| ObjectiveTo discuss the application value of metagenomic next-generation sequencing(mNGS)in the diagnosis and treatment of elderly patients with severe pneumonia and analyze the relevant risk factors for death of elderly patients with severe pneumonia.MethodsThe elderly patients with pneumonia,who were presented in the Department of Intensive Care Medicine of No.967 Hospital of PLA Integrated Logistic Support Force and had undergone conventional pathogenic test and mNGS pathogenic test from May 2021 to October 2022,were selected.The patients’ first-course,admission,routine,discharge or death medical records were reviewed to collect their general information such as age,sex and history of underlying diseases,and the clinical data such as the results obtained with the two test methods,final clinical diagnosis,the culture time(d)required for conventional pathogenic test,the time(d)required to perform mNGS,whether the treatment regimen was changed based on the results of mNGS and outcome.In addition,the drug-resistant gene test was performed with mNGS.Finally,the detection rate,test efficiency and test speed of the two methods in the patients as well as the relevant factors influencing the outcome of the elderly patients with severe pneumonia were analyzed.Results1.Finally 50 elderly patients with severe pneumonia were included into this study,who aged between 65 and 100 years,with a mean ± standard deviation(SD)of(88.04±9.15)years.Among them,there were 39(78.00%)males and 11(22.00%)females,and 31(62.00%)and 33(66.00%)patients had a history of smoking and drinking respectively.2.The pathogen distribution for the patients showed:(1)In the conventional pathogenic test,10 kinds of pathogens were detected in the 30 bronchoalveolar lavage fluid(BALF)specimens of the elderly patients with severe pneumonia;no pathogen was detected in all of the blood specimens.(2)In the mNGS pathogenic test,Gram-negative bacilli,especially Acinetobacter baumannii(40.00%),were dominant among the bacteria detected,and Candida albicans(8.00%)was dominant among the fungi detected in all specimens.3.The analysis of pathogen detection rate for the patients showed:(1)In the conventional pathogenic test,among the bacteria detected,Gram-negative bacilli were dominant,with a higher detection rate occurring for Acinetobacter baumannii(30.00%);among the fungi detected,a high detection rate occurred for Candida glabrata(4.00%).(2)In the mNGS pathogenic test,Gram-negative bacilli,especially Acinetobacter baumannii(40.00%),were dominant among the bacteria detected,and Candida albicans(8.00%)was dominant among the fungi detected in all specimens.4.The comparison between the detection rates of two methods showed:(1)According to the analysis of overall detection,the conventional test method had a detection rate of 54.00%,while mNGS had a detection rate of 82.00%,and the agreement between the two methods in overall pathogenic detection was merely fair.(2)According to the analysis of bacterium test,the conventional test method had a detection rate of 52.00%,while mNGS had a detection rate of 78.00%,and the agreement between the two methods in bacterium pathogenic detection was merely fair.(3)According to the analysis of fungus test,the conventional test method had a detection rate of 8.00%,while mNGS had a detection rate of 12.00%,and the agreement between the two methods in fungus pathogenic detection was merely fair.(4)According to the analysis of pathogenic test of BALF specimens,the conventional test method had a detection rate of 54.00%,while mNGS had a detection rate of80.00%,and the agreement between the two methods in pathogenic detection of BALF specimens was merely fair.(5)According to the analysis of pathogenic test of blood specimens,the conventional test method had a detection rate of 0.00%,while mNGS had a detection rate of 18.00%,and the agreement between the two methods in pathogenic detection of blood specimens was poor.5.The result of comparison between the two methods in detection efficacy showed:(1)Overall: The mNGS results showed a higher sensitivity(94.87% vs.64.10%)and negative predictive value(77.78% vs.39.13%)but a lower specificity(63.64% vs.81.82%)and positive negative value(90.24% vs.90.24%)as compared with the conventional test results.The mNGS results showed a strong agreement with the clinical diagnosis,while the conventional test results only showed a merely fair agreement with the clinical diagnosis.(2)For bacterium test,the mNGS results showed a higher sensitivity(92.11% vs.63.16%)and negative predictive value(72.73%vs.41.67%)but a lower specificity(66.67% vs.83.33%)and positive negative value(89.74% vs.92.31%)as compared with the conventional test results.The mNGS results showed a strong agreement with the clinical diagnosis,while the conventional test results only showed a merely fair agreement with the clinical diagnosis.(3)For fungus test,the mNGS results showed a higher sensitivity(66.67% vs 50.00%),negative predictive value(95.45% vs.93.18%)but a lower positive predictive value(66.67% vs.75.00%),specificity(93.18% vs.97.73%)as compared with the conventional test results.The mNGS results showed a moderate agreement with the clinical diagnosis,the conventional test results showed a moderate agreement with the clinical diagnosis.(4)For pathogenic test of BALF specimens,the mNGS results showed a higher sensitivity(97.30% vs.67.57%)and negative predictive value(90.00%vs.47.83%)but a lower specificity(69.23% vs.84.62%)and positive negative value(90.00% vs.92.59%)as compared with the conventional test results.The mNGS results showed a strong agreement with the clinical diagnosis,while the conventional test results showed a moderate agreement with the clinical diagnosis.(5)The mNGS results of blood specimens showed a sensitivity of 41.03%,positive predictive value of 84.21%,negative predictive value of 25.80% and specificity of 72.73%.The mNGS results showed a strong agreement with the clinical diagnosis.6.The comparison between the two methods in test speed showed that the conventional pathogenic test and mNGS test took(4.06±0.93)d and(2.94±0.82)d on average respectively,with a statistically significant difference(t=7.325,P=0.000).7.In the pathogenic drug-resistant gene test performed with mNGS for the elderly patients with severe pneumonia,40 cases of 9 drug-resistant genes were detected,and the highest detection rate occurred in the aminoglycoside(22.00%)andβ-lactam(20.00%)drug-resistant genes.8.No adjustment was made to the treatment regimens based on the mNGS test results.Being a male was a significant risk factor for the death of the elderly patients with severe pneumonia,while an absence of smoking and drinking history is a protective factor.Conclusions1.In the pathogenic test of elderly patients with severe pneumonia,the mNGS test showed a higher pathogenic detection rate and test speed as compared with the conventional pathogenic test method.2.Gram-negative bacilli were dominant among the bacteria detected,especially Acinetobacter baumannii with a higher detection rate.3.Among the detected drug-resistant genes of the elderly patients with severe pneumonia,a high detection rate occurred in β-lactam and aminoglycoside ones.4.No adjustment was made to the treatment regimens based on the mNGS test results.Being a male was a significant risk factor for the death of the elderly patients with severe pneumonia,while an absence of smoking and drinking history is a protective factor. |
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