This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Joyce, L F Articles by Andrew, J H Search for Related Content PubMed PubMed Citation Articles by Joyce, L F Articles by Andrew, J H

Comparison of five methods, including the PDM Epsilometer test (E test), for antimicrobial susceptibility testing of Pseudomonas aeruginosa.

Microbiology Department, St. Vincent's Hospital, Melbourne, Victoria, Australia.

ABSTRACT

The antimicrobial susceptibilities of 100 clinical isolates of Pseudomonas aeruginosa to six antipseudomonal antibiotics were tested by five methods: the National Committee for Clinical Laboratory Standards (NCCLS) methods for broth microdilution, agar dilution, and agar disk diffusion; the Vitek Automicrobic System method (Vitek Systems, Hazelwood, Mo.); and the PDM Epsilometer test (E test) (AB Biodisk, Solna, Sweden). The E test results showed excellent correlation with agar dilution results, with over 90% agreement within 1 doubling dilution between the E test and reference agar dilution MICs for all antimicrobial agents tested. The E test results also showed good correlation with the results from the reference agar disk diffusion method, with 90 to 99% complete agreement and 100% essential agreement on categories for all antibiotics tested (essential agreement is the agreement obtained when minor discrepancies are ignored). Comparison of categories with the E test and broth microdilution methods, using the broth microdilution method as the reference method, gave only 59% complete agreement for gentamicin, with 28 minor discrepancies and 13 very major discrepancies. Some discrepancies were observed between results from the E test and broth methods for gentamicin, with the broth microdilution and Vitek methods giving higher MICs than the E test and other methods using agar. The most recent NCCLS guidelines for broth dilution testing have reduced the recommended levels of cation supplementation, which may enhance future agreement between results for the aminoglycosides and P. aeruginosa on broth and on agar. We found that the E test offers a simple, labor-efficient, and accurate method for MIC determination on an agar medium.

This article has been cited by other articles:

• Heine, H. S., England, M. J., Waag, D. M., Byrne, W. R. (2001). In Vitro Antibiotic Susceptibilities of Burkholderia mallei (Causative Agent of Glanders) Determined by Broth Microdilution and E-Test. Antimicrob. Agents Chemother. 45: 2119-2121 [Abstract] [Full Text]  
• Di Bonaventura, G., Ricci, E., Della Loggia, N., Catamo, G., Piccolomini, R. (1998). Evaluation of the E Test for Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates from Patients with Long-Term Bladder Catheterization. J. Clin. Microbiol. 36: 824-826 [Abstract] [Full Text]