Quinupristin

BACKGROUND: ;The recent emergence of glycopeptide-resistant enterococci limits the treatment of enterococcal infections. The aim of this study was to evaluate the in vitro activity of a new streptogramin, quinupristin/dalfopristin, against 30 clinical isolates of vancomycin-resistant enterococci and compared with those of other 15 antimicrobials.;MATERIAL AND METHODS: ;Enterococci were identified by using Rapid ID 32 Strep system. Genotyping of the isolates was performed by PCR. The MICs of quinupristin/dalfopristin were determined by the agar dilution technique recommended by the NCCLS. Susceptibilities to the rest of antibiotics tested (teicoplanin, ampicillin, penicillin, imipenem, doxycicline, chloramphenicol, gentamicin, streptomycin, rifampin, levofloxacin, fleroxacin, trovafloxacin, sparfloxacin, pefloxacin and clinafloxacin) were determined by using the E test. beta-lactamase production was examined with nitrocefin disks.;RESULTS: ;Quinupristin/dalfopristin has demonstrated excellent activity against Enterococcus faecium (MIC90' 2 micrograms/ml). Enterococcus faecalis was considerably less susceptible than E. faecium, at concentration of 4 micrograms/ml inhibited only 31% of tested strains.

Lipophilic species of Corynebacterium are increasing problem in hospital infections. The aim of this study was to evaluate occurrence of these microorganisms in the materials taken from patients in the day of admission and during the hospitalization as well as comparison of their antibiotic sensitivity. The investigation included 65 strains isolated from hospitalized patients and 48 strains isolated from unchanged skin. Using Api Coryne test 5 species were identified. C. urealyticum dominated, the other were C. subsp. lipophilum and C. jeikeium. Among strains isolated from unchanged diseased skin the most C. jeikeium and C. accolens occurred. All strains were sensitive to glycopeptide, quinupristin/dalphopristin. The strains isolated from hospitalized patients were usually sensitive to fuside acid, doxycycline as well as tetracycline. Strains isolated from unchanged skin were sensitive to almost all tested antibiotics. In the group of 65 strains isolated from hospitalized patients 99.0% were multiresistant. In the group of strains isolated from unchanged skin only two strains were multiresistant. Differences in antibiotic sensitivity among analysed Corynebacterium sp. were confirmed.

In case of resistance to quinupristin, the bacteriostatic synergism is preserved but the in vivo bactericidal effect of Synercid declines. On the other hand, no selection of resistant mutants has been observed. In case of isolated resistance to dafopristin, there is no reduction in the bactericidal effect of Synercid; there is however a possible risk of selecting resistant mutants. To become resistant to Synercid, S. aureus strains have to become resistant to both quinupristin and dafopristin, a highly unlikely situation.;POTENTIAL COMBINATIONS: ;Among the combinations of Synercid with other antibiotics, the combination with vancomycin would have particular interest for clinical applications, increasing bactericidal activity. This would be the case for severe S. aureus infections with a large inoculum and even more so for meti-R resistant strains with a C-MLSB phenotype. Combination with rifampicin would be another possibility, but only for strains not resistant to quinupristin.