Bacterial Infection and Pathogenesis

infection Conception factors pathogen virulence 、 amount 、 route host non-specific immunity specific immunity environment

source exogenous infection patient carrier animal endogenous infection normal flora latent pathogen

transmission portals of entry of pathogen respiratory tract gastrointestinal tract skin sex attach multiple

types of bacterial infection inapparent infection apparent infection acute infection chronic infection local infection systemic infection

types of systemic infection bacteremia toxemia endotoxemia septicemia pyemia ）

pathogenesis pathogen pathogenicity virulence LD 50 / ID 50 毒力基因的表达及其调节 pathogenicity isoland ， PAI ） two-component signal transduction system cell signal transduction

bacterial pathogenicity virulence invasiveness toxin numbers portals of entry

invasiveness adherence ） pilus: type I pili ， P pilus CFA/I ， CFA/II adhesin capsule ， microcapsule bacterial biofilm invasive enzyme

Mannose Type 1 fimbriae (adhesin) E. coli Bladder

biofilm 20  m

biofilm

细菌生物膜 粘附、增殖、成熟、脱落

exotoxin Definition: a soluble protein toxin usually secreted from a living bacterium. Origin and release: produced by Gram-positive bacteria as well as Gram-negative cells Physical and chemical properties: proteins and usually heat-labile.

exotoxin neurotoxin cytotoxin entrotoxin

endotoxin Origin and release: produced only by Gram-negative bacteria and released only when bacteria lyze. Chemical and physical properties: lipopolysaccharide of the outer membrane of Gram-negative bacteria; heat-stable

Biological activity of endotoxin fever leukopenia endotoxemia shock DIC Enhance the non-specific immunity