Efflux pump gene hefA of Helicobacter pylori plays an important role in multidrug resistance

Table 1 Chloramphenicol-induced multidrug resistance profiles of H pylori strains

Strains	Exptl condition	Agar dilution test MIC (μg/mL)
		MTZ	ERY	CIP	TET	PEN
03154	Before induction	0.125	0.125	0.25	0.25	0.125
	After induction (fold)	8×	4×	4×	8×	16×
12025	Before induction	2	0.063	0.125	0.03	0.063
	After induction (fold)	16×	2×	8×	4×	16×
12021	Before induction	4	0.125	0.25	0.125	0.063
	After induction (fold)	16	1×	16×	8×	8×
11032	Before induction	1	0.063	0.063	0.063	0.25
	After induction (fold)	8×	4×	4×	16×	16×
03174	Before induction	0.5	0.125	0.25	0.125	0.125
	After induction (fold)	8×	1×	8×	4×	32×
11637	Before induction	0.5	0.063	0.125	0.03	0.25
	After induction (fold)	4×	2×	4×	8×	16×

MTZ: Metronidazole; ERY: Erythromycin; CIP: Ciprofloxacin; TET: Tetracycline; PEN: Penicillin G.

Table 2 Relative expression of hefA in PT and MDR strains

Strains	PT (hefA/gyrB)	MDR (hefA/gyrB)
03154	1.87	2.67
12025	0.32	2.84
12021	1.22	8.94
11032	3.84	5.04
03174	4.16	6.03
11637	4.41	9.56
Total (mean ± SD)	2.6356 ± 1.7245	5.8466 ± 2.9370

PT: Parent isolates; MDR: Multidrug resistant strains.