Pathogenesis o Pathogenesis is a multi-factorial process which depends on the immune status of the host, the nature of the species or strain(virulence factors)and the number of organisms in the InItial exposure
Pathogenesis ⚫ Pathogenesis is a multi-factorial process which depends on the immune status of the host, the nature of the species or strain (virulence factors) and the number of organisms in the initial exposure
Source of infection o Exogenous infection: patient, carrier, diseased animal or animal carrier o Endogenous condition: most are normal flora cause infection under abnormal condition Routes of infection Transmission Respiratory Gastroenteric Airborne droplets ● Genitourinary tract Food ● closely contact Water insectbitting ● blood transfuse0m Sexual contact ● Parenteral route ● Mucous membranes
Source of infection ⚫ Exogenous infection : patient, carrier, diseased animal or animal carrier. ⚫ Endogenous condition : most are normal flora, cause infection under abnormal condition. • Airborne droplets • Food • Water • Sexual contact Transmission ⚫ Respiratory ⚫ Gastroenteric ⚫ Genitourinary tract ⚫ closely contact ⚫ insect bitting ⚫ blood transfusion ⚫ Parenteral route ⚫ Mucous membranes Routes of infection
According to According to infectious state infectious sites Local infection o Inapparent or subclinical infection e Generalized or systemic Latent infection infection 1. Toxemia: is the presence of parent infection: cause exotoxins in the blood apparent clinic syndrome 2. Endotoxemia: is the presence e Carrierstate: carrier of endotoxins in the blood 3. Bacteremia is an invasion of the bloodstream by bacteria 4. Septicemia: illness that occurs when poisonous substances (toxins) produced by certain bacteria enter the bloodstream 5. Pyemia: is caused by pyogenic microorganisms in the blood
According to infectious sites ⚫ Local infection ⚫ Generalized or systemic infection 1. Toxemia : is the presence of exotoxins in the blood. 2. Endotoxemia : is the presence of endotoxins in the blood. 3. Bacteremia : is an invasion of the bloodstream by bacteria. 4. Septicemia : illness that occurs when poisonous substances (toxins) produced by certain bacteria enter the bloodstream. 5. Pyemia : is caused by pyogenic microorganisms in the blood. ⚫ Inapparent or subclinical infection ⚫ Latent infection ⚫ Apparent infection : cause apparent clinic syndrome ⚫ Carrier state: carrier According to infectious state
TABLE 7-1 Types of Bacterial Infections Type of Infection Examples apparent (subclinical) No detectable clinical symptoms Asymptomie gonorrhea in women of infection and men Dormant (latent Carmer state ephod cartier Zoonosis or environmental or Anthrax, cryptococcal infection. inadvertent exposures and laboratory exposure, respectively Opportunistic I by normal flora 洲m nf or Candida infection of the nar tract Prima invasion and in body tissues using local tissue injury) Microbial invasion subsequent to serial pneumonia primary intection wing viral lung infection Mixed wo or more microbes infecting Anaerobic abscess the same tissue (E col and Bacteroides fragilis) Acute Rapid onset (hours or days) Diphtheria bnef duration(days or weeks) Prolonged duration (months or years) Localized Confined to a small area or to an argar Staphylococcal boil Generalized Disseminated lo many body regions Tam.n egative bacteremia PUS-forming Staphyloccal and Retrograde s ascending in a duct or tube E cof urinary tract infection the fiow of secretions Fulminant elections that occur suddenly Airbome Yersina pest and intensely (pneumonic plague)
BACTERIAL VIRULENCE FACTORS ADHESION EXOTOXIN CAPSULE VIRULENT SURFACE PROTEINS VIRULENGE PLAMID E VIRULENT ENZYME BINDING PROTEIN LPs FLAGELLA Environmental signals often control the expression of the virulence genes Common signals include: Temperrature/ron availability: C diphtheriae Alow ion/Osmolality/Growth phase/pH/Specific ions
Environmental signals often control the expression of the virulence genes. Common signals include:Temperrature/Iron availability : C diphtheriae /low ion/Osmolality /Growth phase/pH/Specific ions BACTERIAL VIRULENCE FACTORS