RESUMEN
Objective To determine the prevalence and risk factors on second-line drug resistance in patients with multidrug resistant tuberculosis (MDR-TB) in Shanghai,China.Methods All pulmonary TB patients with sputum culture positivity detected in Shanghai during January to December,2009,were enrolled.All of the pretreatment sputum-positive cultures samples were tested for routine specimen identification and routine drug susceptibility testing for first-line drugs (Isoniazid,Rrifampin,Ethambutol and Streptomycin).Drug susceptibility testing on second-line anti-TB drugs (Ofloxcin,Amikacin,Kanamycin,Capreomycin,P-aminosalicylic acid and Prothionamide) was routinely performed on isolates of Mycobacterium (M.) TB with MDR.Logistic regression analysis was conducted to determine the risk factors regarding second-line drug resistance.Results A total of 1867 patients infected with M.TB isolates were diagnosed at the TB hospitals/clinics in Shanghai during the study period,of whom 112 (6.0％) were MDR-TB,in which 58 cases (51.8％) showed resistant to at least one of the second-line drugs tested and 10 cases belonged to extensively drug-resistant.In the multivariate analyses,MDR-TB patients who were aged 45-59 years (aOR=4.76,P=0.001 ),with sputum smear positivity (aOR=6.51,P=0.026) were significantly more likely to show resistance to second-line drugs.Conclusion The prevalence of second-line drug resistance among MDR-TB patients was high in Shanghai.MDR-TB patients who were under age of 45-59 years and with sputum smear positivity would represent important common risk factors for the resistance to second-line drugs.