Sensitization of Burkholderia cepacia to antibiotics by cationic drugs.

Chlorpromazine and prochlorperazine have previously been shown to enhance the susceptibility of Burkholderia cepacia to aminoglycosides. To screen other non-antibiotic drugs containing similar amine (-N-CH3) groups, we examined a range of such agents that are in current clinical use for the treatment of non-infectious diseases, in combination with antibiotics that are ineffective against B. cepacia. At a concentration of 0.2 mM, theobromine, theophylline, trifluoperazine, fluophenazine and coumarin-152 significantly reduced (by four-fold) the MICs of gentamicin and ceftazidime. Theobromine and theophylline also reduced the MICs of amikacin and azithromycin.