TABLE 4.

Competitive growth of a 1:1 mixed inoculum of the RMB7201 wild type with an FS mutant or variant in semisolid agar and shake and still cultures.

Culture conditions	Strain mixed with wild type	Ratio of FS to wild-type cells ± SDa
Shake cultureb in 1/10 TY	FS1	1.0 ± 0.12
	FS17	1.0 ± 0.03
	SV8	1.0 ± 0.04
Still culturec in 1/10 TY	FS1	1.8 ± 0.37
	FS17	1.6 ± 0.10
	SV8	1.6 ± 0.09
Agar (0.3%), 1/20 TYd	FS1	33 ± 9.6
	FS17	30 ± 4.0
	SV8	35 ± 2.7
	SV68	27 ± 4.0
	SV69	20 ± 1.7
	SV3	36e ± 3.3
Agar (0.3%), CB	FS1	10 ± 1.2

^aThese values are from three replicate cultures in a representative experiment after correction for the ratio of the two strains in the inoculum. The ratio of wild-type to FS isolate colonies was determined by differential antibiotic sensitivity, colony morphology, and swarm tests for FS17 and by colony morphology and swarm tests on at least 100 colonies for SV3, SV8, SV68, and SV69. 

^bReplicate cultures with 15 ml of medium were inoculated with about 10⁷ cells each of the FS strain and the wild type, cultured at 200 rpm at 28°C for 2 days to stationary phase, and then plated to determine relative CFU. 

^cReplicate cultures in 6 ml of medium in culture tubes (18 by 150 mm) were inoculated with about 10⁶ cells each of the FS strain and the wild type, cultured at 28°C undisturbed for 5 days to stationary phase, and then plated to determine relative CFU. 

^dReplicate swarm agar plates were inoculated with about 10⁶ cells of the FS strain and the wild type and cultured for 3 days, and then the agar was vortexed vigorously for 2 min and the suspension was plated for determination of relative CFU. 

^eThe swarm rate of colonies of SV3 cells from the periphery of the swarm was about 1.8-fold that of the wild type during tests to determine the ratio of the two strains in the 3-day swarm colony, faster than the swarm rate of the original isolate, ca. 1.4-fold faster than the wild type.