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Antimicrobial susceptibility testing
|Approval req'd?||No, for aerobic bacteria. Contact Infectious Diseases Service or ID Pharmacy to obtain approval for susceptibilities on yeast and anaerobes|
|In House Availability||Set up daily on day shift|
|Method||Broth dilution, Disk Diffusion, Etest, or Agar diffusion|
|Units||µg/mL (mcg/mL) for MICs|
|Synonyms||Anaerobic sensitivity; Broth dilution susceptibility; Sensitivity testing; Drug susceptibility; Yeast susceptibility; Disk diffusion; E-test; MIC; Minimum inhibitory concentrasion; agar dilution|
|Turn around times||1-3 days|
|Additional information||Susceptibity testing of bacterial isolates is performed and charged separately where appropriate for the specific culture request and isolate.
Susceptibility testing may be performed by various techniques, including broth dilution, disk diffusion, Etest, and agar dilution. The method is primarily dependent on the organism and specimen type.
Broth dilution is the method used for the majority of routine testing to provide minimum inhibitory concentration (MIC).
Disk diffusion is performed as a preliminary test on gram negative rods from blood cultures. Also performed routinely on:
1. Group B Streptococcus from OB patients if penicillin allergic
2. Streptococcus pneumoniae from respiratory sites
3. Mucoid strains of Pseudomonas aeruginosa, and Pseudomonas aeruginosa and Burkholderia cepacia from patients with cystic fibrosis
4. Haemophilus influenza and Neisseria gonorrhoeae upon request
Etest is performed on anaerobes, upon request, to provide MICs.
Agar dilution, using a concentration of 6 mcg/mL of vancomycin, is used for screening Enterococcus spp. from inpatients for vancomycin resistance.
Yeast susceptibility testing is only performed on Candida spp. Testing is performed by broth dilution and provides MICs. The antifungal agents tested include fluconazole, voriconazole, itraconazole, and 5-flucytosine.
For information on specific antibiotics reported on organisms, and range of concentration tested and interpretive criteria for broth dilution MICs Click here
|LDT or Mod FDA?||No|
|Last Updated||5/22/2013 11:47:26 AM|
If you have additional questions regarding this test, please call: 415-353-1667