Details for BIL Poster TEM ENBAER Susceptibility ICAAC 2006

Name:BIL Poster TEM ENBAER Susceptibility ICAAC 2006

Background: Temocillin is a ticarcillin derivate with increased β-lactamase stability, active against Enterobacteriaceae. We compared the performance of 5 different methods for temocillin susceptibility testing on E. aerogenes strains with the broth microdilution (BM) method.

Methods: On 151 consecutive isolates of E. aerogenes collected in 5 Belgian Hospitals, temocillin susceptibility testing with 6 different methods was performed: BM as reference method, disk diffusion with paper disks (Oxoid)(DP), disk diffusion with Rosco tabs (Neo-Sensitabs ®)(DR), E-test ® strips (AB Biodisk)(ET), Phoenix (BD)(PH) and Vitek 2 (bioMérieux)(VI). Results were categorized as susceptible (S), intermediate (I) or resistant (R). Discrepancies in SIR-category were categorized as minor (1 step difference), major (BM S, experimental method R) and very major error (BM R, experimental method S). Association was further analyzed by means of odds ratios. Agreement was analyzed by the κ-statistic. The Pearson correlation was calculated between the experimental methods and BM for MIC-results.

Results: Minor, major and very major errors were seen in respectively 11, 6 and 1% of results with DP, in 5, 0 and 5% with DR, in 0, 7 and 4% with ET, in 0, 49 and 0% with PH and in 0, 7 and 5% with VI. All methods were significantly associated with BM, however odds ratios were only slightly above 1, indicating a weak association. Agreement was found to be rather low. The 3 methods with MIC results were significantly correlated by Pearson correlation; but the correlations were not very high. E-test was the strongest correlated with BM.

Conclusions: Major discrepancies with BM were seen for all experimental methods. Agreement and association were fairly low. For MIC determination E-test looks the most reliable of the tested methods.