The aetiology of severe community-acquired pneumonia requiring intensive care unit admission in the Western Cape Province, South Africa

BACKGROUND: Community-acquired pneumonia (CAP) is a common condition, with mortality increasing in patients who require intensive care unit (ICU) admission. A better understanding of the current aetiology of severe CAP will aid clinicians in requesting appropriate diagnostic tests and initiating appropriate empiric antimicrobials. OBJECTIVES: To assess the comorbidities, aetiology and mortality associated with severe CAP in a tertiary ICU in Cape Town, South Africa. METHODS: We retrospectively analysed a prospective registry of all adults admitted to the medical intensive care unit at Tygerberg Hospital with severe CAP over a 1-year period. RESULTS: We identified 74 patients (mean (SD) age 40.0 (15.5) years; 44 females). The patients had a mean (SD) APACHE II score of 21.4 (7.9), and the mean ICU stay was 6.6 days. Of the 74 patients, 16 (21.6%) died in ICU. Non-survivors had a higher mean (SD) APACHE II score than survivors (28.3 (6.8) v. 19.4 (7.1); p<0.001). Mycobacterium tuberculosis (n=16; 21.6%) was the single most common agent identified, followed by Pseudomonas aeruginosa (n=9; 12.2%). All P. aeruginosa isolates were sensitive to first-line treatment. No organism was identified in 32 patients (43.2%). CONCLUSION: M. tuberculosis was the single most common agent identified in patients presenting with CAP. The mortality of CAP requiring invasive ventilation was relatively low, with a strong association between mortality and a higher APACHE II score.