Synergy between M/R and MeSNA was assessed using a microbroth dilution
checkerboard assay and lowest fractional inhibitory concentration (FIC) analysis as described by the Clinical Microbiology Procedures Handbook [33].
Checkerboard assay results were generated using resazurin assays (Palomino et al., 2002).
In vitro synergy testing using E-test and
checkerboard assay (CBA)
Moreover, we have evaluated antifungal activity and synergistic effects of EOMS, with fluconazole and micafungin by NCCLS microdilution method, associated with the broth microdilution
checkerboard assay.
Data from
checkerboard assay were analysed and interpreted using the fractional inhibitory concentration index and the response surface approach using the [DELTA]E model.
An isobologram represents the results of the
checkerboard assay and the FICI values.
The
checkerboard assay was carried out as described by Lorian (2005) with slight modifications as stated in the broth microdilution method above (Lorian 2005).
Determination of minimum inhibitory concentration (MIC),
checkerboard assay and time - kill curves
Fractional inhibitory concentration (FIC) from
checkerboard assay of ceftazidime plus clavulanic acid, apigenin.
aureus used in the
checkerboard assay. Strain Median MIC ([mu] g/ml) (range) Antibiotic CLI ERY GEN LVX OXA ATCC43300 8192 (512-1024) (64-256) 256 [less (8-16) 8 1024 than or equal to] 0.5 AQ004 8192 (512-1024) (16-32) 32 (16-64) (128-256) 1024 16 128 AQ006 (64-128) 512 (128-256) 128 (8-32) 2048 128 8 AQ007 (32-64) 32 (16-64) 64 128 (16-64) (256-512) 16 256 AQ012 16384 (1024-2048) (32-64) 64 32 (256-512) 1024 512 Clindamycin, erythromycin, gentamicin, levofloxacin and oxacillin were chosen for the drug-interaction assay, since they belong to different classes of antimicrobial agents, respectively, lincosamides, macrolides, aminoglycosides, quinolones and [beta]-lactams.
The
checkerboard assay described by Verma (2007) was followed with modifications.
Keywords: Usnic acid MRSA
Checkerboard assay Antimicrobial activity