Abstract
Studies were undertaken to select tentative criteria for susceptibility testing of quinupristin/dalfopristin againstStreptococcus pneumoniae andHaemophilus influenzae. Against 612 isolates ofStreptococcus pneumoniae, MICs of quinupristin/dalfopristin were ≤1.0 μg/ml for all but one strain. With a tentative MIC breakpoint of either ≤ 1.0 μg/ml or ≤2.0 μg/ml for susceptible, a disk diffusion zone diameter breakpoint of ≥19 mm embraced all but two of the susceptible pneumococci; ≥16 mm included all strains. ForHaemophilus influenzae, MICs of quinupristin/dalfopristin clustered near the tentative breakpoints; 91.5% of the MICs were 2.0 to 8.0 μg/ml. This precluded satisfactory performance of the disk diffusion test in discriminating between resistant and susceptible isolates unless MIC breakpoints are modified for this species: clinical experience will be needed before that can be justified. Based on data from a multilaboratory study, the following quality control limits are proposed forStreptococcus pneumoniae ATCC 49619 when testing quinupristin/dalfopristin: 0.25 to 1.0 μg/ml for broth microdilution tests and 19 to 24 mm for disk diffusion tests. For tests ofHaemophilus influenzae ATCC 29247, MIC limits are 2.0 to 16 μg/ml; disk tests were very reproducible but are not yet recommended.
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References
Bouanchaud DH: In-vitro and in-vivo synergic activity and fractional inhibitory concentration (FIC) of the components of a semisynthetic streptogramin, RP59500. Journal of Antimicrobial Chemotherapy (1992) 30, Supplement A:95–99
Archer GL, Auger P, Doern GV, Ferraro MJ, Fuchs PC, Jorgensen JH, Low DE, Murray PR, Reller LB, Stratton CW, Wennersten CB, Moellering RC: RP59500, a new streptogramin highly active against recent isolates of North American staphylococci. Diagnostic Microbiology and Infectious Disease (1993) 16:223–226
Barry AL, Fuchs PC: In vitro activities of a streptogramin (RP59500), three macrolides and an azalide against four respiratory tract pathogens. Antimicrobial Agents and Chemotherapy (1995) 39:238–240
Fass RJ: In vitro activity of RP59500, a semisynthetic injectable pristinamycin, against staphylococci, streptococci and enterococci. Antimicrobial Agents and Chemotherapy (1991) 35:553–559
Johnson CC, Slavoski L, Schwartz M, May P, Pitsakis PG, Shur AL, Levison ME: In vitro activity of RP59500 (quinupristin/dalfopristin) against antibiotic-resistant strains ofStreptococcus pneumoniae and enterococci. Diagnostic Microbiology and Infectious Disease (1995) 21:169–173
Low DE: Quinupristin/dalfopristin: spectrum of activity, pharmacokinetics, and initial clinical experience. Microbial Drug Resistance (1995) 1:223–234
Neu HC, Chin N-X, Gu J-W: The in vitro activity of new streptogramins, RP59500, RP57669 and RP54476, alone and in combination. Journal of Antimicrobial Chemotherapy (1992) 30, Supplement A:83–94
Barry AL, Fuchs PC, Brown SD: Provisional interpretive criteria for quinupristin/dalfopristin disk susceptibility tests. Journal of Antimicrobial Chemotherapy (1997) 39, Supplement A:87–92
National Committee for Clinical Laboratory Standards: Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. Approved standard M7-A3. NCCLS, Wayne, PA (1993)
National Committee for Clinical Laboratory Standards: Performance standards for antimicrobial disk susceptibility tests. Approved standard M2-A5. NCCLS, Wayne, PA (1993)
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Fuchs, P., Barry, A., Brown, S. et al. Provisional quality control parameters and interpretive criteria for testing susceptibility ofStreptococcus pneumoniae andHaemophilus influenzae to quinupristin/dalfopristin (RP59500). Eur. J. Clin. Microbiol. Infect. Dis. 17, 197–201 (1998). https://doi.org/10.1007/BF01691118
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DOI: https://doi.org/10.1007/BF01691118