TABLE 2.

MICs determined for sulfamethoxazole-resistant transformants^a

Donor strain	Sulfamethoxazole MIC (μg/ml)
	Donor	Transformants (whole DNA)	Transformants (PCR product)
111	4,096	4,096	1,024
8	1,024	1,024	1,024
45	512	512	1,024
13	2,048	2,048	1,024
104	512	512	1,024
42	256	256	512
11	1,024	1,024
85	512	512

^aTransformants were selected on antibiotic plates containing 16 and 32 μg of sulfamethoxazole per ml. MICs were determined for two to four transformants, according to the method outlined in the experimental section. The frequencies of the transformations achieved were dependent on the size of the fragment used and the degree of homology between the PCR product and the recipient strain. The average frequencies of transformation obtained for the PCR products obtained with primer pairs F3-R2 and F3-R5 and with whole DNA were 5.5 × 10⁻⁶, 4.9 × 10⁻³, and 2.5 × 10⁻², respectively.