The Diagnostic Value Of Gold Immunochromatography Method Detecting Candida Antigen In Patients With Invasive Candida Pneumonia

With the aging process of population,the escalating incidence of cancer,the increasing number of ICU patients,the extensive use of immunosuppressive drugs in our country,and the incidence of invasive fungal pneumonia increased significantly.Candida is the most common pathogen of fungal pneumonia.However,the clinical characteristics of various pneumonia patients can be cough,fever,wheezing and no specificity,imaging can not distinguish the fungal pneumonia caused by what pathogens.The diagnosis of candida pneumonia requires aseptic body fluid and histopathology.However,patients with fungal pneumonia are usually in poor condition,so it is difficult to obtain pathological tissue by invasive examination.Sputum and alveolar lavage fluid are relatively easy to obtain,but the test results can not determine whether it is infection or colonization,and the diagnosis time is long.Therefore,the existing detection methods can not meet the clinical needs for the diagnosis of fungal pneumonia.Detection of 1,3-?-d-glucan in blood or alveolar lavage fluid is a commonly used method for rapid detection of fungal pneumonia.However,1,3-?-d-glucan also exists in Aspergillus,which does not distinguish the type of fungal infection.The detection of candida specific antigen antibody and specific antigen is worth exploring,but it is seldom used in clinical research.Colloidal gold immunochromagraphy method has been widely used in HIV,hepatitis virus and other clinical diagnosis such as early pregnancy screening,has a very good clinical significance.To study the sensitivity and specificity of gold immunochromatography in candida antigen,improve the sensitivity and specificity of candida pneumonia diagnosis and shorten the diagnosis time,has important clinical significance for the diagnosis and treatment of candida pneumonia,and provides help for clinicians to make more accurate diagnosis and treatment.Objective:To develop a detection reagent of candida antigen using colloidal gold immunochromatography method for the diagnosis and treatment of patients with invasive fungal pneumonia,to verify the diagnostic efficacy of invasive candida pneumonia.Methods:By means of colloidal gold immunoassay,a reagent for detecting candida antigen by colloidal gold immunochromatography was developed.From April 2015 to September 2019,253 suspected cases of invasive candida pneumonia,invasive aspergillus pneumonia and non fungal infection were included in our hospital's diagnosis and treatment.The colloidal gold immunochromatographic reagent developed jointly by us and Academy of Military Medical Sciences was used to detect the Candida antigen in the blood,and the sensitivity and specificity of the detection reagent for Candida pneumonia were studied.Results:In this study,a total of 253 patients-were enrolled,among which 30 were diagnosed as invasive pulmonary candida pneumonia,213 were diagnosed as non-fungal infection,and 10 were diagnosed as invasive pulmonary aspergillus pneumonia.The results of candida antigen determination using colloidal gold immunochromatography method were positive in 26 cases of 30 patients with clinical diagnosis of candida pneumonia,and negative in 4 cases.The results of candida antigen determination using colloidal gold immunochromatography method were negative in 198 cases and positive in 15 cases.One of 10 patients with aspergillus was positive for colloidal gold immunochromatography method and nine were negative.The minimum detection limit of Candida antigen detection reagent is 0.123ug/ml.The patient serum of bacteria infection such as-Staphylococcus aureus,Klebsiella pneumoniae,Acinetobacter baumannii,Pseudomonas aeruginosa,Escherichia coli,Stenotrophomonas maltophilia,Enterobacter cloacae,Morganella morganii,Enterococcus faecalis and Enterobacter aerogenes infections ware tested respectively.The patient serum of fungal infection such as Aspergillus niger,Aspergillus flavus,Aspergillus terreus and Cryptococcus patients infections were also tested respectively.The patient serum of virus and other medical pathogen infection such as influenza A virus and influenza B virus,Mycoplasma pneumoniae and Chlamydia pneumoniae infections were tested respectively too.All the test results above mentioned were negative.The sensitivity,specificity,positive predictive value and negative predictive value of colloidal gold method were 87%,93%,63% and 98% respectively.Thirty patients with clinically diagnosed candida pneumonia were treated with antifungal therapy,18 cases were cured,3 cases were improved,6 cases were improved of pneumonia but the treatment was abandoned due to the aggravation of the primary disease,and 3 cases died,with a total effective rate of 90%.Conclusion:Gold immunochromatography has a very high specificity and negative predictive value for invasive pulmonary candida pneumonia.If the test results are positive,pneumonia caused by candida infection can be considered.There are also good sensitivity and positive predictive values.If the test result is negative,it is suggested to comprehensively analyze the possibility of candida infection causing pneumonia in combination with clinical conditions.In summary,colloidal gold immunochromatography is rapid and convenient for the detection of candida antigen,which can be used in the detection of invasive candida pneumonia.