Diagnostic Use
General
Standard bacterial antimicrobial susceptibility testing is performed in accordance with current EUCAST protocols.
Susceptibility to common antimicrobial agents are reported routinely. Others are available on request.
Antimicrobial susceptibility summaries for aerobic and anaerobic Gram positive and Gram negative isolates can be found in the “Antimicrobial Susceptibility Report” on the Health NZ LabPLUS webpage.
Nocardia and other aerobic actinomycetes
The laboratory tests Nocardia and other aerobic actinomycetes to a set panel of antimicrobials using the CLSI microbroth method. The antimicrobials in this panel are co-trimoxazole, ceftriaxone, imipenem, minocycline, clarithromycin, linezolid, amikacin and moxifloxacin.
Results available 5 – 10 days after receipt.
Rapidly growing Mycobacteria
The laboratory tests rapid growing Mycobacterium species to a set panel of antimicrobials using the CLSI microbroth method. The antimicrobials in this panel are co-trimoxazole, tobramycin, imipenem, cefoxitin, clarithromycin, doxycycline, amikacin, moxifloxacin and linezolid plus tigecycline gradient MIC.
Results available 5 – 10 days after receipt.
Yeasts and Filamentous Fungi
The laboratory performs antifungal susceptibility testing in accordance with Clinical and Laboratory Standards Institute (CLSI) protocols.
Results available 5 -10 days after receipt.
Interpretation
For standard bacteria tested using the EUCAST system the antimicrobial susceptibility results are reported as S, I, or R.
S = Susceptible, standard dosing regimen: A bacteria is categorised as “Susceptible, standard dosing regimen”, when there is a high likelihood of therapeutic success using a standard dosing regimen of the agent.
I = Susceptible, increased exposure: A bacteria is categorised as “Susceptible, Increased exposure” when there is a high likelihood of therapeutic success because exposure to the agent is increased by adjusting the dosing regimen or by its concentration at the site of infection.
R = Resistant: A bacteria is categorised as “Resistant” when there is a high likelihood of therapeutic failure even when there is increased exposure.