6.1 PCR tests

PCR is carried out using:

  • commercial or in-house primers
  • microarrays
  • commercial ‘plug-in’ kits.

  • Can you name any resistance mechanisms where there are commercial PCR kits available for the detection of the resistance genes? Perhaps your laboratory uses these?

  • Examples of commercial PCR kits include:

    • MecA (for S.aureus resistance identification) for rapid MRSA detection. Remember, the mecA gene is carried on a mobile genetic element present in all MRSA strains
    • rapid carbapenemase tests for various genes
    • you may be familiar with other commercial PCR kits that are used in your laboratory.

Benefits of commercial PCR kits include accuracy and speed. Days can be saved on turnaround times for results in the clinical setting, allowing appropriate antimicrobial treatment or infection control intervention to start earlier.

However, the negatives include:

  • high cost per test
  • expensive and high-maintenance equipment required
  • specimens must still be cultured to look for resistance to other antimicrobials ‒ for example, if the isolate is confirmed to be MRSA, it will be β-lactam-resistant but there is no information about possible resistance to macrolides, tetracyclines et cetera.

6 Genotypic tests

6.2 Genome sequencing techniques