Infection Flashcards
3 mechanisms through which bacteria can cause disease
- Directly eg cell destruction
- Exotoxin production
- Activate immune system
Process of gram staining bacteria
CIAS Crystal violet Iodine Alcohol Safranin
What is gram positive bacteria
Bacteria that retain crystal violet stain because of thick peptidoglycan wall
PURPLE
What are gram negative bacteria
Bacteria with thin peptidoglycan cell wall so crystal violet stain washes out and counter stain with pink safranin remains
Name gram -ve cocci
Neiserria meningitidis (aer)
Neiserria gonorrhoea
Moraxella catarrhalis
Name gram - rods and infection
- E coli
- Klebsiella pneumoniae and oxytoca (UTI)
- Proteus murabilis
- Shigella
- H pylori
- Typhoid
- whooping
Name gram + cocci and infection
- Staph (coag + = aureus, coag - = epidermis) skin + st infections
- Strep
pneumoniae
beta haemolytic = nec fasc, cellulitis
vividans = endocarditis - Enterococcus
faecalis = amox sens
faecium = amox neg
endocarditis + abdo infection
Name gram + rods
- Actinomyces = coil
- Bacillus cereus = rice
- Corynebacterium = diptheria
- Listeria = food, meningitis
- C diff
What does Ziehl Neelsen stain pick up
Acid fast bacilli ( rods that are ?mycobacteria, nocardia)
TB typical tx
6 MONTHS RIPE rifampicin isoniazid pyrazinamide ethambutol
Dyes used in ZN stain
malachite green
or methylene blue
HSV appearance
fried egg
What kind of infections does HSV cause
HSV1 - oral
HSV2- genitals
HSV tx
Aciclovir
Tx of influenza
Tamiflu = Oseltamivir
What drug are anaerobes most sensitive to
metronidazole
aerobes
gram -ve cocci = n men
gram + rods = diptheria + listeria
Main mechanisms of AMR
- Enzyme production
- changes to antimicrobial target/pathway
- efflux pumps
3 big resistant pathogens
Methicillin resistant staph aureus (MRSA)
Vancomycin resistant enteroccoci (VRE)
Extended spectrum beta lactamase producing enterobacteriacae (ESBL)
UTI RF
DM Pregnancy Impaired voiding GU malformation Prostatic hypertrophy Renal stones
Organisms causing sore throat
- Viral
- Bacterial = group A beta haemolytic strep
also group C/G step - Bacterial = corynebacterium diptheria
- fusobacterium necrophorum
What criteria is used to see if abx should be given for sore throat
Centor to rule in/out group a strep
- fever?
- inflammation?
- no cough or runny nose
- present within 3 days
- pus on tonsils
Management of group A strep pharyngitis
- 10 days oral penicillin V or macrolide like clarithromycin if allergy
- isolate if in hospital
What happens if you don’t treat group A strep pharyngitis
- quinsy (paratonsillar abscess)
- scarlet fever
- rheumatic fever
- glomerulonephritis
- nec fasc
How can diptheria manifest
- pharyngitis/tonsilitis(stuck)
2. myocarditis, neuropathy
Features of mono
Fever, tired, sore throat
lymphadenopathy
splenomegaly
rash if given amoxicillin
EBNA
+ for EBV 2 months later
Management of mono
symptomatic
avoid contact sports for 6 weeks risk of splenic rupture
Organisms usually causing otitis media + sinusitis
- viral
- strep pneumoniae (mastoiditis and meningitis risk)
- haemophilus influenzae
Symptoms of OM/sinusitis
Fever, pain, tenderness
- deafness, dizziness
Organism causing acute epiglottitis
Haemophilus influenzae B