呼吸道细菌生物被膜感染研究进展

细菌生物被膜(BBF)系指黏附于活体或无活性物体表面,被自身分泌的基质包绕的有一定结构的细菌群体~([1]).BBF是细菌为了适应恶劣环境、维持生存的特殊存在形式,具有极强耐药性和免疫逃避性,给临床治疗带来很大困难和挑战,在呼吸系统疾病中尤为如此.     

甲壳素对大肠埃希菌生物被膜形成的作用

目的 探讨甲壳素对大肠埃希菌生物被膜形成的作用.方法 以空白导管(对照组)和包被甲壳素的导管(实验组)为裁体,构建7 d的大肠埃希菌生物被膜模型,然后对每组细菌计数、测定结晶紫染色后的吸光度值、扫描电镜(SEM)观察.结果 对照组和实验组的细菌计数值(×107 cfu/ml)是2.29和2.15;吸先度值是0.137和0.138.扫描电镜下,对照组的细菌分布较均匀、密集;实验组的细菌分布不均匀、密集.结论 甲壳素对形成7 d的大肠埃希茼生物被膜不具有抑制作用.     

铜绿假单胞菌生物被膜密度感应系统

无论在自然环境(如岩石、海藻、珊瑚等表面)或人体内外(皮肤、牙齿、肠道和呼吸道)，绝大多数细菌粘附于非生物或活性组织表面，形成细菌群，并包被在自己产生的粘液性不均一聚合基质中，以生物膜(biofilm，BF)方式，而非浮游方式生长。生物膜中菌细胞间相互协调，具有明显的组织结构，这些粘附在一一起的细菌集合体被称作细菌生物膜。     

某医院临床分离细菌菌株耐药检测结果与分析

目的 了解该院院内获得病原菌对药物的耐药率和敏感率情况,指导临床用药.方法 收集2010年6月至2011年8月院内患者感染占前5位的病原菌,采用K-B纸片法、ATB药敏试剂盒比色法鉴定对抗菌药物耐药,并进行分析探讨.结果 大肠埃希菌耐药率大于或等于75%的抗菌药物有9种,敏感率大于或等于75%有3种;金黄色葡萄球菌耐药率大于或等于75%的抗菌药物有13种,敏感率50%～74%只有1种;凝固酶阴性葡萄球菌耐药率大于或等于75%的抗菌药物10种,敏感率大于或等于75%只有1种;铜绿假单胞菌耐药率大于或等于75%的抗菌药物有1种,敏感率大于或等于75%有3种;嗜麦芽窄食单胞菌耐药率大于或等于75%的抗菌药物有12种.结论 阿米卡星、美罗培南、亚胺培南对大肠埃希菌保持了较高的抗菌活性;舒普深对凝固酶阴性葡萄球菌保持较高的抗菌活性;阿米卡星、美罗培南、妥布霉素对铜绿假单胞菌保持较高的抗菌活性;复方新诺明对嗜麦芽窄食单胞菌保持较高的抗菌活性,环丙沙星、氨苄西林/舒巴坦对3种细菌耐药率大于或等于75%.     

细菌生物被膜及相关感染

随着现代医学的发展 ,新型生物医学材料的普遍应用 ,生物医学材料相关感染的发生率也呈上升趋势。近年来 ,在对生物医学材料相关感染和临床一些慢性顽固性感染发生机制的研究中 ,提出了细菌生物被膜(ｂａｃｔｅｒｉａｌｂｉｏｆｉｌｍ ,ＢＢＦ)和ＢＢＦ相关感染的概念。本文拟将就细菌生物被膜与生物被膜相关感染作一综述 ,以期为临床防治生物被膜相关感染提供参考。1　细菌生物被膜的概念及形成细菌生物被膜是细菌为适应自然环境、有利于生存而特有的生命现象。系细菌吸附于惰性物体如生物医学材料或机体粘膜表面后 ,分泌多糖基质、纤维蛋…     

绿脓假单胞菌生物被膜形成中相关基因的表达

目的通过检测绿脓假单胞菌生物被膜形成过程中藻酸盐合成相关基因的表达，研究藻酸盐在绿脓假单胞菌生物被膜形成过程中的作用。方法改良平板培养法建立黏液型绿脓假单胞菌PA17和非黏液型绿脓假单胞菌PA01生物被膜模型，半定量RT-PCR测定生物被膜形成不同时间点algD、algU的表达，并进行统计学分析。结果PA01和PA17分别于第3天和第6天形成成熟生物被膜。algD和algU均在微菌落分化为成熟生物被膜的阶段表达增高。单因素方差分析示同一菌株的相同基因在生物被膜形成过程的不同时间点表达的差异有统计学意义；两独立样本秩和检验示同一基因在不同菌株生物被膜形成过程中表达的差异无统计学意义。结论藻酸盐在绿脓假单胞菌生物被膜形成过程中微菌落分化为成熟生物被膜的阶段发挥作用，不受绿脓假单胞菌表型影响。     

细菌生物被膜及其相关感染的研究进展

细菌生物被膜(bacterial biofilm，BBF)是细菌为适应自然环境，在生长过程中附着于固体表面而形成的特殊存在形式，是由多细菌组成的膜状结构，而并非单一细菌的膜成分。早在1676年Antonie van Leeuwenhoek便从牙菌斑中观察到了细菌生物被膜的存在，但直到1978年Costerton等才首先提出了生物被膜的相关理论。细菌生物被膜广泛存在于自然环境中，临床上细菌生物被膜可形成于各种生物置入材料表面及体内黏膜表面，具有极强的耐药性及免疫逃避性，是造成临床慢性感染的主要原因之一。     

壳聚糖对大肠埃希菌生物被膜耐药性的影响

目的探讨壳聚糖对大肠埃希菌生物被膜(BF)细菌耐药性的影响。方法应用改良培养法建立大肠埃希菌BF。表型法检测ESBLs、AmpC、超超广谱β内酰胺酶(SSBL),K-B法做药敏试验。结果空白组、对照组、实验组产ESBLs分别为16.7%、50%、41.7%;产AmpC分别为0、25%、25%;产SSBL分别为0、16.7%、16.7%。对照组和实验组中各酶的检出率均明显高于空白组(P<0.05),对照组和实验组酶的检出率无差异(P>0.05)。大肠埃希菌除亚胺培南全部敏感外,对其他抗生素的耐药率均较高。结论生物被膜的形成增加了细菌耐药性;壳聚糖对生物被膜细菌的耐药性没有影响。     

罗红霉素联合敏感抗生素治疗铜绿假单胞菌生物被膜病的临床研究

目的:探索治疗铜绿假单胞菌(pseudomonas aeruginosa,PA)生物被膜病的临床方法。方法:82例PA生物被膜病患者随机分为治疗组和对照组。治疗组给予口服罗红霉素0.15Bid,同时联合应用一种对PA药敏试验敏感的抗生素。对照组仅给予一种对PA药敏试验敏感的抗生素。两组选用的对PA药敏试验敏感的抗生素有:头孢他啶3g静脉滴注Bid、哌拉西林-他唑巴坦6.75g静脉滴注Bid或头孢派酮-舒巴坦3g静脉滴注Bid。两组疗程均为2周。结果:治疗组症状、体征好转的平均天数以及体温降至正常、中性粒细胞比例恢复正常的平均天数均比对照组减少,两者差异有统计学意义(P&lt;0.05)。治疗组的治愈率(68.3%)和总有效率(92.7%)均高于对照组的治愈率(34.1%)和总有效率(70.7%),两者差异有统计学意义(P&lt;0.05)。结论:罗红霉素联合敏感抗生素治疗PA生物被膜病,疗效优于单用敏感抗生素。罗红霉素联合敏感抗生素为治疗PA生物被膜病提供了一种有效的方法。     

低频超声联合环丙沙星对铜绿假单胞菌生物被膜的杀菌作用及其结构的影响

目的 研究低频超声联合环丙沙星对铜绿假单胞菌PAO1菌株生物被膜(biofilm,BF)的杀菌作用及其结构的影响.方法 建立PAO1菌株BF模型,设空白对照组,低频超声组,环丙沙星组,环丙沙星+低频超声组(超声辐射前给药),低频超声+环丙沙星组(超声辐射后给药),XTT比色法测定BF细菌活力的变化;激光共聚焦显微镜观察并结合图像结构分析软件对BF结构进行定量分析;扫描电镜观察BF结构的改变.结果 环丙沙星+低频超声组和低频超声+环丙沙星组BF细菌活力明显降低,BF厚度变薄,区域孔径增大,平均扩散距离与结构熵减小,与空白对照组、低频超声组、环丙沙星组比有显著性差异(P＜0.05);扫描电镜显示,低频超声联合环丙沙星对BF清除明显.结论 低频超声联合环丙沙星对PAO1菌株BF有很好的杀菌作用,且能破坏其结构.     

呼吸道感染病原菌分布及耐药分析

目的了解呼吸道感染致病茵茵谱及耐药性。方法对诊断为下呼吸道感染的住院患者合格211份痰标本进行细菌学检查，阳性茵采用法国梅里埃生物公司细菌鉴定条鉴定。采用K-B纸片扩散法进行药敏试验。结果211份痰标本分离出致病菌216株，以G^-茵为主，占43．5％，G^ 茵占27．3％；表皮葡萄球菌、铜绿假单胞茵、其他假单胞茵、流感嗜血杆菌和肺炎克雷伯杆菌。占分离茵前5位，分别为13．8％、8．3％、8．8％、5．1％、5．1％。药敏结果提示D群链球菌、肠球菌、其他假单胞茵、肺炎克雷伯和鲍曼不动杆茵对多种抗生素呈现高比例耐药。铜绿假单胞茵对三代头胞、喹诺酮及氨基甙类仍敏感。万古霉素对G^ 茵高度敏感。结论呼吸道感染以G^-茵为主，其比例较以往报道下降，耐药率较高，且多重耐药。临床宜根据药敏结果选择抗生素并合理使用。     

下呼吸道感染的菌群分布及耐药性分析

目的 分析下呼吸道感染后的菌群分布及细菌对抗生素耐药情况,为临床合理使用抗生素提供科学依据.方法对下呼吸道感染患者进行菌群分布及细菌对抗生素耐药情况分析.结果 共检测到422株致病菌,菌群分布:铜绿假单胞菌、大肠埃希菌、肺炎克雷伯菌、副流感嗜血杆菌、鲍曼不动杆菌为5种主要致病菌.对5种抗菌药物较敏感:左氧氟沙星、阿米卡星、环丙沙星、头孢哌酮、亚胺培南;对5种抗菌药物较耐药:氨苄西林、苯唑西林、哌拉西林、头孢他啶、头孢唑林.结论 引起该院下呼吸道感染的病原菌主要为革兰阴性杆菌,其耐药情况可为临床抗菌药物合理应用提供参考.     

Upper respiratory tract infections

Upper respiratory tract infections are among the most common acute infections in humans. This review discusses the clinically important aspects of the epidemiology, etiology, clinical presentation, diagnosis, management, complications, and prevention of the common cold, pharyngitis, otitis media, and sinusitis. Most episodes of the common cold and pharyngitis are of viral origin, and curative therapy is not available. Streptococcal pharyngitis, acute otitis media, and sinusitis are secondary to bacterial infections, and antibiotic therapy is important.     

Lower respiratory tract infections

Although lower respiratory tract infections are frequently diagnosed in a primary care setting, they are still associated with a significant morbidity and mortality, which warrants a careful approach to treatment. Knowledge of the most common cause based on the age of the patient, location where the infection was acquired, and clinical presentation helps to direct empiric treatment. A few basic laboratory studies, especially a sputum Gram stain, can allow for more specific treatment. Identification of patients at increased risk for virulent organisms should make the primary care physician consider inpatient treatment along with an aggressive diagnostic workup and broad-spectrum antimicrobial treatment. Prevention should always be considered.     

Tackling upper respiratory tract infections

URTIs are the most common reason for general practice consultations. On average adults suffer two to three such infections per year. When assessing a patient with a URTI in general practice it is important to recognise which patients may require antibiotics, further investigations and/or hospital referral. NICE recommends immediate antibiotics or further investigation and/or management in the following patients who are at risk of complications: Systemically very unwell. Features suggestive of serious illness and complications. Pre-existing comorbidities Older than 65 years with acute cough and two or more of the following, or older than 80 years with acute cough and one or more of the following: hospitalisation in the previous year; diabetes; history of congestive heart failure; current use of oral glucocorticoids. Antibiotics should also be considered for patients with three or more Centor criteria. In other cases (acute otitis media, acute sore throat/pharyngitis/acute tonsillitis, common cold, acute rhinosinusitis or acute cough/acute bronchitis) NICE advocates a no prescribing or delayed prescribing strategy. Most URTIs are self-managed. Patients who do seek consultations often benefit from reassurance, education and instructions for symptomatic home treatment.     

Single-dose azithromycin for respiratory tract infections

OBJECTIVE: To describe the pharmacology, efficacy, and safety data of the use of single-dose azithromycin for respiratory tract infections in children and adults. DATA SOURCES: A MEDLINE search (1990-September 2003) was performed to identify all pertinent studies and review articles. When appropriate information was not available in the literature, data were obtained from the product manufacturers or abstracts from international conferences. STUDY SELECTION AND DATA EXTRACTION: All available studies were reviewed to provide pharmacokinetic, pharmacodynamic, efficacy, and safety data on use of single-dose azithromycin for respiratory tract infections. DATA SYNTHESIS: Several studies have demonstrated that shorter regimens of azithromycin (1500 mg over 3 day vs 5 day or single dose vs 3 day) provide higher serum exposures compared with the longer regimens. This makes it possible to give the same dose over a shorter period of time and achieve the same efficacy with the potential for enhanced adherence. Single-dose azithromycin 30 mg/kg was approved in 2003 for treatment of acute otitis media (AOM) in children. Studies have demonstrated that, when administering azithromycin as a single dose, its efficacy and safety are comparable to that of other standard regimens for AOM. Single-dose regimens for treatment of respiratory tract infections in adults have not been studied widely, with only 2 studies being conducted for treatment of community-acquired pneumonia and one study for treatment of tonsillitis; all demonstrated at least equal efficacy with the single-dose regimen compared with comparators given for longer periods of time. CONCLUSIONS: Available data regarding single-dose azithromycin are promising. Although use of this regimen in children is warranted based on studies to date, additional large-scale trials are needed prior to mainstream use of the regimen in adults.     

Host-pathogen relationships in respiratory tract infections

The respiratory tract is continuously exposed to inhaled particles. The mucous membrane and the mechanisms of sneezing, coughing, and mucociliary clearance are the first line of defense. For the bronchioli and alveoli, the phagocytic cells are the cornerstone of defense against invading microorganisms. Alveolar macrophages and polymorphonuclear leukocytes are responsible for phagocytosis. For optimal phagocytosis, antibodies and complement are needed; phagocytic cells possess receptors for the Fc fragment of the immunoglobulin (IgG) molecule and complement. Receptors for cytokines are also present. These cytokines are important for activating the alveolar macrophage and recruiting other phagocytic cells and lymphocytes to the site of infection. Alveolar macrophages also contain cytophilic antibodies, IgG molecules that are bound to the cell via the F(ab)2 fragments. These cytophilic antibodies can interfere with the process of phagocytosis. They can bind to bacteria containing an Fc receptor (eg, Staphylococcus aureus protein A) and therefore provide the alveolar macrophage with a means to bind and digest staphylococci. Pulmonary surfactant proteins enhance the uptake of bacteria and viruses by alveolar macrophages and viruses. Thus surfactant contributes to the defense mechanisms of the lung. Phagocytic cells can injure alveoli. During the process of phagocytosis, toxic oxygen species and enzymes, needed for killing bacteria, are produced. These toxic substances may leak out of the cell and damage the surrounding tissues. All these phenomena contribute to the processes of inflammation. The function of phagocytic cells is decreased in smokers and by certain air pollutants. Phagocytic cells are crucial for the elimination of microorganisms.(ABSTRACT TRUNCATED AT 250 WORDS)