Table 4.

Contribution of the MexEF-OprN efflux operon to antimicrobial susceptibility of P. aeruginosa biofilms

AntibioticStrain K1241 (parental strain expressing mexEF-oprN)Strain K1240 (PAO2375 nfxC; hyperexpresses mexEF-oprN)
MBEC (μg/ml)MIC (μg/ml)MBEC (μg/ml)MIC (μg/ml)
Aztreonam>1,024641,02432
Chloramphenicol>1,02464>1,02464
Ciprofloxacin2<264<2
Erythromycin>1,024128>1,024128
Gentamicin844<2
Piperacillin>1,02416>1,0248
Tetracycline>1,024321,02464
Tobramycin128<264<2