Comparison of the Micronaut Merlin automated broth

Authors: B Balke L Hoy H Weissbrodt S Häussler

Publish Date: 2004/09/15

Volume: 23, Issue: 10, Pages: 765-771

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Abstract

The aim of this study was to compare a commercially available automated broth microdilution system Merlin Micronaut Germany with the standard agar dilution method for susceptibility testing of pulmonary isolates from cystic fibrosis patients Accurate susceptibility testing of bacterial isolates from cystic fibrosis patients is known to pose problems Although commercially available automated test systems could facilitate susceptibility testing of such isolates in routine diagnostics these systems have not been recommended thus far However a pilot study recently indicated that the Merlin system which is based on an endpoint measurement rather than on growth curves might be applicable in the susceptibility testing of isolates from cystic fibrosis patients In the present study the Merlin system was further evaluated using an extended panel of nonmucoid and mucoid Pseudomonas aeruginosa isolates The results showed that the MICs obtained with the Merlin system tended to be lower than those obtained with the agar dilution method a finding that became increasingly apparent when mucoid Pseudomonas aeruginosa strains were tested The correlation coefficients r values of the MIC results for all strains tested were between 06 and 08 for five of the seven antimicrobial agents with r values exceeding 08 for only meropenem and ciprofloxacin However since the overall rate of serious discrepancies was within an acceptable range the Merlin system appears to be applicable for routine clinical use in susceptibility testing of P aeruginosa isolates from cystic fibrosis patientsWe thank Inder Sarpal for outstanding technical assistance Gisela Rademacher for helpful comments and especially Dieter BitterSuermann for valuable discussions and strong encouragement Financial support was provided by the Bundesministerium für Bildung und Forschung BMBF Germany project number 01KI0216

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