Neisseria gonorrhoeae penicillin susceptibility: a comparison of three testing methods.

The 3-disc sensitivity method and the PDM Epsilometer (E-Test) were compared against the agar plate dilution reference method for the testing of N. gonorrhoeae penicillin susceptibility. Forty-six clinical isolates and five reference strains were examined. Both methods showed a high level of correlation in the detection of both high and moderate levels of resistance and both should be considered suitable for routine use. The E-Test had the advantage of producing a precise breakdown of the level of moderate resistance and may have a role to play in the diagnostic laboratory for this type of work.