Background: The proportion of penicillin-resistant Streptococcus pneumoniae
isolates and associated risk factors varies by geographic area in the Unit
ed States. We conducted a retrospective study to determine the extent of pe
nicillin-nonsusceptible S pneumoniae bacteremia and associated risk factors
in a tertiary care medical center in San Diego.
Methods: Patients with S pneumoniae bacteremia at the University of Califor
nia, San Diego Medical Center from September 15, 1991, through July 31, 199
8, were identified by hospital-based computerized microbiology records. Hos
pital records included demographic information, patient data, and antibioti
c prescription records for patients with bacteremia as a result of S pneumo
niae. Univariate and multivariate analyses were used to determine risk fact
ors for penicillin-nonsusceptible S pneumoniae bacteremia.
Results: Of 281 isolates of S pneumoniae identified, 192 (68%) were from ho
spitalized patients. After controlling for other factors, patients from 1 t
o 5 years of age (P = .01; odds ratio [OR] = 3.96; 95% CI, 1.50 to 10.44),
6 to 18 years of age (P = .04; OR = 6.42; 95% CI, 1.13 to 36.51), and HIV s
eropositive patients (P = .002; OR = 5.12; 95% CI, 1.83 to 14.32) were more
likely to have penicillin-nonsusceptible S pneumoniae bacteremia. There wa
s a significant increasing trend of penicillin-nonsusceptible S pneumoniae
bacteremia from 14% in 1991 to 42% in 1998 (P = .001; OR = 1.42; 95% CI, 1.
16 to 1.73); this included only 2 isolates that were highly resistant to pe
nicillin. There was no increase in mortality in patients who had penicillin
-nonsusceptible S pneumoniae bacteremia.
Conclusion: With the increase in S pneumoniae resistance to penicillin, it
is important to continue surveillance of infections caused by S pneumoniae.
Hospital-based studies are useful for tracking epidemiologically important
pathogens.