Pneumococcal bacteremia in patients aged over 65 years. A study of 161 cases

BACKGROUND: Here we present the results from a prospective analysis of pneumococcal bacteremia in patients older than 65 years, highlighting its differences with regard to patients aged from 15 to 64 years. PATIENTS AND METHOD: We performed a prospective follow-up study (1988-1999) of patients older than 14 years who had blood cultures positive for Streptococcus pneumoniae (S. pneumoniae). S. pneumoniae was identified using standard techniques. The antimicrobial sensitivity was analysed usióng the broth midrodiólution technióque and the serotype was studied in a reference laboratory. Statistical analyses were performed by means of the SPSS ® program, version 9.0. RESULTS: 161 out of 321 bacteremias occurred in 154 patients older than 65 years (86 males). Most frequent underlyióng diseases were chronic obstructive pulmonary disease (COPD), diabetes and neoplasia. Most patients had pneumonióa, 29.7% with ilfiltrates involvióng at least two lung lobes. 9.4% of bacteremias were nosocomial. Among patients older than 65 years, 32.5% of straións were resistant to penicillin, compared to 21.7% in patients younger than 65 years (p = 0.034). Mortality in patióents over 65 years was higher than in younger patióents (25.3% vs 11.5%; p = 0.002) and mortality predióctive factors in a multivariate analysis were age, nosocomial bacteremia and multi-lobe involvement (in patients with pneumonia). CONCLUSIONS: There is a high incidence of pneumococcal bacteremióa in patients over 65 years of age. These patients have a higher rate of resióstance to penicillin and a hiógher mortality rate than younger patients. Mortality predióctive factors are age, nosocomial bacteremióa and multilobe iónvolvement.