TABLE 1.
MICs of antibiotics and adjuvants (EPIs) alone or combined against reference strains and clinical isolates in broth
| Strain | Phenotype | Reference | Antibioticb | AB alone (mg/liter) | PAβN alone (μM) | NV731 alone (μM) | NV716 alone (μM) | MIC in mg/liter (fold dilution decrease versus antibiotic alone)a |
||
|---|---|---|---|---|---|---|---|---|---|---|
| AB+PAβNc | AB+NV731c | AB+NV716c | ||||||||
| PAO1 | Wild type | 48 | CIP | 0.25 | >200 | >250 | 50 | 0.06 (2) | 0.06 (2) | 0.03 (3) |
| DOX | 16 | 4 (2) | 4 (2) | 1 (4) | ||||||
| CHL | 32 | 8 (2) | 16 (1) | 1 (5) | ||||||
| RIF | 16 | 8 (1) | 8 (1) | 0.125 (7) | ||||||
| PAO509 | PAO1[Δ(MexAB-OprM), Δ(MexCD-OprJ), Δ(MexJK), Δ(MexXY), Δ(MexEF-OprN)] | 49 | CIP | 0.016 | >200 | >250 | 25 | 0.008 (1) | 0.016 (0) | 0.008 (1) |
| DOX | 1 | 1 (0) | 0.125 (3) | 0.03 (4) | ||||||
| CHL | 2 | 2 (0) | 1 (1) | 0.125 (4) | ||||||
| RIF | 16 | 4 (2) | 8 (1) | 0.06 (7) | ||||||
| BV1 | Clinical isolate (expressing truncated, nonfunctional MexAB-OprM) | 45 | CIP | 1 | >200 | >250 | 50 | 1 (0) | 0.5 (1) | 0.125 (3) |
| DOX | 64 | 8 (3) | 2 (5) | 0.125 (9) | ||||||
| CHL | 8 | 4 (1) | 0.5 (4) | 0.06 (7) | ||||||
| RIF | 32 | 16 (1) | 4 (3) | 0.008 (12) | ||||||
| 205-2 | Clinical isolate (overexpressing functional MexAB) | 46 | CIP | 4 | >200 | >250 | 50 | 2 (1) | 4 (0) | 1 (2) |
| DOX | 16 | 4 (2) | 8 (1) | 0.5 (5) | ||||||
| CHL | 64 | 32 (1) | 32 (1) | 1 (6) | ||||||
| RIF | 16 | 8 (1) | 16 (0) | 0.125 (16) | ||||||
a
Values in bold denote a decrease of at least 2 doubling dilutions versus antibiotics alone.
b
AB, antibiotic; CIP, ciprofloxacin; DOX, doxycycline; CHL, chloramphenicol; RIF, rifampin. MICs were determined in at least two independent experiments.
c
PAβN was used at 38 μM (20 mg/liter); NV731 and NV716 were used at 10 µM (4 mg/liter).