Background: We studied clinical features and predictors of outcome of lower respiratory tract infections caused by Haemophilus influenzae in hospitalized adults in a general hospital.
Material/methods: Medical records of hospitalized adults with H. influenzae lower respiratory tract infections during the period 1996 to 2002 were retrospectively reviewed using a standardized questionnaire.
Results: Eleven female (24%) and 34 male (76%) patients were identified. Median age was 68 years (range 28-86 years). Most patients had a smoking history (n=37; 82%) and an underlying medical condition, with chronic obstructive pulmonary disease being the most common (n=28; 62%). Pneumonia was diagnosed in 34 patients (76%). Among them, 10 (29%) showed lobar and 24 (71%) showed segmental opacification on chest radiograph. Parapneumonic pleural effusion was observed in 10 patients (22%). Fifteen patients (33%) had positive blood cultures for H. influenzae. Based on results of sputum, blood, and pleural cultures, empirical antibiotic regimens were appropriate in 40 patients (89%). Nonserotypeable H. influenzae accounted for the majority of cases (n=26; 58%). Thirty-six (80%) H. influenzae isolates were resistant to amoxicillin. Forty patients (89%) with infection had a favorable outcome. All 5 patients who died had pneumonia with respiratory failure and underlying disease. Linear logistic regression analysis revealed leukocytosis and cancer as independent risk factors of death.
Conclusions: H. influenzae lower respiratory tract infections were observed mainly in elderly patients with severe comorbidities. Pneumonia was associated with high mortality, especially in patients with underlying malignancy and H. influenzae isolates resistant to amoxicillin.