Twenty-four Staphylococcus species and their subspecies were examined for their susceptibilities to teicoplanin by disk diffusion (30-,ug disk) and agar dilution for the determination of MICs. Moderately susceptible and resistant clinical strains were further tested for their susceptibilities to oxacillin and vancomycin. Teicoplanin resistance was not observed in the reference strains of the various Staphylococcus species isolated from healthy volunteers or animals. However, the novobiocin-resistant species Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, Staphylococcus kloosii, and Staphylococcus gallinarum were less susceptible to teicoplanin (MIC, 2 to 8 ,ug/ml) than most of the novobiocin-susceptible species were (MIC, 0.5 to 4 ,Ig/ml). Clinical isolates of coagulase-negative species were generally less susceptible to teicoplanin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were moderately susceptible (MIC,16 ,u.g/ml) to teicoplanin. Of these strains, 70% were oxacillin resistant. For Staphylococcus haemolyticus strains, 11% were resistant (MIC, >16 ,ug/ml) and 21% were moderately susceptible to teicoplanin. Of these strains, 95% were oxacillin resistant. No strains of S. epidermidis or S. haemolyticus were intermediate or resistant to vancomycin. Teicoplanin appears to be less active in vitro against oxacillin-resistant S. haemolyticus. However, teicoplanin is an effective antimicrobial agent against many Staphylococcus species.The frequent isolation of clinically significant Staphylococcus species is a major concern for the medical community. In the past, patients were commonly treated with various penicillins, erythromycin, clindamycin, and/or gentamicin for staphylococcal infections. However, owing to many factors, including the extensive use of these antibiotics, staphylococci have developed resistant populations (17). For this reason, new antibiotics are being developed and tested on Staphylococcus species.Teicoplanin is a glycopeptide that targets the peptidoglycan synthesis of gram-positive bacteria (8,15). It is considered by some to be a drug of choice for the treatment of severe infections caused by antibiotic-resistant, gram-positive bacteria, especially the coagulase-negative staphylococci which often produce infections that are difficult to manage.In this study, 24 Staphylococcus species and 4 subspecies were tested for their susceptibilities to teicoplanin by disk diffusion and agar dilution for the determination of MICs. The moderately susceptible and resistant clinical strains were tested further for their susceptibilities to oxacillin and vancomycin.(A preliminary report of this work was presented previously [2].)Reference strains of the 24 Staphylococcus species and their subspecies were obtained from our laboratory's collection of isolates from the skin of healthy human volunteers or animals. The clinical strains used in this study were isolated from a variety of patients at Rex Hospit...

Twenty-four Staphylococcus species or subspecies were examined for their susceptibilities to the fluoroquinolone fleroxacin (Ro 23-6240) by disk diffusion (5-jig disk) and by agar dilution for the determination of MICs.Resistant strains were further tested for their susceptibilities to oxacillin and the fluoroquinolone ciprofloxacin. Reference strains of the novobiocin-resistant species (Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, and Staphylococcus gallinarum) had an intrinsic intermediate susceptibility (MIC,4 ,ug/ml) to fleroxacin. Fleroxacin resistance was not observed in the reference strains of the novobiocin-susceptible species (MIC, 0.5 to 2.0 ,uglml). Clinical isolates of coagulase-negative species were generally less susceptible to fleroxacin than were reference strains. Fleroxacin (Ro 23-6240) is a new orally and intravenously administered trifluoroquinolone with a half-life of 9 to 10 h in humans and peak levels of 2.3 VLg/ml in serum after a single 200-mg oral dose (12). The drug has shown excellent activity against most members of the family Enterobacteriaceae, inhibiting 90% of isolates per species at concentrations of <1 p.g/ml (2, 3). Because of its broad spectrum of activity, fleroxacin may also have use for treating staphylococcal infections; a previous report has shown the in vitro effectiveness of fleroxacin against two species of staphylococci (9). In the current study, 24 Staphylococcus species or subspecies were tested for their susceptibilities to fleroxacin by disk diffusion and by agar dilution for determination of MICs. The resistant strains were further tested for their susceptibilities to oxacillin and to the fluoroquinolone ciprofloxacin.(A preliminary report of this work was presented previ-Reference strains of the 24 Staphylococcus species or subspecies were obtained from our laboratory's collection of isolates from the skin of healthy human volunteers or from animals. Clinical strains used in this study were isolated from April 1989 to February 1990 from a variety of patients at Rex Hospital, Raleigh, N.C. All the clinical strains were identified by using the criteria of Kloos and coworkers (4, 5). The reference and clinical strains were maintained on P agar (11) at 4°C for up to 2 months and preserved by desiccation on steatite fish spine insulator beads at 4°C. These storage conditions do not alter the antibiograms or plasmid compositions of strains tested in this laboratory.Fleroxacin as powder and in 5-,ug disks was kindly provided by Hoffmann-La Roche, Inc. Md.). Disk diffusion susceptibility testing was performed by the procedure outlined by the National Committee for Clinical Laboratory Standards (7). Agar dilution susceptibility tests for fleroxacin and oxacillin were performed by the procedure outlined by the National Committee for Clinical Laboratory Standards (8) with Mueller-Hinton agar. Oxacillin plates were supplemented with 4% NaCl. The plates were inoculated by using the Steers replicator (10). Ciprofloxac...

A Microsoft FORTRAN 77 program is presented that computes a global test and the subsequent multiple range procedure for testing differences among independent first-order partial correlations.