E test as susceptibility test and epidemiologic tool for evaluation of Neisseria meningitidis isolates.
The E test (AB Biodisk, Solna, Sweden), a new approach developed to test antimicrobial susceptibility, was compared with the agar dilution method for seven-drug antibiogram analysis of Neisseria meningitidis isolates. The overall E-test quantitative accuracy (+/- 1 log2 dilution) was 93% compared with that of agar dilution testing. The E test was then used to perform the susceptibility tests on a 10-year sample of 102 N. meningitidis isolates, including 5 from a recent epidemic outbreak in the University of Iowa (Iowa City) community. The E test proved to be an efficient methodology for identifying common source clusters of meningococcal disease having resistance to rifampin or sulfonamides. Moreover, the data demonstrated a recent increase in penicillin MICs (MIC for 90% of strains, 0.094 microgram/ml) and an escalation of high-level resistance to trimethoprimsulfamethoxazole (33%) and rifampin (14%). The E test should be considered a simple and accurate susceptibility method for the emerging need to test meningococci and other pathogenic neisserias. Chocolate Mueller-Hinton agar was observed to provide the best support of growth and E-test MIC results that correlated well with results of the reference agar dilution method previously used for neisserias.
Hughes
J H
JH
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
Biedenbach
D J
DJ
Erwin
M E
ME
Jones
R N
RN
D000362:Agar; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D004812:Epidemiologic Methods; D005069:Evaluation Studies as Topic; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D008589:Meningococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000706:statistics & numerical data; D009345:Neisseria meningitidis / Q000187:drug effects* / Q000302:isolation & purification*
D000362:Agar