Antimicrobial susceptability assays Flashcards
why you would test for antimicrobial susceptability?
- To test for epidemiology/ spread of resistance
- Assess which doses may be required for treatment
- To know which antiniotics can or cant be ued for treatment
What are three phenotypic tests for antimicrobial susceptability?
- Disc diffusion assay
- Broth dilution test (MIC test)
- E-test
What is the MIC?
minimal inhibitory concentration/ the lowest concentration of an antibiotic that inhibits growth
What are the two controls that you would use in a broth dilution test?
- One without bacteria
- One without the antibiotic
What are some advantages of phenotypic testing?
- Provides resistance/ susceptability
- You can test for multiple antimicrobials in a single experiment
- Some tests give the MIC value> informs treatment
What are some disadvantages of phenotypic tests?
- Slow> potentially too slow in some specific cases
- Requires available culture
What kind of test is a PCR test?
a genotypic test
What are some disadvantages of a rapid diagnostics (PCR) test?
- Sensitive for contamination
- Requires an expensive thermocycler
- Can be difficult to multiplex (requires a separate marker for each assay, it is not robust)
What is LAMP?
Loop-Mediated Isothermal amplification
a simple DNA extraction method
What are some advantages of LAMP?
- more rapid and semi-quantitative
- less-specialised equipment requirement
- Can be used with easy detection systems
What is AMR?
Use of genomics/ Genome sequencing in AMR and drug discovery
What can AMR be used for?
- large collections of genomes
- Can be used for predicting antimicrobial resistance genes
What are some potential weaknesses for computational methods
- It is based on search algorithms and scores (so may miss point mutations)
- The presence of a gene does not neccesarily mean functionality
- There is a 90-99% correlation found in different studies/ bacteria
