Abstract: Objective  To understand the age distribution of primary and acquired MDR-TB patients and the status of their drug resistance, and provide a scientific basis for prevention and treatment of MDR-TB.  Methods  We made a retrospective analysis of MDR-TB cases admitted in our hospital between January 2005 and December 2010 (47 cases of primary and 274 cases of acquired  multidrug-resistant cases respectively). Patients were divided into 4 groups by age, 5 cases in ＜20 age group, 183 cases in 20- age group, 105 cases of  40- age group, and 28 cases of 60- age group, respectively, to analyze the status of TB drug resistance.  Results  In 47 primary and 274 acquired MDR cases,age between 20 to 30 had the highest number of cases, which were 30(63.8%)and 153 (55.8%) respectively. However the difference of primary and acquire MDR-TB distribution in different age group is not statistically significant(primary MDR-TB: 1 case of ＜20 age group (2.1%), 14 cases of age over 40 (29.8%), 2 cases of age over 60(4.3%), acquired MDR-TB: 4 cases of ＜20 age group(1.5%), 91 cases of age over 40 (33.2%),  26 cases of age over 60 (9.5%). (Fisher’s exact test, P=0.515). As for the distribution of the first-line drug resistance (respectively, resistance to the HR, HRE, HRS and HRSE), in primary MDR cases, 1 cases in ＜20 age group (resistant to HRS), 30 cases of age over 20 (10 resistant to HR, 13 to HRE，5 to HRS, and 2 to HRSE), 14 cases of age over 40 (4 resistant to HR, 7 to HRE, 3 to HRS), 2 cases of age over 60 (1 resistant to HRE and 1 to HRS). In acquired MDR-TB cases, 4 cases in ＜20 age group (resistant to HR, HRE, HRS and HRSE respectively), 153 cases of age over 20 (56 (36.6%) resistant to HR, 26(17.0%) to HRE，46(30.1%) to HRS, and 25(16.3%) to HRSE), 91 cases of age over 40 (34(37.4%) resistant to HR, 26(28.6%) to HRE, 17(18.7%) to HRS, 14(15.4%)to HRSE), 26 cases of age over 60 (5(19.2%) resistant to HR and 5(19.2%)  to HRS, 13(50.0%)to HRE, 3(11.5%) to HRSE). The distribution is statistically significant different between different age group (Fisher’s exact test, P=0.030).Further multiple comparison found that the difference is statistically significant between 20- age group and 60- age group. In primary MDR and acquired MDR cases, they were mainly resisted to one or two second-line drugs(seven drugs in total: amikacin (Am), clarithromycin (Clr), levofloxacin (Lfx), moxifloxacin (Mfx), sodium aminosalicylate (PAS), rifabutin (Rfb), propylthiouracil isonicotinoyl amine (Pto)］, the resistant rate were 25(53.2%) and 115(42.0%) respectively, however the difference is not statistically significant (χ²=3.123, P=0.211).  Conclusion  The primary and acquired MDR-TB predominantly affects young people, and the situation of MDR-TB is serious. We should strengthen the diagnosis and treatment of TB patients, and reduce the incidence of multi-drug-resistant.

Key words: Tuberculosis,multidrug-resistant, Drug resistance,multiple,bacterial