ABSTRACT
Objective To explore the laboratory culture and identification of Mycobacterium tuberculosis L forms (MTB-L),isolation rate and drug resistance in smear-positive tuberculosis patients,and to improve clinical attention to MTB-L.Methods 222 smear-positive pulmonary tuberculosis patients treated in our hospital from September 2017 to December 2017 were randomly selected for MGIT 960 and 92-3TB-L liquid culture.After MGIT 960 was reported positive,acid-fast staining was performed on the precipitated smears of 92-3TB-L liquid medium for preliminary screening.The suspected L-positive strain culture was transformed into improved TSA-L solid medium to observe the colony characteristics and microscopic characteristics.The properties of the strain were confirmed by acid-fast staining and tuberculosis DNA amplification.Drug susceptibility and mutation sites of drug resistance genes were analyzed in MTB-L.Results Ⅰ-dentification of MTB-L:after the positive strain has been cultured,the colonies have the characteristics of "fried egg sample","particle-like" and " filament-like".MTB confirmed by tubercle DNA amplification experiments.Isolation rate:after cultured by MGIT 960 and Modified 92-3TB-L medium,the positive rate of single bacterial type was 50.90％,(113/222) the positive rate of both bacterial type and L type was 15.32％ (34/222),and the positive rate of MTB-L type was 2.25％ (5/222).Drug resistance:MTB-L was resistant to Streptomycin,Isoniazid,Rifampin,and Ethanol butylamine.No mutation was found in the drug resistance gene loci.Conclusions Clinical laboratory should routinely develop the culture of L-form of Mycobacterium tuberculosis bacteria,and increase the clinical attention to MTB-L.
ABSTRACT
Objective To investigate the effect of artesunate (ASN) on the expression of Heme oxygenase-1 (HO-1) in THP-1 cells induced by the early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) antigens of Mycobacterium tuberculosis and to investigate its possible mechanism.Methods THP-1 ceils were cultured in vitro.The effects of ESAT-6 and CFP-10 on cell viability were detected by methyl thiazolyl tetrazolium (MTT) assay.THP-1 cells were pre-treated with or without ASN prior to incubation with or without ESAT-6 and CFP-10,the mRNA expression of HO-1 was detected by real time quantitative polymerase chain reaction (RT-qPCR) and Toll-like receptor 2 (TLR2) level was measured by Western blot.Results MTF assay showed that ESAT-6 and CFP-10 were non-toxic to cells in the range of 0-5 μg/ml.Compared with the control group,5 μg/ml ESAT-6 and 5 μg/ml CFP-10 could significantly increased the mRNA expression of HO-1 (P ＜ 0.05).In addition,20 μg/ml ASN could significantly enhance the mRNA expression of HO-1 induced by ESAT-6 and CFP-10,and inhibit the expression of TLR2 induced by ESAT-6.Conclusions ASN in combination with ESAT-6 or CFP-10,may have potential value in treatment of pathogen-associated inflammatory diseases.
ABSTRACT
Objective To investigate the drug resistance of 1 031 Mycobacterium tuberculosis to rifampicin and isoniazide in the Center Hospital of Changsha from January 1 ,2013 to September 30 ,2014 .Methods A total of 1 031 strains with positive culture result and identified as strains of Mycobacterium tuberculosis were used absolute concentration method to do the conventional drug susceptibility ,and detected rifampicin and isoniazide resistance gene including rpoB ,katG and inhA gene locus mutation by chip technology ,the results of two methods were compared using card square test statistics .Results By gene chip method ,the sensitive strain of rifampicin was 896 ,the drug-resistant strains was 135 ,the sensitive strains of isoniazide was 901 strains ,130 drug-resistant strains .Compared with the absolute concentration method ,resistance chip detection results were consistent with rifampicin resistant strains 1 011 strains(including 894 drug-resistant strains ,and 117 sensitive strains) ,the coincidence rate was 98 .00% ,consistent with isoniazideresistant strains 1 005 strains(including 890 drug-resistant strains ,115 sensitive strains) ,the coincidence rate was 97 .48% .The most common spot of rifampin resistance related mutations of rpoB gene was 531TCG to TTG ,accounted for 51 .11% ,followed by 526CAC→TAC ,accounted for 10 .37% ,11 strains with 526TCG to TTG ,accounted for 8 .15% .Isoniazid re-sistance was caused by mutations in katG315AGC→ACC resistant strains ,accounted for 83 .85% ,inhA-15C→T mutations accoun-ted for only 12 .30% .Conclusion The results of gene chip method is highly consistent with that of absolute concentration method , could be a fast and effective method for screening rifampicin and isoniazide ,the resistant gene of Mycobacterium tuberculosis to rif-ampicin and isoniazide almost mutate in rpoB531 ,526 and katG315 in Changsha .