Retrospective Pathogen Diagnostic Investigation For Severe Community-acquired Pneumonia Via Rapid Detection Technology Of Liquid Chip And Clinical Analysis

Objective:The rapid detection technology of liquid chip is used to test the nucleic acid of qualified sputum samples from patients with severe community-acquired pneumonia,to investigate the spectrum of common bacteria,virus,and atypical pathogens and analysis the clinical characteristic,aimed at assessing the clinical value,setting up a system of severe community-acquired pneumonia,to guide the early and specific treatment.Methods: 54 cases of severe community-acquired pneumonia in Fujian Provincial Hospital are collected from February 2013 to September 2014,including the qualified sputum samples,the acute phase serum and clinical data.The liquid chip technology established by our research group,is used to test the nucleic acid of sputum samples.It can detect 6 kind of bacteria(Staphylococcus aureus,Streptococcus pneumonia,Klebsiella pneumonia,Acinetobacter baumannii,Pseudomonas aeruginosa,Stenotrophomonas maltophilia),12 kind of virus(Human cytomegalovirus,Adenovirus,Human parainfluenza virus 1,Human parainfluenza virus 2,Human parainfluenza virus 3,Respiratory syncytial virus,Coronavirus,Influenza A virus,Influenza A virus H5,Influenza A virus N1,Human metapneumovirus,Human Boca virus)and 2 kind of atypical pathogens(mycoplasma pneumonia,chlamydia pneumonia)simultaneously.Then the spectrum is analyzed retrospectively,compared with sputum culture,Real-Time PCR test results and enzyme-linked immunosorbent,to evaluate coincidence rate and the sensitivity and specificity.According to the result of golden criterion,we divide the cases into groups of bacteria or virus,Fisher discriminant analysis is applied to predict the pathogen,including general characteristics,symptoms,physical sign,biomarkers and imaging features.Results: Of the 54 sputums detected by liquid chip technology,18 cases(33.3%)belong to the infection of bacteria,8 cases(14.8%)of virus,6 cases(11.1%)of mixed infection.Gram-negative bacteria is the predominat pathogen(72.7%).Pseudomonas aeruginosa(18.5%),Klebsiella pueumonia(14.8%)and Influenza A virus(13.0%)have the high positive rate.The positive rate of bacterial detection,by liquid chip technology is 40.7%,higer than the conventional sputum culture(P<0.05),the specificity and sensitivity is 93.5% and 78.6%.The positive rate of viral detection,by liquid chip technology is 25.9%,the specificity and sensitivity is 91.3% and 76.5%.it shows no significant difference compared with Real-Time PCR test(P>0.05).The positive rate of atypical pathogens detection is 3.7%,the specificity and sensitivity is 100%.it shows no significant difference compared with enzyme-linked immunosorbent assay(P>0.05).The new technology may have significant value in clinic.We use the fuction F=0.191X6+0.168X7+1.606X2(White cell count,procalcitonin and immunosuppressive)to distinguish the infection of bacteria or virus,when Z≥ 0.261,it belongs to bacteria group;Z<0.261,it belongs to the viral group.The accuracy is 87.0%.Conclusions:The liqid chip technology can test bacteria,viral and mycoplasma pneumonia,it have a significant value in clinic considering the rapid,high through-put and flexihle multi analyte profiling.The bacteria and virus is the major pathogen of SCAP,Pseudomonas aeruginosa,Klebsiella pueumonia and Influenza A virus have high positive rate.The mixed infection cannot be igored.White cell count,procalcitonin and immunosuppressive have high value for indentifying infection of bacteria or virus.