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

BACKGROUND: Here we present the results from a prospective analysis of pneu mococcal bacteremia in patients older than 65 years, highlighting its diffe rences 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 Strept ococcus pneumoniae (S, pneumoniae). S. pneumoniae was identified using stan dard techniques. The antimicrobial sensitivity was analysed using the broth midrodilution technique and the serotype was studied in a reference labora tory. Statistical analyses were performed by means of the SPSS(R) program, version 9.0. RESULTS: 161 out of 321 bacteremias occurred in 154 patients older than 65 years (86 males). Most frequent underlying diseases were chronic obstructiv e pulmonary disease (COPD), diabetes and neoplasia. Most patients had pneum onia, 29.7% with ilfiltrates involving at least two lung lobes. 9.4% of bac teremias were nosocomial. Among patients older than 65 years, 32.5% of stra ins were resistant to penicillin, compared to 21.7% in patients younger tha n 65 years (p = 0.034). Mortality in patients over 65 years was higher than in younger patients (25.3% vs 11.5%; p = 0.002) and mortality predictive f actors in a multivariate analysis were age, nosocomial bacteremia and multi -lobe involvement (in patients with pneumonia), CONCLUSIONS: There is a high incidence of pneumococcal bacteremia in patien ts over 65 years of age. These patients have a higher rate of resistance to penicillin and a higher mortality rate than younger patients. Mortality pr edictive factors are age, nosocomial bacteremia and multilobe involvement.