SURVEILLANCE FOR ANTIMICROBIAL RESISTANCE IN ENTEROCOCCI

Aim. To describe antimicrobial resistance patterns of Enterococcus spe cies in Auckland. Background: Antimicrobial resistant enterococci have emerged as major nosocomial pathogens in overseas hospitals. It is re commended that hospitals perform periodic surveys to determine local e nterococcal resistance patterns. Methods. Enterococcal isolates from f our patient groups were tested: group I were recovered from routine cl inical specimens; group II were stool isolates from patients at risk o f having vancomycin resistant enterococci, eg, intensive care unit pat ients, patients receiving vancomycin, and immunocompromised patients r eceiving antibiotics; group III were enterococci from stool specimens sent for Clostridium difficile toxin testing; group IV were isolates f rom steal specimens submitted to a community laboratory for enteric pa thogen testing. All enterococci isolated were tested for the presence of beta-lactamase, susceptibility to amoxycillin, teicoplanin, vancomy cin, and for high level gentamicin and streptomycin resistance. Result s. There were 121 group I enterococcal isolates. 628 stool specimens w ere cultured. Enterococci were isolated from: 76/148 (51%) group II sp ecimens; 166/279 (60%) group III specimens; and 70/201 (35%) of group IV specimens. Antimicrobial susceptibility testing was performed on 43 3 isolates; 74% were E faecalis, 12% E faecium, 6% E gallinarum/cassel iflavus group and 8% other enterococcal species. No isolate produced b eta-lactamase. All E faecalis were susceptible to amoxycillin. Two E f aecium and one enterococcus species were resistant to amoxycillin (MIC s all 16 mg/L). All isolates were susceptible to teicoplanin. Fourteen E gallinarum/casseliflavus group isolates had intermediate susceptibi lity to vancomycin (MICs of 8 mg/L). One E faecium had intermediate su sceptibility to vancomycin (MIG 8 mg/L). High level gentamicin and str eptomycin resistance occurred in 64 (15%) and 50 (12%) isolates respec tively. Conclusion. Vancomycin resistance is rare and is essentially r estricted to species that are rarely clinical pathogens, ie, E casseli flavus and E gallinarum. Our results have established the local suscep tibility profile for enterococcal isolates. This allows comparison wit h other locations and the detection of emerging trends of resistance.