Novel Microdilution Method to Assess Double and Triple Antibiotic Combination Therapy In Vitro
Table 1
Schematic diagram showing the distribution of tested antibiotics in the wells.
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2
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5
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12
A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Drug A
Positive control (culture medium + organism)
A
B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
Drug B
B
C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
Drug C
C
D
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
Drugs A + B
D
E
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
Drugs A + C
E
F
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
Drugs B + C
F
G
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
Drugs A + B + C
G
H
Negative control (culture medium only)
UN
H
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12
(i) The tested concentrations of the antibiotic were as follows: ciprofloxacin, 16–0.015 g/mL; amikacin, 32–0.031 g/mL; ceftazidime, 32–0.031 g/mL; piperacillin, 128–0.125 g/mL; imipenem, 32–0.031. (ii) Higher dilutions of ciprofloxacin were tested in second set of experiments in double and triple combinations with other antibiotics when needed. (iii) UN: unused well.
