TABLE 2.

Phenotypes of fluoroquinolone-resistant S. pneumoniae and S. mitis strains and amino acid changes in their DNA topoisomerase genes

Strain	Yr iso- lated	Type	Susceptibility by the opto- chin assaya	Bile solubility	CIPb MIC (μg/ml)	Amino acid change in the QRDR ofc:
						ParC	GyrA	ParE
S. pneumoniae ATCC 49619		19F	S	+	1	None	None	None
S. pneumoniae R6			S	+	0.5	None	None	None
S. pneumoniae 3180	1994	NTd	S	−	128	S79F, N91D	S81Y, S114G	None
S. pneumoniae 3870	1996	NT	S	−	64	S79F, N91D	S81Y, S114G	None
S. pneumoniae 4391	1997	23F	S	+	128	S79Y, N91D	S81F, S114G	None
S. pneumoniae 4589	1998	NT	S	+	64	S79F, N91D	S81F, S114G	None
S. pneumoniae 4638	1998	23F	S	+	32	S79Y, K137N	S81F	1460V
S. pneumoniae 5237	1999	23F	S	+	8	S79N, N91D, I126V,E135D	S81Y	None
S. oralis ATCC 10557			R	−	2	N91D	S114G	None
S. oralis NCTC 11427			R	−	2	N91D	S114G	None
S. mitis NCTC 12261			R	−	1	N91D	S114G	None
S. mitis 75414-2	2000		R	−	>32	D83Y, N91D	S81F, S114G	None
S. mitis 181731-3	1999		R	−	64	S79F, N91D	S81F, M90G, S114G	None
S. mitis 181732-2	1999		R	−	>32	S79F, N91D	S81Y, S114G, N150S	P424A, I460L, A463E, K466N, A468S

^aS, susceptible; R, resistant.

^bCIP, ciprofloxacin

^cResidues involved in ciprofloxacin resistance are indicated in boldface, and double underlining indicates that the residue is located in a gene with a mosaic structure. No changes in GyrB were found.

^dNT, not typeable.