Antibiotic resistance,virulence factors and biofilm formation ability in Escherichia coli strains isolated from chicken meat and wildlife in the Czech Republic

Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals. Consequently, these commensal bacteria might serve as indicator of antimicrobial usage for human and veterinary purposes in the Czech Republic. Further, 46 out of 66 resistant isolates (70%) were able to form biofilm and we found out statistically significant correlation between prevalence of antibiotic resistance and biofilm formation ability. The highest prevalence of antibiotic resistance was observed in weak biofilm producers. Biofilm formation was not statistically associated with any virulence determinant. However, we confirmed the correlation between prevalence of virulence factors and host origin. Chicken isolates possessed more virulence factors (66%), than isolates from wildlife (37%). We can conclude that the potential spread of antibiotic resistance pattern via the food chain is of high concern for public health. Even more, alarming is that E. coli isolates remain pathogenic potential with ability to form biofilm and these bacteria may persist during food processing and consequently lead to greater risks of food contamination.     

某沿海城市典型行业NMHCs排放特征及对二次污染物生成潜势研究

采用SUMMA罐采样、GC-FID技术分析了威海市渔具、造船和橡胶等6种典型行业代表企业废气中59种非甲烷碳氢化合物(NMHCs)组分及占比,并计算了各行业NMHCs的臭氧(O3)和二次有机气溶胶(SOA)生成潜势,提出了NMHCs治理建议.结果表明,涉及溶剂使用的渔具、造船、汽车制造业喷涂工序的NMHCs组分以芳香烃...     

汽车工业区大气挥发性有机物(VOCs)变化特征及来源解析

挥发性有机物(volatile organic compounds,VOCs)作为臭氧和细颗粒物的重要前体物已日益受到关注.鲜有针对汽车工业区大气VOCs 长期观测的报道.2019-01-01～2019-12-31 期间在上海某汽车工业园区边界,采用在线气相色谱仪对79 种VOCs 组分定量检测,分析大气VOCs 组成...     

Preozonation of bromide-bearing source water in south China

The effectiveness of preozonation was evaluated on treating a bromide-bearing dam source water in south China through batch-scale experiments. Preozonation at ozone doses of 0.5-1.0 mg/L （at ozone consumption base） enhanced total organic carbon （TOC） removal through coagulation, and resulted in an almost linear reduction of ultraviolet absorbance at 254 nm （LW2s4）. The removals of TOC （after coagulation） and UV254 at the ozone dose of 1.0 mg/L were 36% and 70%, respectively. Preozonation at an ozone dose between 0.5 and 1.0 mg/L resulted in the removal of disinfection byproducts formation potential （DBFP） including trihalomethane formation potential （THMFP） and haloacetic acid formation potential （HAAFP） for about 50%. The removals of THMFP and HAAFP decreased with the further increase of ozone dose. Ozonation of bromide-bearing water （bromide concentration, 34 μg/L） produced a bromate concentration under the detection limit（2μg/L） at ozone doses 〈1.5 mg/L. However, bromate 〉10μg/L could be produced when the bromide concentration was increased to 96 μg/L.     

活性炭滤池深度处理水中有机物

生物活性炭滤池能有效去除常规工艺出水中CODMn、UV254、三氯甲烷生成势和一溴二氯甲烷生成势,但在相同水力停留时间下,新鲜活性炭滤池对这些有机物去除效果更显著。生物活性炭滤池出水二溴一氯甲烷生成势升高,而新鲜活性炭滤池对二溴一氯甲烷生成势有时有一定的去除效果。     

Assessment of the impact of landfill on groundwater quality: A case study of the Pirana site in western India

In present study focus has been given on estimating quality and toxicity of waste with respect to heavy metals and its impact on groundwater quality, using statistical and empirical relationships between different hydrochemical data, so that easy monitoring may be possible which in turn help the sustainable management of landfill site and municipal solid waste. Samples of solid waste, leachate and groundwater were analyzed to evaluate the impact of leachates on groundwater through the comparison of their hydrochemical nature. Results suggest the existence of an empirical relationship between some specific indicator parameters like heavy metals of all three above mentioned sample type. Further, K/Mg ratio also indicates three groundwater samples heavily impacted from leachate contamination. A good number of samples are also showing higher values for and Pb than that of World Health Organization (WHO) drinking water regulation. Predominance of Fe and Zn in both groundwater and solid waste samples may be due to metal plating industries in the area. Factor analysis is used as a tool to explain observed relation between numerous variables in term of simpler relation, which may help to deduce the strength of relation. Positive loading of most of the factors for heavy metal clearly shows landfill impact on ground water quality especially along the hydraulic gradient. Cluster analysis, further substantiates the impact of landfill. Two major groups of samples obtained from cluster analysis suggest that one group comprises samples that are severely under the influence of landfill and contaminated leachates along the groundwater flow direction while other assorted with samples without having such influence.     

Grouping and representativeness of monitoring stations based on wind speed and wind direction data in urban areas of Japan

Data on wind speed and wind direction from 27 air pollution monitoring stations in an urban area of Japan were analyzed and studied for the future assessment of the urban heat island phenomenon. A cluster analysis clarified the regionality of the wind speed and wind direction. In the study area, land and sea breeze developed and controlled the wind direction. On the other hand, the mountain and valley wind should be studied to determine their typical behavior.     

洪湖水质空间特异性及主导因子分析

运用聚类分析和主成分分析方法对洪湖湿地12个采样点的理化特性进行分析。聚类分析表明,根据各采样点水质组分的相似性将洪湖大致分为3个空间区域,各空间区域正好分属于核心区、实验区、河口区,各区域间特征差异显著。对各区域水质的主成分分析表明,洪湖不同空间区域水质信息差异很大。第1组核心区主要体现富营养化信息;第2组实验区主要体现总氮、氧化还原电位、浊度信息;第3组河口区主要体现溶解氧及亚硝酸盐氮等污染物信息。揭示了洪湖水质现状及其成因,为洪湖水资源合理利用及生态保护提供基础数据。同时,运用地统计学方法为生态环境研究提供新的思路与方法。     

长江南京段水质自动监测点位优化

简述了长江南京段监测断面现状,用相关分析与聚类分析方法对水质监测数据进行了统计分析,对长江南京段水质自动监测优化布点提出了相关建议。     

生物过滤除臭填料挂膜驯化试验研究

将填料装入生物滤塔之前,对其进行挂膜驯化培养,待其成功后即可装填使用。试验结果表明,第12d后,发现树皮表面长有生物膜。在没有营养盐供应的情况下,微生物依然可以利用有机填料作为碳源进行代谢反应。42d后,从生物膜的镜检和混合液的pH值变化可知,用于除臭的优势微生物驯化成功。