Bacterial pneumonia Flashcards
What is the definition of community acquired pneumonia (CAP)?
A pneumonia acquired outside of the hospital setting or within 48h hospital admission
*most common. great mortality and morbidity
What is the definition of Ventilator associated pneumonia?
Hospital acquired pneumonia 48h post tracheal intubation
*in ICU being assisted with breathing
What is the definition of hospital acquired pneumonia?
A pneumonia that develops 48h or more post admission to hospital (and was not incubating upon admission)
What is the definition of atypical pneumonia ?
Variable although ‘A pneumonia caused by atypical pathogens that are not detectable by Gram stain and traditional culture’ is common
What are the symptoms of CAP?
- dyspnoea
- cough
- fever
How is CAP treated?
- empirical selection of antibiotic treatment
What is the main causative agent of CAP?
- Streptococcus pneumoniae
- causes 35% of european cases
- can also cause meningitis
- Strep pneumonia is a coccus, stains gram positive (dark purple)
- Lots of people carry it in the nose and mouth as a commensal bacterium – part of normal flora
- Any bacterium that can degrade blood is pathogenic – doing so to obtain nutrients etc
What decreases the incidence of penicillin resistant cases?
PCV vaccine
What is the second most causative agent of CAP?
- Haemophilus influenzae
- does NOT cause flu
- Most virulent – type b (capsule)
- Frequently produce beta-lactamases (degrades beta-lactam antibiotics)
- Hib vaccine has decreased childhood cases
- Isolated from the nose
- Also part of commensal bacteria
- Also virulent by means of capsule
- Gram NEGATIVE bacteria
- Difficult to grow
- Agar made from blood that is heated and changed colour – degrades the haemoglobin - chocolate agar
- Needs a small bit of oxygen
What is involved in diagnosis?
- Blood tests: look for biomarkers e.g. CRP, procalcitonin (if eleveated, infection is present)
- Microbiology: Send a sample for microbiology of sputum that has ideally come from the lungs. Reduces treatment failure risk. Distinguish between natural flora and pathogen, gram stain and culture. Can look for antigens present in the urine for strep and L pneumophila
- Imaging: Thoratic images essential. Chest X-ray up to 75% accurate but CT is the gold standard. CT – cost and radiation exposure, Ultrasound is an accurate tool (cheaper)
What are indicators of how serious the risk is?
- confusion
- Urea in blood
- respiration rate
- Blood pressure
(CURB)
What happens with low risk patients?
Low risk patients: may be admitted if there were struggle in the community (ideally avoid hospital). Give monotherapy (one drug), won’t have any other risk factors or conditions
What happens with moderate risk patients?
Moderate risk patients: admitted to hospital but not to ICU. Need to identify what’s causing the pneumonia –microbiology to asses what drugs to give - combination of antibiotics or quinolone
What happens with high risk patients?
High risk: straight to ICU – combination of drugs given to eradicate as quickly as possible. Combination of antibiotics: beta-lactam plus macrolide or beta-lactam plus quinolone
What are new antibiotics for CAP?
Ceftaroline fosamil completed phase III trial
Solithromycin is a potential new antimicrobial for macrolide resistant bacteria (side chain makes it useful for macrolide resistant)
