The E-Test applied to susceptibility tests of gonococci, multiply-resistant enterococci, and Enterobacteriaceae producing potent beta-lactamases.
The E-Test (AB Biodisk, Solna, Sweden), a new and novel approach developed to test antimicrobial susceptibility, was compared with the agar dilution method. A collection of 57 organisms, including those with known resistances to various antimicrobial agents was tested against 15 drugs using the National Committee for Clinical Laboratory Standard (NCCLS) methods. The E-Test quantitative accuracy (+/- 2 log2 dilutions) compared with agar dilution results was 99% for Neisseria gonorrhoeae, 95% for Escherichia coli strains with extended-spectrum beta-lactamases, 100% for Enterobacter-Citrobacter spp. with type-1 stably derepressed enzymes, and 95% for Enterococcus spp. with various drug resistances (penicillins, ciprofloxacin, gentamicin, and vancomycin). The E-Test procedures with these species were easy to perform, reproducible, and quantitatively and qualitatively accurate (89%-100%). The E-Test appears to be an acceptable option for susceptibility testing of these difficult-to-treat, drug-resistant bacterial strains.
Sanchez
M L
ML
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
Barrett
M S
MS
Jones
R N
RN
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology; D016983:Enterococcus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000187:drug effects* / Q000201:enzymology; D010403:Penicillin Resistance; D010405:Penicillinase / Q000096:biosynthesis; D001618:beta-Lactamases / Q000096:biosynthesis
D000900:Anti-Bacterial Agents; D010405:Penicillinase; D001618:beta-Lactamases