Abstract:

Objective To test the drug susceptibility of 16 Mycobacteria tuberculosis isolates from patients with cutaneous tuberculosis, and to provide a basis for the treatment of this entity. Methods Sixteen strains of mycobacterium were isolated from patients with cutaneous tuberculosis, and they were consistently identified as M. tuberculosis by biochemistry and molecular biology. Absolute concentration method was used to test the susceptibility of these isolates to isoniazid, streptomycin, rifampicin and ethambutol. For two strains resistant to streptomycin, PCR and sequencing were performed to analyse the mutation of rpsL gene. Results Out of the 16 strains of M. tuberculosis, 2 were resistant to streptomycin but sensitive to isoniazid, rifampicin and ethambutol, and 14 were sensitive to isoniazid, streptomycin, rifampicin and ethambutol. Sequencing of the rpsL gene revealed a mutation of AAG to AGG at codon 43 in one streptomycin- resistant strain and a substitution of CGC by CAC at codon 54 in another resistant strain. Conclusions In past five years, the resistance ratio of M. tuberculosis was low in patients with cutaneous tuberculosis, and streptomycin resistance predominated in these strains.