Objective: To investigate the susceptibility to antibiotics and the mechanism of the resistance in Mycobacterium chelonei. Methods: To determine the susceptibility of antibiotics by the method of ag ar dilution and to test the combination drug susceptibility by the method of the filter paper. 12 strains of Mycobacterium chelonei were isolated from cases of the hospital infection in the factory clinics in Chongqing and the plasmids were extracted and eliminated by norfloxacin in these bacteria. Results: In 42 antibiotics

3 of M. chelonei subspecies were susceptible to most of antibiotics

such as aminoglycosides

fluoroquinolones and rifampin

pyrafat

ethambutol in the antituberculosis agents and 9 of M. Chelonei subspecies abscesses were susceptible to most of antibiotics of aminoglycosides

ciprofloxacin in fluoroquinolones but resistant to antituberculosis agents in the test. The noncorrelation between any 2 antibiotics was observed. A 9.1 Kb plasmids profile was observed in 6 bacteria

but as it was eliminated

the resistance to antibiotics was not c hanged. Conclusion: The bacteria are multiply resistant and have great differences in their susceptibility. The resistance to antibiotics was not translated by plasmid.