title: E test as susceptibility test and epidemiologic tool for evaluation of Neisseria meningitidis isolates.
abstract: 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.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
authors.forename: J H
authors.initials: JH
authors.lastname: Hughes
authors.forename: D J
authors.initials: DJ
authors.lastname: Biedenbach
authors.forename: M E
authors.initials: ME
authors.lastname: Erwin
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
mesh_terms: 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*
chemical_list: D000362:Agar