Urinary infection with coagulase-negative staphylococci in a teaching hospital

In the eight-month period of study of all urine samples processed in our routine laboratory, only 85 out of 12 152 specimens yielded a bacteriologically significant growth of either Staphylococcus epidermidis or micrococci. Their growth on MacConkey medium was strictly comparable to that on cysteine lactose electrolyte-deficient (CLED) media. Most micrococci isolated were from urine samples of non hospitalised women patients, were resistant to a novobiocin (5 micrograms) disc, and belonged to Baird Parker type 3. Staph. epidermidis came mainly from postoperative surgical in-patients. Their antibiotic sensitivity patterns are variable whereas micrococci are fully sensitive to all urinary antibiotics. We agree that the use of a novobiocin (5 micrograms) disc for provisional identification of micrococci and Staph. epidermidis is simple and practical for a busy routine diagnostic laboratory. The use of more extensive systems to biotype these organisms in a routine laboratory is not practical and not relevant to patient management.