Anaerobic Bacterial Infections Flashcards
Clostridia
what type of anaerobic rods are these?
spore forming
Clostridia
which two Clostridia are the two most potent biological toxins known to humans?
- botulinum
- tetani
Clostridia
4 different disorders
- botulism
- tetanus
- gas gangrene
- c. diff
Clostridium botulinum
3 types
- foodborne
- wound (not as common as the others)
- infant
Clostridium botulinum
what is associated w/ foodborne bot?
canning, smoking, vaccuum packing food
Clostridium botulinum
what is associated with wound bot?
IV drug use
Clostridium botulinum
what is seen with infant bot?
honey ingestion
Clostridium botulinum
what does bot toxin do?
paralysis
Clostridium botulinum
how does bot toxin cause paralysis?
prevents release of ACH at neuromuscular junctions and autonomic synapses
Clostridium botulinum
signs and sx
8 components
- development of sudden, fluctuating, severe weakness w/ intact sensation
- diplopia, loss of accomodation, ptosis, impairment of extraocular muscles, pupils fixed/dilated
- dry mouth
- dysphagia
- dysphonia
- symmetrical paralysis that is descending
- tendon reflexes in tact
- normal sensory exam
Clostridium botulinum
why are infants more susceptible to spores that wouldn’t typically make adults ill?
Infant Bot
incompletely developed intestinal flora
Clostridium botulinum
first sign of infant bot? followed by?
- constipation
- lethargy, poor feeding
Clostridium botulinum
Dx
- notify PH/CDC at first suspicion
- analysis of serum, stool, gastric contents
- consider electrophysiologic studies
Clostridium botulinum
Tx
5 things
- anti-toxin
- give before confirmation if suspicions are high enough
- must be released by PH
- hospitalize pt ASAP
- intubation/mech vent if respiratory failure occured
Clostridium botulinum
Antitoxin contraindication
horse serum allergy
Clostridium botulinum
what do you give for infant bot?
babybig (bot immunoglobin)
Clostridium tetani
pathophys
- produces neurotoxin tetanospasmin
- interferes with neurotransmission at spinal synapses of inhibitory neurons
Clostridium tetani
incubation period
8-12 days
Clostridium tetani
at risk population
unvax people
Clostridium tetani
initial signs & sx
- pt remains awake/alert
- pain at wound site
- spasticity of regional muscles
- jaw muscle stiffness
- stiffness of neck/other muscles
- dysphagia
- irritability
Clostridium tetani
later signs & sx
- hyperreflexia
- spasm of jaw or facial muscles
- rigidity and spasms of abdomen/neck/back
- painful tonic convulsions precipitated by minimal stimuli
- asphyxia if pumlp spasms
Clostridium tetani
dx
clinical observation
Clostridium tetani
tx
- human tetanus immuneglobin 500 units, IM
- wound debridement
- Metrondiazole, 7.5 mg/kg IV/PO, Q6 hrs, 7-10 days
- bed rest
- sedation, paralysis, mech vent often needed
- g-tube nutrition
Clostridium tetani
when must human tetanus immune globin be given by?
w/in 24 hrs of sx onset
Clostridium tetani
prognosis
- high mortality rate with rapid onset & delayed care
- spasms for 3-4 wks
- complete recovery may take weeks
- toxin binding is irreversible, so pt must regenerate new axonal terminals
Clostridium tetani
prevention
natural infection, passive immunization, active immunization
- natural infection does not result in immunity
- passive immunization if unsure of vax status with at risk wound (give immune globin)
- active immunization for adults
Clostridium tetani
Immunization schedule
general series, boosters, pregnancy
- primary immunization: 2 doses 4-6wks apart, 3rd dose 6-12 mo later
- boosters: every 10 yrs or at time of major injury if occurs > 5 yrs after dose
- TDAP with each pregnancy (27-36 wks, but ab concentrations best for baby 27-30 wks)
Clostridial myonecrosis
AKA
gas gangrene
Clostridial myonecrosis
commonly due to?
trauma or IV drug use
Clostridial myonecrosis
where are toxins produced? what do the toxins lead to?
- affected tissue
- shock, hemolysis, tissue necrosis
Clostridial myonecrosis
Signs & sx
- sudden onset
- rapidly worsening pain
- hypotension
- tachycardia
- fever
- delirium
- wound- swelling, pallor, foul smelling drainage
Clostridial myonecrosis
Later changes to wound
- skin turns dusky then deeply discolored
- red fluid filling vesicles
- gas may be palpable in tissue
Clostridial myonecrosis
Dx
- x-ray
- anaerobic culture
Clostridial myonecrosis
tx
- surgical debridement
- PCN, 2 mil units, Q3 hrs
- Clindamycin, 600-900mg IV, Q8 hrs
C. diff
associated with?
recent abx use (as long as 8 wks prior to sx)
C. diff
mode of transmission
fecal oral
C. diff
MOA of infection
disrupts normal bacterial flora in bowel, colonizes the colon and releases 2 toxins
C. diff
most common abx that lead to C. diff?
- fluoroquinolones
- clindamycin
- PCN
- Cephalosporins (2-4th gens)
- Carbapenems
C. diff
signs & sx
- green, foul, watery diarrhea (5-15x daily)
- mucus in stool, rarely bloody
- mild LLQ tenderness
C. diff
signs & sx in severe disease
4 sx, 4 test results
- profuse diarrhea (> 30 per day)
- fever
- hemodynamic instability from hypovolemia
- abd pain/distension
Labs
* WBC: > 30,000
* Albumin: < 2.5
* Elevated serum lactate
* Rising CR
C. diff
why is albumin low with C. diff?
protein losing enteropathy
C. diff
Dx
stool toxin/antigen assay available
* immunoassay for glutamate dehydrogenase (GDH) protein
* PCR for C. diff toxin gene
* Rapid enzyme immunoassy for presence of 2 C. diff toxins
* non-contrast abd CT
C. diff
which test can differentiate colonization vs infection?
rapid enzyme immunoassay
C. diff
what will non-contrast abdominal ct show? when to get one?
- colonic dilation and wall thickening
- with severe/fulminant infections
C. diff
complications
6 things
- hemodynamic instability
- resp failure
- metabolic acidosis
- megacolon (> 7 cm)
- perforation
- death
C. diff
when to consider surgical consult?
10 things
- hypotension
- fever greater than 38.5degC
- ileus or severe abd distension
- peritonitis or severe abd tenderness
- mental status changes
- WBC > 20,000
- serum lactate levels > 2.2
- admission to ICU
- end organ failure
- no improvement after 3-5 of therapy
C. diff
Tx
- complex abx decision tree
C. diff
prevention
- minimize abx use
- don’t suppress gastric acid
- contact precautions in facilities
Corynebacterium diphtheriae
AKA
diphtheria
Corynebacterium diphtheriae
4 forms
- nasal
- laryngeal
- pharyngeal
- cutaneous
Corynebacterium diphtheriae
mode of transmission
respiratory secretions
Corynebacterium diphtheriae
exotoxin causes what 2 things?
- myocarditis
- neuropathy
Corynebacterium diphtheriae
clinical diagnosis
consider diphtheria if relevant clinical sx and incomplete vax
Corynebacterium diphtheriae
incubation period
2-5 days
Corynebacterium diphtheriae
signs & sx
- sore throat
- malaise
- cervial lymphadenopathy
- low-grade fever
- early on: mild erythema/isolated spots of gray and white exudate on pharynx
Corynebacterium diphtheriae
complications
- myocarditis (arrhythmia, heart block, heart failure)
- neuropathy (diplopia, slurring, dysphagia)
Corynebacterium diphtheriae
dx
- clinical dx
- can confirm with pos culture
Corynebacterium diphtheriae
important to detect what not what?
- toxigenic
- non-toxigenic strains
Corynebacterium diphtheriae
tx
- administer antitoxin upon clinical suspicion
- involve PH/CDC in diagnostic/treating if strongly suspected
- erythromycin: 500mg, Q8 hrs, 14 days
Corynebacterium diphtheriae
considerations for antitoxin
- have epi ready, 10% risk of hypersensitivity
- must be obtained from CDC
- dose varies based on severity
Corynebacterium diphtheriae
prevention
- childhood vax series
- TDAP
- booster indicated with exposure
Corynebacterium diphtheriae
prophylactic abx
Erythromycin: 500mg PO, Q8 hrs, 7 days
