TABLE 3.

Susceptibility to antimicrobial agents of S. enterica serovar Typhimurium lacking or overexpressing an efflux pump

Serovar Typhimurium strain or characteristica	MIC (μg/ml)b
	NAL	CIP	TET	CHL	CTB	TRIC
CLSI recommended breakpoint concn	32	4	16	32
BSAC recommended breakpoint concn	16	2	2	16
SL1344 (wild type)	4	0.06	4	4	128	0.12
acrB::kan	1	0.015	2	0.5	64	0.06
acrB+++	32	0.5	16	16	>256	0.5
acrD::kan	4	0.03	4	4	>256	0.06
acrF::kan	4	0.06	4	1	256	0.12
tolC::kan	1	0.015	0.5	1	64	0.015

^a+++, overexpressing mutant.

^bNAL, nalidixic acid; CIP, ciprofloxacin; CHL, chloramphenicol; TET, tetracycline; TRIC, triclosan. Data extracted from Piddock et al. (165), Eaves et al. (40), and Buckley et al. (25).