Bacteria Chapter 20 Clostridium- Bacillus Flashcards
what type of microbe is clostridium
- gram positive rods
- endospore forming
- obligate anaerobic
- environment (soil) and intestinal mucus
what color do the endospores in clostridium stain
green
what is the virulence factor for clostridium
- spore formation
- spores are resistance against destruction or sterilization
- spores are not subject to antibiotics
what does clostridium botulinum cause
-botulism
- severe form of food poisoning
- paralysis
what is wound botulism possible from
soil or fecal contamination
what is infant botulism and when does it resolve
- occurs in 3-20 week infants without full intestinal flora
- causes muscle weakness but rarely severe and generally resolves as intestinal flora develops
what are the virulence factors for clostridium botulinum
- botulinum neurotoxin blocks acetylcholine release
- flaccid muscles including respiratory paralysis -> death
is there tissue invasion in clostridium botulinum
no it acts through toxins
while spores are _____, botulinum toxin is _______
heat stabile, heat labile
how long does anti toxin neutralization take
weeks to months
describe the neurotoxins in clostridium botulinum
- proteolytic and saccharolytic
what is another toxin effect of clostridium botulinum
no wrinkles and flaccid paralysis
what are opportunities for anaerobic growth of C. tetani
dirty, puncture wounds like knife, bullet, tattoo
what are the virulence factors for clostridium tetani
- tetanospasmin blocks GABA and glycine release -> loss of inhibitory input to motor neuron excitation -> uncontrolled muscle contraction “ spastic paralysis”
- toxin effect may be localized and one sided ; anti-toxin usually too late
what does tetanus toxin prevent
muscle relaxation
tetanus effects can be ____ or _____
general or localized
what can prevent neonatal tetanus death by umbilical infection
passive immunization of pregnant women
what is the vaccine for tetanus
DTP vaccine with tetanus toxoid
- 10 year booster vaccination is standard
what is the only clostridium species with tissue invasion
clostridium perfringens
what are the virulence factors for clostridium perfringens and what do they do
- alpha toxin-> membrane destruction
- omega toxin -> cytolytic toxin
- collagenase, hyaluronidase : facilitates tissue invasion from the edges of necrotizing tissues
what causes gas gangrene of clostridium perfringens
- anaerobic fermentation of amino acids -> gas increase (H2 and CO2)
what is the mortality rate for clostridium perfringens
40-100%
what causes uterine gangrene
puerperal fever
is there vaccine for clostridium perfringens
no
what does antibody do to alpha toxin
fails to stop gas gangrene: amputate
does clostridium difficile invade tissue
acts through toxins
what does antibiotic associated pseudomembranous colitis result from
broad spectrum antibiotics that kill much of the other normal intestinal bacterial flora, giving resistant species like toxin producing clostridium difficile a chance to take over
what is another name for clostridium difficile
-hospital diarrhea
what are the virulence factors for clostridium difficile and what does each do
- toxin A: inhibits intestinal tight- junctions -> fluid leak
- toxin B: rounding of epithelial cells -> fluid leak
- diarrhea results from both
what is the treatment and epidemiology for clostridium botulinum
- botulinum antitoxin
- environment
and GI tract
what is the treatment and epidemiology for c tetani
- toxoid vaccination and anti-tetanus serum
- environment and GI tract
what is the treatment and epidemiology for c. perfringens
- surgery intervention and amputation
- environment and GI tract
what is the epidemiology for C difficile
- colonized intestines, genital tract
- hospital environment
- prior antibiotics
describe bacillus anthracis
- zoonotic infection “woolsorter’s disease”
- gram positive rods, facultative anaerobes
what are the virulence factors for anthrax toxins and what do each cause
- EF: adenylate cyclase -> cAMP increase -> edema
-LF: metallo- protease -> cell death with pulmonary edema - poly- glutamic acid capsule: inhibition of phagocytosis
what is anthrax caused by
when spores germinate and produce toxins
inhalation anthrax:
- entry lungs, uptake by lung phagocytes - latency of 2 months or more may occur
- to lymph nodes - pneumonial and meningitis type symptoms are seen
- bloodstream -> powerful toxins (macrophage TNF alpha: toxic shock death in 1-2 days)
gastrointestinal anthrax:
- ulcers in mouth, esophagus -> edema and sepsis
- lethality if in lower intestines: 100%
what does macrophage TNF increase cause
toxic shock and death
describe skin anthrax and what is the lethality
- redness (inflammatory cytokines)
- edema with vascular and vesicle rupture
- lethality - 20%
what is the epidemiology for bacillus anthracis
- animal workers
- microbiological accidents
- bioterrorism
- contaminated meat
what does bacillus cereus cause
-gastroenteritis, ocular infections, bacteremia
- heat stable and heat labile toxins, necrotic toxins
what is bacillus sp mostly resistant to
penicillin
what type of microbe is bacillus
-gram positive rods
- strict aerobes or facultative anaerobes
