In vitro activity of quinupristin/dalfopristin against clinical isolates of common gram-positive bacteria in Taiwan.
The MICs of quinupristin/dalfopristin against common Gram-positive bacteria isolated from various clinical specimens at a university hospital in Taiwan were determined by the agar dilution method. The tested bacteria included methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), Streptococcus pyogenes, Streptococcus pneumoniae, and Enterococcus faecalis. With the exception of E. faecalis all bacteria were susceptible to quinupristin/dalfopristin. The MIC50 and MIC90 were, respectively, 0.25 microgram/mL and 0.5 microgram/mL for both MRSA and MSSA; 0.25 microgram/mL and 0.5 microgram/mL for MRSE; 0.25 microgram/mL and 0.25 microgram/mL for MSSE; 0.125 microgram/mL and 0.125 microgram/mL for S. pyogenes; and < or = 0.03 microgram/mL and 0.25 microgram/mL for S. pneumoniae. Eighty-two percent of the tested E. faecalis isolates were intermediately resistant or resistant to quinupristin/dalfopristin, with an MIC50 of 2 micrograms/mL and an MIC90 of 4 micrograms/mL. Quinupristin/dalfopristin seems to be a promising antimicrobial agent against common Gram-positive bacteria other than E. faecalis in Taiwan.
Chang
S C
SC
Section of Infectious Diseases, National Taiwan University Hospital, Taipei.
Fang
C T
CT
Hsueh
P R
PR
Luh
K T
KT
Hsieh
W C
WC
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D013624:Taiwan; D014769:Virginiamycin / Q000031:analogs & derivatives* / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D014769:Virginiamycin; C113825:quinupristin; C113826:dalfopristin