Legionella pneumonia

- Outbreak seen in previously fit individuals staying in hotels/institution where shower facilities/cooling systems are contaminated with the organism
- Flu-like symptoms, fever, malaise and myalgia typically precede a dry cough and dyspnea
- associated with hyponatraemia, lymphopenia and diarrhea
- diagnosis is by urinary Legionella antigen test, and four-fold increase in antibody titres
- treatment: Macrolide (Clarithromycin), ciprofloxacin and rifampicin
- mortality is 15-30% especially in elderly