Comparison and evaluation of antimicrobial susceptibility testing of enterococci performed in accordance with six national committee standardized disk diffusion procedures

Studies were conducted to compare and evaluate antimicrobial susceptibility test results for enterococci obtained by six national committee disk diffu sion procedures. Variations in the incidence of isolates in resistance cate gories and errors were associated with the use of ciprofloxacin, gentamicin , nitrofurantoin, rifampin, and teicoplanin in a number of committee proced ures. Results indicate that laboratories performing disk diffusion antimicr obial susceptibility testing may have problems correctly identifying resist ance in enterococci with agents used to combat infections and that it may b e difficult to compare resistance data for surveillance purposes.