An integrated appraisement of multiple faecal indicator bacteria and sterols in the detection of sewage contamination in subtropical tidal creeks

The quality of water bodies has been regulated by national environmental agencies and based on faecal indicator bacteria, such as thermotolerant coliforms Escherichia coli and Enterococcus sp. Additionally, faecal sterols (mainly coprostanol) have been used to corroborate sewage discharge in marine environments. In this study, faecal material input was evaluated in two sampling campaigns in transects of two tidal creeks using bacterial and chemical indicators to both compare and establish the water quality in a South Atlantic subtropical estuary. The Itiberê tidal creek (S1) was classified as “contaminated” by faecal material, while the Peças tidal creek (S2) presented variable water quality according to the sampling period and sewage indicators considered in this evaluation. Then, the integrated application of chemical and bacterial indicators was applied for tidal creeks with different sewage contamination levels and under distinct environmental conditions and confirmed that Enterococcus sp. and coprostanol are the most suitable for estuarine environments.     

Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality

Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014–2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks.     

Escherichia coli pollution in a Baltic Sea lagoon: A model-based source and spatial risk assessment

Tourism around the Oder (Szczecin) Lagoon, at the southern Baltic coast, has a long tradition, is an important source of income and shall be further developed. Insufficient bathing water quality and frequent beach closings, especially in the Oder river mouth, hamper tourism development. Monitoring data gives only an incomplete picture of Escherichia coli (E. coli) bacteria sources, spatial transport patterns, risks and does neither support an efficient bathing water quality management nor decision making. We apply a 3D ocean model and a Lagrangian particle tracking model to analyse pollution events and to obtain spatial E. coli pollution maps based on scenario simulations. Model results suggests that insufficient sewage treatment in the city of Szczecin is the major source of faecal pollution, even for beaches 20 km downstream. E. coli mortality rate and emission intensity are key parameters for concentration levels downstream. Wind and river discharge play a modifying role. Prevailing southwestern wind conditions cause E. coli transport along the eastern coast and favour high concentration levels at the beaches. Our simulations indicate that beach closings in 2006 would not have been necessary according to the new EU-Bathing Water Quality Directive (2006/7/EC). The implementation of the new directive will, very likely, reduce the number of beach closings, but not the risk for summer tourists. Model results suggest, that a full sewage treatment in Szczecin would allow the establishment of new beaches closer to the city (north of Dabie lake).     

Evaluation of the microbial risk reduction due to selective closure of the raw water intake before drinking water treatment

Short-term peaks in pathogen concentrations may increase the risks for waterborne diseases considerably. In this study the occurrence of indicator organisms and pathogens in the river G?ta ?lv at the raw water intake to G?teborg was evaluated and related to risk for drinking water consumption. About half of the 24 pathogen samples, taken during event and non-event conditions, were positive for at least one of the following: Cryptosporidium, Giardia, norovirus, enterovirus, Campylobacter and E. coli O157. Positive pathogen detects were often associated with heavy rainfalls and viruses with a sewage emergency discharge. The annualised probability of infection from this type of event was calculated from pathogen concentrations in a QMRA model. Given that the water intake is not closed, the risk given present water treatment seems to be acceptable for Giardia; however, it is at a borderline for Cryptosporidium and insufficient for noro- and enteroviruses. Present results emphasise the need for an appropriate intake regulation with respect to high pathogen loads, as the risk increases with time of exposure to pathogen contaminants. Rather than a threshold level on E. coli, reports on upstream microbial discharges are valuable for quick pathogen indications.     

Sewage sludge and liquid pig manure as possible sources of antibiotic resistant bacteria

Within the last decades, the environmental spread of antibiotic resistant bacteria has become a topic of concern. In this study, liquid pig manure (n=305) and sewage sludge (n=111) - used as agricultural fertilizers between 2002 and 2005 - were investigated for the presence of Escherichia coli, Enterococcus faecalis and Enterococcus faecium. Bacteria were tested for their resistance against 40 chemotherapeutics including several “reserve drugs”. E. coli (n=613) from pig manure were at a significantly higher degree resistant to streptomycin, doxycycline, spectinomycin, cotrimoxazole, and chloramphenicol than E. coli (n=116) from sewage sludge. Enterococci (Ent. faecalis, n=387, and Ent. faecium, n=183) from pig manure were significantly more often resistant to high levels of doxycycline, rifampicin, erythromycin, and streptomycin than Ent. faecalis (n=44) and Ent. faecium (n=125) from sewage sludge. Significant differences in enterococcal resistance were also seen for tylosin, chloramphenicol, gentamicin high level, fosfomycin, clindamicin, enrofloxacin, moxifloxacin, nitrofurantoin, and quinupristin/dalfopristin. By contrast, aminopenicillins were more effective in enterococci from pig manure, and mean MIC-values of piperacillin+tazobactam and third generation cefalosporines were significantly lower in E. coli from pig manure than in E. coli from sewage sludge. 13.4% (E. coli) to 25.3% (Ent. faecium) of pig manure isolates were high-level multiresistant to substances from more than three different classes of antimicrobial agents. In sewage sludge, high-level-multiresistance reached from 0% (Ent. faecalis) to 16% (Ent. faecium). High rates of (multi-) resistant bacteria in pig manure emphasize the need for a prudent - cautious - use of antibiotics in farm animals.     

Contamination of potable water by enterotoxigenic Escherichia coli: qPCR based culture-free detection and quantification

Tourists visiting to endemic zones may acquire Enterotoxigenic Escherichia coli (ETEC) infection resulting into diarrhea due to consumption of contaminated potable waters. In this study, a qPCR assay (SYBR Green), targeting LT1 and ST1 genes was designed to quantify ETEC in potable waters derived from civic water supply. The assay could detect lowest 1 CFU/PCR targeting LT1/ST1 gene from ten-fold diluted culture of the reference strain (E. coli MTCC 723) and is ten-fold more sensitive than the conventional PCR. The quantification of the ETEC in potable waters collected from civic supply of a major city of the northern India exhibiting high flow of tourists reveals that all the sites that ran along sewage line were contaminated by the ETEC. Contamination was due to percolation of sewage. The assay could be used for the regular monitoring of potable water in places exhibiting heavy flow of tourists to prevent ETEC induced diarrhea.     

Human and animal microbial source tracking in a tropical river with multiple land use activities

The enhancement and restoration of the water quality of deteriorating surface water resources can be challenging, particularly for rivers with multiple usages, such as agriculture, animal husbandry, human residence, and industries. Recently, the performance of DNA-based microbial source tracking (MST) indicators detected by end-point and quantitative PCR assays for identifying sources of fecal pollution from human sewage, swine, and cattle and non-host-specific (universal) fecal pollution in the Tha Chin River basin, Thailand, was evaluated. The present study monitored these validated MST markers and various physicochemical and microbial water quality parameters in samples collected from twelve stations along the Tha Chin River during four sampling events in the wet and dry seasons. No significant difference in precipitation was observed between the wet and dry samplings. Universal markers (both PCR and qPCR) were detected in all 48 samples, indicating persistent and continuing fecal contamination. The sewage- and swine-specific qPCR marker concentrations did not vary among the sampling events, whereas cattle-specific qPCR markers were detected only in the wet season. Animal-specific markers were detected in the lower Tha Chin River section, which is characterized by intensive animal farming. Sewage-specific markers were also found in the lower section and near an upstream residential area. The high agreement (87.5–100%) between the PCR and qPCR results suggested that PCR could serve as a lower-cost MST screening test that requires less technical expertise. A multivariate analysis conducted using the survival analysis procedure to include censored data also emphasized the high pollution in the lower section of the river at all sampling events. Universal and swine-specific markers showed moderate correlations with microbial indicators, including total coliforms, fecal coliforms, E. coli, and enterococci. None of the MST markers or microbial parameters were associated with the measured physicochemical parameters. This study provides the first evaluation of MST markers for monitoring surface freshwater in Thailand, and the findings might aid the pollution surveillance of impaired water bodies and the development of strategies for improving their water quality.     

Meeting Report: Risk Assessment of Tamiflu Use Under Pandemic Conditions

On 3 October 2007, 40 participants with diverse expertise attended the workshop Tamiflu and the Environment: Implications of Use under Pandemic Conditions to assess the potential human health impact and environmental hazards associated with use of Tamiflu during an influenza pandemic. Based on the identification and risk-ranking of knowledge gaps, the consensus was that oseltamivir ethylester-phosphate (OE-P) and oseltamivir carboxylate (OC) were unlikely to pose an ecotoxicologic hazard to freshwater organisms. OC in river water might hasten the generation of OC-resistance in wildfowl, but this possibility seems less likely than the potential disruption that could be posed by OC and other pharmaceuticals to the operation of sewage treatment plants. The work-group members agreed on the following research priorities: a) available data on the ecotoxicology of OE-P and OC should be published; b) risk should be assessed for OC-contaminated river water generating OC-resistant viruses in wildfowl; c) sewage treatment plant functioning due to microbial inhibition by neuraminidase inhibitors and other antimicrobials used during a pandemic should be investigated; and d) realistic worst-case exposure scenarios should be developed. Additional modeling would be useful to identify localized areas within river catchments that might be prone to high pharmaceutical concentrations in sewage treatment plant effluent. Ongoing seasonal use of Tamiflu in Japan offers opportunities for researchers to assess how much OC enters and persists in the aquatic environment.     

Cholera studies. 3. Bacteriology

The morphological characteristics, biochemical properties, and cultural characteristics of V. cholerae are described in great detail in this study. The author also discusses the resistance of the organism to temperature, humidity, sunlight, and various chemicals, as well as the viability of V. cholerae outside the body (in faeces, contaminated material, food, beverages, water, etc.).     

城镇污水综合处理卫生学指标评价

目的观察城镇污水处理厂污水处理前后微生物数值变化,分析对环境的影响,探讨排放标准.方法定点定时采集污水源水和经处理后的出厂水,按国家规定的方法检测细菌和病毒,同时收集理化指标检测数据.结果出厂水菌落总数高达720000cfu/L总大肠菌群和粪大肠菌群＞16000个/L;源水肠道病毒阳性率为58.33%出厂水肠道病毒阳性率为16.67%.结论理化指标处理效果较好,细菌、病毒处理效果较差,应加强对城镇污水综合处理厂出厂水有关标准的研究.     

Microbial contamination of drinking water at the source and household storage level in the peri-urban area of southern Chennai and its implication on health, India

Aim

Microbial contamination of drinking water at the water source and household storage is the prime reason for the diarrheal prevalence in the developing counties. The goal of the study is to assess the microbial quality of household stored drinking water and its implication on health, particularly diarrhea.

Subjects and methods

To assess the microbial contamination of drinking water in Pallikaranai panchayat union located in southern Chennai, the samples were collected from seven source wells, at the point of distribution and from the household storage for 1–5 days. Total coliform and E. coli are analysed as it is the main indicator of microbial contamination. Most probable number and standard spread-plate method were used to enumerate the total coliform and E. coli bacteria respectively. Data on diarrheal disease were obtained from 290 children, and information on the source of water, household storage vessels and water treatment adopted by the household with recall period of 2 weeks was collected. The study was conducted in 2010 and 2012.

Results

The E. coli and total coliform were detected at the source level and the colony counts were increased gradually at the point of distribution and at the place of household storage. The analysis revealed that out of 26.2 % of respondents depending on the piped water supply, 22.3 % were affected with the diarrheal disease.

Conclusion

Household storage water is more contaminated than the piped water, indicating that interventions are needed to decrease the contamination of water at the place of household storage. The appropriate intervention for the low income category is chlorination and improving personal hygiene behaviour in regards to household water storage.     

Culture-free detection and enumeration of STEC in water

Shiga toxin-producing Escherichia coli (STEC) causes worldwide outbreaks of food and waterborne diseases. Rapid identification of causative agents is critical for early intervention in the case of widespread diarrheal epidemics to prevent mortality. In this study, a Molecular-Beacon targeting stx2 gene (highly associated with human illness) was designed to develop a culture-independent real-time PCR assay for detection and quantification of STEC in water samples. The assay could detect lowest 10 genomic equivalent (GE) of the reference strain (E. coli I.T.R.C.-18) per PCR or 100 GE/mL. The presence of 10⁶ CFU/mL of non-pathogenic E. coli DH5α has no impact on sensitivity of the assay. The assay could successfully enumerate STEC in surface water (collected from a sewage impacted river) and potable water samples collected from Lucknow city without prior enrichment. The assay will be useful in pre-emptive monitoring of surface/potable waters to prevent waterborne outbreaks caused by STEC.     

Factors associated with post-treatment E. coli contamination in households practising water treatment: a study of rural Cambodia

The purpose of this study was to assess factors associated with Escherichia coli (E. coli) contamination in rural households in Cambodia that have adopted household water treatment. The following factors were significantly associated (α < 0.05) with apparent E. coli contamination: cleaning the drinking vessel with untreated water, not drying the cup (with a cloth), accessing treated water by the use of a scoop (ref: using a tap), having more than one untreated water storage container, having an untreated water storage container that appeared dirty on the outside, and cows living within 10 m of the household. This study provides further evidence confirming previous studies reporting an association between inadequate cleanliness of water storage containers and household drinking water contamination, and identifies practical recommendations statistically associated with reduced post-treatment E. coli contamination in the household setting in rural Cambodia.     

Development of a relative risk model for drinking water regulation and design recommendations for a peri urban region of Argentina

Argentina is a developing Latin American nation that has an aim of achieving the United Nations Millennium Development Goals for potable water supplies. Their current regulations however, limit the continued development of improved potable water quality and infrastructure from a microbiological viewpoint. This is since the current regulations are focused solely to pathogenic Eschericia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and fecal indicators. Regions of lower socioeconomic status such as peri-urban areas are particularly at risk due to lessened financial and political ability to influence their environmental quality and infrastructure needs. Therefore, a combined microbiological sampling, analysis and quantitative microbial risk assessment (QMRA) modeling effort were engaged for a peri-urban area of Salta Argentina. Drinking water samples from home taps were analyzed and a QMRA model was developed, results of which were compared against a general 1:10,000 risk level for lack of a current Argentinian standard. This QMRA model was able to demonstrate that the current regulations were being achieved for E. coli but were less than acceptable for P. aeruginosa in some instances. Appropriate health protections are far from acceptable for Giardia for almost all water sources. Untreated water sources were sampled and analyzed then QMRA modeled as well, since a significant number of the community (∼9%) still use them for potable water supplies. For untreated water E. coli risks were near 1:10,000, however, P. aeruginosa and Giardia risks failed to be acceptable in almost all instances. The QMRA model and microbiological analyses demonstrate the need for improved regulatory efforts for the peri-urban area along with improved investment in their water infrastructure.     

Water quality at points-of-use in the Galapagos Islands

Piped drinking water is often considered a gold standard for protecting public health but research is needed to explicitly evaluate the effect of centralized treatment systems on water quality in developing world settings. This study examined the effect of a new drinking water treatment plant (DWTP) on microbial drinking water quality at the point-of-use on San Cristobal Island, Galapagos using fecal indicator bacteria total coliforms and Escherichia coli. Samples were collected during six collection periods before and after operation of the DWTP began from the freshwater sources (n = 4), the finished water (n = 6), and 50 sites throughout the distribution system (n = 287). This study found that there was a significant decrease in contamination by total coliforms (two orders of magnitude) and E. coli (one order of magnitude) after DWTP operation began (p < 0.001). However, during at least one post-construction collection cycle, total coliforms and E. coli were still found at 66% and 28% of points-of-use (n = 50), respectively. During the final collection period, conventional methods were augmented with human-specific Bacteroides assays – validated herein – with the goal of elucidating possible microbial contamination sources.Results show that E. coli contamination was not predictive of contamination by human wastes and suggests that observed indicator bacteria contamination may have environmental origins. Together these findings highlight the necessity of a holistic approach to drinking water infrastructure improvements in order to deliver high quality water through to the point-of-use.     

Sanitary-hygienic assessment of microbial biofertilizer]

Biological treatment of sewage from pig-breeding complexes allowed to produce microbial biomass and primary sediments. The mixture of these components (1:1) after rendering harmless and drying out become the high effective biofertilizer. The results of chronic experiment on sanitary status of soil (microbial and helminthological indexes) under this biofertilizer usage are discussed, and the harmlessness of it is demonstrated.     

Influence of sewage and pharmaceuticals on soil microbial function

Although sewage effluent application to land is a common approach to recycle water and provide nutrients to plants, bioactive pharmaceuticals contained in sewage may change soil quality by affecting soil microbial communities. Establishing causal effects, however, is difficult, because trace levels of pharmaceuticals are confounded with other effluent constituents. Therefore, two originally similar soil microbial communities, one irrigated in situ with sewage effluent for 12 years and another nonirrigated, were exposed to high levels of acetaminophen, aspirin, carbamazepine, chlorpromazine, and tetracycline. The objectives of the current study were to determine the influence of high levels of pharmaceuticals on several soil microbial properties, the effect that prolonged effluent irrigation with ambient levels of pharmaceuticals had on soil microbial function, and how this effect would change in response to pharmaceutical exposure. Several pharmaceuticals, at high exposure levels, imposed stress on the soil microbial community as judged by increased CO(2) respiration, decreased biomass carbon, and altered substrate utilization affinities. Prolonged effluent irrigation, which altered the genetic fingerprint of the microbial community, also mitigated the response that exposure to pharmaceuticals had on the microbial community and enabled degradation of the antimicrobial salicylic acid after aspirin exposure. In conclusion, prolonged irrigation with sewage effluent containing pharmaceuticals at ambient levels influenced the microbial community so that they were able to better cope with sudden exposure to high levels of pharmaceuticals.     

Spray dried human and chimpanzee adenoviral-vectored vaccines are thermally stable and immunogenic in vivo

Cold chain-free vaccine technologies are needed to ensure effective vaccine delivery and coverage, particularly in resource-poor countries. However, the immunogenicity and thermostability of spray dried live viral vector-based vaccines such as recombinant adenoviral-vectored vaccines remain to be investigated. To address this issue, we have spray dried human adenoviral (AdHu5)- and chimpanzee adenoviral (AdCh68)-vectored tuberculosis vaccines in a mannitol and dextran matrix. Spray dried powders containing these two vaccines display the morphologic and chemical properties desired for long-term thermostability and vaccination. Upon reconstitution, they effectively transfected the cells in vitro with relatively small losses in viral infectivity related to the spray drying process. Following in vivo vaccination, AdHu5- and AdCh68-vectored vaccines were as immunogenic as the conventional fresh, cryopreserved liquid vaccine samples. Of importance, even after cold chain-free storage, at ambient temperatures and relatively low humidity for 30 and 90 days, the vaccines retained their in vivo immunogenicity, while the liquid vaccine samples stored under the same conditions lost their immune-activating capability almost entirely. Our results support further development of our spray drying technologies for generating thermally stable adenoviral-vectored and other viral-vectored vaccines.     

不同手卫生方式及干手措施对手卫生效果的影响

 

目的 调查不同手卫生方式和干手措施对手卫生效果的影响,提高手卫生质量。方法 选择河南省8所哨点医院不同科室的医务人员为调查对象。观察医护人员手卫生方式及干手措施,比较不同手卫生方式及干手措施的手卫生微生物检测合格率。结果 共调查医护人员699人次,执行手卫生者572人次,手卫生依从率为81.83%。洗手是最常用的手卫生措施,占39.34%。监测结果显示,采用速干手消毒剂进行卫生手消毒的合格率最高,为97.92%,不同手卫生方式的手卫生合格率比较,差异有统计学意义（χ²=20.203,P<0.001）。干手措施以自然风干为主（79.37%）,一次性纸巾、自动风干机和其他方式所占比率分别为14.69%、1.75%和4.20%。不同干手措施后的手卫生合格率比较,差异有统计学意义（P=0.013）。洗手组和先洗手后卫生手消毒组别中,均为使用一次性纸巾干手后的合格率最高,分别为80.70%、96.30%。结论 涂抹速干手消毒剂进行卫生手消毒效果可靠,最佳干手措施应首选一次性干手纸巾。

     

Investigation of microbial contamination of the air and equipment of a biological waste water purification station

The paper describes the results of a study of ambient air microbiological pollution in the working premises and equipment surfaces in the main shops of the biological waste water purification station of a cardboard-polygraphic plant. The findings suggest that there is high microbial contamination of the working environment, which should be born in mind on developing measures to optimize working conditions and on studying morbidity rates among the workers.