Virulence Factors of Bacteria

Flagella

 Motility

 Gain access to anatomic areas

 Escape from phagocytes

Capsules

 Antiphagocytic function

Pili

 Attachment

Coagulase

 Produce clots for hiding

Kinases

 Dissolve clots

Hyaluronidase

 Dissolves hyaluronic acid

Lecithinase

 Destroys cell membrane

Necrotizing Enzymes

 Massive destruction of tissues

Endotoxin

 Gram negative

 Release from cell wall (outer membrane) through cell lysis

 Fever, diarrhea, vomiting

 Septic shock

Exotoxin

 Produce within the cell

 Release from cell

Endotoxin

 Lipopolysaccharide-lipoprotein complexes

 Extremely heat stable

 Weakly toxic (rarely fatal)

Endotoxin

 Poor immunogen (not sufficient to neutralize toxin)

 Toxoid (none)

 Pyrogenic

Exotoxin

 Proteins

 Gram – and Gram +

 Heat stable

 Cytotoxin, enterotoxin, neurotoxin

Exotoxin

 Highly toxic (fatal)

 Highly immunogenic (stimulate production of antitoxin) toxoid neutralizing antibody

 Do not produce fever

Neurotoxin

Enterotoxin

Exfoliative toxin

Toxic Shock Syndrome Toxin

Leukocidins

Erythrogenic Toxin

Diptheria toxin

Types of Exotoxin

Neurotoxin

 Damage to CNS

- Tetanus and botulinum toxin

Enterotoxin

 Gastrointestinal diseases

Exfoliative toxin

 SSSS (Staphylococcal Scalded Skin Syndrome)

 S. aureus

Toxic Shock Syndrome Toxin

S. aureus

Leukocidins

 Destruction of leukocytes

Erythrogenic Toxin

 Scarlet fever

S. pyogenes

 Diptheria

 Corynebacterium diptheriae