Table 2.

Contribution of the MexAB-OprM efflux operon to antimicrobial susceptibility of P. aeruginosa biofilms

AntibioticK767 (wild type)K1119 (ΔmexAB-oprM)OCR1 (K767nalB; hyperexpresses mexAB-oprM)
MBEC (μg/ml)MIC (μg/ml)MBEC (μg/ml)MIC (μg/ml)MBEC (μg/ml)MIC (μg/ml)
Aztreonam1,0243251264>1,02432
Chloramphenicol1,0241281,02464>1,0241,024
Ciprofloxacin16<2<2<28<2
Erythromycin1,024321,0248>1,024256
Gentamicin1644<2324
Piperacillin1,024321,02432>1,024128
Tetracycline5126412864>1,024256
Tobramycin64<216<2512<2