Drug resistance trends among previously treated tuberculosis patients in a national registry in Peru, 1994-2001.
METHODS
National mycobacteriology reference laboratory in Peru conducting routine testing of susceptibility to isoniazid, rifampin, ethambutol, pyrazinamide, and streptomycin, in Mycobacterium tuberculosis isolates from previously treated patients.


OBJECTIVE
To determine the percentage of isolates resistant to each of five anti-tuberculosis agents and to ascertain in these data the presence of trends of clinical relevance.


METHODS
Retrospective study of a national registry of M. tuberculosis isolates from patients referred for drug susceptibility testing between 1994 and 2001.


RESULTS
Among 14,736 isolates tested, 10,837 (73.5%, 95%CI 72.8-74.3) demonstrated anti-tuberculosis resistance, and 8455 (57.4%, 95%CI 56.6-58.2) demonstrated resistance to at least both isoniazid and rifampin, by convention defined as multidrug-resistant tuberculosis (MDR-TB). A significant increasing trend could be discerned for resistance to each of the drugs tested and in isolates classified as MDR-TB (P < 0.001 for trend). Additional clinically relevant trends were found in polyresistance and multidrug resistance percentages.


CONCLUSIONS
Data from a national reference laboratory can be used to inform the design of retreatment regimens.
Vásquez-Campos
L
L
Instituto Nacional de Salud, Laboratorio de Referencia de Micobacterias, Lima, Peru.
Asencios-Solis
L
L
Leo-Hurtado
E
E
Quispe-Torres
N
N
Salazar-Lindo
E
E
Bayona
J
J
Becerra
M C
MC
D000995:Antitubercular Agents / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D004977:Ethambutol / Q000627:therapeutic use; D006801:Humans; D007538:Isoniazid / Q000627:therapeutic use; D010568:Peru; D011718:Pyrazinamide / Q000627:therapeutic use; D012042:Registries; D012189:Retrospective Studies; D012293:Rifampin / Q000627:therapeutic use; D013307:Streptomycin / Q000627:therapeutic use; D016896:Treatment Outcome; D014376:Tuberculosis / Q000188:drug therapy*
D000995:Antitubercular Agents; D011718:Pyrazinamide; D004977:Ethambutol; D007538:Isoniazid; D012293:Rifampin; D013307:Streptomycin