Abstract
During the 4-month period from January to April, 1998, 476 patients with
Streptococcus pneumoniae
infections were detected in 12 metropolitan New York hospitals and 112 penicillin-resistant (PRP)
isolates (24%) were identified in 11 institutions. A case control study of 100 patients with penicillin-resistant and susceptible pneumococci from four of the widely dispersed hospitals revealed a high
incidence of underlying medical illnesses in adult patients (74%), a preponderance of patients with pneumonia (63%), and a majority of patients who had underlying risk factors for pneumonia or invasive
disease (51%). In this limited case control study, no difference was noted between cases and controls regarding known risk factors for penicillin-resistant pneumococcal infections. The percentage of single-patient
PRP isolates varied among individual hospitals but the mean percentages of PRP from the four participating University Medical Centers and seven community hospitals were similar: 26% and 22% respectively.
By E-test, 60% and 26% were high-level penicillin and ceftriaxone resistant, respectively. Pulsed-field gel electrophoresis identified 26 chromosomal macrorestriction patterns among the 103 PRP isolates
available for analysis, but almost half (50 isolates or 48%) of these belong to two drug-resistant internationally spread clones, SP
23
-1 and SP
9/14
-3, that were detected in all hospitals
and were recovered from invasive and noninvasive sites in both children and adults.