Community-acquired pneumonia due to Legionella pneumophila, the utility of PCR, and a review of the antibiotics used

Paul Zarogoulidis^1,2, Ioanna Alexandropoulou^1,2, Gioulia Romanidou³, Theocharis G Konstasntinidis^1,2, Eirini Terzi³, S Saridou¹, Athanasios Stefanis¹, Kostas Zarogoulidis^1,2, TC Constantinidis^1,2
1Regional Laboratory of Public Health, East Macedonia-Thrace, Komotini, Greece; ²Laboratory of Hygiene and Environmental Protection, Medical School, Democritus University of Thrace, Komotini, Greece; ³Department of Internal Medicine, General Municipal Hospital (“Sismanoglio” of Komotini), Komotini, Greece

Introduction: There are at least 40 types of Legionella bacteria, half of which are capable of producing disease in humans. The Legionella pneumophila bacterium, the root cause of Legionnaires’ disease, causes 90% of legionellosis cases.
Case presentation: We describe the case of a 60-year-old woman with a history of diabetes mellitus and arterial hypertension who was admitted to our hospital with fever and symptoms of respiratory infection, diarrhea, and acute renal failure. We used real-time polymerase chain reaction (PCR) to detect L. pneumophila DNA in peripheral blood and serum samples and urine antigen from a patient with pneumonia. Legionella DNA was detected in all two sample species when first collected.
Conclusion: Since Legionella is a cause of 2% to 15% of all community-acquired pneumonias that require hospitalization, legionellosis should be taken into account in an atypical pulmonary infection and not be forgotten. Moreover, real-time PCR should be considered a useful diagnostic method.

Keywords: Legionnaires’ disease, Lionella pneumophila