Prevalence and clinical features of Chlamydia pneumoniae pneumonia at Srinagarind Hospital, Khon Kaen, Thailand.

Between October 2000 and December 2002, a prospective study was conducted among hospitalized community acquired pneumonia (CAP) patients admitted to Srinagarind Hospital, Khon Kaen, Thailand. The diagnosis of Chlamydia pneumoniae infection was based on serologic testing. The prevalence of C. pneumoniae among patients hospitalized with CAP was 8.7%; 24 cases of 276 hospitalized CAP patients. The mean age was 42.7 (range, 17-79) years and the male to female ratio was 1:2.4. More than half (54.2%) of them were without underlying disease. The mean duration of symptoms prior to admission was 5.5 (SD 3.7) days. Leukocytosis was found in 62.5% of patients. Localized patchy alveolar infiltration was the most common radiographic finding, followed by bilateral interstitial infiltration. Over half (52.4%) of the patients had a non-productive cough. Gram-positive diplococci or no organisms predominated in cases where adequate sputum was obtained. Dual infection was found in 45.8% of cases, mostly with Streptococcus spp or Klebsiella pneumoniae. Four patients (16.7%) had an initial clinical presentation of severe CAP; 3 of 4 had a dual infection. Ten patients (41.7%) received macrolides or a macrolide plus a third generation beta-lactam at the beginning of management. Two patients (8.3%) did not improve clinically and were transferred home. The average hospital stay was 11 .5 (range, 1-45) days. Parapneumonic effusions complicated 20.8% of the cases. Other complications included acute respiratory failure (16.7%), shock (8.3%), hospital-acquired pneumonia (8.3%), and acute renal failure (4.2%). We concluded that C. pneumoniae caused a wide variation of clinical presentations ranging from mild disease to severe CAP. Co-infection with other bacterial pathogens was a common finding. Use of macrolides or new fluoroquinolones as part of an initial therapeutic regimen should be considered to cover this organism.