Abstract: ObjectiveTo investigate the resistant situation of Ofloxacin to mycobacterium tuberculosis isolated from sputum of patients with pulmonary tuberculosis and to provide scientific evidence for utilizing Ofloxacin in antituberculosis regimen. MethodsAll strains isolated from patients hospitalized in Shanghai Pulmonary Hospital Affiliated Tongji University from August 2007 to March 2008 were conducted to strain identification and drug susceptibility tests with Ofloxacin, Isoniazid, Rifampin, Streptomycin and Ethambutol. ResultsThe total Ofloxacin resistant rate was 24.9% among 233 mycobacterium tuberculosis strains, lower than those of the first-line drugs. The difference of Ofloxacin resistant rates between in the initial treatment group (12.3%) and in the retreatment group (46.0%) were significant statistically (χ²=31.16,P<0.01), but there was no statistically significant difference about the Ofloxacin resistant rates between in the first-time retreatment group (41.7%) and in the other retreatment group (49.0%) (χ²=0.46,P=0.50). The Ofloxacin resistant rates were 57.8% in the multi-drug resistant (MDR) group, 35.1% in the poly-drug resistant (PDR) group, 6.3% in the single-drug resistant group, and 5.2% in the first-line drug susceptible group. The difference of resistant rates between the multi-drug resistant group and the other three groups was significant statistically（χ²=6.04、10.52、59.87, all P<0.05）, the difference of resistant rates between the poly-drug resistant group and the first-line drug susceptible group was also significant statistically(χ²=17.97，P<0.05）. The rates of Ofloxacin resistance in the youth group, the middle age group and the elder group were 24.5%, 26.5%, and 14.0%,respectively. There was statistically significant difference between the youth group and the elder group (χ²=2.741,P>0.05). Primary Ofloxacin resistant rate was 9.9％ and secondary Ofloxacin resistant rate was 78.4％ with significant difference（χ²=96.47, P<0.01）. ConclusionsThe Ofloxacin resistance rate in the MDR group was much higher than that of in the other groups. The secondary Ofloxacin resistant rate was much higher than that of the primary Ofloxacin resistant rate. Unreasonable utilization of Ofloxacin can easily lead to its resistance.

Key words: Tuberculosis,pulmonary/drug therapy, Mycobacterium tuberculosis, Ofloxacin, Drug resistance,bacterial