Beckman Coulter MicroScan B1016-138 Manuel D'utilisation page 5

B. Place a clean Cover Tray on top of each group of panels to prevent evaporation. Cover Trays may be reused. Do
not decontaminate the Cover Trays with alcohol. They may be cleaned with soap and water. Rinse well and allow
to air dry.
C. Incubate the panels for 16-20 hours at 35°C in a non-CO
Reading the Panels
Panels can be read manually using the MicroScan Microdilution Viewer and results recorded or on MicroScan instrumentation
(autoSCAN-4 and WalkAway systems). Refer to the LabPro Operator's Guide for instructions on reading panels with
MicroScan instrumentation.
1. Following 16-20 hours incubation, remove the panels from the incubator.
2. Wipe off the bottom of the panel with a lint-free tissue to remove any condensation or debris that may be present.
3. Read the panels only if the control well is clear and the growth control well is turbid. Do not read the antimicrobics if the
control well is turbid or if there is no growth in the growth well. Growth in the wells appears as turbidity, which may take
the form of a white haze throughout the well, a white button in the center of the well, or a fine granular growth throughout
the well. Inadequate growth is defined as a slight whiteness in the well or the broth is clear.
4. If results are read manually, record results on the appropriate worksheet.
5. Reading Antimicrobial Susceptibilities (MICs)
A. Read all antimicrobics, CV, MS, NOV, OPT, NACL, and BAC, against a black (indirectly lighted) background.
B. Perform β-lactamase testing for staphylococci with a Penicillin MIC of ≤0.12 μg/mL.
C. Record MIC results as follows:
a. Following 16-20 hours incubation, record the MIC as the lowest antimicrobial concentration showing inhibition
of growth.
b. When growth occurs in all concentrations of an antimicrobic, the MIC is recorded as greater than (>) the
highest concentration.
c. When no growth occurs in any of the concentrations of the antimicrobics, the MIC is recorded as less than or
equal to (≤) the lowest concentration.
d. A clear well in a series of growth wells, e.g., growth at 1, 2 and 8 μg/mL, but not at 4 μg/mL is called a skipped
well and should be ignored.
e. Spot growth in isolated wells indicates contamination. The test should be repeated.
f. For staphylococci with oxacillin, any growth should be considered significant.
D. Accurate detection of resistance requires extended incubation times for the following:
Incubation
24 hours
24-48 hours
1. 24 hour incubation is not required for Staphylococcus species for panels containing the Cefoxitin Screen Well.
E. The performance of vancomycin on MicroScan panels was compared to the microbroth dilution methods
recommended by CLSI. Vancomycin results with staphylococci after 16-20 hours incubation (18-20 h for
autoSCAN-4 instrument reads) were comparable to those obtained at 24 hours with the reference method.
F. For panels containing oxacillin only: Staphylococci should be reported as resistant (regardless of the MIC)
to ampicillin, amoxicillin/K clavulanate, ampicillin/sulbactam, ertapenem, imipenem, meropenem, penicillin,
piperacillin/tazobactam, ticarcillin/K clavulanate and the cephalosporin antimicrobics (except ceftaroline)
when oxacillin MICs are >2 μg/mL for S. aureus and S. lugdunensis and ≥0.5 μg/mL for coagulase negative
staphylococci other than S. lugdunensis.
G. For panels containing both oxacillin and the Cefoxitin Screen Well (CfxS): Staphylococci should be reported
as resistant (regardless of the MIC) to ampicillin, amoxicillin/K clavulanate, ampicillin/sulbactam, ertapenem,
imipenem, meropenem, penicillin, piperacillin/tazobactam, ticarcillin/K clavulanate and the cephalosporin
antimicrobics (except ceftaroline) when CfxS is >4 μg/mL for all staphylococci or oxacillin MICs are >2 μg/mL for
S. aureus and S. lugdunensis or oxacillin is ≥0.5 μg/mL for other coagulase negative staphylococci.
For coagulase negative staphylococci other than S. lugdunensis when CfxS is ≤4 μg/mL and oxacillin MIC is 0.5,
the mecA status has been shown to be negative and the oxacillin interpretation will be reported as S*; when
CfxS is ≤4 μg/mL and oxacillin MIC is 1 or 2 mecA status is variable and must be checked before reporting these
antimicrobial agents as susceptible.
C29870–AD
Organism
Enterococci
Staphylococci
Streptococci
Enterococci
incubator.
2
Antimicrobics
Kanamycin Synergy Screen
Oxacillin 1
Kanamycin Synergy Screen
Streptomycin Synergy
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