Research On Drug Sensitivity Of Mycobacterium Tuberculosis L Form

Objective: The detecting rates of Mycobacterium tuberculosis L form(MTB-L)and the distribution characteristics of MTB-L was analyzed in the initial treatment and retreatment patients.The positive rate of MTB-L was compared in initial treatment and retreatment patients with MTB(+)or MTB(-).MTB and MTB-L to the first-line drug and second-line drug sensitivity test was analyzed.The aim is to improve the cure rate of tuberculosis and provide laboratory evidence for tuberculosis treatment.Method:1 Specimen collection and cultureDuring the period from Juauary 2014 to Juauary 2015,the patients including the initial treatment of tuberculosis patients who were 105 cases and the retreatment patients who were 115 cases were collected in Chest Hospital of Hebei province.The bronchoalveolar lavage specimens were cultured in L-J medium which MTB was cultured and TSA-L medium which MTB-L was cultured,inoculated in incubator in 37? containing 5% CO2,observed every three day till eight weeks.2 Identification of MTB and MTB-LThe suspected colony was identified by acid fast staining and reversed mutation test methods.3 MTB and MTB-L drug susceptibility testingDrug sensitivity test for MTB and MTB-L positive samples were carried out.The resistant states of MTB and MTB-L to first line drug(streptomycin,isoniazid,rifampicin,ethambutol)and the seconds line drugs(macrolides,quinolones)were analyzed.Result:1 Positive rate of MTB and MTB-L in patients with primary andretreatment patientsThe positive rate of MTB-L was 12.3% in initial treatment of patients.The positive rate of MTB-L was 33% in retreatment of patients.There was statistically significant between the two groups(P <0.05).2 Distribution of MTB and MTB-L in initial treatment and retreatment patientsThe initial treatment patients with MTB(+)MTB-L(+)were 6 cases(5.7%).Retreatment patients with MTB(+)MTB-L(+)were 16 cases(13.9%).There was statistically significant between the two groups(P <0.05).The initial treatment patients with MTB(+)MTB-L(-)were 27 cases(25.7%),Retreatment patients with MTB(+)MTB-L(-)were 25 cases(21.7%).There was not statistically significant between the two groups(P >0.05).The initial treatment patients with MTB(-)MTB-L(+)were 7 cases(6.7%),Retreatment patients with MTB(-)MTB-L(+)were 22 cases(19.1%).There was statistically significant between the two groups(P <0.05).3 Comparison of the positive rate of MTB-L in patients with MTB(+)or MTB(-)in initial treatment and retreatment patientsIn initial treatment of patients,the detection rate of MTB-L in MTB positive specimens was 18.2%(6/33).In retreatment patients,the detection rate of MTB-L in MTB positive specimens was 39%(16/41),compared with the initial treatment group,the results were statistically different(P < 0.05).In initial treatment of patients,the detection rate of MTB-L in MTB negative specimens was 9.7%(7/72);in retreatment patients,the detection rate of MTB-L in MTB negative specimens was 29.7%(22/74).Compared with the initial treatment group,the results were statistically significant(P < 0.05).4 MTB and MTB-L to the first-line drug sensitivity testDrug sensitivity tests were carried out in 74 cases of MTB positive and51 cases of MBL-L positive samples,the results showed that drug resistance of MTB-L increased significantly to isoniazid(INH),streptomycin(SM),Li Fu ping(RFP)and ethambutol(EMB).Compared with MTB,the results were statistically significant difference(P < 0.05).5 MTB and MTB-L to the second-line drug sensitivity testDrug sensitivity tests were carried out in 74 cases of MTB positive and51 cases of MTB-L positive samples,the results showed that the MTB-L have relatively low resistance to clarithromycin(CLR),ofloxacin(OFLX).Compared with MTB,the results were not statistically significant difference(P > 0.05).Conclusion:1 The positive rate of MTB-L in retreatment patients was significantly higher than in initial treatment patients.2 Inoculation of MTB and MTB-L culture can increase the positive rate of bacteria.3 Whether in the initial treatment or retreatment of patients,MTB-L canstill be detected in MTB negative patients.4 MTB-L has different degrees of resistance to first-line anti-tuberculosis drugs.5 Quinolones and macrolides which act on cytoplasmic drugs have goodantibacterial activity against MTB-L.