Preliminary Studyon The Drug Resistance Of 49 Strains Of Mycobacterium Tuberculosis In Nanchang Area

Objective: In order to compare the drug sensitivities and drug resistance gene loci distribution of the 49 strains of mycobacterium tuberculosis in Nanchang area, and to provide a laboratory basis for early, reasonably, and effectively clinical medication.Methods: Seperating and cultivating TB bacteria strains of 49 inpatient and outpatient positive sputum in Jiangxi province chest hospital from September 2012 to July 2013, and then testing the drug sensitivity and drug resistance gene loci:(1) the drug sensitivity test according to "the national tuberculosis bacteriology procedures" applied the absolute concentration method of 4 kinds of first-line drugs(isoniazid(INH), rifampicin(RFP), streptomycin(SM), ethambutol(EMB)) and 5 kinds of second-line drugs(amino salicylic acid(PAS), capreomycin(CMP), sulfur isoniazid(TH1312), amikacin(AMK), levofloxacin(LVFX)) with low/high two concentrations. The samples were divided according to three factors: 1) age including youth group(?25), middle-aged group(26-59 years old) and elderly group(?60); 2) medical history including initial group and recurrent group; 3) gender including male group and female group.(2) the resistance gene loci test randomly selected mdr-tb or xdr-tb or all anti-tb first-line drugs sensitive 6 strains from the whole 49 strains, and the gene loci were the three more common mutations of rifampicin resistant genes pro B: 531 loci, 526 loci and 531 loci.Results: 1. First-line drug resistant rate of 49 strains reached 81.6%; sensitivity to all the first-line drugs had 9 strains, accounting for 18.3% of the total resistance; 1 strain of the single drug resistance was accounting for 2.0% of the total resistance; MDR had 39 strains, accounting for 79.6% of the total resistance; the XDR had 25 strains, accounting for 51.0% of the total resistance.2. Drug resistant percentages in all age group patients: Youth group was sensitive to SM, INH, RFP, EMB, PAS, TH1312, but 100% CMP resistance, 25 % AKM resistance, 50 % LVFX resistance; middle-aged group showed 62.1% SM resistance, 100% INH resistance, 100% RFP resistance, 6.9% EMB resistance, 10.3% PAS resistance, 6.9% TH1312 resistance, 89.7% CMP resistance, 31.0% AKM resistance, 69.0% LVFX resistance; elderly group was 56.2% SM resistance, 62.5% INH resistance, 68.8% RFP resistance, 6.3% EMB resistance, 6.3% PAS resistance, 25.0% TH1312 resistance, 87.5% CMP resistance, 25.0% AKM resistance, 50.0% LVFX resistance. Anti-TB first-line INH and RFP resistant rates in the middle-aged and elderly groups exist significant differences(P < 0.05).3. Drug resistant percentages in the initial and recurrent groups: resistant percentages of the intial group against SM, INH, RFP, EMB, PAS, CMP, TH1312, AKM, LVFX were 48.3%, 71.0%, 74.2%, 19.7%, 9.7%, 93.5%, 9.7%, 22.6%, 48.3% respectively; resistant percentages of the recurrent group against SM, INH, RFP, EMB, PAS, CMP, TH1312, AKM, LVFX were in turns 66.7%, 94.4%, 94.4%, 5.6%, 5.6%, 94.4%, 22.2%, 38.9%, 66.7%. The INH and SM resistance of the initial and recurrent groups had significant differences(P < 0.05).4. Drug resistant percentages in the female and male groups: resistant percentages of the female group against SM, INH, RFP, EMB, PAS, CMP, TH1312, AKM, LVFX were 70.0%, 100%, 100%, 10.0%, 10.0%, 80.0%, 40.0%, 40.0%, 80.0% respectively; resistant percentages of the recurrent group against SM, INH, RFP, EMB, PAS, CMP, TH1312, AKM, LVFX were in turns 53.8%, 82.0%, 84.6%, 5.1%, 7.7%, 92.3%, 10.3%, 28.2%, 56.4%. The TH1312 resistance of the female and male groups had significant difference(P < 0.05).5. 49 strain Bacteria identification: 48 strains of human mycobacterium tuberculosis and 1 strain of bovine mycobacterium tuberculosis.6. Preliminary analysis of gene sequences of drug-resistant strains: 6 strains sensitive to rifampicin did not mutate, and the mutation rate was 61.6%(11/18); 11 strains among the 12 strains resistant to rifampicin had mutated, and the drug resistant mutation rate was 91.7%(11/12).Conclusion: 1. Mycobacterium tuberculosis has normally appeared drug resistance in the local region, and tends to become resistant to a variety of drugs, and is easy to develop into MDR, XDR, which suggests clinicians to consider combination for treatment. In the second-line drugs, capreomycin resistance is generally on the high side.2. Detection specificity and sensitivity of rifampicin resistant gene pro B were 100% and 91.7% respectivelt, which can used to predict the multidrug-resistant tuberculosis(NDR-TB).