University day - infection (01/03) Flashcards
How to choose an antibiotic?
- Active against organism?
- Reach the site of infection? - BBB, skin, bone
- Formulation - IV vs oral - difficult swallowing etc?
- Half life - determines dosing freq
- Interact with other drugs?
- Toxicity issues?
- Monitoring?
When to think sepsis?
- High NEWS score
- = high risk deterioration
Stratified score for pneumonia
CURB 65
* Confusion
* Urea >7mmol/L
* RR 30 or more
* BP <90 S or <60 diastolic
* Age 65 or more
Investigations for pneumonia
- Bloods - FBC, U&Es, clotting, CRP
- Sputum sample for culture
- Blood culture
- Urine sample - legionella and pneumococcal antigen
- Throat swab for respiratory virus PCR - in viral transport medium
- Consider atypical investigations - cannot usually culture with sputum
HAP vs CAP
- CAP - acute infection of lung tissue with onset outside of healthcare setting or within 48hrs of admission
- HAP - onset after 48hrs of admission
Other types of pneumonia
- VAP - pneumonia devloping >48hrs after intubation and mechanical ventilation (get microaspirations, more gram -ve, and like plastic pseudomonas aeruginosa often)
- Aspiration pneumonia - aspiration of oral and gastric contents into lungs, secondary pneumonia may develop (chemical pneumonitis usually main cause of damage, abx do not always work)
Signs/symptoms of pneumonia
- Cough
- SOB
- Pleuritic chest pain
- Purulent sputum
- Bronchial breathing
- Fevers
- Myalgia
- Rigors
Likely causative organisms for pneumonia
- Streptococcus pneumonia
- Haemophilus influenzae
- Staphylococcus aureus
- Mycoplasma pneumoniae
- Legionella pneumophila
- Chlamydophila pneumoniae
- Moraxella catterhalis
- Klebsiella pneumonia - alcohol dependency
Bold = atypical
Treatment for pneumonia
- Amoxicillin - enterally or IV if cannot take orally
- 2nd line - Doxycycline
- 3rd line - Clarithromycin
Preventing pneumonia
- Pneumococcal vaccine - some protection against streptococcal pneumoniae (but only some serogroups)
- Dose given at 12 weeks, 1yr and over 65
- Prevents pneumococcal sepsis and meningitis too
Other:
* Viral infections can predispose to secondary bacterial infection
* Influenza and COVID vaccine is protective
Features of IECOPD
- Increased SOB
- Increased sputum purulence
- Increase amount of sputum
- Colour change sputum
- CXR does not show consolidation - this would be pneumonia
IECOPD pathogens
- Virus eg RSV, rhinovirus
- Bacterial - same as other causes
Treatment IECOPD
- Do not always need abx
- We usually give amoxicillin if needed
- If resistance - Co-amoxiclav
- 2nd line - Doxycycline
Features to check for UTI
- Symptoms suggesting upper UTI
- Check for sexual infection symptoms
- Check for FH PCKD/any other urinary tract disease
- Any chance pregnancy?
- Any OTC tried?
Common pathogens causing UTI
- Escherichia coli
- Klebsiella pneumoniae
- Enterococcus faecalis
Urine dip interpretattion
- Positive for nitrites, leukocytes and blood - UTI likely
- If nitrite and leukocyte positive - send culture
- If negative for all - do not send culture
When to send culture?
- Pregnant
- Older 65
- Symptoms perisstent or do not resolve with abx
- Recurrent UTI (2 within 6 months or 3 in 12)
- Catheter
- RF for resistance/atypical symptoms
Sample collection for culture
- MSU
- Clean area
- Pass first bit
- Hold urine in
- Then catch mid stream
- Collect in boric acid containing tube - prevents overgrowth, in unavailable, put in fridge
- Catheterised - collect from sampling port and not collection bag (has been sat for a long time)
Problem with ciprofloxacin
- Floroquinolone = MRHA warning
- High risk of toxicity and side effects
- Choose another sensitive abx
How long to treat UTI for?
- Non pregnant women - 3 days
- Men or women with urological abnormalities, pregnancy, diabetes, immunosupression or catheter long term - 7 days
- Pyeonephritis - 10 days if ising beta lactams, 7 days for fluroquinolones
Abx used for UTI
- Trimethoprim
- Nitrofurantoin
- Fosfomycin
- Co-amoxiclav - if pyelo
Most likely pahogens cellulitis
- Staphylococcus aureus
- Streptococcus pyogenes (Group A)
- Group C and G streptococcus (Streptococcus dysgalactiae)
All gram +ve skin commensals
Staphylococcus epidermidis and cellulutis?
- If central venous catheters, portocath etc then often occurs
- Very slow growthing
- Can cause bacteraemia
- But not often cause of cellulitis
- Is usually cause of IE in prosthetic valve - at point of implantation
- Causes several weeks later, low virulance (but within 2 months)
- Also joint replacement
Causative organism for catheter infection
Pseudomonas