Severe community-acquired pneumonia due to Acinetobacter baumannii

Study objectives: To investigate the clinical, epidemiologic, and microbiol ogical characteristics of community-acquired pneumonia (CAP) due to Acineto bacter baumannii. Methods: Retrospective chart and radiographic reviews of all patients who w ere admitted to National Taiwan University Hospital from January 1993 to Au gust 1999, fulfilled the criteria for CAP, and had an isolate of A baumanni i from blood or pleural fluid at hospital admission. Results: Thirteen patients (9 men and 4 women; age range, 37 to 85 years) m et the criteria. Conditions associated with the infection included male gen der, old age, alcoholism, malignancy, cerebrovascular disease, diabetes mel litus, renal disease, and liver cirrhosis. Eleven patients (85%) acquired t he infection during the warmer months of April to October. Twelve patients (92%) had a fulminant course presenting with septic shock and respiratory f ailure, and 11 patients (85%) needed ventilator support and were treated in an ICU. Six patients (46%) had leukopenia. Lobar consolidations were found in 12 patients (92%), and pleural effusions were present in 4 patients (31 %). All patients had positive blood culture results, two patients (15%) had positive pleural effusion culture findings, and nine patients (69%) positi ve sputum culture results. All the isolates were susceptible to imipenem, a nd most were susceptible to aminoglycosides, ceftazidime, ciprofloxacin, an d extended-spectrum penicillins. Eight patients (62%) died. Four of the fiv e survivors were initially treated with combination of a third-generation c ephalosporin and an aminoglycoside. Conclusion: A baumannii should be considered as a possible etiologic agent in community-acquired lobar pneumonia when (1) patients with a fulminant co urse present during the warmer and more humid months of the year, and (2) p atients are younger alcoholics. A good sputum smear, defined as a Gram stai n smear of an adequate sputum specimen that comes from the lower respirator y tract and contains > 25 leukocytes per high-power (100x) field on microsc opic examination, can help early diagnosis and treatment. A combination of a third-generation cephalosporin and an aminoglycoside may be appropriate e mpirical therapy.