel Carbohydrate-Active Enzymes Involved in Xylan Degradation in the Hyperthermophilic Euryarchaeon Thermococcus sp. Strain 2319x1E

Activity-based protein profiling (ABPP) has so far scarcely been applied in Archaea in general and, especially, in extremophilic organisms. We herein isolated a novel Thermococcus strain designated sp. strain 2319x1E derived from the same enrichment culture as the recently reported Thermococcus sp. strain 2319x1. Both strains are able to grow with xylan as the sole carbon and energy source, and for Thermococcus sp. strain 2319x1E (optimal growth at 85°C, pH 6–7), the induction of xylanolytic activity in the presence of xylan was demonstrated. Since the solely sequence-based identification of xylanolytic enzymes is hardly possible, we established a complementary approach by conducting comparative full proteome analysis in combination with ABPP using α- or β-glycosidase selective probes and subsequent mass spectrometry (MS)-based analysis. This complementary proteomics approach in combination with recombinant protein expression and classical enzyme characterization enabled the identification of a novel bifunctional maltose-forming α-amylase and deacetylase (EGDIFPOO_00674) belonging to the GH57 family and a promiscuous β-glycosidase (EGIDFPOO_00532) with β-xylosidase activity. We thereby further substantiated the general applicability of ABPP in archaea and expanded the ABPP repertoire for the identification of glycoside hydrolases in hyperthermophiles.

Production of a newly discovered PHA family member with an isobutyrate-fed enrichment culture

Using microbial enrichment cultures for the production of waste-derived polyhydroxyalkanoates (PHAs) is a promising technology to recover secondary resources. Volatile fatty acids (VFAs) form the preferred substrate for PHA production. Isobutyrate is a VFA appearing in multiple waste valorization routes, such as anaerobic fermentation, chain elongation, and microbial electrosynthesis, but has never been assessed individually on its PHA production potential. This research investigates isobutyrate as sole carbon source for a microbial enrichment culture in comparison to its structural isomer butyrate. The results reveal that the enrichment of isobutyrate has a very distinct character regarding microbial community development, PHA productivity, and even PHA composition. Although butyrate is a superior substrate in almost every aspect, this research shows that isobutyrate-rich waste streams have a noteworthy PHA-producing potential. The main finding is that the dominant microorganism, a Comamonas sp., is linked to the production of a unique PHA family member, poly(3-hydroxyisobutyrate) (PHiB), up to 37% of the cell dry weight. This is the first scientific report identifying microbial PHiB production, demonstrating that mixed microbial communities can be a powerful tool for discovery of new metabolic pathways and new types of polymers. Key points • PHiB production is a successful storage strategy in an isobutyrate-fed SBR • Isomers isobutyrate and butyrate reveal a very distinct PHA production behavior • Enrichments can be a tool for discovery of new metabolic pathways and polymers Graphical abstract

Isolation and Characterization of Biosurfactant-producing Alcaligenes sp. YLA11 and its Diesel Degradation Potentials

This study aimed to isolate and identify biosurfactant producing and diesel alkanes degrading bacteria. For this reason, bacteria isolated from the diesel contaminated site were screened for their potential to produce biosurfactants and degrade diesel alkanes. Primary selection of diesel degraders was carried out by using conventional enrichment culture technique where 12 bacterial strains were isolated based on their ability to grow on minimal media supplemented with diesel as sole carbon source, which was followed by qualitative screening methods for potential biosurfactant production. Isolate B11 was the only candidate that shows positive signs for drop collapse, foaming, haemolytic test, oil displacement of more than 22 ± 0.05 mm, and emulsification (E24) of 14 ± 0.30%. The effect of various culture parameters (incubation time, diesel concentration, nitrogen source, pH and temperature) on biodegradation of diesel was evaluated. The optimum incubation time was confirmed to be 120 days for isolates B11, the optimum PH was confirmed as 8.0 for the isolate, Similarly, the optimum temperature was confirmed as 35oC. In addition, diesel oil was used as the sole carbon source for the isolates. The favourable diesel concentration was 12.5 % (v/v) for the isolate. The isolate has shown degradative ability towards Tridecane (C13), dodecane, 2, 6, 10-trimethyl- (C15), Tetradecane (C14), 2,6,10-Trimethyltridecane (C16), Pentadecane (C15). It degraded between 0.27% - 9.65% individual diesel oil alkanes. The strain has exhibited the potential of degrading diesel oil n-alkanes and was identified as Alcaligenes species strain B11 (MZ027604) using the 16S rRNA sequencing.

Anaerobic biodegradation of chloroform and dichloromethane with a Dehalobacter enrichment culture

Chloroform (CF) and dichloromethane (DCM) are among the more commonly identified chlorinated aliphatic compounds found in contaminated soil and groundwater. Complete dechlorination of CF has been reported under anaerobic conditions by microbes that respire CF to DCM and others that biodegrade DCM. The objectives of this study were to ascertain if a commercially available bioaugmentation enrichment culture (KB-1® Plus CF) uses an oxidative or fermentative pathway for biodegradation of DCM; and to determine if the products from DCM biodegradation can support organohalide respiration of CF to DCM in the absence of an exogenous electron donor. In various treatments with the KB-1 ® Plus CF culture to which 14 C-CF was added, the predominant product was 14 CO 2 , indicating that oxidation is the predominant pathway for DCM. Recovery of 14 C-DCM when biodegradation was still in progress confirmed that CF first undergoes reductive dechlorination to DCM. 14 C-labeled organic acids, including acetate and propionate, were also recovered, suggesting that synthesis of organic acids provides a sink for the electron equivalents from oxidation of DCM. When the biomass was washed to remove organic acids from prior additions of exogenous electron donor and only CF and DCM were added, the culture completely dechlorinated CF. The total amount of DCM added was not sufficient to provide the electron equivalents needed to reduce CF to DCM. Thus, the additional reducing power came via the DCM generated from CF reduction. Nevertheless, the rate of CF consumption was considerably slower in comparison to treatments that received an exogenous electron donor. IMPORTANCE Chloroform (CF) and dichloromethane (DCM) are among the more commonly identified chlorinated aliphatic compounds found in contaminated soil and groundwater. One way to address this problem is to add microbes to the subsurface that can biodegrade these compounds. While microbes are known that can accomplish this task, less is known about the pathways used under anaerobic conditions. Some use an oxidative pathway, resulting mainly in carbon dioxide. Others use a fermentative pathway, resulting in formation of organic acids. In this study, a commercially available bioaugmentation enrichment culture (KB-1 ® Plus CF) was evaluated using carbon-14 labelled chloroform. The main product formed was carbon dioxide, indicating the use of an oxidative pathway. The reducing power gained from oxidation was shown to support reductive dechlorination of CF to DCM. The results demonstrate the potential to achieve full dechlorination of CF and DCM to nonhazardous products that are difficult to identify in the field.

Screening, Isolation and Characterization of dye degrading bacteria from textile dye effluents.

Textile dye industry waste is one among the foremost serious issues within the atmosphere. The dye wastes are severely harmful to surface water bodies. The dye degradation and decolorisation processes, that embody several physical and chemical strategies having inherent drawbacks, like cost accounting, economically impracticable (require additional energy and chemicals), unable to get rid of a number of the recalcitrant dyes and production of huge quantity of sludge that if not properly treated, successively will cause secondary pollution. So, biological degradation, being eco-friendly and cheap methodology, is taken into account as an efficient methodology for the removal of nephrotoxic radical dyes. Our present study was therefore aimed to isolate dyestuff decolorizing microorganism from dyeing industry effluent associate degreed to check their characteristics so as to use them as an economical bio agent for decolorizing and mineralizing nephrotoxic radical dyes.Various microorganism like Bacillus subtilis, Aeromonas hydrophila and Bacillus Cereus, fungi & actinomycetes are found to possess dye decolorizing activity. For the aim of finding out their characteristics, water sample was subjected to enrichment culture technique and then isolated on sterile nutrient agar plates containing 0.005%, 0.01%, and 1% of Congo red dye. The probable isolated organism from Congo red dye i.e. Pantoea agglomerans was found which can possess the ability to decolorize Congo red at lower concentration. The probable isolates obtained must be additional investigated relating to varied factors like dye degradation capability, media composition affecting dye degradation & mechanism of dye degrading activity.

Analysis of the Bioprotective Potential of Different Lactic Acid Bacteria Against Listeria monocytogenes in Cold-Smoked Sea Bass, a New Product Packaged Under Vacuum and Stored at 6 ± 2°C

The aim of the work was to monitor the presence of Listeria monocytogenes in cold-smoked fish products (trout, salmon, and sea bass) marketed in Italy. Cold-smoked sea bass is a new product that has not yet been commercialized and was collected from the production facility. Monitoring data have shown that cold-smoked products can be contaminated by L. monocytogenes, the presence of which has been highlighted mainly by enrichment culture (presence in 25 g). The isolated Listeria were serotyped and belonged mainly to low-virulence serotypes (1/2c), followed by serotypes 1/2a, 1/2b, and 4b. Furthermore, considering the ability of L. monocytogenes to grow in these products due to their chemical–physical characteristics (pH > 6.0, Aw > 0.97) and long shelf life at 4°C, an additional aim was to verify the activity of different bioprotective starters, including Lactilactobacillus sakei (LAK-23, Sacco srl, Via Alessandro Manzoni 29/A, 22071 Cadorago, CO, Italy), Carnobacterium spp., Lacticaseibacillus casei (SAL 106), and Lacticaseibacillus paracasei (SAL 211), in cold-smoked sea bass. All starters were bacteriocin producers. For this experiment, smoked sea bass samples were intentionally inoculated with a mixture of three different strains of L. monocytogenes and of each starter culture. After inoculation, the smoked sea bass were vacuum-packed and stored at 6 ± 2°C for 60 days, simulating the typical abuse storage temperature of markets and home refrigerators. At 0, 15, 30, 45, and 60 days, the sea bass samples were analyzed to evaluate the effectiveness of the starters against L. monocytogenes. Listeria monocytogenes growth was prevented only by the addition of the LAK-23 starter. Indeed, at the end of the shelf life, the amount of L. monocytogenes observed was similar to that in the inoculum. Consequently, the use of this starter can allow the inclusion of cold-smoked sea bass or smoked fish products in category 1.3 of Regolamento CE 2073/2005, which are products that do not support the growth of this microorganism. Finally, the activity of the LAK-23 starter did not produce an off flavor or off odor in the smoked sea bass.

Azospira inquinata sp. nov., a nitrate-reducing bacterium of the family Rhodocyclaceae isolated from contaminated groundwater

Two novel Gram-stain-negative bacterial strains, Azo-3T and Azo-2, were isolated from a toluene-producing enrichment culture that originated from contaminated groundwater at a site in southeast Louisiana (USA). Cells are non-spore forming straight to curved rods with single polar flagella. Strains Azo-3T and Azo-2 are oxidase-positive, catalase-negative, use nitrate and nitrite as electron acceptors, and are able to fix nitrogen. Poly-β-hydroxybutyrate storage granules are produced. Dominant fatty acids when grown in R2A medium at 37 °C are C16:0, summed feature 3 (C16:1 ω7c and/or C15:0 iso 2OH), C17:0 cyclo and C18:1 ω7c. 16S rRNA gene sequence based phylogenetic analysis indicated that the strains cluster within the family Rhodocyclaceae , class Betaproteobacteria , most closely related to but distinct from type strains of the species Azospira oryzae (96.94% similarity) and Azospira restricta (95.10% similarity). Complete genome sequences determined for strains Azo-3T and Azo-2 revealed DNA G+C content of 62.70 mol%. Genome-wide comparisons based on average nucleotide identity by orthology and estimated DNA–DNA hybridization values combined with phenotypic and chemotaxonomic traits and phylogenetic analysis indicate that strains Azo-3T and Azo-2 represent a novel species within the genus Azospira for which the name Azospira inquinata sp. nov. is proposed. The type strain of Azospira inquinata is Azo-3T (=NRRL B-65590T=DSM 112046T).

Dehalobium species implicated in 2,3,7,8-tetrachloro-p-dioxin dechlorination in the contaminated sediments of Sydney Harbour Estuary

Polychlorinated dibenzo-p-dioxins and furans (PCDD/F) are some of the most environmentally recalcitrant and toxic compounds. They are naturally occurring and by-products of anthropogenic activity. Sydney Harbour Estuary (Sydney, Australia), is heavily contaminated with PCDD/F. Analysis of sediment cores revealed that the contamination source in Homebush Bay continues to have one of the highest levels of PCDD/F contamination in the world (5207 pg WHO-TEQ g-1) with >50% of the toxicity attributed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) the most toxic and concerning of the PCDD/F congeners. Comparison of congener profiles at the contamination source with surrounding bays and historical data provided evidence for the attenuation of 2,3,7,8-TCDD and other congeners at the source. This finding was supported by the detection of di-, mono- and unchlorinated dibenzo-p-dioxin. Microbial community analysis of sediments by 16S amplicon sequencing revealed an abundance of lineages from the class Dehalococcoidia (up to 15% of the community), including the genus Dehalobium (up to 0.5%). Anaerobic seawater enrichment cultures using perchloroethene as a more amenable growth substrate enriched only the Dehalobium population by more than six-fold. The enrichment culture then proved capable of reductively dechlorinating 2,3,7,8-TCDD to 2,3,7-TCDD and octachlorodibenzo-p-dibenzodioxin to hepta and hexa congeners. This work is the first to show microbial reductive dehalogenation of 2,3,7,8-TCDD with a bacterium from outside the Dehalococcoides genus, and one of only a few that demonstrates PCDD/F degradation in a marine environment.