TABLE 2.

Transfer of gyrA, parC, and parE mutations into S. pneumoniae CP1000 by genetic transformation

Donor strain	Donor gene	Resulting amino acid substitution(s) transferreda	No. of ciprofloxacin-resistant transformants/μlb	No. of putative transformants analyzed	MIC (μg/ml) for transformants ofc:				Amino acid substitution(s) in transformant(s)
					C	L	S	T
RT1	gyrA	Ser81→Tyr	2.80 × 10−5						NDd
	parE	Asp435→Asn	1.78	4	2.0	2.0	0.5–1.0	0.5	Asp435→Asn
		Ile460→Val							Ile460→Val
6406	parC	Ser79→Phe	1.43	2	1.0–2.0	2.0	0.5	0.5	Ser79→Phe
	parE	Ile460→Val	3.12 × 10−5						ND
6711	gyrA	Ser114→Gly	1.2 × 10−5						ND
	parC	Asn91→Asp	2.1 × 10−5						ND
6678	parC	Asp83→Tyr	1.77	2	2.0	2.0	0.5	0.5	Asp83→Tyr
	parE	Ile460→Val	1.72 × 10−4	2					No change
6513	gyrA	Ser114→Gly	2.53 × 10−5						ND
	parE	Ile493→Leu	1.04 × 10−5						ND

^aPCR-amplified regions bearing mutations corresponding to the indicated amino acid substitutions were used as donor DNA. 

^bFor normalization of transformation values, each recipient was transformed in parallel with a segment of chromosomal DNA from strain CP1550 carrying a chromosomal marker for Nov-R (nov-r1), and the ratio of ciprofloxacin-resistant and novobiocin-resistant transformants listed here was determined. 

^cC, ciprofloxacin; L, levofloxacin; S, sparfloxacin; T, trovafloxacin. 

^dND, no data available.