異なる培地組成でのニューキノロン系抗菌薬6剤のMycobacterium tuberculosis 臨床分離株に対するin vitro抗菌活性の測定

抄録

The minimum inhibitory concentrations (MICs) to the fluoroquinolones, ofloxacin (OFLX), ciprofloxacin (CPFX), sparfloxacin (SPFX), norfloxacin (NFLX), balofloxacin (BLFX) and CS-940, were determined in 100 clinical isolates of Mycobacterium tuberculosis. The MICs were determined with 1% egg-based Ogawa or agar -based Middlebrook 7H10 and each of them supplemented with oxidation-reduction color dye, 2, 3-diphenyl 5-thienyl-(2)-tetrazolium chloride (STC) by using the microculture technique. The MICs determined with Ogawa medium were approximately two to four-fold higher when compared to those determined with Middlebrook agar medium. The supplement with STC slightly increased the MICs, probably as a result of easily recognizing small initial colonies. Among the six fluoroquinolones, CS-940 and SPFX showed the greatest antimy cobacterial activities with inhibition of 50% of all the isolates at the concentrations between 0.25 to 0.5μg/ml. OFLX, CPFX and BLFX followed in potency at 0.5 to 2.0μg/ml. NFLX was less potent requiring 8 to 16μg/ml to inhibit 50% of the isolates.