Tests for determining in-use concentrations of antibiotics and disinfectants are based on entirely different concepts: “Resistance” has different meanings

There are concerns that more extensive application of disinfectants in the food industry could result in increased resistance of bacteria to antibiotics and that therapeutic failure could ensue. This paper highlights the differences in application and mode of action between antibiotics in human or animal medicine and disinfectants in the food industry. It describes the completely different methods used to determine in-use concentrations in the two contexts. It points out that the minimum inhibitory concentration (MIC) is never the concentration at which disinfectants should be applied. It also discusses erroneous conclusions that may be drawn when the failure of therapy or disinfection is attributed to intrinsic properties of the molecules rather than to misuse of antibiotics or disinfectants. The paper suggests that the intended meaning of the word “resistance” be carefully defined in scientific articles with due reference to the measurement mentioned in the abstract and possibly reflected in the title. It also suggests that in matters of disinfection the word “resistance” be preferred when the phenomenon being studied is killing and “tolerance” when it is the adaptation to inhibitory concentrations.