Atypical aetiology in patients hospitalised with community-acquired pneumonia is associated with age, gender and season; a data-analysis on four Dutch cohorts.

BACKGROUND: Microorganisms causing community-acquired pneumonia (CAP) can be categorised into viral, typical and atypical (Legionella species, Coxiella burnetii, Mycoplasma pneumoniae, and Chlamydia species). Extensive microbiological testing to identify the causative microorganism is not standardly recommended, and empiric treatment does not always cover atypical pathogens. In order to optimize epidemiologic knowledge of CAP and to improve empiric antibiotic choice, we investigated whether atypical microorganisms are associated with a particular season or with the patient characteristics age, gender, or chronic obstructive pulmonary disease (COPD). METHODS: A data-analysis was performed on databases from four prospective studies, which all included adult patients hospitalised with CAP in the Netherlands (N = 980). All studies performed extensive microbiological testing. RESULTS: A main causative agent was identified in 565/980 (57.7 %) patients. Of these, 117 (20.7 %) were atypical microorganisms. This percentage was 40.4 % (57/141) during the non-respiratory season (week 20 to week 39, early May to early October), and 67.2 % (41/61) for patients under the age of 60 during this season. Factors that were associated with atypical causative agents were: CAP acquired in the non-respiratory season (odds ratio (OR) 4.3, 95 % CI 2.68-6.84), age <60 year (OR 2.9, 95 % CI 1.83-4.66), male gender (OR 1.7, 95 % CI 1.06-2.71) and absence of COPD (OR 0.2, 95 % CI 0.12-0.52). CONCLUSIONS: Atypical causative agents in CAP are associated with respectively non-respiratory season, age <60 years, male gender and absence of COPD. Therefore, to maximise its yield, extensive microbiological testing should be considered in patients <60 years old who are admitted with CAP from early May to early October. TRIAL REGISTRATION: NCT00471640 , NCT00170196 (numbers of original studies).

Pharmacokinetics of oral vs. intravenous dexamethasone in patients hospitalized with community-acquired pneumonia.

AIM: The use of corticosteroids as adjunctive therapy might be effective in patients with community-acquired pneumonia (CAP). Oral administration of dexamethasone is a practical and safer alternative to the intravenous route. Since patients hospitalized with pneumonia might have delayed gastric emptying, this study explored systemic exposure in terms of area under the concentration-time curve (AUC) of oral dexamethasone in patients hospitalized with CAP. METHODS: In this randomized, open label study, 30 patients admitted with CAP were randomized to receive either 4 mg intravenous or 6 mg oral dexamethasone for 4 consecutive days. Serial blood samples were obtained before and after drug administration. RESULTS: Median AUC to infinity was 626 µg l(-1) h (IQR 401-1161) for the intravenous group and 774 µg l(-1) h (IQR 618-1146) for the oral group. The AUC ratio of 6 mg oral and 4 mg intravenous dexamethasone was 1.22 (95% confidence interval (CI) 0.81, 1.82), which represents a bioavailability of 81% (95% CI 54, 121) after correction for differences in dexamethasone dose. CONCLUSIONS: Bioavailability of oral dexamethasone in patients hospitalized with pneumonia is sufficient. This makes oral dexamethasone an appropriate alternative for intravenous administration in these patients.