Table 4. The correlation between amino acid mutations at different sites of GyrA and MIC₅₀ (µg/mL) of quinolones.

No. amino acid mutation	No. isolates (n)	Amino acid of GyrA			MIC range (MIC50)
		83	87		Levofloxacin	Ciprofloxacin	Gatifloxacin	Moxifloxacin
Wild	21	–	–		≤0.25–32 (0.5)	≤0.25–>32 (0.5)	≤0.25–16 [1]	≤0.25–8 (≤0.25)
1	1	–	Asp87Gly		1	1	1	0.5
1	50	Ser83Val	–		8–16 [8]	16–>32 [32]	4->32 [8]	2–32 [4]
1	1	Ser83Tyr	-		8	32	32	4
2	3	Ser83Phe	Asp87Gly		32–>32 (>32)	>32	16–>32 (>32)	8–>32 (>32)
2	59	Ser83Tyr	Asp87Gly		8–>32 (>32)	>32	8–>32 [32]	4–>32 [16]

MIC₅₀, minimal inhibitory concentration for 50% isolates.