| Objective(s):To explore the etiological characteristics of pulmonary infection in patients with renal transplantation and the diagnostic value of macrogene sequencing in bronchoalveolar lavage fluid,so as to provide accurate diagnosis and treatment basis for clinicians.Methods:A retrospective study was conducted to collect 81 patients initially diagnosed with pulmonary infection after kidney transplantation admitted to our hospital from September 2020 to November 2022 in Kunming first people’s Hospital.All of them had received bronchoalveolar lavage fluid mNGS and routine detection(blood culture,BALF and sputum culture,smear staining,antigen detection,viral nucleic acid etc.).Baseline data,major symptoms,imaging examination,mNGS test results,routine method results,underlying diseases,length of hospital stay and other data of patients were collected,and clinical diagnosis was determined based on all data.Comparison of the distribution characteristics of pathogens between mNGS and routine detection methods.Using clinical diagnosis as the gold standard,sensitivity,specificity,positive predictive value,negative predictive value and other indicators were calculated to compare the detection efficiency of mNGS,conventional detection and combined diagnosis.The number of cases detected by mNGS and conventional methods in mixed infection and various pathogens was compared,and the negative results of mNGS were analyzed.Results:1.Among the 81 patients with kidney transplantation,74 cases were positive for mNGS,and 127 strains of 33 kinds of pathogens were detected for reference.The top five pathogens were 46 strains of Pneumocystis carinii,25 strains of cytomegalovirus,6 strains of Epstein-Barr virus,4 strains of glucococcus aureus and 4 strains of Candida albicans.47 cases were positive by routine detection methods,and 20 kinds of pathogens and 65 strains were detected for reference,among which the top five pathogens were: 16 strains of cytomegalovirus,14 strains of Epstein-Barr virus,8strains of Pneumocystis carinii,5 strains of Acinetobacter baumannii,and 4 strains of cryptococcus/Aspergillus fumigatus.Compared with routine detection methods,mNGS detected more abundant strains and strains.2.Compared with routine detection methods,mNGS can significantly increase the positive rate of pathogens of pulmonary infection in patients with renal transplantation,and the difference is statistically significant(P<0.01).However,the consistency is poor(Kappa=0.060<0.4,P<0.001).In both positive cases,the number of pathogens detected by mNGS was higher than that of routine detection,and the detection time of mNGS was significantly shorter than that by conventional methods(P<0.001).The positive rate of mNGS in fungal detection was higher than that in routine detection,and the difference was statistically significant(P<0.05),but there was no significant difference in bacterial and viral detection(P>0.05).3.Clinical diagnosis was confirmed by etiological detection and clinical comprehensive analysis.A total of 30 species and 120 strains pathogenic pathogens were detected in 73 patients by mNGS,including 18 species of bacteria,5 species of fungi,5 species of viruses and 2 kinds of atypical pathogens.A total of 19 species and58 strains of pathogenic pathogens were detectedin 46 patients by routine detection,including 11 species of bacteria,5 species of fungi,2 kinds of viruses and 1 species of atypical pathogens.4.Combined with the clinical data and the results of the two detection methods,77 patients were finally diagnosed with pulmonary infection.Clinical diagnosis was taken as the gold standard.The sensitivity of the combined diagnosis,mNGS and routine detection were 98.70%,94.81% and 59.74%,respectively,and the Joden index was 0.74,0.70 and 0.35,respectively.The Kappa values were 0.737,0.515 and 0.076,respectively,and the negative predictive values were 75.00%,42.86% and 8.82%,respectively.The sensitivity of mNGS in detecting bacteria and fungi was higher than that of routine detection,and the difference was statistically significant(P<0.05).5.Compared with routine detection,mNGS has obvious advantages in the detection rate of ≥ 3 pathogens(P=0.005).In addition,the efficacy of Gram positive bacteria,Pneumocystis carinii,Candida albicans,cytomegalovirus and rare virus was higher than that of routine detection,the difference was statistically significant(P<0.05).6.42 patients were diagnosed with mixed infection,and the detection rate of mNGS for mixed infection was significantly higher than that of conventional methods,with statistical significance(71.43% vs 33.33%,P<0.05).The most common types of mixed infection were viral-fungal infection(18/42)and fungal-viral-bacterial infection(8/42).7.mNGS were found in 7 patients with negative results,including 3 true negative cases and 4 false negative cases.In the true negative group,2 patients had interstitial lung disease and 1 patient had lung adenocarcinoma.In the false negative group,1case was mycobacterium tuberculosis,1 case was cryptococcus,1case was Aspergillus and 1 case was Legionella pneumophila.Conclusion(s):1.In patients with pulmonary infection after renal transplantation,mNGS issuperior to conventional methods in detecting pathogen type,detection speed,positive rate,sensitivity and diagnosis rate of mixed infection,among which,mNGS has obvious advantages in Pneumocystis carinii,cytomegalovirus and rarepathogens.2.The diagnostic efficiency of mNGS is higher than that of routine detection,and the combined detection of both has better value for the detection of pathogenic bacteria.3.The negative results of mNGS help to rule out pulmonary infection and provide supporting evidence for the diagnosis of non-infectious diseases. |
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