Infectious diseases Flashcards
What infections are patients without a spleen at risk of?
Encapsulated organ sepsis.
What are the most important encapsulated organisms for patients who have had a splenectomy?
Meningicocci and streptococci
Gram positive bacteria are what colour?
Purple. Take up the crystal violet and don’t let go.
Gram negative bacteria are what colour?
Pink. The crystal violet washes out and the take up the safrin counter stain.
What bacteria don’t gram stain?
Mycoplasma, coxiella burnetti, ricettsiae, ureaplasma, and mycobacteria (ZN stain needed).
Do gram -ve or +ve form spores?
+ve - like clostrium.
What is the signfiicance of the periplasmic space in gram -ve bacteria?
This space between the cell wall and plasma membrane is used to store abx and inactivate it with enzymes.
What does catalase do?
Turns hydrogen peroxide into hydrogen and oxygen. This means neutrophil burst hydrogen peroxide production is nullified. Staph aureus is catalase positive and causes chronic infections due to this.
The escappm group are interesting because…?
When you treat them with a beta-lactam ab, then they start to produce a beta-lactamase. May not be detected in laboratory testing though because it is switched off at rest.
What is the escappm group of bacteria?
Enterobacter species
Serratia specia
Citrobacter freundi
Aeromonas
Preoteus vulgaris (not! mirabiulus) AND pseudomonas
Providencia
Morganella morganii
What are superantigens?
They bind T-cells potently and non-specifically in the absence of MHC, causing toxic shock syndrome. Typical of staphyloccoal infection.
What is sclalded skin syndrome?
Toxic shock from staph aures produces exfoliative toxin that causes skin to fall off.
Syphillis primary phase looks like what?
Happens 21 days after exposure usually. Appears near site of infection (penis, anus, vagina, pharynx)
What does secondary syphillis look like?
Constitutional symptoms with a rash (maculopapular, doesn’t spare palms and soles), alopecia, hepatitis, GI abnormalities, musculoskeletal symptoms, renal, neurological disease, lymph adenopathy
Does tertiary syphillis cause lymphadenopthy?
No.
What is the most common vitrically transmitted viral disease?
CMV
Why does HIV cause lymphopoenia?
HIV enters CD4 cells and replicates there. It destroys them when it is released.
Hydatid disease in australia is usually from?
Consuming food contaminated by dog faeces.
