Determinations of minimum bactericidal concentrations, kill curves, and postantibiotic effects with the Etest technology.
The bactericidal activity of antimicrobial agents is generally determined following broth dilution minimum inhibitory concentrations (MIC) procedures. These methods are cumbersome, require advanced technical experience, and lack proven reproducibility. Etest (AB Biodisk, Solna, Sweden) is a predefined antimicrobial gradient on a plastic carrier strip that is used to generate a precise MIC on an agar plate. A pilot study was conducted to investigate whether a drug's bactericidal effect could be assessed by transferring the "growth-inhibition pattern" from the Etest MIC ellipse onto a drug-free agar plate. The transfer was performed using four techniques of replica plating, a filter method, drug inactivation, and sampling of growth alongside the Etest strip. Defined antimicrobial-organism models were used to determine the minimum bactericidal concentrations (MBCs), killing curves (KCs), and postantibiotic effects (PAEs) of several drugs. Preliminary results suggest that the Etest provides an alternative method for studies determining the MBCs, KCs, and PAEs of various antimicrobial agents.
Bolmström
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AB Biodisk Research Laboratories, Solna, Sweden.
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D008954:Models, Biological; D010865:Pilot Projects; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
D000900:Anti-Bacterial Agents