[Primary resistance to anti tuberculosis drugs in Chile 2011-2012].

UNLABELLED: This publication presents the results of the Chilean initial study of resistance to first line anti-tuberculous drugs. The study was carried out between 2011 and 2012 by the National Reference Laboratory of the Institute of Public Health, as part of the Drug Surveillance Resistance in tuberculosis (TB) promoted by the World Health Organization.

METHODOLOGY: Cross-sectional study performed using cluster sampling, representative of the entire country as recommended by the World Health Organization. Susceptibility testing to isoniazid, rifampicin, streptomycin, ethambutol and pyrazinamide was performed through the proportion method or Wayne's enzymatic method, as appropriate.

RESULTS

594 susceptibility tests were performed, showing an overall level of TB drug resistance of 8.6% and a prevalence of multidrug resistance of 1.3%. Indeed, the study showed a decrease in streptomycin resistance and an increase of isoniazid resistance in both mono-resistance and accumulated resistance compared to previous studies. No cases of mono-resistance to rifampicin were detected.

CONCLUSION

An increased resistance to anti-TB drugs in Chile is observed, which despite being still low, is no less worrisome. Since 2014 the monitoring of drug resistance to TB is universally performed to avoid sub - diagnosis and treat each case according to the susceptibility profile.