Disease primer: Bacterial infections

A bacterial infection is classified according to the site of infection, and sometimes also the source of infection.

Sepsis

Sepsis is a special life-threatening state. Occurs rarely in UTI, mostly in lung infections.

The SOFA-score is often used to assess organ failure in septic patients.

Septic chock is a development of sepsis that is even more severe.

Biomarkers not specific
- 3 markers + WBC (but unspecific)
  - CRP (comes late)
  - PCT (quicker than CRP)
  - IL-6
Microbroth
- Accurate + expensive
Vitek (turbidity), (will be replaced by MALDI-TOF?)
- Not as accurate as microbroth

Efficacy of ABX treatment is judged by signs and symptoms (Are you feeling better than yesterday?), and the course of inflammatory markers (WBC, CRP, PCT)
Most infections can be treated in 5–7 days
Right treatment gets 90% success, wrong treatment gets 60% success (“90/60 rule”)
95% empirical treatment first (“hit hard and hit early” -Paul Erlich), no time to wait for culture results
1. Focus? (sepsis)
- Lung > IAI >> Wounds/UTI
1. Where acquired? Immune deficiency?
- “Pneumonia triade”
1. Additional risk factors for MDR?
2. Co-morbidities?
3. Interactions?
Treatment re-evaluation after 3 days
- 48 h needed to see if ABX works
- Empiric treatment should ideally be switched to targeted treatment once culture results are available (2-3 days)

Probable infection source
1. History
2. Examination (lab tests, x-ray, CT-scan)
Probable bacteria & antibiotic susceptibility
1. Medical training
2. Local epidemiology
Individual resistance risk
1. Previous infection with resistant bacteria
2. Recent travel
3. Hospitalization or antibiotics
Other considerations
1. Allergy
2. Other drugs (interaction risk)
3. Co-morbidities
4. PK

Resistance rates: how many are resistant? In percent.