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
Group patient at risk of cellulitis
- Any breakage of skin so eg scrape injury
- Severe eczema
- Iatrogenic eg cannula
Preventing cellulitis
- Check sites daily
- Non-touch aseptic technique
- Maintain skin integrity eg in eczema
Treatment for cellulitis
- Flucloxacillin oral if localised and systemically well
- 2nd line - Doxycycline
- IV fluclox if unwell/spread (vancomycin IV if allergic)
Investigations for meningococcal sepsis
- Bloods
- Blood culture
- Assess for increased ICP
- As long as no signs, lumbar puncture
CSF interpretation
- Bacterial - cloudy, elevated WBC, primarily polymorphic neutrophils, elevated protein, low glucose, elevated opening pressure
- Viral - clear, elevated WBC (less than bacterial), primarily lymphocytes, elevated protein (less than bacterial), normal glucose (>60% serum), normal or elevated opening pressure
NEED serum glucose to be done at same time
Also do microscopy, gram stain and culture and PCR (only if needed for PCR)
Causes of meningitis
- Neisseria meningitidis
- Streptococcus pneuminiae
- Listeria monocytogenes - older or immunocompromised adults (also pregnant)
- Streptococcus pyogenes
- TB
- E-coli - esp infants
Treatment meningitis
- Ceftriaxone (meropenem if allergic penicillin)
- IV dexamethasone before abx or within first 12 hours of first abx dose (for strep pneumoniae), stop if not pneumococcas
Age 60 years and older
* Cefrtiazone and Amoxicillin (for listeria)
* Meropenem if allergic
* IV dexamethasone (same again), stop if not pneumococcas
Meningitis notifiable?
YES
* Household contacts may need prophylaxis
Preventing meningitis
- Pneumoccal vaccine
- Men ACWY vaccine
Management of pneumoperitoneum
- Surgery - laparotomy for source control, washout needed
- Need abx for any residual infection as peritoneal caviry usually sterile
- Supportive care - IV fluids, ITU?
Likely organisms of peritonitis
- Enterobacterales
- Streptococci
- Anaerobes
- Enterococci
Need broad spectrum as gram -ve and +ve
Abx for perforated bowel
- Co-amoxiclav
- Ciprofloxacin/cefuroxime/ceftazidime + Metronidazole
- Tazocin
- Meropenem
Infection in surgery cause
From own patient or due to external infection
Timing for surgical site infections
- Up to 30 days
- Extends up to 1 year if prosthesis is inserted
Surgical wound classification
CHECK THIS
Pre op infection prevention
- Shower patients
- Nasal decolonisation
- Hair removal not recommended - clippers not razors
- Scrubs for theatre
- Removal of nails/jewellery
- Abx prophylaxis for some procedures
