Test Methods in Detecting Antimicrobial Resistance
There are several antimicrobial susceptibility testing methods
available today, and each one has their respective advantages and
disadvantages. They all have one and the same goal, which is to provide
a reliable prediction of whether an infection caused by a
bacterial isolate will respond therapeutically to a particular
antibiotict reatment. This data may be utilized as guidelines for
chemotherapy, or at the population level as indicators of emergence and
spread of resistance based on passive or active surveillance.
Some examples of antibiotic sensitivity tesing methods are:
- Dilution method (broth and agar dilution method)
- Disk-diffusion method
- Automated methods
- Mechanism-specific tests such as beta-lactamase detection test and chromogenic cephalosporin test
- Genotypic methods such as PCR and DNA hybridization methods
Selection of the appropriate method will depend on the intended degree of accuracy, convenience, urgency, availability of resources, availability of technical expertise and cost.. Interpretation should be based on veterinary standards whenever possible, rather than on human medical standards, which may not always be applicable. Among these available tests, the two most commonly used methods in veterinary laboratories are the agar disk-diffusion method and the broth microdilution method.