caa a22 4500 477069800 CHVBK 20180405111422.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF01691316 doi (NATIONALLICENCE)springer-10.1007/BF01691316 Risks related to lack of standardization of tests to detect in vitro metronidazole resistance in Helicobacter pylori [Elektronische Daten] [T. Henriksen, Ö. Brorson, R. Schöyen, T. Thoresen] The correlation between metronidazole MIC readings obtained in vitro on two different media for two different inoculum dilutions was studied after two, three, and five days of incubation using 20 clinical isolates ofHelicobacter pylori. The PDM epsilometer (E test) was used. After two days of incubation, log MIC values on chocolate PDM and Vestfold charcoal medium, a new charcoal medium, showed good correlation. Charcoal media can thus be used for metronidazole sensitivity tests. In terms of double-dilution gradients, prolongation of incubation time from two to three days and change of inoculum dilution from 0.5 to 4 McFarland had little impact when studied separately. However, the combined effect of the two variables was marked. The matching of a sparse inoculum incubated for two days against a heavy inoculum incubated for three days resulted in readings which, for 30% of the pairs, differed by two double-dilution gradients or more. On the other hand, the separate influence of both variables was found to affect the correlation coefficients significantly. Five days of incubation was associated with a poor correlation when the variables were studied both separately and combined. Thus, the real influence of separate variables on MIC readings was not exposed in a scale of double-dilution gradients because the intervals were too large. For this reason, scales without thresholds are recommended. MMV Medizin Verlag GmbH, 1996 Henriksen T. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut Brorson Ö. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut Schöyen R. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut Thoresen T. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut European Journal of Clinical Microbiology and Infectious Diseases Springer-Verlag 15/6(1996-06-01), 484-488 0934-9723 15:6<484 1996 15 10096 https://doi.org/10.1007/BF01691316 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01691316 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Henriksen T. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut NATIONALLICENCE 700 1- Brorson Ö. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut NATIONALLICENCE 700 1- Schöyen R. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut NATIONALLICENCE 700 1- Thoresen T. Department of Microbiology, Vestfold Sentralsykehus, N-3116, Tönsberg, Norway aut NATIONALLICENCE 773 0- European Journal of Clinical Microbiology and Infectious Diseases Springer-Verlag 15/6(1996-06-01), 484-488 0934-9723 15:6<484 1996 15 10096 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer