Prevalence of tuberculosis drug resistance in 10 provinces of China.

Background: The emergence of drug-resistant tuberculosis (TB) hampers TB control. Ten provinces in China performed drug resistance surveys among tuberculosis (TB) patients in 1996-2004 to assess levels of drug resistance.

Methods: Provincial drug resistance surveys included all isolates from newly diagnosed, smear-positive TB patients. Drug susceptibility testing (DST) against isoniazid, rifampicin, streptomycin and ethambutol was carried out in the provincial laboratories. For purposes of quality assurance, a random sample (11.6%) was re-tested by the national reference laboratory (NRL).

Results: Of 14,059 patients tested 11,052 (79%) were new TB cases. The weighted mean prevalence of multi-drug resistant tuberculosis (MDR-TB) among all cases was 9.3% (range 2.2%-10.4%); 5.4% (range 2.1% - 10.4%) among new cases and 25.6% (range 11.7%-36.9%) among previously treated cases. Adjusting the drug resistance proportions using the re-testing results did not change the estimated national mean prevalence significantly. However, in some individual provinces the estimated resistance proportions were greatly influenced, especially among re-treatment patients.

Conclusion: MDR-TB levels varied greatly between provinces in China, but on average were high compared to the global estimated average of 4.8%. This study shows the importance of quality-assured laboratory performance. Programmatic management of drug-resistant TB, including high quality DST for patients at high risk of resistance and treatment with second-line drugs, should become the standard, especially in high MDR-TB settings.