蜂蜜抑菌作用的研究进展及其遏制细菌耐药性的潜力

抗生素耐药已成为全球公共卫生的重大威胁,人体肠道及环境中的细菌在抗生素及环境压力的长期选择下产生适应性进化从而产生耐药性。目前因细菌对抗生素不敏感而导致的细菌耐药已成为全球生态环境与健康的重大威胁,因此迫切需要寻找和开发抗生素的有效替代品。蜂蜜在抗生素问世之前就已被用于外伤感染的局部治疗,具有良好的抑菌效果。目前,蜂蜜已经被证实可以抑制多种耐药菌。由于其含有多种抑菌成分,而且各成分之间还具有一定的协同作用,以致细菌很难对蜂蜜产生耐药性。本文系统回顾了抗生素问世前蜂蜜用作抗感染药物的早期应用,以及抗生素发明以来产生的细菌耐药性问题,通过阐述蜂蜜的抑菌作用机理,提出了将蜂蜜作为抗生素替代品的可行性。未来可考虑将蜂蜜与抗生素联用从而增强抗生素的治疗效果,蜂蜜有潜力成为对抗耐药细菌的一种有效手段。     

传粉蜜蜂介导的细菌耐药性传播及其生态与健康风险

目前,抗菌药物的滥用造成了临床和环境中普遍存在的细菌耐药性问题,而细菌耐药性在环境中不断富集和传播扩散会通过食物网对生态安全及人体健康构成威胁。蜜蜂作为最重要的传粉昆虫,在世界各地广泛分布。然而,蜜蜂近年来频繁暴露于抗生素、杀虫剂和杀螨剂等药物,而野外杀虫剂的大量使用被认为是导致世界各地蜜蜂种群数量下降的关键因素。蜜蜂传花授粉的生物学特性使得蜂群与周围环境之间发生频繁的交流,可能导致蜜蜂传粉过程中蜂群与周围环境的交叉污染并发生细菌耐药性的传递。因此,蜜蜂可能成为生态系统中细菌耐药性传播的潜在“帮凶”。传粉蜜蜂介导下的细菌耐药性传播也将对蜂群健康、食品安全乃至生态系统安全构成威胁。本文综合国内外相关研究进展,系统分析了环境污染物暴露对蜜蜂以及蜜蜂肠道耐药基因组的潜在影响,并详细阐述了传粉蜜蜂介导下的细菌耐药性的传播,总结了蜜蜂主要通过蜜蜂-蜜蜂、蜜蜂-植物以及蜜蜂-环境的途径促进细菌耐药性的传播。最后,探讨了蜜蜂介导的细菌耐药性传播对蜂群健康、生态环境以及人体健康的潜在影响。     

畜禽养殖场附近污水中多粘菌素E耐药性肠杆菌的分离分析及内源质粒检测

畜禽养殖业大量使用抗生素引起了广泛的微生物耐药性问题,研究抗生素耐药菌株可以了解环境中细菌的耐药性情况和抗性基因的传播机制。采集畜禽养殖场周边的污水,分析了污水中多粘菌素E耐药性细菌和耐药性肠杆菌的丰度;同时以一株具有较高多粘菌素E耐药水平的肠杆菌R11为例,首先进行16S r DNA测序和抗生素耐药谱分析,然后通过质粒提取、酶切电泳以及脉冲场凝胶电泳(PFGE),分析其内源性质粒等情况。结果表明:在畜禽养殖场周边污水环境中,多粘菌素E耐药性细菌占细菌总数的0.14%~0.35%,多粘菌素E耐药性肠杆菌占肠杆菌总数的1.50%~7.40%,而肠杆菌占细菌总数的1.13%~2.45%,说明肠杆菌可能是携带多粘菌素E抗性基因的主要细菌种类,同时也是养殖业污水中细菌的主要组成部分。16S r DNA序列分析确定R11是一株Enterobacter cloacae,抗生素耐药谱分析R11具有多重耐药性,除对林可霉素敏感外,阿米卡星、四环素和环丙沙星的最小抑菌浓度(MICs)为10μg?m L~(-1),阿莫西林的MICs为25μg?m L~(-1),磺胺甲恶唑的MICs为32μg?m L~(-1),氨苄西林的MICs为40μg?m L~(-1),链霉素的MICs为90μg?m L~(-1),而多粘菌素E的MICs最高,达到96μg?m L~(-1)。质粒提取酶切和PFGE分离鉴定结果显示,R11菌株可能有多个内源性质粒。综上所述,R11菌株具有较高水平的多粘菌素E耐药性,并且具有多重耐药性和多个内源性质粒,对于研究多粘菌素E耐药性机制具有一定的参考价值。     

耐药菌的环境分布、传播及新型抗菌技术研究进展

抗生素的广泛使用导致细菌耐药性增加、多重耐药菌菌群数量急剧增多,严重威胁着人类生命健康.环境中耐药菌（ARB）及耐药基因（ARGs）的存在给临床治疗耐药菌感染带来了巨大挑战.有关医院中常见耐药致病菌的研究已有很多,尚缺乏环境中耐药菌的分布、传播及新型耐药菌抗菌技术等的相关研究.本文综述了耐药菌的环境分布特征及其传播机制,概述了新型抗菌技术及其应用,最后展望了有关环境耐药菌研究的未来发展方向.     

生态毒理学教学专栏寄语

抗生素的长期滥用,使得环境细菌耐药性不断增强,加速了耐药基因(antibiotics resistance genes,ARGs)在环境中的传播扩散,并给饮用水带来健康风险。在介绍饮用水中抗生素和耐药基因污染现状的基础上,阐述了耐药基因在饮用水中的来源和归趋,对环境中抗生素和耐药基因的人体健康风险做了初步探讨,针对目前饮用水的污染现状,对今后有关饮用水中细菌耐药的研究进行了展望。     

机舱空气环境耐药基因及耐药细菌的污染特征研究

研究表明飞机旅行是传染病在世界范围内传播的主要途径之一。由于飞机机舱内的密闭性,具有乘客密度大、污染物负荷大、新风量小等特点,使机舱成为极易传播疾病的场所。为了探究机舱环境中耐药细菌和耐药基因的分布情况,选择一架国际航线空客A320机舱内高效空气过滤器滤膜颗粒物作为研究对象。结果显示,在该空客机舱滤膜上31种耐药基因的检出频率为83.9%。Ⅰ类整合子基因的相对含量高于所有耐药基因,为3.94×10-1(基因拷贝数/16S rRNA拷贝数)。β内酰胺类耐药基因的相对含量在1.51×10-5～1.26×10-2之间。3种磺胺类耐药基因的相对含量都相对较高,sul2的含量最高,为4.81×10-2。Ⅰ类整合子介导的耐药基因水平转移可能是机舱内耐药基因传播扩散的主要机制之一。此外,对分离出的64株细菌进行耐药表型检测发现,具有磺胺甲恶唑耐受性的细菌为50株(78.1%),具有庆大霉素耐受性的细菌为41株(64.1%),具有亚胺培南耐受性的细菌为24株(37.5%)。其中61株菌至少含有两重耐药性,只有4株芽孢杆菌对四环素具有耐药性。样本中分离出很多条件致病菌,比如阴沟肠杆菌和蜡样芽胞杆菌等,这对乘客和机组人员的安全造成直接危胁。上述研究结果表明机舱环境成为耐药基因跨境传播的重要途经。     

饮用水中细菌耐药及其健康风险研究进展

抗生素的长期滥用,使得环境细菌耐药性不断增强,加速了耐药基因(antibiotics resistance genes,ARGs)在环境中的传播扩散,并给饮用水带来健康风险。在介绍饮用水中抗生素和耐药基因污染现状的基础上,阐述了耐药基因在饮用水中的来源和归趋,对环境中抗生素和耐药基因的人体健康风险做了初步探讨,针对目前饮用水的污染现状,对今后有关饮用水中细菌耐药的研究进行了展望。     

链霉菌S227抗耐药性物质的分离及其活性研究

在抗耐药性活性筛选过程中,发现分离自四川峨嵋山森林土壤的一株链霉菌S227(Streptomyces sp.)的发酵液具有抗细菌抗生素耐药性生物活性.利用已建立的抗耐药性的活性检测方法(专利号:ZL01128969.4)[1]为跟踪手段,采用有机溶剂萃取、硅胶柱层析以及薄层层析等方法,对该菌发酵液中抗耐药性活性物质进行分离纯化,得到了具有抗耐药性的活性单体S227-4,初步鉴定为四聚糖.利用MIC法对该样品的抗耐药活性进行研究:在证明该样品本身不具有抗菌活性的基础上,以临床分离的耐药菌株为指示菌,考察了该样品与抗生素联合使用时对耐药菌抗生素MIC(最小抑菌浓度)值的影响,结果表明,S227-4在不影响耐药菌生长的浓度下与不同的抗生素联合使用,可以明显提高不同耐药菌对不同抗生素的敏感性,如S227-4(200μg/mL)可以使S.aureus12334对红霉素的敏感性提高128倍.图2表2参8     

银系抗菌剂与有机抗菌剂对大肠杆菌的联合毒性效应

抗菌剂的长期滥用导致细菌耐药性问题不断加剧,这对人类的健康生存和长期发展构成巨大威胁.银系抗菌剂作为不易产生耐药性的无机抗菌材料,可以将其与有机抗菌剂联合使用以提高抗菌效果,从而达到减少抗菌剂滥用的目的.但由于有机抗菌剂的结构及单一作用机制不同,使得银系抗菌剂与其联合后会产生不同的抗菌效果,因此有必要研究银系抗菌剂与不...     

农村固体废弃物中抗生素及耐药基因的赋存及风险管理

全球范围内抗生素抗性的传播扩散严重威胁人类健康。固体废弃物中的生活垃圾、污泥和畜禽粪便是抗生素及耐药基因的重要储库。针对新型环境污染物抗生素和耐药基因,综述了农村固废中抗生素及耐药基因的赋存和传播扩散,阐述了农村固废中抗生素及细菌耐药的生态风险、控制管理和消除方法,并结合目前抗生素及耐药基因的污染状况,对今后研究重点进行了展望。     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture