Table 1

Antibiotic susceptibility in unadapted and triclosan-adapted P.aeruginosa

P. aeruginosa L2

Antibiotic MIC (mg/L) ^b

TET

CIP

AMK

LVX

CAR

CHL

Unadapted

32

16

4

8

128

128

Unadapted plus PAβN (50 μM)

16

4

2

2

64

64

Unadapted plus CCCP (100 μM)

16

8

2

4

64

64

Adapted ^a to 3,400 mg/L triclosan

64

32

8

16

256

256

Adapted ^a to 3,400 mg/L triclosan plus PAβN (50 μM)

32

8

4

4

64

64

Adapted ^a to 3,400 mg/L triclosan plus CCCP (100 μM)

32

16

4

8

64

64

^aAdaptation was achieved by serial subculturing in stepwise increasing triclosan concentrations up to 3,400 mg/L triclosan (see Methods). The experimental data were confirmed by three independent replicates

^bBreakpoint criteria were as follows. TET: susceptible, ≤ 4 mg/L; intermediate, 8 mg/L; resistant, ≥ 16 mg/L; CIP: susceptible, ≤ 1 mg/L; intermediate, 2 mg/L; resistant, ≥ 4 mg/L; AMK: susceptible, ≤ 16 mg/L; resistant, ≥ 32 mg/L; LVX: susceptible, ≤ 2 mg/L; intermediate, 4 mg/L; resistant, ≥ 8 mg/L; CAR: susceptible, ≤ 128 mg/L; intermediate, 256 mg/L; resistant, ≥ 512 mg/L; CHL: susceptible, ≤ 8 mg/L; intermediate, 16 mg/L; resistant, ≥ 32 mg/L [12]

MIC minimal inhibitory concentration; PAβN RND pump inhibitor phenyl-arginine-β-naphthylamide; CCCP protonophore carbonyl cyanide m-chlorophenylhydrazone; TET tetracycline; CIP ciprofloxacin; AMK amikacin; LVX levofloxacin; CAR carbenicillin; CHL chloramphenicol

D'Arezzo et al. BMC Research Notes 2012 5:43   doi:10.1186/1756-0500-5-43