Table 1. Mutations described in M. tuberculosis strains implicated in “acquired” resistance to quinolones.

Mutation		Effect on quinolone susceptibility	Reference
GyrA	GyrB
G88A		resistance	13
A90V		resistance	21
D94A, G, N		resistance	21
	N499D	resistance	21
T80A		no effect	21
T80A+A90G		hypersusceptibility	21

Summary of mutations described in M. tuberculosis strains (e.g. clinical strains or strains cultured in vitro in presence of quinolone in order to select a resistant strain), which have been unequivocally demonstrated as implicated in “acquired” resistance.