TABLE 1.

Amino acid compositions of the gyrA and parC quinolone resistance-determing regions (QRDRs) in fluoroquinolone-sensitive and quinolone-resistant Haemophilus parainfluenzae strains

Strain number	Fluoroquinolone MIC values by Etest (μg/mL)			Amino acid composition
	Levofloxacin	Ciprofloxacin	Moxifloxacin	QRDR of gyrA*			QRDR or parC†
ATCC 33392‡	<0.03	Not done	Not done	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
87-0092	0.016	0.023	0.125	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
88-0043	0.012	0.008	0.032	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
88-0194	0.023	0.012	0.064	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
88-0283	0.016	0.006	0.032	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
89-0518	0.012	0.006	0.094	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
89-0796	0.064	0.047	0.250	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
90-0572	0.032	0.008	0.094	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
95-0376	0.032	0.016	0.125	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
95-0377	0.023	0.016	0.094	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
08-013	0.023	0.016	0.125	Asp	Ser	Asp	Gly	Asp	Ser	Tyr
07-020	2.0	4.0	>32	Asp	Phe§	Tyr§	Gly	Asp	Phe§	Tyr
07-028	12	12	>32	Asp	Phe§	Tyr§	Gly	Asp	Phe§	Tyr

Etest (bioMerieux, Canada). The minimum inhibitory concentration (MIC) of levofloxacin was determined by Sensititre plates (Trek Diagnostic Systems Inc, USA).

^*QRDR of gyrA at amino acid positions 83, 84 and 88 (14);

^†QRDR of parC at amino acid positions 82, 83, 84 and 88 (14);

^‡ATCC 33392 is a H parainfluenzae-type strain sensitive to fluoroquinolones;

^§Mutations in QRDRs. Asp Aspartate; Gly Glycine; Phe Phenylalanine; Ser Serine; Tyr Tyrosine