Consumption of antibiotics in three clinical departments and antimicrobial susceptibility of clinically significant isolates of coagulase-negative Micrococcaceae.

A total of 67 clinically significant isolates of coagulase-negative Micrococcaceae originating from blood specimens from oncologic patients, from dialysate from patients on peritoneal dialysis, and from cerebrospinal fluid from neurosurgical patients with ventricular drainage devices were identified and classified 1) according to the scheme of Baird-Parker and 2) by means of a simplified Kloos and Schleifer nomenclature. All blood isolates were classified as Staphylococcus epidermidis biotype 1 (Baird-Parker), while approximately 20% of dialysate isolates and cerebrospinal fluid isolates fell into other staphylococcal biotypes or were classified as micrococci. Using the simplified Kloos and Schleifer nomenclature, five staphylococcal isolates (8%) (four from dialysate, one from cerebrospinal fluid) were classified as "Species other than S. epidermidis". Isolates from blood exhibited a high frequency of resistance to the antibiotics tested, and 92% were found multiple-resistant (i.e. were resistant to three or more antibiotics). Isolates from cerebrospinal fluid showed multiple-resistance in 28%, while isolates from dialysate formed an intermediate group, 42% being multiple-resistant. The frequency of multiple-resistance was found to be correlated to the total consumption of antibiotics in the three clinical departments.