UWorld Microbio Notes

denniskwinn's version from 2015-04-25 18:28

MicroBio Connections

Question Answer
Most common cause of aseptic meningitisEnterovirus = ssRNA viruses that include coxsackieviruses, echo, polioviruses - fecal-oral transmission, replicate in GI tract. Do not typically cause gastroenteritis
Fever, headache, feeling weak, photophobia, pain on eye movement - leg weakness (asymmetric), hyporeflexiaPoliovirus
Sexually transmitted viruses that cause meningitisHIV, HSV1&2, EBV,CMV, ***HIV and HSV2 more common
Arbovirusetoga (E,W and Venezuelan equine enceph), flavi(St. Louis), Bunya (California)
Nonseptate hyphae that branch at wide anglesMucor and Rhizopus - cause infection of paranasal sinuses (mucormycosis) - in immunosuppressed patients
Germ cells when incubatedcandida albicans (albicans only)
SpherulesCoccidioides immitis - Exposure in the SW US and Mexico. lung disease and disseminated mycosis - india ink staining of the CSF shows round or oval budding yeast.
Rubeola clinical courseKoplik's spots (blue-white spots on buccal mucosa) then cough, coryza (head cold), conjunctivitis - then followed cutaneous maculopapular rash several days after fever starts starts on the back of the ears and, after a few hours, spreads to the head and neck before spreading to cover most of the body, often causing itching
Legionella outbreakcolonization in water - aerosolized then inhaled. Think Air conditioners and spas
MRSA spreadHealth care workers can be Asx nasal carriers - this leads to wound infections and intravenous catheter related infections
Failed sterilization of mechanical ventilators can lead tonosocomial pneumonia w/E.coli, Klebsiella pneumoa, Acinetobacter, Pseudomonas - large portion of nosocomial occurs in intubated patients
HAV inactivationwater chlorination, bleach, formalin, UV irradiation, boiling to 85C for one minute
Shigella pathogenic mechanismgains access to gut epi - escapes phagosome - spreads laterally - then releases toxin causing cell death (prevents protein synthesis) - does have an exotoxin, but it needs to invade for the toxins to work
Acid fast stain procedureapply aniline dye to a smear and then decolorize with acid alcohol to reveal acid fastness
Anthrax CXRwidened mediastinum
Anthrax microscopylong chains that are described as “serpentine” or “medusa head” on appearance
Anthrax capsulecontains D-glutamate instead of polysaccharide
Viruses enveloped from host nuclear membraneHerpesviruses (HSV1,2, CMV, EBV, VZV, Kaposi)
E. Coli UTI pathogenesisP-fimbriae most important factor - allows them to bind to uroepithelium -
CGD infectionsS.Aureus, Pseudomonas cepacia, Serratia marcesens, Nocardia, Aspergillis - - These are all catalase positive
PID chronic effectsmost likely are ectopic pregnancy and infertility due to salpingitis leading to scarring of fallopian tubes - if not treated appropriately
C.Tetani toxintravels within the motor neuron by retrograde transport into the spinal cord where it causes inhibition of inhibitory and unregulated firing of primary motor neurons -
Wound→neuron axons→salivary glandsrabies virus course - taken up at motor neuron terminal, travels by retrograde axonal transport. Think Cerebral inclusion bodies called Negri bodies are 100% diagnostic for rabies infection
Fibrinous exudate→systemic circulation→cortical neuronsdiptheria route - starts from pseudomembranous exudate to the bloodstream and subsequently to cardiac and cerebral cortical tissues
Food→systemic circulation→meningesListeria route - meningitis in neonates and immunocompromised
Food→systemic circulation→peripheral nervesbotulinum toxin
Rubella vaccinelive attenuated
Rapidly progressive fever, severe sore throat, drooling , progressive airway obstruction and maybe stridoracute epiglottitis - most commonly caused by H.flu -
Mycobacteria virulence microscopyserpentine cords show the presence of cord factor - a mycoside acts by nphil inhibition, mitoch destruction, induced release of tumor necrosis factor
H.Flu grows in presence of S. Aureusneeds factors (exogenous hematin) and V (NAD+) -
Asplenialower antibody synthesis and less phagocytic cells - prone to encapsulated infections - S.pneumonia, H. Influenzae, N. meningitidis