农村生活饮用水安全调查及安全策略

  目的  探索地理信息系统（GIS）技术应用于农村饮用水水质监测分析及疾病监测预警的可行性和适用性。  方法  监测100个有代表性的农村水厂水源水样微生物污染状况,利用健康管理大数据分析平台获取水质监测、法定肠道传染病和感染性腹泻病例信息,应用地理信息系统对数据进行整合与可视化处理,实现农村饮水安全的监测预警和地图展示。  结果  河水（水源水）菌落总数与大肠菌群、大肠埃希菌检出值呈显著正相关（r = 0.850、0.566,P < 0.01）,大肠菌群与大肠埃希菌检出值呈显著正相关（r = 0.501,P < 0.01）,大肠埃希菌与沙门菌检出值呈明显相关性（r = 0.632,P < 0.05）。应用GIS技术将农村水源、水厂、供水区域范围、覆盖人群、疾病、水质监测等数据整合与可视化处理,绘制出农村饮水安全风险监测与预警展示地图,地理信息系统对水质监测和病例聚集情况可直观展示和智能预警。  结论  河水可采用大肠埃希菌作为沙门菌的指示菌,基于GIS技术的农村饮用水微生物污染风险监测预警系统可作为疾病防控和卫生应急处置的重要技术支撑。     

A non‐fatal case of invasive zygomycete (Lichtheimia corymbifera) infection in an allogeneic haematopoietic cell transplant recipient

Post‐transplant infections in allogeneic haematopoietic cell transplant (allo‐HCT) recipients often have severe consequences. This is especially the case when dealing with zygomycete infections where the result is often fatal. A major problem when dealing with zygomycete infections is the need for an accurate and fast diagnosis as the phylum is highly resistant towards the conventional antifungals. We herein describe a non‐fatal case of Lichtheimia corymbifera infection in an allo‐HCT recipient.     

Bacterial flagella explore microscale hummocks and hollows to increase adhesion

Biofilms, surface-bound communities of microbes, are economically and medically important due to their pathogenic and obstructive properties. Among the numerous strategies to prevent bacterial adhesion and subsequent biofilm formation, surface topography was recently proposed as a highly nonspecific method that does not rely on small-molecule antibacterial compounds, which promote resistance. Here, we provide a detailed investigation of how the introduction of submicrometer crevices to a surface affects attachment of Escherichia coli. These crevices reduce substrate surface area available to the cell body but increase overall surface area. We have found that, during the first 2 h, adhesion to topographic surfaces is significantly reduced compared with flat controls, but this behavior abruptly reverses to significantly increased adhesion at longer exposures. We show that this reversal coincides with bacterially induced wetting transitions and that flagellar filaments aid in adhesion to these wetted topographic surfaces. We demonstrate that flagella are able to reach into crevices, access additional surface area, and produce a dense, fibrous network. Mutants lacking flagella show comparatively reduced adhesion. By varying substrate crevice sizes, we determine the conditions under which having flagella is most advantageous for adhesion. These findings strongly indicate that, in addition to their role in swimming motility, flagella are involved in attachment and can furthermore act as structural elements, enabling bacteria to overcome unfavorable surface topographies. This work contributes insights for the future design of antifouling surfaces and for improved understanding of bacterial behavior in native, structured environments.     

Microbial transformation of asiatic acid by Alternaria longipes

Asiatic acid is a major pentacyclic triterpene isolated from Centella asiatica. It shows a variety of bioactivities. In order to obtain its derivatives, potentially useful for detailed pharmacological studies, the substrate was subjected to incubations with selected micro-organisms. In this work, asiatic acid was converted into three new compounds: 2α,3β,23,30-tetrahydroxyurs-12-ene-28-oic acid (1), 2α,3β,22β,23-tetrahydroxyurs-12-ene-28-oic acid (2), and 2α,3β,22β,23,30-pentahydroxyurs-12-ene-28-oic acid (3) by the fungus Alternaria longipes AS 3.2875. The structures of the three metabolites were determined by 1D and 2D NMR spectral data.     

浅析药品微生物限度检查与食品微生物检验的借鉴

浅析药品微生物限度检查法与食品微生物检验的实用性与指导意义。从实验操作和实验思路两方面提出可行性的参考方案。药品微生物限度检查法与食品微生物检验拥有各自的特点,通过交互补充,共同进步。     

产β 内酰胺酶葡萄球菌在临床标本中的检出及耐药性

目的了解某院产β 内酰胺酶葡萄球菌在临床标本中的检出及耐药现状，为防治葡萄球菌感染提供依据。方法回顾性分析该院2005-2010年临床各科送检标本分离的1 725株产β 内酰胺酶葡萄球菌的临床和实验室资料。结果近6年产β 内酰胺酶葡萄球菌总检出率为94.83%（1 725/1 819），各年度（2005-2010年）检出率分别为88.68%（94/106）、89.69%（174/194）、91.72%（155/169）、97.58%（242/248）、96.10%（591/615）、96.30%（469/487），有逐年上升趋势（χ2=51.11, P<0.01）；各菌种以松鼠葡萄球菌β 内酰胺酶阳性率最高（99.50%，198/199），耳葡萄球菌最低（80.37%，86/107），种间差异有统计学意义（χ2＝58.08，P<0.01）。药敏结果显示，除万古霉素、利奈唑烷、呋喃妥因和利福平外，产β 内酰胺酶葡萄球菌对青霉素、氨苄西林、氨苄西林/舒巴坦、苯唑西林、头孢唑林、环丙沙星、四环素、克林霉素、红霉素、庆大霉素和复方磺胺甲口恶唑呈高度耐药（耐药率51.74%～100.00%）和多重耐药，且产酶菌的耐药性均高于非产酶菌（χ2在7.00～485.39之间，P<0.01）。苯唑西林耐药菌株占产β 内酰胺酶金黄色葡萄球菌和凝固酶阴性葡萄球菌的72.86%和78.30%，是产酶葡萄球菌的主要组成菌群。结论产β 内酰胺酶葡萄球菌的高检出率和对临床常用抗菌药物的高耐药率形势严峻，加强对产酶细菌的监测，遏制其快速增长非常必要。     

Microbial life at ?13 °C in the brine of an ice-sealed Antarctic lake

The permanent ice cover of Lake Vida (Antarctica) encapsulates an extreme cryogenic brine ecosystem (−13 °C; salinity, 200). This aphotic ecosystem is anoxic and consists of a slightly acidic (pH 6.2) sodium chloride-dominated brine. Expeditions in 2005 and 2010 were conducted to investigate the biogeochemistry of Lake Vida’s brine system. A phylogenetically diverse and metabolically active Bacteria dominated microbial assemblage was observed in the brine. These bacteria live under very high levels of reduced metals, ammonia, molecular hydrogen (H₂), and dissolved organic carbon, as well as high concentrations of oxidized species of nitrogen (i.e., supersaturated nitrous oxide and ∼1 mmol⋅L⁻¹ nitrate) and sulfur (as sulfate). The existence of this system, with active biota, and a suite of reduced as well as oxidized compounds, is unusual given the millennial scale of its isolation from external sources of energy. The geochemistry of the brine suggests that abiotic brine-rock reactions may occur in this system and that the rich sources of dissolved electron acceptors prevent sulfate reduction and methanogenesis from being energetically favorable. The discovery of this ecosystem and the in situ biotic and abiotic processes occurring at low temperature provides a tractable system to study habitability of isolated terrestrial cryoenvironments (e.g., permafrost cryopegs and subglacial ecosystems), and is a potential analog for habitats on other icy worlds where water-rock reactions may cooccur with saline deposits and subsurface oceans.     

Heat stress risk profiles for three non-woven coveralls

The ACGIH® Threshold Limit Value® (TLV®) is used to limit heat stress exposures so that most workers can maintain thermal equilibrium. That is, the TLV was set to an upper limit of Sustainable exposures for most people. This article addresses the ability of the TLV to differentiate between Sustainable and Unsustainable heat exposures for four clothing ensembles over a range of environmental factors and metabolic rates (M). The four clothing ensembles (woven clothing, and particle barrier, water barrier and vapor barrier coveralls) represented a wide range of evaporative resistances. Two progressive heat stress studies provided data on 480 trials with 1440 pairs of Sustainable and Unsustainable exposures for the clothing over three levels of relative humidity (rh) (20, 50 and 70%), three levels of metabolic rate (115, 180, and 254 Wm^?2) using 29 participants. The exposure metric was the difference between the observed wet bulb globe temperature (WBGT) and the TLV. Risk was characterized by odds ratios (ORs), Receiver Operating Characteristic (ROC) curves, and dose-response curves for the four ensembles. Conditional logistic regression models provided information on ORs. Logistic regressions were used to determine ROC curves with area under the curve (AUC), model the dose-response curve, and estimate offsets from woven clothing. The ORs were about 2.5 per 1°C-WBGT for woven clothing, particle barrier, and water barrier and for vapor barrier at 50% rh. When using the published Clothing Adjustment Values (CAVs, also known as Clothing Adjustment Factors, CAFs) or the offsets that included different values for vapor barrier based on rh, the AUC for all clothing was 0.86. When the fixed CAVs of the TLV were used, the AUC was 0.81. In conclusion, (1) ORs and the shapes of the dose-response curves for the nonwoven coveralls were similar to woven clothing, and (2) CAVs provided a robust way to account for the risk of nonwoven clothing. The robust nature of CAV extended to the exclusion of different adjustments for vapor barrier by rh.     

燃煤氟砷致骨代谢损伤的生物暴露限值初探

目的 探讨燃煤氟砷致暴露人群骨代谢损伤的生物暴露限值(BEL).方法 2009年选择贵州省清镇市流长乡198例氟砷联合暴露者作为调查对象,分别检测尿氟、尿砷及骨代谢效应标志尿羟脯氨酸(UHYP)和尿Ⅰ型胶原交联氨基末端肽(UNTX)、骨强度指数(STI).应用BMDS Version 2.1软件计算燃煤氟砷致骨代谢损伤的尿氟、尿砷基准剂量(BMD)及其可信限下限(BMDL).结果 氟、砷混合暴露引起骨代谢损伤的尿氟BMD及BMDL范围分别为0.68 ～ 1.35 mg/g Cr和0.57 ～ 1.11 mg/g Cr;尿砷BMD及BMDL范围分别为8.36 ～ 18.77 μg/g Cr和7.12 ～ 15.40 μg/g Cr.结论 建议燃煤氟砷混合暴露引起骨代谢损伤的生物暴露限值,尿氟为0.57 mg/g Cr,尿砷为7.12 μg/g Cr.     

An exploration of the disease burden due to Cryptosporidium in consumed surface water for sub-Saharan Africa

The protozoan pathogen Cryptosporidium is an important cause of diarrhoeal disease, but in many contexts its burden remains uncertain. The Global Waterborne Pathogen model for Cryptosporidium (GloWPa-Crypto) predicts oocyst concentrations in surface water at 0.5 by 0.5° (longitude by latitude) resolution, allowing us to assess the burden specifically associated with the consumption of contaminated surface water at a large scale. In this study, data produced by the GloWPa-Crypto model were used in a quantitative microbial risk assessment (QMRA) for sub-Saharan Africa, one of the regions most severely affected by diarrhoeal disease. We first estimated the number of people consuming surface water in this region and assessed both direct consumption and consumption from a piped (treated) supply. The disease burden was expressed in disability adjusted life years (DALYs). We estimate an annual number of 4.3 × 10⁷ (95% uncertainty interval [UI] 7.4 × 10⁶–5.4 × 10⁷) cases which represent 1.6 × 10⁶ (95% UI 3.2 × 10⁵–2.3 × 10⁶) DALYs. Relative disease burden (DALYs per 100,000 persons) varies widely, ranging between 1.3 (95% UI 0.1–5.7) for Senegal and 1.0 × 10³ (95% UI 4.2 × 10²–1.4 × 10³) for Eswatini. Countries that carry the highest relative disease burden are primarily located in south and south-east sub-Saharan Africa and are characterised by a relatively high HIV/AIDS prevalence. Direct surface water consumption accounts for the vast majority of cases, but the results also point towards the importance of stable drinking water treatment performance. This is, to our knowledge, the first study to utilise modelled data on pathogen concentrations in a large scale QMRA. It demonstrates the potential value of such data in epidemiological research, particularly regarding disease aetiology.