Abstract:

Objective: To analyze the in vitro and in vivo activity of Sudapyridine (WX-081) against Mycobacterium abscess. Methods: The standard strain ATCC19977 and 7 clinical isolates of Mycobacterium abscess were selected, and the minimum inhibitory concentration (MIC) of WX-081 against Mycobacterium abscess were measured. In order to further evaluate the in vivo activity of WX-081 against Mycobacterium abscesses, AB type wild zebrafish was selected to construct an infection model of Mycobacterium abscesses. The maximum tolerated concentration (MTC) of WX-081, betaquiline, and azithromycin were tested to evaluate the antibacterial effect of WX-081 against Mycobacterium abscesses. Results: The in vitro MIC range of WX-081 for 1 standard strain of Mycobacterium abscess and 7 clinical isolates was 0.7813-1.5625 μg/ml. The MTCs of zebrafish against azithromycin, betaquiline, and WX-081 were 62.50 μg/ml, 15.60 μg/ml, and 62.50 μg/ml, respectively. When the concentrations of WX-081 were 11.95 μg/ml, 3.91 μg/ml, 7.81 μg/ml, 15.60 μg/ml, 31.20 μg/ml, and 62.50 μg/ml, the whole body fluorescence intensities of zebrafish were 535952±23902, 520519±18208, 492988±17182, 462296±14360, 419947±13302, and 375347±11359, respectively; the fluorescence intensities of zebrafish head were 101579±6065, 101495±10160, 93190±5468, 89877±10333, 76778±4906, and 70976±5726, respectively; with the increase of WX-081 concentration, the values gradually decreased and were lower than those of the untreated infected animal model group (zebrafish whole body fluorescence intensity was 671089±22305; zebrafish head fluorescence intensity was 671089±22305, the differences were statistically significant (comparison of whole body fluorescence intensity of zebrafish: t values were 4.134, 5.229, 6.326, 7.871, 9.670, and 11.815, respectively, all P<0.001; comparison of head fluorescence intensity of zebrafish: t values were 2.639, 2.170, 3.444, 2.872, 4.999, and 5.336, respectively, all P<0.001). On the 4th to 9th day after fertilization, when the WX-081 concentrations of 1.95 μg/ml, 3.91 μg/ml and 7.81 μg/ml, the mortality rates of zebrafish were 90.0% (54/60), 85.0% (51/60), and 81.7% (49/60), respectively. When the concentration of WX-081 gradually increased, the mortality rate gradually decreased (P<0.05). Conclusion: WX-081 effectively inhibits the growth of Mycobacterium abscesses in vitro and in vivo, prolongs the survival time of zebrafish infected with Mycobacterium abscesses, and it has good activity against Mycobacterium abscesses.

Key words: Atypical bacterial forms, Mycobacterium infections, Anti-bacterial agents, Sudapyridine (WX-081)