Table 1.

Growth of flgM–bla strains without or with ampicillin (100 μg ml⁻¹; 30 μg ml⁻¹) on plates.

Strain	Genotype	LB plate	Amp plate 100 μg ml−1	Amp plate 30 μg ml−1	MICa
TH4803	Wild type	+++	− − −	− − −	< 3
TH9480	HBB+flgM–bla	+++	− − −	− − −/+	12.5
TH9481	Ring−flgM–bla	+++	− − −	− − −	6.25
TH9486	Δflk HBB+flgM–bla	+++	− −/+	−/+	50
TH9488	Δflk Ring−flgM–bla	+++	++	+++	100

^aThe minimal inhibitory concentration (MIC) for sensitivity to ampicillin (μg ml⁻¹) in liquid culture was determined for each strain as described in Experimental procedures.

Five levels of growth on the solid medium in the presence or absence of added ampicillin was reproducibly observed ranging from no growth at all (− − −) to a robust, wild-type growth phenotype (+++).