• Chapter 5

• Pathogenicity of B and Immunity against Bacterial Infections(Infection and Immunity)

§1. Normal Flora and opportunistic B (fig)

• 一 .Normal flora :• 1.Biological antagonism

• 2.Nutritional function

• 3.Induction of immune response

• 4.Growth and aging

• 二 .Opportunistic pathogens :• 1.Change of normal habit • 2.Endogenous infection • 3.Dysbacteriosis

• 三 .Hospital acquired infection • (nosocomial infection)• 1.Cross- infection : patients,doctors• 2.Endogenous ~ : from patient himself• 3.Iatrogenic ~ : (instrument)

§2 Mechanisms of Bacterial pathogenicity

virulence : LD50 , ID50 • 一 .Bacterial virulence :• (一 ) Invasiveness :• 1. B surface structure• (1)Adhesive factors: pili and lipoteichoic acid(LTA) • (2)Capsule and microcapsule: M － pro , Vi －Ag . K－Ag.

• 2. Invasive enzyme• coagulase , SK , SD ,spreading factor.

• (二 ) Toxin• 1. Exotoxins:• (1)G+ produce .• (2)Protein in nature• (3)Specific (disease)• (4)Lethal• (5)Neuro ~ , Cyto ~ , Entero ~• (6)A : toxic• B : non-toxic , binding to cells .• 0.3~0.4 %formaldehyde

• (7) Exotoxin ----------------------- toxoid ----------- immunize animal Antitoxin

• 2.Endotoxins• G － , LPS , heat stable .• (1)Fever(pyrogens) • (2)Leukocyte response• (3)Hypotension and shock • (4)DIC• (5)Shwartzman’s phenomenon• (6)etc• a.active B , T , MΦ.• b.induce TNF , IFN ,CSF ,IL-6• Endotoxin detect :

• Limulus test .

表 6-4 外毒素与内毒素的主要区别

区别要点 外 毒 素 内 毒 素 来源 革兰阳性菌与部分革兰阴性菌 革兰阴性菌

存在部分 从活菌分泌出 , 少数菌崩解后释出 细胞壁组分 , 菌裂解后释出

化学成分 蛋白质 脂多糖

稳定性 60 ～ 80℃,30min 被破坏 160℃,2 ～ 4h 才被破坏

毒性作用 强 , 对组织器官有选择性毒害效应 , 较弱 , 各菌的毒性效应大致

引起特殊临床表现 相同 , 引起发热、白细胞增

多、微循环障碍、休克、

DIC 等

抗原性 强 , 刺激机体产生抗毒素 ; 甲醛液处 弱 , 刺激机体产生的中和抗

理脱毒形成类毒素 体作用弱 ; 甲醛液处理不

形成类毒素

• 二 .Number of Invading B

• 三 .Portal of Entry

§3. Host Immunity against Bacterial Infections

• 一 .Non-specific Immunity • (一 )Barrier Structure• 1.Skin and mucous membrane

• (1)mechanical factors

• (2)chemical factors

• (3)biological factors

• 2.Blood-Brain-Barrier

• 3.Placental Barrier

(二 )  Phagocyte• 1. Process and Mechanisms of Phagocytosis• (1)Chemotaxis and adherence• (2)Ingestion • (3)Intracellular killing• a. Oxygen-dependent system • MPO• Non-MPO• b. oxygen-independent system• 2. Fate of B after phagocytosis• (1)complete~• (2)incomplete~: TB

(三 )Anti-bacterial • Substances in serum and body fluids

• 1.Complement

• 2.β-lysin

• 3. Lysozyme

• 二 .Specific Immunity• Humoral ~• Cellular ~

• 三 .Immunity to extracellular bacterial infections• 四 . Immunity to intracellular bacterial infections(cellular immunity)• 五 .Immunity to exotoxins （ Anti-toxins ）

§4. Occuring and Developing of

Infections • 一 .Origins of infections• (一 )Exogenous infection

• 1.Patients

• 2.Carriers

• 3.Animals : suffering from disease

• (Carrying B)

• (二 )Endogenous infection

二 .Ways of infection transmission • 1.Respiratory tract

• 2.Gastrointestinal tract

• 3.Wound / injury

• 4.Contact

• 5.Bites by insects

• 6. Multiple ways

• (一 )No-infection

• (二 )Inapparent infection

• (三 )Latent infection

• (四 )Apparent• 1.Acute infection

• 2.Chronic infection

• Infection Sites

• 1.Local infection

• 2.Systemic infection

• (1)toxemia• (2)bacteremia• (3)septicemia• (4)pyemia• (5)endotoxemia• (五 ) Carrier

• 四 .Influence of Environment on Infection• ( 一 )Natural environment• ( 二 )Social environment

• Chapter 6

• Principles of Diagnosis, Prevention and Treatment for Bacterial Infections

§1. Diagnosis of B

• 一 .Specimens• 1.diseases and sites;

• 2.aseptic

• 3.before using antibiotics

• 4.from obvious diseased sites

• 5.fresh , quickly send to lab

• 6.cold

• 7.labeled

二 .Procedures of Diagnosis • (一 ) Microscopy & stains• (二 )Culture• (三 )Biochemical reaction• (四 )Serology• (五 )Animal test• (六 )Drug sensitivity• (七 )etc• 1.HPLC • 2.PCR • 3.Phage• 4.Bacteriocin• 5.Plasmid fingerprinting

( 一 )Dead Vaccines

( 二 )Live Attenuated Vaccines

( 三 )Toxoid

( 四 )Polysaccharide

( 五 )Autovaccine

§4. Artificial Passive Immunization

• ( 一 )Anti-toxin

• ( 二 )Anti-Bacterial Serum

• ( 三 )Placental globulin , γ ~

• ( 四 )Preparations for CI:

TF,iRNA,IFN,IL,CTL,LAK,etc.