Infection Biology Flashcards
Cause disease only in immunocompromised people
Opportunistic pathogens
Microbes that can cause disease
Pathogens
Measure of a microbe’s ability to cause disease
Virulence
Virulence factors
Capsules
Exotoxins
Endotoxins
Number of organisms required to cause disease in 50% of the population
ID50
Presence of microbes in the body and symptoms of disease
Infection
Mechanisms of bacterial disease
Production of toxins
Induction of inflammation
Modes of Transmission: Human to Human
Direct: sexual or transvaginal Fecal-oral Inhalation Transplacental Blood-borne
Modes of Transmission: Nonhuman to Human
Soil Water Direct animal source Vector-borne Animal excreta Fomites
Surface proteins that mediate binding to endothelium and to extracellular proteins such as fibronectin
Curli
Spread through subcutaneous tissue
Hyaluronidase (destroy connective tissue)
Collagenase
Accelerates formation of a fibrin clot coating organisms with a layer of fibrin
Coagulase
Allows adherence to mucous membranes
Immunoglobulin A (IgA) protease
Destroys both neutrophilic leukocytes and macrophages
Leukocidin
Leukocidin of Staphylococcus aureus
Panton Valentine Leukocidin (PV Leukocidin)
Bacteria with IgA protease
Streptococcus pneumonia
Haemophilus influenzae
Neisseria meningitidis
Neisseria gonorrhoeae
Protect against phagocytosis; Antiphagocytic factor
Polysaccharide Capsule
Proteins produced to attach to bacteria to be easily engulfed
Opsonins
Anticapsular antibodies allow more effective phagocytosis to occur
Opsonization
Cell protein of S. pyogenes: antiphagocytic
M protein
Cell wall protein of S. aureus that prevents complement activation
Protein A
Source of Exotoxin
Gram (+) and (-)
Source of Endotoxin
Gram (-)
Secreted from cell: Endotoxin or Exotoxin?
Exotoxin
Chemistry of Exotoxin
Polypeptide
Chemistry of Endotoxin
Lipopolysaccharide
Location of genes: Exotoxin
Plasmid or Bacteriophage
Location of genes: Endotoxin
Bacterial chromosome