| Backgound:Pulmonary tuberculosis(PTB)is a major public health problem worldwide Accurate diagnosis of PTB is the premise of effective treatment.In addition to the traditional diagnostic methods such as acid-fast staining of sputum smear and Mycobacterium tuberculosis(MTB)culture,the continuous development of molecular diagnostic tools has provided new means for the diagnosis of PTB and the rapid detection of drug sensitivity.GeneXpert MTB/RIF is an automated molecular diagnostic technique for real-time amplification of DNA sequences by semi-nested amplification,targeting rifampicin resistance determination region(RRDR)of rpoB gene as a marker.Through semi-nested PCR containing the entire 81bp RRDR,the 192bp specific sequence of mycobacterium tuberculosis binding rpoB gene was amplified to detect both mycobacterium tuberculosis complex isolates and rifampicin resistance.GeneXpert MTB/RIF can be directly applied to unprocessed clinical samples,but the sensitivity of different samples is quite different.In 2010,WHO approved GeneXpert MTB/RIF for the detection of MTB and rifampicin resistance in sputum smear samples from suspected multidrug-resistant tuberculosis patients,as well as for follow-up testing of smear-negative patients.For patients without sputum,acid-fast staining of sputum smear and MTB culture cannot be performed,so histological evidence can be obtained to confirm the presence of PTB.There are few studies on the diagnostic value of GeneXpert MTB/RIF in histophiological specimens at home and abroadObjective:To explore the diagnostic value of GeneXpert MTB/RIF in surgical lung pathological specimens of PTBMethods:Patients who had been diagnosed as suspected tuberculosis in a hospital from June 2017 to January 2019.Lung cancer could not be ruled out and lung surgery was performed.Calculate the positive detection rate of GeneXpert MTB/RIF,acid-fast staining,combination of the two methods and the detection rates in caseinous necrosis specimens and noncaseinous necrosis specimens,respectively.At the same time,GeneXpert MTB/RIF can assess the presence of rifampicin-resistant tuberculosisResults:Sixty patients were enrolled,16 cases were caseous necrotizing granuloma and 44 cases were granulomas without caseous necrosis.Among pathologically suspected tuberculosis specimens,29 were positive with acid-fast staining and 28 were positive with GeneXpert MTB/RIF.The positive rates of acid-fast staining,GeneXpert MTB/RIF,combination of the two methods were 48.3%,46.7%,55.0%respectively.In the subgroup analysis,the detection rates of GeneXpert MTB/RIF in caseinous necrosis specimens and non-caseinous necrosis specimens were 81.3%and 34.1%,respectively.The positive rates of acid-fast staining in caseous necrosis specimens and non-caseinous necrosis specimens were 87.5%and 34.1%,respectively.GeneXpert MTB/RIF and acid-fast staining showed statistically significant differences in cheese-like and non-cheese-like specimens(P<0.05).Five specimens were positive for acid-fast staining and negative for GeneXpert MTB/RIF.The identification of mycobacterial species showed that all of them were MTB,suggesting that there were some false negatives in GeneXpert MTB/RIF.In addition,of the 28 specimens that were positive for GeneXpert MTB/RIF,three were reported as rifampicin-resistantConclusion:GeneXpert MTB/RIF detection of lung tissue specimens for diagnosis of tuberculosis is acceptable and determine whether there is rifampin-resistant tuberculosis,which has certain clinical value.At the same time,a larger sample size study is still needed to further evaluate the diagnostic efficacy of GeneXpert MTB/RIF in pathological tissues. |
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