Antimicrobial testing using oxygen consumption as the indicator of susceptibility.

Abstract

In the presence of inhibitory concentrations of antibiotics, a decrease in oxygen consumption precedes and predicts changes in growth rates, bacterial stasis, or death of bacteria. The susceptibility of bacteria to various antibiotics was determined by growing the microorganisms in liquid media in the presence of varying concentrations of antibiotics. The oxygen consumption was then measured with an electrode at a specified time at each concentration of the antibiotic plus a positive and negative control. The decrease in oxygen consumption by the bacteria inhibited by the antibiotic precedes changes in numbers of bacteria and is predictive of the outcome of the standard minimum inhibitory concentration. This method determines antibiotic susceptibilities in approximately 3 hours and the minimum inhibitory concentration obtained corresponds with literature values and current minimum inhibitory concentration techniques.