Speciation of coagulase-negative staphylococci in the clinical laboratory

Activities of daptomycin and teicoplanin against Staphylococcus haemolyticus and Staphylococcus epidermidis, including evaluation of susceptibility testing recommendations

The in vitro activities of daptomycin, teicoplanin, and three other antimicrobial agents were determined against 105 strains of Staphylococcus haemolyticus and 92 strains of Staphylococcus epidermidis. The MICs for 90% of strains tested (MIC90s) of fusidic acid and rifampin were less than or equal to 0.25 microgram/ml. The MIC90s of daptomycin and vancomycin were less than or equal to 4 micrograms/ml. Teicoplanin had a comparable MIC90 of less than or equal to 4 micrograms/ml for isolates of S. epidermidis. However, MIC90s were 8 and 16 micrograms/ml for oxacillin-susceptible and oxacillin-resistant S. haemolyticus, respectively. Disk diffusion tests were evaluated for daptomycin and teicoplanin. Disks with 30 micrograms of teicoplanin performed satisfactorily when S. epidermidis was tested, but when S. haemolyticus was tested, there was a very major error rate of 10% and a minor error rate of 38%.

Characterization of Micrococcaceae strains isolated from the human urogenital tract by the conventional scheme and a micromethod

Two hundred and twelve Micrococcaceae isolates were obtained from 82 men with nongonococcal urethritis, 24 women with vaginitis, and 54 girls with vulvovaginitis. Identification and biotyping of these strains were carried out by using the simplified scheme of Kloos and Schleifer (W. E. Kloos and K. H. Schleifer, J. Clin. Microbiol. 1:82-88, 1975) and the commercially available API Staph test (DMS Staph Trac). Staphylococcus epidermidis occurred in about half of these isolates. There was no statistical difference between the urethral and vaginal specimens, except for S. haemolyticus found primarily in males and for S. simulans and S. aureus found primarily in girls between the ages of 1 and 12 years. S. saprophyticus, a major cause of urinary tract infections in young women, was never isolated from the vagina, suggesting the probability of another reservoir.

Characterization of coagulase-negative staphylococci from patients with a malignancy compared with those from other sources

170 strains of coagulase-negative staphylococci isolated from different patient groups have been characterized: 74% were Staphylococcus epidermidis, 18% S. haemolyticus and 7% S. simulans. There were no differences in rates of isolation of the various species from patients with and without a malignancy. Phage typing was not a useful epidemiological tool, but biotyping was possible using the API Staph system. Slime production, a characteristic said to predispose to colonization of catheters, was found to be most common in S. epidermidis strains.