Etiologies and treatment outcomes for out-patients with community-acquired pneumonia (CAP) at Srinagarind Hospital, Khon Kaen, Thailand.

ABSTRACT

Most patients with community-acquired pneumonia are treated as out-patients with empirical therapy, since initially the etiologic agent is unknown. We prospectively assessed the etiologies and treatment outcomes of pneumonia from February 2003 to 2004 at ambulatory clinics. Forty-four patients were included with a mean age of 49.2 (SD 18.2) years. The male to female ratio was 11.4. The incubation period was 6.9 (SD 4.4) days. Half of the patients were healthy. Asthma and COPD were common in patients with underlying diseases. The etiologic diagnosis was determined by a sputum culture and a serology test of paired serum samples. Hemo-culture produced no growth in any patients. Atypical pathogens and H. influenzae were the most common finding, each occurring in 31.8% of the patients followed by S. pneumoniae and H. parainfluenzae (27.3% each). Twenty-two patients were infected with multiple pathogens. C. pneumoniae was the most common co-infecting pathogen. Two of 12 S. pneumoniae isolates were penicillin resistant. Nine of 14 H. influenzae isolates were cotrimoxazole resistant and 8 of 14 were not sensitive to erythromycin. For H. parainfluenzae, 11 of 12 isolates were not sensitive to erythromycin, and 7 of 12 were not sensitive to cotrimoxazole. Oral antibiotics were prescribed as out-patient treatment. Forty patients (90.9%) improved, with symptoms-score improvement averaging 6.4 days. Four patients got worse and needed a change of antibiotics, the symptoms usually worsen within 3-5 days. We conclude that, antibiotics for CAP out-patients should cover atypical pathogens, H. influenzae, S. pneumoniae and H. parainfluenzae. If the clinical symptoms do not respond after 3-5 days of out-patient treatment, resistance or an unusual organism (eg B. pseudomallei) should be considered.