ARE CLINICAL LABORATORIES IN CALIFORNIA ACCURATELY REPORTING VANCOMYCIN-RESISTANT ENTEROCOCCI

In order to determine whether hospital-based clinical laboratories con ducting active surveillance for vancomycin-resistant enterococci in th ree San Francisco Bay area counties (San Francisco, Alameda, and contr a Costa counties) were accurately reporting vancomycin resistance, fiv e vancomycin-resistant enterococcal strains and one vancomycin-suscept ible beta-lactamase-producing enterococcus were sent to 31 of 32 (97%) laboratories conducting surveillance. Each strain was tested by the l aboratory's routine antimicrobial susceptibility testing method. An En terococcus faecium strain with high-level resistance to vancomycin (MI G, 512 mu g/ml) was correctly reported as resistant by 100% of laborat ories; an E. faecium strain with moderate-level resistance (MIC, 64 mu g/ml) was correctly reported as resistant by 91% of laboratories; two Enterococcus faecalis strains with low-level resistance (MICs, 32 mu g/ml) were correctly reported as resistant by 97 and 56% of laboratori es, respectively. An Enterococcus gallinarum strain with intrinsic low -level resistance (MIC, 8 mu g/ml) was correctly reported as intermedi ate by 50% of laboratories. A beta-lactamase-producing E. faecalis iso late was correctly identified as susceptible to vancomycin by 100% of laboratories and as resistant to penicillin and ampicillin by 68 and 4 4% of laboratories, respectively; all 23 (74%) laboratories that teste d for beta-lactamase recognized that it was a beta-lactamase producer, This survey indicated that far clinically significant enterococcal is olates, laboratories in the San Francisco Bay area have problems in de tecting low- to moderate-level but not high-level vancomycin resistanc e. Increasing accuracy of detection and prompt reporting of these isol ates and investigation of cases are the next steps in the battle for c ontrol of the spread of vancomycin resistance.