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| Bacillus - aerobic or anaerobic? |
Bacchus - wine - aerobic |
| Clostridium- aerobic or anaerobic? |
closet - no air - anaerobic |
| What is unique about bacillus anthracis? |
capsule made of protein -- others are made of polysaccharides |
| B. anthracis exotoxin - EF |
EDEMA FACTOR. A subunit, action. Increases cAMP --> impairs neutrophil fxn, causes massive edema |
| B. anthracis exotoxin - LF |
LETHAL FACTOR. Stimulates macrophage release of TNFa and IL-1 |
| B. anthracis exotoxin - PA |
PROTECTIVE ANTIGEN. B subunit - promotes entry of EF into cells. |
| Dysphagia and diplopia, followed by muscle weakness after eating canned foods |
Clostridium botulinum, ate the toxin in the food, need to be intubated |
| Baby ate honey |
Clostridium botulinum, ate spores --> spores in GI tract --> release of toxin in the intestines --> floppy baby --> excellent prognosis |
| Spores or toxin in tetanus? |
Spores enter the body through skin trauma --> releases toxin called tetanospasmin |
| What does tetanospasmin do? |
acts on inhibitory Renshaw cell interneurons preventing the release of GABA and glycine, both are inhibitory NT's --> sustained tetanic contractions |
| Pt presents with lockjaw -- looks like a big grin |
Clostridium tetani |
| What is the test for Clostridium difficile? |
find TOXIN (not spore) in stool samples |
| Mechanism of C. difficile infection |
C. difficile makes toxin --> damage superficial layers of the colon (doesn’t invade) --> pseudomembranes |
| How to treat C. difficile infection? |
Pseudomembranous enterocolitis. Metronidazole and vancomycin -- runs through GI and doesn't get absorbed into bloodstream. |
| Pseudomembrane on pharynx - pediatric patient |
Corynebacterium diptheriae |
| What is the mechanism of damage by Corynebacterium diptheriae? |
exotoxin --> interfere with protein synthesis --> damages heart and neural cells |
| K+ tellurite culture - black colonies |
Corynebacterium diptheria |
| Loeffler's medium (can see reddish granules) |
Corynebacterium diptheria |
| how Corynebacterium diptheria gets its toxin |
lysogenic conversion by a temperate bacteriophage |
| Listeria monocytogenes - cause of meningitis in two groups |
neonates and immunocompromised |
| How to confirm bacterial meningitis? |
Lumbar puncture: CSF with hi neutrophils, high protein, low glucose, gram stain showing organisms) |
| Which organisms cause pseudomembranes? |
Clostridium difficile and Corynebacterium diphtheriae |
| Gram stain for corynebacterium diphtheriae |
G+ rod |
| Gram stain for haemophilus influenzae |
G- rod |
| Gram stain for Moraxella catarrhalis |
G- diplococcus |
| Gram stain for Pseudomonas aeruginosa |
G- rod |
| Gram stain for Klebsiella pneumoniae |
G- fat rod surrounded by mucoid capsule |
| How to see Legionella pneumophila |
IF stain or Dieterle silver stain |
| IgA1 |
Neisseria meningitidis - cleaves IgA in half! |
| What bacteria can extract Fe from human transferrin without requiring energy? |
Neisseria meningitidis |
| What other bacteria can obtain Fe from human transferrin or lactoferrin? |
E. coli (Fe-binding siderophore) |
| Where does Neisseria meningitidis live on the body? |
Nasopharynx |
| At-risk groups for Neisseria meningitidis infection |
1. Infants aged 6 months to 2 years (when children don't yet manufacture their own antibodies and mom's abs are not effective anymore), 2. Army recruits in boot camp (carrier rates > 40%) |
| What should you suspect if baby <2 or army recruit comes in with petechial rash? |
Neisseria meningitidis -biopsy the petechiae and you should see diplococci on gram stain |
| If baby has bulging open anterior fontanelle |
meningitis in neonates |
| Patient is lying supine with leg at 90 angle to trunk. If extension of leg causes pain…. |
Kernig's sign --> meningitis. leg is fully bent in the hip and knee, and subsequent extension in the knee is painful (leading to resistance).[3]. This may indicate subarachnoid haemorrhage or meningitis. |
| Patient involuntarily lifts legs/arms when head is lifted and patient is restrained from sitting up. |
Meningial irriation. Meningitis. Brudzinski's sign |
| How to diagnose meningitis? |
Spinal tap and seeing the organism in the CSF |
| When would you use chocolate agar? |
When Neisseria is suspected (it's blood agar that's been heated) |
| When would you use Thayer-Martin VCN media? |
When Neisseria is suspected. Chocolate agar with abx: vancomycin (kills G+), colistin (kills all G- except Neisseria), nystatin (kills all fungi) |
| How to tell N. meningitidis from N. gonorrhea? |
N. meningitidis ferments maltose while the other does not (meningitidis has an "m" in the name) |
| Man comes in with painful urination and purulent urethral discharge |
N. gonorrhea infection. |
| How to treat N. gonorrhea infection? |
Ceftriaxone. |
| How does N. gonorrheal infection in women present? |
Asymptomatic urethritis, minimal urethral discharge, dyspareunia (painful intercourse) |
| Fitz-Hugh-Curtis syndrome |
N. gonorrhea or Chlamydia infection of capsule surrounding liver. |
| What is most common type of septic arthritis in young, sexually active individuals? |
N. gonorrhea |
| What is most common type of septic arthritis in infants? |
Haemophilus influenzae |
| What causes epiglottitis? |
Haemophilus influenzae Type B. |
| Under microscope, where would you look for Neisseria? |
Inside WBC's |
| Why are babies given that eye gel when they are born? |
Erythromycin eye drugs to protect against N. gonorrhea and chlamydia (can lead to blindness) |
