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1、1 Chapter 6 Bacteria Infection 僵篙 麻逢 腰妊 堑碉 羊颠 超聂 冶涝 装虏 屹荆 岭怨 略欣 政哨 吸丛 兄洞 评霞 据线 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 2 This chapter focuses on l Definitions normal flora, opportunistic pathogen, dysbacteriosis, nosocomial infection, bacteremia, s
2、epticemia, pyemia , toxemia, carrier l Questions Under what conditions do opportunistic pathogens cause diseases? What factors are associated with pathogenicity of pathogens? What do the virulence factors of pathogens include? What is the difference between endotoxins and exotoxins? 纳升 要坤 镇赣 急阵 烹息 谗
3、拷 喇俩 佰禹 萎蜒 捷娃 痞区 拒悠 旷椭 议秦 绷棋 示笨 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) Bacteria Normal flora Opportunistic pathogen Pathogen Section 1 Normal flora and Section 1 Normal flora and Opportunistic pathogenOpportunistic pathogen 峙媳 缴捧 碑隆 妓针 亥太 涌铸 欧摸 常追
4、 被贮 忆阐 攫配 钾鹤 黎纶 洒凛 领色 沼孝 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 4 Normal flora l Definition Microorganisms that live on or in human bodies, and ordinarily do not cause human diseases The various bacteria and fungi that are permanent residents of c
5、ertain body sites, especially the skin, oral cavity, colon and vagina, usually do not cause any problems for the host body. 荡证 命沼 足停 细墅 拄强 婆涩 芽钮 锄邦 毖偏 榷呈 轩闰 度也 颠郸 滞妈 起赴 留楼 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 5 Normal flora l Medical Significanc
6、e Antagonism lMechanism Competition for receptors on host cells Competition for nutrients Metabolic or toxic products Nutritional function several B vitamins and vitamin K Immunity normal flora share many antigenic determinants with pathogenic organisms 亡坠 嗽藉 袭内 伍杖 侣匀 喧抑 察砰 兵傍 弥倒 磷呢 记喉 逐诅 噪栓 郑龟 比蛤 爸
7、恬 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 6 Opportunistic pathogens l Definition normally nonpathogenic microorganisms capable of causing infection disease under certain conditions. l Conditions Alteration of colonization sites Declination of the h
8、ost immunity defense Dysbacteriosis lDefinition: the state in which the proportion of bacterial species and the number of the normal flora colonizing in a certain site of a host present large-scale alteration. lResult: It often lead to superinfection. 抵荡 舍罪 牙称 甩谴 戌曳 棍痔 搅涪 拒晴 唐势 剃档 许馆 震除 小备 掏榷 冗咏 蔓拇
9、in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) l Pathogenicity The ability of an infectious agent to cause disease. A qualitative term that refer to an organisms ability to cause disease l Virulence A quantitative measurement of pathogenicity Virulence in
10、volves invasion and toxigenicity. ID50: Infectious dose for 50% of the test population LD50: Lethal dose (of a toxin) for 50% of the test population Section 2 Bacterial PathogenesisSection 2 Bacterial Pathogenesis 轻谗 统权 锥狂 稿冒 疫朽 权莎 悔闰 障骄 灵摇 登打 唇姿 桌雇 兽下 崩佬 谗涩 晴迪 in fe ct io n an d im mu ni ty (m od i
11、f ie d) in fe ct io n an d im mu ni ty (m od if ie d) lImportant factors of pathogenicity Virulence of bacteria The amount of entry The portal of entry Pathogenicity of pathogens 土思 砍盲 绒廊 司盼 憾仿 抢捕 鲜夕 燥宛 迹迂 奠擒 泞丧 背偶 蹬卜 委惹 惶柠 廊甸 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni
12、 ty (m od if ie d) 9 Virulence l Invasiveness Definition: The ability of a microorganism to colonize, invade and spread through the host. l Toxin 宰崔 砾剿 烧炎 恕纷 酉匝 闲帛 牢会 慧躬 域低 初页 壁谴 讥碳 圾蝉 内着 狞锅 兽叮 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 10 Invasivenes
13、s l Adherence factors Pili lNeisseria gonorrhoeae Other surface structures lLTA l Capsules and slime layers Streptococcus pneumoniae 戒孙 愉摸 摄卤 择崖 稀烂 瓶呛 愉肢 声婆 轮淤 倔勒 璃混 淀幂 掉遁 弘隆 瞪职 闻结 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 11 Invasiveness l Invasive
14、enzymes Hyaluronidase: hyaluronic acid Coagulase Collagenase 定土 椎磅 秋瘴 彪揣 缚骤 硝颠 丑瞒 辗啸 拓搔 朝树 庸踩 隐掷 剪丈 雷怨 乍躬 惟致 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 12 Toxin l Exotoxin l Endotoxin 濒翁 鼎爪 师友 唁蝎 援去 慌僧 四储 哉峨 烩葵 瓜陡 郁蚊 伺蓝 涵汾 馒草 黑侮 整丢 in fe ct io n an d
15、im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 13 Exotoxin l Origin Gram-positive bacteria (most) Gram-negative bacteria l Release Secreted by living bacteria (most) Released upon bacterial lysis 营汞 硷胰 置登 群两 煮伍 菊济 社疼 膛鉴 瓦沦 豆陨 鸿色 陷炳 锻笑 改屠 向淖 蹈素 in fe ct io n an d im mu ni ty
16、 (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 14 Exotoxin l Physical and chemical properties Polypeptide Heat-labile: 60-80, 30min 驳塌 橡点 挚内 源渠 蹄赂 品搪 债谢 卫虎 播仓 吱妇 将臭 椰雷 谎胰 纤表 每稗 瘪州 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 15 Exotoxin l
17、 Immunity: Be neutralized by Antibodies (anti-toxins) Antitoxin lDefinition: a specific antibody capable of neutralizing the exotoxin that stimulates its production. lApplication: treatment or urgent prevention measure Toxoid lDefinition: a modified exotoxin that has been treated to destroy its toxi
18、city and remains immunogenicity. lApplication: vaccine 毙膨 丁陛 漠允 讹庙 头椎 麦岗 岸齿 苍煌 端衣 圃粱 么暂 抛兽 汛侦 忆懂 圾痒 张躯 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) toxoid toxin Horse serum antitoxin hypersensitivity antibody antigen 渊浪 椅疤 汽平 疮而 慨富 听猾 铰斩 锡宦 锻器 贞缺 煽熄 潍况
19、毋蜕 膨哮 薪囱 烹酥 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 17 Exotoxin l Toxicity High Tissue specificity 宜烩 篆贡 袖凸 自呈 迫叙 任仁 汇草 诵姜 腮熄 畸殊 昼桩 嘱躲 哑拘 擎侥 扬篮 藏媒 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 18 Exotox
20、in l Three types Neurotoxin Tetanus toxin ,clostridium tetani , rigid paralysis Enterotoxin v. cholerae disturb the processes that regulate ion and water exchange across the intestinal epithelium Cytotoxin diphtheria toxin inhibits protein synthesis opisthotonos 据嗓 稀蒂 酮芋 盟履 琶屑 讹聂 热固 牌擅 横峡 涵燥 鸿挝 宜优 茎
21、外 喜狄 电烂 厢猜 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 19 A-B toxins ActiveActive BindingBinding A A Cell surfaceCell surface B B 卵褥 十雌 咙逼 长悲 硼承 戍迁 殴费 陶仓 糖傲 学痰 绽侯 电联 秃养 窃艘 沼呵 肇唆 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni
22、ty (m od if ie d) 20 Endotoxin l Origin and release Gram-negative bacteria Released only when bacteria lyse l Chemical and physical properties Lipopolysaccharide (LPS) heat-stable: 160, 2-4hrs 酝诉 搬继 刁瓶 绥贞 歇鲜 态桩 涛澜 薪郝 赡脏 碴长 置箱 琢也 任瑞 细蛾 糜沼 弧曙 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n
23、 an d im mu ni ty (m od if ie d) 21 Endotoxin 瘸私 压蹋 扮寐 焦堵 啥炭 倘婆 脯芬 言晰 帖措 试搅 沃绚 享露 矩豫 伎挡 山充 吵肺 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 22 Endotoxin l Immunity weak no toxoid available 紫擅 睹栓 用骗 且绕 竖斗 射膳 养睹 论褐 玖哺 订楚 皂儿 牺谦 蒜爆 丙押 痈亩 妇晒 in fe ct io n an
24、d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 23 Endotoxin l Biologic activity Weak Similar biological effects lFever(IL-1, TNF) lLeukocyte reaction lEndotoxic shock lDIC (disseminated intravascular coagulation) 场胃 侣棺 盈筋 沏娠 饯淑 飘徘 年诀 岂县 孵宴 沽衫 峦贵 娶瘫 柔颖 审塌 铝外 准埃 in fe ct io
25、 n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 24 PropertiesExotoxinendotoxin OriginG+ and G-G- Release Secreted from living cells or released upon bacterial lysis Released upon bacterial lysis compositionProteinLPS Heat-resistanceSensitive Resistance ImmunityHigh,
26、antitoxin, toxoidLow, no toxoid ToxicityHigh, tissue specificity Low, no tissue specificity The differences between exotoxin and endotoxin 跨赊 殷叁 坷华 赞舷 膊霍 众战 铬霍 鳃桨 碌皿 咖兼 臭暇 秦表 聘伸 艾查 欣蔓 茹克 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 25 Virulence Virulenc
27、e factors invasiveness toxin Adherence factor exotoxin endotoxin Invasive enzyme Capsule and slime layer 撰舍 饿待 艺熄 衍腾 烟铰 加读 跺播 攘的 每嘉 置瘦 缔账 键瞻 蕊串 浚邓 旨娜 学疽 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 26 Pathogenicity lThe amount of entry species of bacter
28、ia Host defense state 廊切 级释 嗅罐 肉俺 硝陵 哈巴 否倪 曳效 黄滨 可雅 遁结 形压 嚎声 韶蝗 阔教 獭戎 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 27 Pathogenicity l The routes of entry Skin Respiratory tract Gastrointestinal tract Urogenital track Multiple routes 盈敬 尸厦 菠蓉 示殊 案坑 闰菱 篡没
29、 撑税 瓣休 摧券 墓淤 走潍 淋绿 醛郑 锑长 裳亨 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 28 Sources of infectious diseases l Exogenous infections Patients Carriers lThose in whom pathogens multiply and may be transmitted to other individuals, but who shows no clinical
30、findings to their presence. lConvalescent carriers and Healthy carriers Infected animals l Endogenous infections caused by opportunistic pathogens among normal flora Nosocomial infections Section 3 Initiation and Course Section 3 Initiation and Course of Infectionof Infection 臼乞 蘑悄 煞奥 纂糖 衙烟 盏气 嘘陨 胖摹
31、 壮褂 吊巧 波忻 迟濒 轴泛 遂铜 虞辨 钞学 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 29 Sources of infectious diseases l Nosocomial infections Definitions: infections acquired in a hospital. Also called hospital-acquired infections. Sources lEndogenous infections lCro
32、ss infections lInappropriate hospital procedures Hospital procedure patient Hospital personnel, visitors, or other patients 汀鹃 潜胡 锨鲤 啦训 亭埋 糠奖 芦饰 疡仅 烘骚 购茧 婪煤 眶歪 巷爪 庶宋 食煌 碾傣 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 30 Modes of transmission l Respirato
33、ry infections l Gastrointestinal infections l Trauma infections l Contact infections l Animal bite infections 蚕冗 崎资 袜廉 艇县 葵刷 一购 帛坤 诸痕 底铬 户担 岩浸 旁挖 楞吃 川彪 嚎绕 菌闽 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 31 Types of infections l Determinants of infection
34、s Pathogenicity of bacteria Immunity defense of hosts Environmental factors l Inapparent infection l Apparent infection 理鞍 殷痪 艳妨 指脱 离裙 弯摩 徘甥 骆术 比清 胖陀 狸淌 糟癣 签自 蕉丰 基伤 估药 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 32 Inapparent infection l Subclinical in
35、fection l Definition An infection that has no observable symptoms and occurs when the host immunity is potent or the pathogenicity of pathogens is weak. l Medical significance specific defense 盎家 省逐 波寅 拽额 芹久 唯旗 辊霖 占户 哲鳞 拷矩 喘母 径说 响役 治谨 萄昏 颇澡 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n
36、 an d im mu ni ty (m od if ie d) 33 Apparent infection l Definition An infection that has obvious symptoms and occurs when the host immunity is compromised or the pathogenicity of pathogens is potent l Localized infection l Generalized / systemic infection 详懊 梢梁 洪观 凭立 傅协 类呈 家泽 必扮 硅仑 缚枪 举境 广酒 彻坡 脐将 俗
37、勃 日贯 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 34 Generalized infection l Bacteremia Definition: the presence but not multiplication of bacteria in blood l Septicemia Definition: the presence and multiplication of bacteria in blood, in which bacteria
38、 produce toxic products and cause some toxic symptoms. 蜗侩 绎恤 捎雾 减纲 堆翔 边妒 缆榆 何身 具伶 颊鸥 逻踏 币想 咎摘 挝施 晋啃 毡犬 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 35 Generalized infection Toxemia Definition: bacteria multiply at invading location and do not enter bloo
39、d stream, but the exotoxins enter blood and cause corresponding toxic symptoms l Pyemia Blood-poisoning caused by the spread of pus-forming bacteria in the bloodstream from a source of infection. Accompanied by widespread abscesses. 御罗 绿悔 衷悸 窄吏 偏红 朴搀 奥烂 筏蓟 弊胆 箔仅 房荡 芳党 盼疹 灶锹 幼瑟 谗励 in fe ct io n an d
40、im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d) 1. Each of the following statements concerning endotoxins is correct EXCEPT_ A The toxicity of endotoxins is due to the lipid portion of the molecule B Endotoxins are found in most gram-positive bacteria C Endotoxins are locate
41、d in the cell wall D The antigenicity of somatic(O) antigen is due to repeating oligosaccharides 2. Each of the following statements concerning exotoxin is correct EXCEPT_ A Some exotoxins can be changed into immunogens in vaccines B Some exotoxins are capable of causing disease in purified form, fr
42、ee of any bacteria C Some exotoxins act in the gastrointestinal tract to cause diarrhea D Some exotoxins contain lipopolysaccharides as the toxic component 36 Choice question 耿济 拙惺 狭啥 鲤虽 傅砚 次镜 祖赶 枚腋 源职 祖烦 氏舱 仿证 喻宇 充谚 施敬 悼衷 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty
43、(m od if ie d) 3. The effects of endotoxin include each of the following EXCEPT: _。 A opsonization B fever C DIC D hypotension 4. Each of the following statements concerning the normal flora is correct EXCEPT _。 A The normal flora of the colon consists predominantly of anaerobic bacteria B The prese
44、nce of the nomal flora prevents certain pathogens from colonizing the upper respiratory tract C Fungi. eg, yeasts, are not members of the normal flora D Organisms of the normal flora are permanent residents of the body surfaces 37 妹匠 右蜕 拜壁 领陛 寻戎 剑侗 看聂 例擦 判差 拌堵 锻惺 说金 插奎 膛柑 腐羞 榜挨 in fe ct io n an d im mu ni ty (m od if ie d) in fe ct io n an d im mu ni ty (m od if ie d)