Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used...Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used for many applications. In this study, HRM assay was developed and evaluated for the detection of PZA resistance in Mycobacterium tuberculosis clinical isolates. Methods: Ninety five M. tuberculosis clinical isolates with different susceptibility patterns to anti-TB drugs were used to evaluate this assay. Isolates were phenotypically (Bactec MGIT 960) and genotypically (HRM and pncA gene sequencing) analysed for PZA resistance. Results: Bactec MGIT 960 analysis revealed that 29 of the 95 M. tuberculosis isolates were PZA resistant. In comparison to the Bactec MGIT 960, HRM showed a sensitivity of 47.7% and specificity of 74.6%, and the overall agreement between the two methods was 68.4%. Based on DNA sequencing, a correlation of 0.67 (significant at p-value pncA mutations was observed. PZA resistance was strongly associated with multi-drug resistant (MDR)-TB as it was shown in 79.3% of the MDR isolates included in the study. Conclusion: HRM is simple and useful for screening clinical M. tuberculosis isolates for PZA resistance, however, further modifications to improve its performance are required.展开更多
Short tandem repeat(STR)profiling is one of the mostly used systems for forensic applications.In certain circumstances,STR profiling is time-consuming and costly,which potentially leads to delays in criminal investiga...Short tandem repeat(STR)profiling is one of the mostly used systems for forensic applications.In certain circumstances,STR profiling is time-consuming and costly,which potentially leads to delays in criminal investigations.LGC(Laboratory of the Government Chemist,UK)Forensics has developed a robust STR profiling platform called the ParaDNAVR Intelligence Test System which can provide early tactical intelligence and aid investigators in making informed decisions on sample prioritization for detection.Here,we validated the ParaDNA^(■) intelligence test for its application in forensic cases using a range of mock evidence items following guidelines set by the Scientific Working Group on DNA Analysis Methods(SWGDAM).Specifically,we tested the sensitivity and accuracy of the ParaDNA intelligence test,as well as the success rates for detecting mock samples and for use in case scenarios.Our findings demonstrate that the ParaDNA intelligence test generates useful DNA profiles,especially for samples such as blood,saliva,and semen that contain ample DNA,indicating the benefits of including ParaDNA as a prior step in forensic STR profiling pipelines.展开更多
文摘Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used for many applications. In this study, HRM assay was developed and evaluated for the detection of PZA resistance in Mycobacterium tuberculosis clinical isolates. Methods: Ninety five M. tuberculosis clinical isolates with different susceptibility patterns to anti-TB drugs were used to evaluate this assay. Isolates were phenotypically (Bactec MGIT 960) and genotypically (HRM and pncA gene sequencing) analysed for PZA resistance. Results: Bactec MGIT 960 analysis revealed that 29 of the 95 M. tuberculosis isolates were PZA resistant. In comparison to the Bactec MGIT 960, HRM showed a sensitivity of 47.7% and specificity of 74.6%, and the overall agreement between the two methods was 68.4%. Based on DNA sequencing, a correlation of 0.67 (significant at p-value pncA mutations was observed. PZA resistance was strongly associated with multi-drug resistant (MDR)-TB as it was shown in 79.3% of the MDR isolates included in the study. Conclusion: HRM is simple and useful for screening clinical M. tuberculosis isolates for PZA resistance, however, further modifications to improve its performance are required.
基金This study was supported by grants from National Key R&D Program of China[grant number 2016YFC0800703]the National Natural Science Foundation of China[grant number 81601651 and 81625013]+2 种基金the Ministry of Finance of China[grant number GY2016D1,GY2018G-9,KF1813]the Shanghai Science and Technology Innovation Fund[grant number 16DZ1205500,16DZ2290900,17DZ2273200]the funders had no role in study design,data analysis,decision to publish,or preparation of the manuscript.
文摘Short tandem repeat(STR)profiling is one of the mostly used systems for forensic applications.In certain circumstances,STR profiling is time-consuming and costly,which potentially leads to delays in criminal investigations.LGC(Laboratory of the Government Chemist,UK)Forensics has developed a robust STR profiling platform called the ParaDNAVR Intelligence Test System which can provide early tactical intelligence and aid investigators in making informed decisions on sample prioritization for detection.Here,we validated the ParaDNA^(■) intelligence test for its application in forensic cases using a range of mock evidence items following guidelines set by the Scientific Working Group on DNA Analysis Methods(SWGDAM).Specifically,we tested the sensitivity and accuracy of the ParaDNA intelligence test,as well as the success rates for detecting mock samples and for use in case scenarios.Our findings demonstrate that the ParaDNA intelligence test generates useful DNA profiles,especially for samples such as blood,saliva,and semen that contain ample DNA,indicating the benefits of including ParaDNA as a prior step in forensic STR profiling pipelines.
