Table 1.

The B. fragilis strains used in this study. The minimal inhibitory concentration (MIC) was defined as the lowest metronidazole concentration at which no more B. fragilis growth on WC plates could be observed.

B. fragilis Strain/Clone	nim gene	Accession Numbers of Nim proteins	Location of nim gene	MIC of metronidazole observed in this study	reference
638R	none		-	< 1 mg/L	Sebald et al. 1990
638R (nimA)	nimA	gi|435265	pIP417	4 mg/L	Stubbs et al. 2000
638R (nimD)	nimD	gi|440387	pIP421	4 mg/L	Stubbs et al. 2000
388/1	nimE	gi|435261	pBF388C	32 mg/L	Sóki et al., 2004
BF8	nimB	gi|70559779	chromosome	2 mg/L	Sebald et al., 1990