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Evaluation of the cobas bact automated system for susceptibility testing of enterobacteriaceae, pseudomonas aeruginosa, and enterococcus faecalis to azlocillin, mezlocillin, and ciprofloxacin compared to NCCLS and DIN standards

Untersuchungen zur Zuverlässigkeit der Empfindlichkeitstestung von Azlocillin, Mezlocillin and Ciprofloxacin im Cobas Bact verglichen mit NCCLS- und DIN-Richtlinien

  • Addendum: Computer-Assisted Microbiological Diagnosis Supported By Hoffmann-La Roche
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Summary

The aim of automated susceptibility testing systems like the Cobas Bact is to provide the clinicians with rapid and reliable results for the care of patients and to decrease the work load in microbiological laboratories. Because data about accuracy on mezlocillin, azlocillin and ciprofloxacin were lacking, we investigated 184 bacterial strains and compared the results of the Cobas Bact susceptibility testing to standardized agar dilution and agar diffusion methods. Essential correlations for all methods compared exceeded 90% for the three chemotherapeutics and all species investigated, with the exception ofPseudomonas aeruginosa. On an average only 1.5% very major errors were observed with the several species of Enterobacteriaceae, whereasP. aeruginosa andEnterococcus faecalis were characterized by the complete absence of very major errors when Cobas Bact was correlated to NCCLS agar diffusion.

Zusammenfassung

Automatisierte Testsysteme wie der Cobas Bact sollen Klinikern schnelle und zuverlässige Ergebnisse zur Patientenversorgung liefern und die Arbeitsbelastung mikrobiologischer Laboratorien vermindern. Da Daten über die Zuverlässigkeit von Mezlocillin, Azlocillin und Ciprofloxacin fehlten, untersuchten wir 184 Bakterienstämme und verglichen die Ergebnisse der Testungen im Cobas Bact mit standardisierten Agardilutions- und -diffusionsmethoden. Wesentliche Übereinstimmungen von über 90% fanden sich bei allen drei untersuchten Chemotherapeutika und allen untersuchten Spezies mit Ausnahme vonPseudomonas aeruginosa. Bei Enterobacteriaceae wurden in Abhängigkeit von der getesteten Spezies und der Chemotherapeutika im Durchschnitt nur 1,5% sehr schwere Fehler beobachtet, während beiP. aeruginosa- undEntercoccus faecalis-Stämmen keine sehr schweren Fehler im Vergleich Cobas Bact zur Agardiffusion nach NCCLS gefunden wurden.

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  1. Abt. Med. Mikrobiologie, Hygiene-Institut der Universität, Silcherstr. 7, D-7400, Tübingen

    W. Heizmann,  H. Werner & F. Heilmann

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  1. W. Heizmann
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  2. H. Werner
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  3. F. Heilmann
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Heizmann, W., Werner, H. & Heilmann, F. Evaluation of the cobas bact automated system for susceptibility testing of enterobacteriaceae, pseudomonas aeruginosa, and enterococcus faecalis to azlocillin, mezlocillin, and ciprofloxacin compared to NCCLS and DIN standards. Infection 16, 63–68 (1988). https://doi.org/10.1007/BF01646936

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