| Objectives:To retrospectively analyze the distribution of pathogenic bacteria in the lower respiratory tract(sputum and alveolar lavage fluid)specimens of elderly patients in the Seventh Medical Center of the Chinese People’s Liberation Army General Hospital in 2020.In this context,the application value of microfluidic loop-mediated isothermal amplification technology(microfluidic LAMP)in the detection of pathogenic bacteria in the lower respiratory tract of elderly patients is explored,with the aim of providing clinicians with rapid and accurate diagnosis.Methods:Use WHONET 5.6 to process the data of 2527 results of lower respiratory tract specimens from January 1,2020 to December 31,2020,and perform statistical analysis.At the same time,153 qualified lower respiratory tract specimens with clinically confirmed or suspected respiratory tract infections were collected from the First Medical Center(76 copies)and Seventh Medical Center(77 copies)of the PLA General Hospital.Taking sputum culture as the gold standard,the microfluidic LAMP technology is used to detect pathogens.By comparing the accuracy of the two pathogen detections(sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,Youden’s index and likelihood ratio),reliability(Kappa Value,coincidence rate)and predictive value;at the same time,combined with white blood cell count,neutrophil percentage,CRP and PCT and other indicators to comprehensively judge the clinical application value of microfluidic LAMP technology in the detection of elderly lower respiratory tract specimens.Results:1.There are 2527 specimens of lower respiratory tract samples from elderly patients in the hospital,and a total of 477 strains of pathogenic bacteria were isolated,mainly Gram-negative bacteria(70.69%,316/447),mainly:Pseudomonas aeruginosa(32.44%,145/447),Acinetobacter baumannii(19.02%,85/447)and Klebsiella pneumoniae(10.29%,46/447).2.Statistical analysis of 394 positive specimens from elderly patients.The main type of infection was infection by single dominant bacteria(86.29%,340/394),and the top three were still Pseudomonas aeruginosa,Acinetobacter baumannii and Klebsiella pneumoniae;mixed pathogen infections(two pathogens)are mainly mixed infections of Acinetobacter baumannii and Pseudomonas aeruginosa(24.07%,13/54).3.In terms of accuracy,compared with sputum culture,the microfluidic LAMP technology has a lower sensitivity and a higher missed diagnosis rate of Stenotrophomonas maltophilia,and the sensitivity of other pathogens is greater than 66%;Pseudomonas aeruginosa The specificity is 78.95%,and the others are greater than 91%.The Youden’s index and positive likelihood ratio of Escherichia coli are the highest,respectively:0.97 and 38.00,and the Youden’s index of fastidious bacteria Haemophilus influenzae reaches 0.95.4.In terms of reliability and predictive value,Acinetobacter baumannii(Kappa=0.684),Pseudomonas aeruginosa(Kappa=0.588)and Klebsiella pneumoniae(Kappa=0.498)are in good agreement,among which Bowman does not move The consistency of the bacilli is the best;the negative predictive value of each detected bacteria is greater than 94%;the total coincidence rate is higher than 81%.5.The number of pathogen-positive strains detected by the microfluidic LAMP technology has a high correlation with the increase in white blood cell count,the percentage of neutrophils,the increase in CRP and PCT,and the correlation coefficients are all greater than 0.951.6.The detection rate of this technology between male and female patients There is a statistical difference(P=0.023).The detection rate of males(68.60%)is higher than that of females(46.88%).7.This technology has detected 9 pathogens this time,which can cover 64.29%of common respiratory pathogens in elderly patients.Conclusions:1.The pathogens of the lower respiratory tract specimens of elderly patients in the hospital are mainly Pseudomonas aeruginosa,Acinetobacter baumannii and Klebsiella pneumonia;the mixed pathogen infections are mainly caused by Acinetobacter baumannii and Pseudomonas aeruginosa.Mixed infections are predominant.2.The microfluidic LAMP technology in the detection of pathogenic bacteria in the lower respiratory tract in the elderly has the characteristics of simple operation,short time-consuming,fast and high efficiency,and can simultaneously detect some fastidious bacteria with unsatisfactory culture results.It can be used as an auxiliary diagnostic technology for Clinicians provide rapid test results of lower respiratory tract specimens of elderly patients. |
