Bioenergetics of simultaneous oxygen and nitrate respiration and nitric oxide production in a agar colony biofilm.

is a biofilm forming pathogen commonly associated with infection of the cystic fibrosis (CF) lung, chronic wounds and indwelling medical devices. is a facultative aerobe that can use nitrate (NO) found in healthy and infected tissues and body fluids to generate energy through denitrification. Further, the expression of denitrification genes has been found in specimens from people with CF.

Nitrate respiration occurs throughout the depth of mucoid and non-mucoid Pseudomonas aeruginosa submerged agar colony biofilms including the oxic zone.

Pseudomonas aeruginosa is an opportunistic pathogen and well characterized biofilm former. P. aeruginosa forms strong oxygen gradients inside biofilms due to rapid oxygen respiration in the top layers and the poor solubility of oxygen coupled with diffusion limited transport.

Calculating expected effects of treatment effectivity and river flow rates on the contribution of WWTP effluent to the ARG load of a receiving river.

Concentrations of genetic markers for antibiotic resistance genes (ARGs) were measured in the effluents of three Norwegian wastewater treatment plants (WWTPs) and in a receiving river upstream and downstream of the discharge point of one WWTP. Calculations based on mass balances were carried out to evaluate the impact of river flow rates and treatment effectivity on the WWTP's contribution to the load of genetic markers in the river. At average river flow rates, the WWTP effluent contributes 5-15% to the genetic marker load of the respective river.

A global multinational survey of cefotaxime-resistant coliforms in urban wastewater treatment plants.

The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this transnational study, we developed, validated, and tested a low-cost surveillance and easy to implement approach to evaluate antibiotic resistance in wastewater treatment plants (WWTPs) by targeting cefotaxime-resistant (CTX-R) coliforms as indicators.

Antibiotic resistance genes in treated wastewater and in the receiving water bodies: A pan-European survey of urban settings.

There is increasing public concern regarding the fate of antibiotic resistance genes (ARGs) during wastewater treatment, their persistence during the treatment process and their potential impacts on the receiving water bodies. In this study, we used quantitative PCR (qPCR) to determine the abundance of nine ARGs and a class 1 integron associated integrase gene in 16 wastewater treatment plant (WWTP) effluents from ten different European countries. In order to assess the impact on the receiving water bodies, gene abundances in the latter were also analysed.

Removal of antibiotic resistant E. coli in two Norwegian wastewater treatment plants and by nano- and ultra-filtration processes.

The effectivity of different treatment stages at two large wastewater treatment plants (WWTPs) located in Oslo, Norway, to remove antibiotic resistant Escherichia coli from municipal wastewater was investigated. The WWTPs were effective in reducing the total cultivable E. coli.

High Throughput Analysis of Integron Gene Cassettes in Wastewater Environments.

Integrons are extensively targeted as a proxy for anthropogenic impact in the environment. We developed a novel high-throughput amplicon sequencing pipeline that enables characterization of thousands of integron gene cassette-associated reads, and applied it to acquire a comprehensive overview of gene cassette composition in effluents from wastewater treatment facilities across Europe. Between 38 100 and 172 995 reads per-sample were generated and functionally characterized by screening against nr, SEED, ARDB and β-lactamase databases.

Effect of nitrate on sulfur transformations in sulfidogenic sludge of a marine aquaculture biofilter.

The effect of NO(3)(-) addition on dissimilatory SO(4)(2-) reduction and sulfide conversion in organic-rich sludge from the digestion basin of a recirculating marine aquaculture system was studied. SO(4)(2-) reduction could only explain a minor fraction (up to 4-9%) of the observed total sulfide production (up to 35 mmol L(-1) day(-1)), indicating that the main source of sulfide in the sludge was not SO(4)(2-) reduction, but desulfuration during the decomposition of organic matter. Although NO(3)(-) inhibited SO(4)(2-) reduction, but not desulfuration, the primary NO(3)(-) mitigation effect was the onset of NO(3)(-)-mediated sulfide oxidation (up to 75 mmol L(-1) day(-1)), partially to elemental sulfur (S(0)).

Sulfide-induced nitrate reduction in the sludge of an anaerobic digester of a zero-discharge recirculating mariculture system.

The anaerobic digester is a vital component in a zero-discharge mariculture system as therein most of the organic matter is mineralized and nitrogen-containing compounds are converted to gaseous N(2). Although denitrification is a major respiratory process in this nitrate-rich treatment stage, also sulfate respiration takes place and may cause undesirable high sulfide concentrations in the effluent water. To examine the effect of sulfide on nitrate reduction, in situ depth profiles of inorganic nitrogen and sulfur compounds were determined.

Impact of nitrate on the structure and function of bacterial biofilm communities in pipelines used for injection of seawater into oil fields.

We studied the impact of NO(3)(-) on the bacterial community composition, diversity, and function in in situ industrial, anaerobic biofilms by combining microsensor profiling, (15)N and (35)S labeling, and 16S rRNA gene-based fingerprinting. Biofilms were grown on carbon steel coupons within a system designed to treat seawater for injection into an oil field for pressurized oil recovery. NO(3)(-) was added to the seawater in an attempt to prevent bacterial H(2)S generation and microbially influenced corrosion in the field.

Nitrosomonas Nm143-like ammonia oxidizers and Nitrospira marina-like nitrite oxidizers dominate the nitrifier community in a marine aquaculture biofilm.

Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated with a recirculating marine aquaculture system are presented.