| Background:Aspiration pneumonia is an infection or chemical inflammation of the lungs caused by inhalation of oropharyngeal secretions containing pathogens or inhalation of aseptic gastric contents and so on.Aspiration pneumonia is common in community-acquired pneumonia(CAP),but it is sometimes difficult to distinguish due to the diversity of its clinical presentation.According to the 2022 Expert Recommendations for the Diagnosis and Treatment of Aspiration Pneumonia in Adults,the diagnosis of aspiration pneumonia depends on 3 main aspects: history of aspiration,risk factors associated with aspiration,and gravitydependent pulmonary segmental exudate shadowing on imaging,which needs to be further confirmed in conjunction with the patient’s clinical presentation,laboratory tests,and swallowing function tests.Without a witnessed aspiration,the diagnosis is more difficult.Community-acquired aspiration pneumonia,although treated as part of CAP,has a poor prognosis and a high mortality rate,which is further increased when complicated by pleural effusion.Aspiration pulmonary infections involve the use of antibiotics.Prophylactic use of antibiotics does not improve prognosis and may lead to resistance,but inadequate empirical antibiotic therapy is also an independent risk factor for mortality.Therefore,identification of the presence of the infecting agent and identification of the infecting pathogen and targeted application of antibiotics become the key to the treatment of aspiration pneumonia.Traditional pathogen culture methods are time-consuming,biased,and have low positive rates,with lagging feedback to the clinic,and the search for alternative pathogen detection methods is of great importance for infectious diseases.Metagenomic next-generation sequencing(m NGS)has been widely used to rapidly identify potential pathogens and can be used for a variety of specimen types,allowing direct high-throughput sequencing of nucleic acids from clinical samples without differentiation and selection,improving the detection rate and efficiency of pathogens.The pleural cavity is a confined space,and no studies have yet shown microbial colonization in the healthy pleural cavity.Therefore,when pathogens are detected in pleural effusions,based on the observation of pneumonia,they are usually considered to be due to bacterial breakthrough of the visceral pleura and should be give high priority.It has been shown that inhalation of oral colonizing bacteria plays an important role in the etiology and pathogenesis of pleural infections.The application of m NGS for pleural fluid detection can be used to understand the bacteriology of pleural infections in aspiration pneumonia,which in turn can influence the diagnosis and treatment decisions of aspiration pneumonia.Objective:This study aimed to analyze the clinical characteristics of patients diagnosed with aspiration pneumonia after detecting pleural effusion by m NGS and combining them with the2022 Expert Recommendations for the Diagnosis and Treatment of Aspiration Pneumonia in Adults,and to explore the prospects of the application of m NGS in the diagnosis and treatment of aspiration pneumonia.Methods:To retrospectively analyze the clinical data of patients who attended the Department of Respiratory and Critical Care Medicine of the Second Norman Bethune Hospital of Jilin University from January 2020 to December 2022 with a supplementary diagnosis of aspiration pneumonia after parallel m NGS detection of pleural effusion,including general basic information,clinical manifestations,laboratory tests,imaging,treatment,and prognosis.Results:(1)The 17 patients included 15 males and 2 females.Four cases had no previous underlying disease.All patients denied a history of aspiration.Fever was present in 15 patients,14 of whom had significant chest pain,14 had cough,13 had sputum,and 4 had odorous sputum.Four patients had dysphagia,2 patients had an onset or exacerbation clearly associated with alcohol consumption,and 1 patient had vomiting during the course of the disease.The imaging findings suggested unilateral pneumonia in 11 cases,with no significant difference between left and right,and when it was a limited lobe inflammation,it was more common in the lower lobe,2 cases of pneumonia combined with lung abscess,12 cases of unilateral non-encapsulated pleural effusion,3 cases of unilateral encapsulated pleural effusion,and 2 cases of liquid pneumothorax.The white blood cell count,neutrophil count,monocyte count,C-reactive protein,and sedimentation were significantly elevated.The lymphocyte count was decreased in 5 patients.All 17 cases were exudative pleural effusions,and three cases had pleural effusion odor.(2)Six cases had positive sputum culture results,four for Canidia albicans,one for Stenotrophomonas maltophilia,and one for Klebsiella pneumoniae.One case had pleural effusion culture results of Streptococcus viridans.One case had BALF culture results of Stenotrophomonas maltophilia.The blood culture results were all negative.(3)The m NGS results suggested that 16 samples presented 2 or more pathogenic infections,all of which were oral colonizing bacteria,inconsistent with conventional pathogenic results,with Fusobacterium nucleatum and Parvimonas micra being the most common bacteria and in high relative abundance,both of which were exclusively anaerobic.(4)A total of 4 cases were treated with anti-infective regimens containing nitroimidazole antibiotics at initial treatment,12 cases were treated with anti-infective regimens that did not contain nitroimidazole antibiotics,but the selected antibiotics were effective against anaerobic bacteria,and 1 case had an anti-infective regimen that did not cover anaerobic bacteria.After the presentation of the m NGS test results,combined with other clinical information and guidelines,the clinical diagnosis of aspiration pneumonia was added in all 17 patients.The anti-infective regimen was changed in a total of 12 cases,and 4 patients eventually underwent surgery.The white blood cell count,neutrophil count,and monocyte count were lower than before treatment,and the difference was statistically significant(P<0.05);the lymphocyte count was higher before treatment than after treatment,and the difference was statistically significant(P<0.05).After treatment,16 patients had a good prognosis,and 1 case was lost to follow-up.Conclusion:(1)Even in the absence of a clear witnessed aspiration,patients should be alerted to aspiration pneumonia if they have fever,chest pain,cough,and sputum as the main clinical manifestations,with or without advanced age,swallowing disorder,history of alcohol consumption,and overweight,as well as imaging examinations suggesting gravity-dependent distribution of the lesions with pleural effusion.(2)The detection of pleural effusion by m NGS can provide an effective basis for clinical diagnosis of aspiration pneumonia,improve the diagnosis rate of aspiration pneumonia,reduce the misdiagnosis rate,and clarify the pathogen spectrum in parapneumonic pleural effusion for timely adjustment of anti-infection treatment plan,assist clinical precision diagnosis,reduce the rate of patient surgery,and clarify the timing of surgery. |
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