bacterial infections Flashcards
community acquired infections: define an outbreak of infectious disease and explain how outbreaks are identified; list bacterial pathogens that cause community acquired infection, explain the routes and types of infection caused, and list important bacterial virulence factors
components of bacterial cell
ribosomes, DNA, cell wall, cytoplasm, cell membrane; capsule, flagellum, pili
common virulence factors
diverse secretion systems, flagella (move, attach), pili (adhere), capsule (protect vs phagocytosis), endospores (dormant bacteria which are temperature, dessication and chemical resistant), biofilms (organised aggregates which cause antibiotic resistant), endotoxins, exotoxins
bacteria with capsule
Step. pneumoniae
2 bacteria with endospores
Bacillus sp., Clostridium sp.
2 bacteria with biofilms
Pseudomonas aeruginosa, Staph. epidermidis
5 types of exotoxins and what they act on/stimulate/allow
neurotoxins (act on nerves or motor endplate), enterotoxins (act on GI tract), pyrogenic exotoxins (stimulate release of cytokines), tissue invasive exotoxin (allow bacteria to destroy and tunnel through tissue), miscellaneous exotoxin (specific/not well understood)
examples of bacteria producing neurotoxins
Tetanus, Botulinum
examples of bacteria producing enterotoxins (infectious diarrhoea)
V. cholera, E. coli
examples of bacteria producing enterotoxins (food poisoning)
B. cereus, Staphy. aureus
examples of bacteria producing pyrogenic toxins
Staph. aureus, Strep. pyogenes
what do bacteria which cause tissue invasive exotoxin contain
enzymes that destroy DNA, collagen, fibrin, RBC, WBC etc.
examples of bacteria causing tissue invasive exotoxin
Staph. aureus, Strep. pyogenes
example of bacteria causing miscellaneous exotoxin
B. anthracis
what is an endotoxin
lipid A component of LPS (not protein) in gram -ve bacteria
gram +ve vs gram -ve
gram +ve has thick peptidoglycan layer, gram -ve has thin peptidoglycan layer and another layer of LPS
why can treating patient with gram -ve infection with antibiotics sometimes worsen condition
bacteria lyse, releasing large quantities of LPS and endotoxin, causing septic shock