Penicillin resistance and other predictors of mortality in pneumococcal bacteremia in a population with high human immunodeficiency virus seroprevalence

Abstract

Rates of invasive disease caused by penicillin-resistant pneumococci are rising. Previous reports have found no association between resistant pneumococci and increased mortality. To evaluate the impact of penicillin resistance and other variables on mortality, we retrospectively studied all cases of pneumococcal bacteremia identified by our microbiology laboratory from 1 January 1992 through 31 December 1996. There were 462 cases of pneumococcal bacteremia in 432 patients. The mean age was 35 years; 55% of the cases occurred in male patients, 58% were in black patients, and 40% were in Hispanic patients. One-half of the cases occurred in patients with documented human immunodeficiency virus (HIV) infection. Penicillin resistance was first noted in 1994 and increased yearly, accounting for 17% of 1996 isolates. Of all resistant isolates, 65% were resistant to penicillin at a high level. The overall mortality was 17%. On multivariate analysis, high-level penicillin resistance, older age, severe disease, multilobar infiltrates and/or effusion(s) on chest roentgenogram, and Hispanic ethnicity were independent predictors of mortality in pneumococcal bacteremia. In HIV- infected patients, a CD4 cell count below the median just missed statistical significance. This is the first report demonstrating penicillin resistance as an independent predictor of mortality among patients with pneumococcal bacteremia.