The
chitinase 3-like 1 (CHI3L1) inhibitor, specifically
kasugamycin, provided by the present invention, suppresses the expression or activation of
chitinase 3-like 1 (CHI3L1), thereby effectively preventing or treating infections with acid-fast
bacteria, particularly non-tuberculous mycobacteria and various diseases caused by infection with acid-fast
bacteria, particularly
nontuberculous mycobacteria. In addition, by measuring the expression level of
chitinase 3-like 1 (CHI3L1)
protein, when the expression level is higher than that of a control group, it is possible to effectively predict infection with acid-fast
bacteria, particularly non-tuberculous mycobacteria, the onset of diseases caused by infection with acid-fast bacteria, particularly non-tuberculous mycobacteria, or the prognosis of diseases related to infection with
acid fast bacteria, particularly
nontuberculous mycobacteria.