Table 3.
Efflux Pump Inhibition Decreases the MIC of Clarithromycin for Non-Susceptible Isolatesa
| Treatment | Number (%) of Isolates Exhibiting a Significant Decrease in CLA Resistanceb | |||
|---|---|---|---|---|
| Intermediate (n = 6) | Resistant with rrl Mutation (n =7) | Resistant Without rrl Mutation (n = 6) | Total (n=19) | |
| CLA + PaβN | 4 (66.7) | 0 (0) | 5 (83.3) | 9 (47.4) |
| CLA + CCCP | 5 (83.3) | 0 (0) | 5 (83.3) | 10 (52.6) |
| CLA + VP | 5 (83.3) | 1 (14.2) | 6 (100) | 12 (63.2) |
Notes: aIsolates exhibiting MIC ≥4 mg/L after 3 days incubation were considered non-susceptible. bAfter the addition of the inhibitor, a decrease in MIC of ≥2-fold was considered significant.
Abbreviations: PaβN, phenylalanine-arginine β-naphthylamide; CCCP, Carbonyl cyanide 3-chlorophenylhydrazone; VP, verapamil.