Volume 13, Number 3—March 2007
Worldwide Emergence of Extensively Drug-resistant Tuberculosis
|Pattern||No. tested||No. (%) resistant|
|Any resistance (total)||3,520||1,542 (43.8)|
|Aminoglycosides (AG)§||3,442||630 (18.3)|
|Capreomycin (CM)||2,743||279 (10.2)|
|Fluoroquinolones (FQ)||3,492||673 (19.3)|
|Thioamides (TA)||3,132||605 (19.3)|
|Cycloserine (CS)||2,615||141 (5.4)|
|Para-aminosalicylic acid (PAS)||2,860||450 (15.7)|
|Extensively drug-resistant TB (XDR-TB, total)¶||3,520||347 (9.9)|
|AG + CM + FQ||2,656||90 (3.4)|
|AG + CM + TA||2,498||77 (3.1)|
|CM + FQ + TA||260||50 (19.2)|
|AG + FQ + TA||3,040||102 (3.4)|
|AG + FQ + CS||139||39 (28.1)|
|FQ + TA + PAS||2,505||94 (3.8)|
*Tested for ≥3 second-line drug classes; SRLs, Supranational Reference Laboratories.
†Not all isolates were tested for each second-line drug class (with the exception of the Republic of Korea SRL), so results are reported as a proportion of isolates tested to the specified class of drugs. For combination resistance patterns, results are reported as a proportion of isolates tested to all of the classes of drugs in the specific combination.
‡Cells are not mutually exclusive.
§Other than streptomycin (e.g., kanamycin, amikacin).
¶XDR-TB, extensively drug-resistant tuberculosis, i.e., multidrug-resistant tuberculosis (resistant to at least isoniazid and rifampin) with additional resistance to ≥3 classes of second-line drugs.