Changing susceptibilities of coagulase-negative staphylococci to teicoplanin in a teaching hospital.
The susceptibility of two collections of coagulase-negative staphylococci (CNS) isolated from clinical specimens for teicoplanin and vancomycin were compared. They comprised 91 and 101 isolates, collected in 1985 and 1994 respectively, from different departments of a teaching hospital. MICs of vancomycin and teicoplanin were determined by a modified Etest method. Additionally, a disc diffusion test was performed for teicoplanin. All isolates were susceptible to vancomycin (MIC < or = 4 mg/L). Two of the 91 isolates collected in 1985 were intermediate to teicoplanin (MIC between 8 and 32 mg/L), whereas in 1994 the number of intermediate isolates was 20 out of 101 (P < 0.01). The correlation between MICs, as determined by the modified Etest assay, and disc diffusion zones was poor (r = -0.35). Results show that resistance to teicoplanin in CNS has increased in the study hospital over a period of 9 years. This increase is likely to be correlated with the introduction of teicoplanin. Furthermore, a disc diffusion method does not appear to be the first method of choice for detection of strains of CNS with diminished susceptibility to teicoplanin.
Department of Medical Microbiology, Leiden University Medical Center, The Netherlands.
J H
JH
Sloos
J A
JA
van de Klundert
L
L
Dijkshoorn
C P
CP
van Boven
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003030:Coagulase / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D006784:Hospitals, Teaching; D006801:Humans; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000382:microbiology*; D013210:Staphylococcus / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification; D017334:Teicoplanin / Q000494:pharmacology*; D014640:Vancomycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D003030:Coagulase; D017334:Teicoplanin; D014640:Vancomycin