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Rapid method of MIC determinations utilizing tetrazolium reduction.

T L Johnson·B A Forbes·M O'Connor-Scarlet·A Machinski·K D McClatchey
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Abstract

A rapid preliminary method of determining antibiotic susceptibilities of clinically isolated gram-negative fermentative organisms has been evaluated. The method utilizes tetrazolium dye reduction as a colorimetric indicator of bacterial growth. Tetrazolium dye reduction is incorporated into the standard Micro-Media MIC microdilution testing system and shortens the required incubation period from 15 to 18 hours to 4 hours. Parallel MIC determinations were made by the standard MIC method and by the rapid tetrazolium method. The test organisms included 218 gram-negative fermentative clinical isolates. The overall correlation between the standard and the rapid MIC methods was 93%. Of the 7% discordant results, 6.3% represented minor discrepancies and 0.7% represented major discrepancies. There were no very major discrepancies. The study concluded that the rapid tetrazolium MIC method is an accurate, low-cost, easily implemented method of preliminary antibiotic susceptibility testing for gram-negative fermentative organisms.

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Anti-Bacterial AgentsGram-Negative BacteriaHumansMicrobial Sensitivity TestsOxidation-ReductionTetrazolium SaltsComparative StudyJournal Article

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T L Johnson, B A Forbes, M O'Connor-Scarlet, A Machinski, K D McClatchey. 1985. Rapid method of MIC determinations utilizing tetrazolium reduction.. https://doi.org/10.1093/ajcp%2F83.3.374

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