Infection by systems (pulmonary) Flashcards
Expected pathogens of community-acquired pneumonia (CAP)
Typical: streptococcus pneumoniae, Haemophilus influenzae
Atypical : mycoplasma pneumoniae, chlamydia pneumoniae, legionella pneumophila
Expected pathogens of hospital-acquired pneumonia (HAP)
- Streptococcus pneumoniae
- Haemophilus influenzae
- Pseudomonas aeruginosa
- Coliforms eg. E.coli
- Other gram -ve bacteria eg Acinetobacter
- MRSA
Hospital-acquired pneumonia (HAP) is pneumonia which occurs ____after hospital admission
≥ 48hrs
Ventilator-associated pneumonia (VAP) is pneumonia which occurs _____ after endotracheal admission
48-72 hrs
Aspiration pneumonia is from aspiration of food/mouth flora/ gastric content in patients with _____, _____ or _____
aspiration of food/mouth flora/ gastric content in patients with poor gag reflex, difficulty swallowing or loss of consciousness
Expected pathogens of aspiration pneumonia
- Patient’s mouth flora (streptococci, anaerobes)
- HAP pathogens if patient has been in hospital
Infections in immunocompromised : rare pathogens are
Candida species, Aspergillus species (bone marrow), Pneumocystis jirovecii (HIV)
To test for CAP and HAP bacteria, order:
Gram stain, culture & sensitivity (C&S)
To test for virus/atypical bacteria, order:
PCR
If patient is septic or pyrexial, order:
blood culture
Extra test for immunocompromised patients:
fungal culture
Best technique for identifying TB
Acid-fast aerobic bacilli
How does mycobacterium TB spread
Spread via inhalation of droplet nuclei, aerolised by coughing, sneezing, talking
Sputum AFB smear positive means:
highly infectious
Latent TB:
symptomatic?
infectious?
Asymptomatic and non-infectious
Is latent TB able to reactivate?
yes
1) Tests to send for latent TB
2) The tests depend on ______ and CANNOT differentiate ______
- Tuberculin skin test (TST)
- Interferon Gamma Release Assay (IGRA)
The tests depend on cell-mediated immunity and CANNOT differentiate btw active and latent TB
Most common (stage)TB
Post-pri TB
Tests to send for active TB
Step1 : Early morning sputum: 2 specimens
Step 2: AFB staining and culture
How long does TB culture take?
3-8 weeks!
Treatment of TB
Empirical treatment with 4 drugs: Rifampicin, Isoniazid, Ethembutol, Pyrazinamide
Usual duration of TB treatment
6 months
TB drugs CANNOT interact with
HIV drugs eg. lamivudine
Why is MDR TB or XDR TB a problem?
Both are more difficult to manage; treatment options are not as effective and associated with side effects.
Prolonged treatment duration is required.
XDR-TB is associated with poorer outcomes
Normal process for testing (duration)
- Gram stain
- Culture
- Sensitivity
How does the normal process defer from TB process?
- Send for gram stain (gram stain results come back on the day itself)
- Culture (1-3 days) (but some bacteria if need to take longer: 3-5 days)
- Sensitivity: the day after culture results
TB–
Culture: 3-8 weeks
Sensitivity: several weeks after culture
