Extensively drug-resistant tuberculosis (XDR TB), a more severe form of drug-resistant TB, is defined as MDR TB with additional resistance to any fluoroquinolone and to any of the 3 second-line injectables (amikacin, capreomycin
, or kanamycin) (2).
([paragraph][paragraph]) A case of TB caused by a strain of Mycobacterium tuberculosis that is resistant to isoniazid and rifampin as well as any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin
Any MDR TB strain resistant to fluoroquinolones and one of three injectable drugs (kanamycin, amikacin and capreomycin
) may be termed as extensively drug resistant (XDR) tuberculosis.6
Extensive resistance (XDR) is multidrug-resistance pattern plus resistance to fluoroquinolone and second-line injectable drugs (capreomycin
, amikacin, kanamycin).
XDR: Resistance to both isoniazid and rifampicin, a fluoroquinolone, and one or more of the following injectable drugs: amikacin, capreomycin
, or kanamycin.
Burkeev et al., "Synthesis and characterization of polyethyl cyanoacrylate nanoparticles loaded with capreomycin
sulfate," Pharmaceutical Chemistry Journal, vol.
In addition, leucine was also utilized in a Phase I investigation to treat drug-resistant tuberculosis by means of inhaled DPI formulation of capreomycin
, without provoking toxicity .
MDRTB attributes to isoniazid (INH) and rifampicin (RIF) resistance, while extensively drug-resistant tuberculosis (XDR-TB) involves extra resistance to fluoroquinolones along with one of the three injectable medications, kanamycin, amikacin, or capreomycin
Rodwell, "Evaluation of genetic mutations associated with Mycobacterium tuberculosis resistance to amikacin, kanamycin and capreomycin
: a systematic review," PLoS ONE, vol.
By definition, MDR-TB are resistant at least to rifampicin and isoniazid; while XDR-TB is due to MDR strains that are resistant to all fluoroquinolones and to at least one of the three second-line injectable agents (amikacin, kanamycin and capreomycin