Antibiotic resistant bacteria and resistance genes in biofilms in clinical wastewater networks

Increasing isolation rates of resistant bacteria in the last years require identification of potential infection reservoirs in healthcare facilities. Especially the clinical wastewater network represents a potential source of antibiotic resistant bacteria. In this work, the siphons of the sanitary installations from 18 hospital rooms of two German hospitals were examined for antibiotic resistant bacteria and antibiotic residues including siphons of showers and washbasins and toilets in sanitary units of psychosomatic, haemato-oncological, and rehabilitation wards. In addition, in seven rooms of the haemato-oncological ward, the effect of 24 h of stagnation on the antibiotic concentrations and MDR (multi-drug-resistant) bacteria in biofilms was evaluated. Whereas no antibiotic residues were found in the psychosomatic ward, potential selective concentrations of piperacillin, meropenem and ciprofloxacin were detected at a rehabilitation ward and ciprofloxacin and trimethoprim were present at a haemato-oncology ward. Antibiotic resistant bacteria were isolated from the siphons of all wards, however in the psychosomatic ward, only one MDR strain with resistance to piperacillin, third generation cephalosporins and quinolones (3MRGN) was detected. In contrast, the other two wards yielded 11 carbapenemase producing MDR isolates and 15 3MRGN strains. The isolates from the haemato-oncological ward belonged mostly to two specific rare sequence types (ST) (P. aeruginosa ST823 and Enterobacter cloacae complex ST167). In conclusion, clinical wastewater systems represent a reservoir for multi-drug-resistant bacteria. Consequently, preventive and intervention measures should not start at the wastewater treatment in the treatment plant, but already in the immediate surroundings of the patient, in order to minimize the infection potential.     

Evaluation of genotoxicity potential of household effluents from onsite wastewater treatment systems using umu test

ABSTRACT

Household effluents are predominantly treated by wastewater treatment plants (WWTPs). Other treatment methods, which were examined in this study, are also used in the countryside. These treatment modes include (1) onsite toilet wastewater treatment system (OTWTS), (2) onsite wastewater treatment system (OWTS), (3) community wastewater treatment system (CWTS), and (4) onsite vault toilet (OVT). Household effluents consist of excrements and urine released from toilets as well as wastewater released from kitchens and bathrooms. In the present study, household effluents that were discharged from the residential areas having undergone similar treatment methodologies were compared using the umu test, an in vitro bioassay to assess genotoxicity potential. The different treatment methodologies were categorized based upon whether the two kinds of wastewater were mixed or not mixed and treated or not treated. Treated wastewater containing excrements and urine from the OTWTS exhibited the strongest genotoxicity potential compared to other effluents, whereas most of the kitchen and bathroom wastewater from OVT did not display genotoxicity. Data indicated that the genotoxicants in the effluents originated primarily from excrements and urine, and may increase an adverse environmental risk.     

Penta-block copolymer microspheres: Impact of polymer characteristics and process parameters on protein release

Here, we aimed to develop protein loaded microspheres (MSs) using penta-block PLGA-based copolymers to obtain sustained and complete protein release. We varied MS morphology and studied the control of protein release. Lysozyme was used as a model protein and MSs were prepared using the solid-in-oil-in-water emulsion solvent extraction method. We synthesized and studied various penta-block PLGA-based copolymers. Copolymer characteristics (LA/GA ratio and molecular weight of PLGA blocks) influenced MS morphology. MS porosity was influenced by process parameters (such as solvent type, polymer concentration, emulsifying speed), whereas the aqueous volume for extraction and stabilizer did not have a significant effect. MSs of the same size, but different morphologies, exhibited different protein release behavior, with porous structures being essential for the continuous and complete release of encapsulated protein. These findings suggest strategies to engineer the morphology of MSs produced from PLGA-based multi-block copolymers to achieve appropriate release rates for a protein delivery system.     

基于污水流行病学的广州和珠海4种心血管药物消费量的估算研究

目的了解广州和珠海城市污水处理厂进水中的4种心血管药物浓度,并对其消费量进行估算。方法分别于2017年5月9至22日(春季)和9月27日至10月12日(秋季)采集广州1座污水厂进水水样,2017年1月23日至2月5日(冬季)采集珠海1座污水厂进水水样,采用固相萃取-液相色谱-串联质谱法检测美托洛尔(MET)、阿替洛尔(ATE)、吉非罗齐(GFB)、苯扎贝特(BZB)的浓度,应用污水流行病学方法估算4种心血管药物在广州和珠海的消费量。结果 4种心血管药物均有检出,浓度范围在未检出~889.73 ng/L之间,检出率在14.29%~100%之间。在4种心血管药物中,以MET和BZB浓度较高,其最高浓度分别达733.71和889.73 ng/L。与珠海市比较,广州市污水厂进水中MET、BZB、GFB的浓度较高,差异均有统计学意义(P<0.01);而ATE的浓度无明显差异。不论在广州市还是珠海市,MET的消费量均远高于BZB、GFB、ATE,4种药物在两城市的消费模式均为MET>BZB>GFB>ATE。与珠海市比较,广州市MET、BZB、GFB消费量较高,差异均有统计学意义(P<0.01);而ATE的消费量无明显差异。不论是春季还是秋季,MET均为消费量最高的药物,ATE均为消费量最低的药物。与春季比较,秋季ATE的消费量较低,差异有统计学意义(P<0.01);而MET、BZB、GFB无明显改变。结论不同地区的心血管药物消费存在较大差异,广州市的MET、BZB、GFB、ATE消费量高于珠海。     

Neuroprotective effect of gold nanoparticles composites in Parkinson's disease model

Parkinson’s disease (PD) is second most common neurodegenerative disorder worldwide. Although drugs and surgery can relieve the symptoms of PD, these therapies are incapable of fundamentally treating the disease. For PD patients, over-expression of α-synuclein (SNCA) leads to the death of dopaminergic neurons. This process can be prevented by suppressing SNCA over-expression through RNA interference. Here, we successfully synthesized gold nanoparticles (GNP) composites (CTS@GNP-pDNA-NGF) via the combination of electrostatic adsorption and photochemical immobilization, which could load plasmid DNA (pDNA) and target specific cell types. GNP was transfected into cells via endocytosis to inhibiting the apoptosis of PC12 cells and dopaminergic neurons. Simultaneously, GNP composites are also used in PD models in vivo, and it can successfully cross the blood-brain barrier by contents of GNP in the mice brain. In general, all the works demonstrated that GNP composites have good therapeutic effects for PD models in vitro and in vivo.     

Effect of salinity variations on the performance of activated sludge system

Objective To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC),oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. Results The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/t, and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. Conclusion The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.     

Potential impact of the sewer system on the applicability of alcohol and tobacco biomarkers in wastewater‐based epidemiology

Understanding the actual consumption of alcohol and tobacco in the population is important for forming public health policy. For this purpose, wastewater‐based epidemiology has been applied as a complementary method to estimate the overall alcohol and tobacco consumption in different communities. However, the stability of their consumption biomarkers – ethyl sulfate, ethyl glucuronide, cotinine, and trans‐3′‐hydroxycotinine – in the sewer system has not yet been assessed. This study aimed to conduct such assessment using sewer reactors mimicking conditions of rising main, gravity sewer, and wastewater alone, over a 12‐hour period. The results show that cotinine and trans‐3′‐hydroxycotinine are relatively stable under all sewer conditions while ethyl sulfate was only stable in wastewater alone and gradually degraded in rising main and gravity sewer conditions. Ethyl glucuronide quickly degraded in all reactors. These findings suggest that cotinine and trans‐3′‐hydroxycotinine are good biomarkers to estimate tobacco consumption; ethyl sulfate may be used as a biomarker to estimate alcohol consumption, but its in‐sewer loss should be accounted for in the calculation of consumption estimates. Ethyl glucuronide, and probably most of glucuronide compounds, are not suitable biomarkers to be used in wastewater‐based epidemiology due to their in‐sewer instability.     

Two-stage vertical flow multi-soil-layering (MSL) technology for efficient removal of coliforms and human pathogens from domestic wastewater in rural areas under arid climate

This paper investigates the removal efficiency of organic matter, nitrogen, phosphorus, coliforms and pathogens from rural domestic wastewater in a two-stage vertical flow multi-soil-layering (MSL) system. The effects of wastewater quality, season and arid climate conditions on pollutants removal efficiency by the system were examined for one year. The experimental setup included two similar MSL systems composed of two layers: soil-mixture-layers (SML) and gravel permeable layers (PL) that are arranged in a brick like pattern. The applied hydraulic loading rate was 1000 L m^?2 day^?1. Results showed that most of the physicochemical contaminants elimination occurred while the wastewater percolated through the first MSL stage. The second stage demonstrated an improvement in the reduction of all pollutants, especially fecal bacteria indicators and pathogens. The mean overall removal rates performed by the two-stage MSL system were 97% for TSS, 96% for BOD₅, 91% for COD, 96% for TN and 95% for TP. For bacterial indicators, the combination of two-stage MSL system achieved high log removals between 2.21 and 3.15 log units. Contaminants reduction processes in MSL technology are more dependent on internal than external environmental factors. The effectiveness of the two-stage MSL system to treat domestic wastewater was strongly influenced by wastewater quality. Significant relationships between influent contaminants level and their removal efficiency were found. The efficiency of MSL technology to reduce contaminants is not sensitive to season and air temperature fluctuations. This is due to the capacity of MSL system materials to withstand the air temperature variation, which highlights one of the advantages of MSL’s technology. Wastewater quality is the most important factor affecting the removal of contaminants in the MSL, which could be a critical parameter to considered when designing MSL system. Two-stage MSL system achieved a high treated wastewater quality amenable for treated wastewater reuse in agriculture recommended by Moroccan code of practice. Therefore, the combination of two-stage vertical flow MSL system could be considered an efficient and promising domestic wastewater treatment solution in arid countries to promote environmental protection and wastewater reuse.