Diagnostic Value Of Quantitative Procalcitonin Detection And Time To Positivity In Candida Bloodstream Infection And Rapid Identification Of Candida Parapsilosis With Loop-mediated Isothermal Amplification

Chapter1Diagnostic value of quantitative procalcitonin detection inCandida bloodstream infectionObjective To evaluate the application value of quantitative procalcitonin(PCT)in Candida bloodstream infection. Methods The medical records of1032patients with blood culture and PCT detection were collected, retrospectively.The relationship between blood culture results and PCT levels were investigated.PCT levels in gram-negative bacteria, gram-positive bacteria and Candidaswere compared. Results In the patients with negative blood culture, themedian of PCT was0.37ng/ml.But in the patients with gram-negative bacteria,gram-positive bacteria and Candidas infections were3.86ng/ml,1.46ng/ml and1.48ng/ml, the positive rate of PCT in gram-negative bacteria, gram-positivebacteria and Candidas were86.6%,72.0%,75.7%, respectively. ConclusionsQuantitative PCT was proved to be an effective method to rapid diagnosis ofbloodstream infection. The diagnostic value of quantitative procalcitonindetection in Candida bloodstream infection is similar to bacteria infections.Chapter2Diagnostic value of time to positivity in Candida bloodstreaminfectionObjective To analyse the clinical characteristics of patients with candidemia andto assess the clinical value of the time to positivity (TTP) of blood cultures in patients of Candida bloodstream infection. Methods To retrospectively analysethe correlation of TTP with clinical parameters of82patients with candidemia. Allstatistical calculations were performed by using SPSS17.0statistical software.Results the average TTP in patients of C. tropicalis bloodstream infection is theshortest (17±4.9h), C. glabrata is the longest（43.6±18.9h), C. albicans and C.parapsilosis is26.6±14.3h and33.7±7.8h,respectively. Among the clinicalparameters of patients of blood stream infection:78%of patients receivedlong-term antibiotic therapy and35%of patients underwent abdominal surgery.Among the first diagnosis in patients, tumor amounted to the highestpercentage(20.7%) and35.4%of patients suffered from respiratory infection atthe same time.TTP were no significantly difference between survival group anddeath group. In the30candidemic patients with multiple blood cultures, themortality of the patients with extended TTP was16.7%, which was significantlylower than that of the patients with shortened TTP (66.7%). Conclusions Moreattention should be paid to the infection of Candida for patients rececinglong-term antibiotic therapy,abdominal surgery, or with tumor and respiratoryinfection. The change of TTP is releted to the prognosis of the patient.Chapter3Diagnostic value of time to positivity in Candida bloodstreaminfectionObjective Loop-mediated isothermal amplification (LAMP) was selected torapidly identify Candida parapsilosis and to evaluate infection diagnosis inbloodstream. Methods Two pairs of primers were designed against ITS1, aregion of18SrRNA and5.8SrRNA to amplify Candida parapsilosis sequences,four Candida strains (Candida albicans, Candida tropicalis, Candida glabrataand Candida krusei) as well as some common clinical strains (Cryptococcusneoformans, Saccharomyces cerevisiae, Staphylococcus aureus and Escherichiacoli). A total of35Candida smaples in clinical blood culture bottles were testedwith LAMP. Results The primers are effective to amplify the target genes of Candida parapsilosis with high specificity. The sensitivity to detect pure Candidaparapsilosis culture was1.6×10~4CFU/ml. Moreover. Results of LAMP wereconsistent with VITEK II microbial identification system for35samples(accounting for100%). more than48hours was saved with LAMP in this study.Conclusions LAMP detection is effective for rapid detection of Candidaparapsilosis in bloodstream infections with its high sensitivity, high specificity,short time-consuming, simple procedures and high agreement rate.