Etiological Characteristics,Drug Resistance Analysis And Etiological Diagnosis Methods Of Severe Pneumonia In Adults

Background and ObjectivesSevere pneumonia has a high mortality rate and poor prognosis.Timely etiological diagnosis and reasonable antibiotic use are essential to reduce mortality and improve prognosis.Due to the serious changes in etiology and drug resistance,and the insufficient diagnostic rate of pathogens,the realization of precise treatment is still a big problem.Therefore,the purpose of this subject is to study the distribution characteristics of pathogens and drug resistance of severe pneumonia in adults,and to explore the clinical application value of multiplex PCR in the etiological diagnosis of severe pneumonia by comparing with traditional detection methods.Methods(1)The data of lower respiratory tract infection cases in the respiratory tract infection case database of Guangdong Second People’s Hospital in 2020 and 2021 were collected,and the etiological diagnosis was carried out by RT-PCR of multiple respiratory pathogens.The overall distribution characteristics and seasonal change trend of the etiology were analyzed retrospectively,and the subgroup analysis was carried out according to the location and severity of the disease.(2)By means of prospective research methods,patients with severe pneumonia admitted to the Department of respiratory and critical care medicine of Guangdong Second People’s Hospital from 2021 to 2022 were enrolled.BALF was collected for FilmArray PN detection and traditional culture,then clinical data of patients were collected.The pathogenic distribution and drug resistance of severe pneumonia were analyzed.(3)Comparing the difference in positive rates between FilmArray PN detection and conventional culture and calculating the coincidence rate.Comparing drug resistance genes detected by FilmArray PN with drug sensitivity results,then calculating positive predictive value and negative predictive value of drug resistance genes.Results1.In the lower respiratory tract infection,men accounted for 64.2%,and 42.5%were over 65 years old.Compared with the mild group,the severe group had a larger proportion of elderly men,with a higher proportion of fever,shortness of breath and changes in consciousness(P<0.01).More patients were complicated with diabetes,cerebrovascular accident and COPD history(P<0.01),and the hospital mortality rate was 8.0%(P<0.01).2.The retrospective study showed that the pathogen of severe pneumonia was mainly virus(60.0%),the proportion of mixed infection was 48%,and the detection rate of bacteria was 48.6%.The top three of bacteria were Klebsiella pneumoniae,Staphylococcus aureus,and Haemophilus influenzae,and 4 cases of Pneumocystis yersiniae were detected(8%).3.The prospective study showed that the pathogens of severe pneumonia were mainly bacteria,with mixed infection accounting for 65.5%.The top three of bacteria were Pseudomonas aeruginosa,Acinetobacter baumannii complex and Klebsiella pneumoniae.The detection rate of virus was 13.9%,and human rhinovirus/enterovirus was the most common.4.In the etiology of severe pneumonia,79.5%were multi-drug or extensively drug resistant bacteria,72.4%of drug resistance genes were detected.The negative predictive value of drug resistance gene was 81.3%,the positive predictive value of KPC,NDM,VIM,IMP or Oxa-48-like was 64.9%,and the positive predictive value of CTX-M was 67.7%.5.The positive rate of FilmArray PN was 82.8%,and the detection rate of mixed infection was 65.5%,which was significantly higher than that of traditional culture methods.The coincidence rate between FilmArray PN and traditional culture results was 79.3%.Conclusions1.Severe pneumonia is mainly caused by elderly men,with many basic diseases,atypical clinical manifestations,high mortality and poor prognosis.The clinically practical problems of high mortality and poor prognosis in severe pneumonia are greatly needed to be solved.2.Through different detection methods,the pathogenic results of severe pneumonia are different.Generally,the infection pathogens are complex,the proportion of mixed infection is large,the detection rate of virus is increased,and the phenomenon of bacterial resistance is serious.3.The drug resistance genes and drug resistance phenotypes are not completely consistent,and the negative predictive value is high.In clinical practice,drug use should be cautious according to the actual situation.4.Compared with traditional detection methods,FilmArray PN detection has the advantages of fast speed,high sensitivity and wide detection range,and the detected resistance genes have strong predictive value,which can quickly and accurately guide clinical medication.