Table 2.

Summary of MIC range, MIC₅₀ and MIC₉₀ values (μg/ml) of the isolated Mycoplasma synoviae strains with the suggested non-official breakpoints (in μg/ml; S: susceptible, R: resistant) and MIC values for the type strain WVU1853

	Non-official breakpoints	WVU1853 initial	WVU1853 final	Range initial	Range final	MIC50 initial	MIC50 final	MIC90 initial	MIC90 final
Fluoroquinolones
Enrofloxacin	S ≤ 0.5; R ≥ 2 [5]	0.312	1.25	0.312 – >10	0.312 – >10	1.25	1.25	>10	>10
Difloxacin	S ≤ 0.5; R ≥ 4 [5]	1.25–2.5	1.25–2.5	0.625 – >10	0.625 – >10	2.5	2.5	10	>10
Aminocyclitol
Spectinomycin	S ≤ 2; R > 4 [28]	2	8	≤0.25–8	1–16	2	2	4	8
Aminoglycoside
Neomycin	S ≤ 4; R > 4 [25]	64 – >64	>64	4 – >64	8 – >64	32	>64	>64	>64
Lincosamide
Lincomycin	S ≤ 2; R ≥ 8 [43]	0.5	0.5	≤0.25 – >64	≤0.25 – >64	0.5	1	1	4
Tetracyclines
Doxycycline	S ≤ 4; R ≥ 16 [25]	≤0.039	0.156	≤0.039–0.312	0.078–1.25	0.078	0.156	0.312	0.625
Oxytetracycline	S ≤ 4; R ≥ 16 [5]	≤0.25	0.5	≤0.25–1	≤0.25–8	≤0.25	1	1	4
Chlortetracycline	S ≤ 4; R ≥ 16 [25]	0.5	1	≤0.25–8	≤0.25–16	0.5	2	2	8
Macrolides
Tylosin	S ≤ 1; R ≥ 4 [5]	≤0.25	≤0.25	≤0.25–2	≤0.25–8	≤0.25	≤0.25	≤0.25	≤0.25
Tilmicosin	S ≤ 8; R ≥ 32 [5]	≤0.25	≤0.25	≤0.25–64	≤0.25 – >64	≤0.25	≤0.25	1	2
Tylvalosin	S ≤ 0.5; R > 2 [28]	≤0.25	≤0.25	≤0.25–0.5	≤0.25–1	≤0.25	≤0.25	≤0.25	≤0.25
Pleuromutilins
Tiamulin	S ≤ 8; R ≥ 16 [7]	0.078	0.078	≤0.039–0.625	0.078–1.25	0.078	0.156	0.312	0.312
Valnemulin	S ≤ 0.125; R > 0.125 [25]	≤0.039	≤0.039	≤0.039	≤0.039	≤0.039	≤0.039	≤0.039	≤0.039
Amphenicol
Florfenicol	S ≤ 2; R ≥ 8 [25]	1–2	1–4	0.5–8	1–16	4	8	8	8
Combination
Lincomycin: Spectinomycin	S ≤ 2(0.666/1.334); R > 4(1.332/2.668) [25]	1 (0.333/0.667)	1–2 (0.333/0.667–0.666/1.334)	0.5–2 (0.167/0.333–0.666/1.334)	0.5–4 (0.167/0.333–1.332/2.668)	1 (0.333/0.667)	1 (0.333/0.667)	2 (0.666/1.334)	2 (0.666/1.334)