The accumulation of organic matter in substratum pores is regarded as an important factor causing clogging separately in the subsurface flow constructed wetlands.In this study,the developing process of clogging caused...The accumulation of organic matter in substratum pores is regarded as an important factor causing clogging separately in the subsurface flow constructed wetlands.In this study,the developing process of clogging caused by biofilm growth or organic particle accumulation instead of total organic matter accumulation was investigated in two groups of lab-scale vertical flow constructed wetlands（VFCWs）,which were fed with glucose（dissolved organic matter） and starch（particulate organic matter） influent.Results showed that the growth of biofilms within the substratum pores certainly caused remarkable reduction of effective porosity,especially for the strong organic wastewater,whereas its influence on infiltration rate was negligible.It was implied that the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging.In comparison with biofilm growth,particles accumulation within pores could rapidly reduce infiltration rate besides effective porosity and the clogging occurred in the upper 0-15 cm layer.With approximately equal amount of accumulated organic matter,the effective porosity of the clogged layer in starch-fed systems was far less than that of glucose-fed systems,which indicated that composition and accumulation mode in addition to the amount of the accumulated organic matter played an important role in causing clogging.展开更多
目的观察气管导管(endotracheal tube,ETT)表面细菌定植及生物膜(biofilm,BF)形成,探讨其与机械通气新生儿伴发下呼吸道感染之间的相关性。方法以我院2005年1至6月,经治的20例机械通气新生儿为研究对象,观察机械通气过程中下呼吸道感染...目的观察气管导管(endotracheal tube,ETT)表面细菌定植及生物膜(biofilm,BF)形成,探讨其与机械通气新生儿伴发下呼吸道感染之间的相关性。方法以我院2005年1至6月,经治的20例机械通气新生儿为研究对象,观察机械通气过程中下呼吸道感染发生情况,收集第一次拔除或更换的 ETT,扫描电镜(Scanning Electron Microscopy,SEM)观察 ETT 表面 BF(ETT-BF)形成情况及结构,并对 ETT 表面和下呼吸道分泌物进行细菌分离、鉴定和药敏分析。结果①20例中13例机械通气前并不存在下呼吸道感染,在机械通气过程伴发了下呼吸道感染,并在整个机械通气期间持续存在;其中有9例 ETT 留置时间与机械通气时间一致(平均机械通气时间为3.6 d)。②SEM 观察发现留置时间超过1 d 的 ETT 表面细菌定植增加(12/20),3 d 左右细菌在 ETT 表面初步形成 BF,超过3 d 表面 BF 结构更加成熟复杂。③ETT 表面培养阳性14例(包括正常菌群4例),分离得到病原菌7种;下呼吸道分泌物培养阳性13例(包括正常菌群1例),分离得到病原菌10种;其中7例 ETT表面和下呼吸道分泌物同时分离得到同种菌种,其 ETT 留置时间为(3.2±1)d,占 ETT 培养阳性的50%。④ETT 表面和下呼吸道分泌物分离得到的 G^-细菌均对抗生素多重耐药。结论 ETT 表面细菌定植及 BF 形成与长时间机械通气新生儿伴发下呼吸道感染之间可能存在一定相关性,ETT-BF 可能是其感染持续存在的一个病原来源。展开更多
金黄色葡萄球菌(Staphylococcus aureus, S. aureus)是医院和社区获得性感染最常见的致病菌,极易黏附在导管和植入式医疗设备表面形成生物膜。传统的抗生素治疗导致耐药菌株的大量产生。患者一旦发生金黄色葡萄球菌生物膜感染,往往难以...金黄色葡萄球菌(Staphylococcus aureus, S. aureus)是医院和社区获得性感染最常见的致病菌,极易黏附在导管和植入式医疗设备表面形成生物膜。传统的抗生素治疗导致耐药菌株的大量产生。患者一旦发生金黄色葡萄球菌生物膜感染,往往难以治愈。频繁的治疗大大加重了患者的痛苦和经济负担。因此,目前亟需开发治疗金黄色葡萄球菌生物膜的新方法。本文就近几年金黄色葡萄球菌生物膜感染的预防和治疗做一综述,旨在为开发金黄色葡萄球菌生物膜新的治疗方法提供思路。展开更多
基金supported by the Natural Science Foundation of Jiangsu Province (No.BK2006710)
文摘The accumulation of organic matter in substratum pores is regarded as an important factor causing clogging separately in the subsurface flow constructed wetlands.In this study,the developing process of clogging caused by biofilm growth or organic particle accumulation instead of total organic matter accumulation was investigated in two groups of lab-scale vertical flow constructed wetlands（VFCWs）,which were fed with glucose（dissolved organic matter） and starch（particulate organic matter） influent.Results showed that the growth of biofilms within the substratum pores certainly caused remarkable reduction of effective porosity,especially for the strong organic wastewater,whereas its influence on infiltration rate was negligible.It was implied that the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging.In comparison with biofilm growth,particles accumulation within pores could rapidly reduce infiltration rate besides effective porosity and the clogging occurred in the upper 0-15 cm layer.With approximately equal amount of accumulated organic matter,the effective porosity of the clogged layer in starch-fed systems was far less than that of glucose-fed systems,which indicated that composition and accumulation mode in addition to the amount of the accumulated organic matter played an important role in causing clogging.
文摘目的观察气管导管(endotracheal tube,ETT)表面细菌定植及生物膜(biofilm,BF)形成,探讨其与机械通气新生儿伴发下呼吸道感染之间的相关性。方法以我院2005年1至6月,经治的20例机械通气新生儿为研究对象,观察机械通气过程中下呼吸道感染发生情况,收集第一次拔除或更换的 ETT,扫描电镜(Scanning Electron Microscopy,SEM)观察 ETT 表面 BF(ETT-BF)形成情况及结构,并对 ETT 表面和下呼吸道分泌物进行细菌分离、鉴定和药敏分析。结果①20例中13例机械通气前并不存在下呼吸道感染,在机械通气过程伴发了下呼吸道感染,并在整个机械通气期间持续存在;其中有9例 ETT 留置时间与机械通气时间一致(平均机械通气时间为3.6 d)。②SEM 观察发现留置时间超过1 d 的 ETT 表面细菌定植增加(12/20),3 d 左右细菌在 ETT 表面初步形成 BF,超过3 d 表面 BF 结构更加成熟复杂。③ETT 表面培养阳性14例(包括正常菌群4例),分离得到病原菌7种;下呼吸道分泌物培养阳性13例(包括正常菌群1例),分离得到病原菌10种;其中7例 ETT表面和下呼吸道分泌物同时分离得到同种菌种,其 ETT 留置时间为(3.2±1)d,占 ETT 培养阳性的50%。④ETT 表面和下呼吸道分泌物分离得到的 G^-细菌均对抗生素多重耐药。结论 ETT 表面细菌定植及 BF 形成与长时间机械通气新生儿伴发下呼吸道感染之间可能存在一定相关性,ETT-BF 可能是其感染持续存在的一个病原来源。
文摘金黄色葡萄球菌(Staphylococcus aureus, S. aureus)是医院和社区获得性感染最常见的致病菌,极易黏附在导管和植入式医疗设备表面形成生物膜。传统的抗生素治疗导致耐药菌株的大量产生。患者一旦发生金黄色葡萄球菌生物膜感染,往往难以治愈。频繁的治疗大大加重了患者的痛苦和经济负担。因此,目前亟需开发治疗金黄色葡萄球菌生物膜的新方法。本文就近几年金黄色葡萄球菌生物膜感染的预防和治疗做一综述,旨在为开发金黄色葡萄球菌生物膜新的治疗方法提供思路。
