Serious streptococcal infections produced by isolates resistant to streptogramins (quinupristin/dalfopristin): Case reports from the SENTRY antimicrobial surveillance program
Kc. Kugler et al., Serious streptococcal infections produced by isolates resistant to streptogramins (quinupristin/dalfopristin): Case reports from the SENTRY antimicrobial surveillance program, DIAG MICR I, 36(4), 2000, pp. 269-272
The emergence and sustained prevalence of Gram-positive organisms resistant
to antimicrobials has been of interest for over a decade. Quinupristin/dal
fopristin (formerly RP 59500 or Synercid(R)) is a new injectable streptogra
min combination that has been reported to have activity against Gram-positi
ve organisms, even those with documented MLS, resistance. However, the two
case reports presented here illustrate three well-documented Streptococcus
spp. strains (S. mitis, S. pneumoniae) to be resistant to quinupristin/dalf
opristin (MICs at 3, 8, and 12 mu g/ml) following referral as routine isola
tes in the SENTRY Antimicrobial Surveillance Program. The S. pneumoniae ple
ural fluid isolate was cross-resistant to erythromycin. Both bacteremic S.
mitis strains were resistant to macrolides (erythromycin, azithromycin, cla
rithromycin), lincosamides (clindamycin), and fluoroquinolones. Patient his
tories indicated no prior use of MLS class antimicrobials for the S. mitis
case, but the patient having the S. pneumoniae isolate did receive prior tr
eatment of erythromycin and clindamycin. All isolates had modestly increase
d penicillin MICs of 0.12 mu g/ml. The mode of resistance to quinupristin/d
alfopristin was not evident (sat A-negative by PCR); and these cases illust
rate the existence of streptogramin-resistant isolates before the introduct
ion of this antimicrobial class into human clinical practice. (C) 2000 Else
vier Science Inc. All rights reserved.