Evaluating The Clinical Value Of C-reactive Protein, Procalcitonin And PCR/MCA Assay In Early Diagnosis Of Sepsis

ObjectivesThe aim of this study is to analysis clinical features,the distribution of the pathogenic bacteria and drug susceptibility information in adult sepsis,provide a reference for the empirical clinical medication,and investigate the clinical value of C-reactive protein(CRP)and procalcitonin(PCT)in the diagnosis of adult sepsis.Preliminary evaluation of the diagnostic value of multiplex probes melting curve analysis based on real-time PCR(PCR/MCA)was applied to identify pathogenic bacteria that caused sepsis.MethodsThe data was collected in Xiamen Zhongshan hospital,455 cases of hospitalized patients were blood cultured positively,including 352 cases of culture-positive sepsis and 103 cases of non-sepsis;1609 cases of hospitalized patients were blood cultured negatively,including 287 cases of culture-negative sepsis,518 cases of non-infection systemic inflammatory response syndrome(SIRS),804 cases of local infection.Patients' age,sex,admission way,admission condition,the concentration of CRP,PCT and WBC were included and the differences were analyzed among the groups respectively.Receiver operating characteristic(ROC)curve analysis was conducted to calculate the optimum cutoff value and their area under curve(AUC).The sensitivity and specificity of CRP,PCT and their combination were also calculated and compared.A total of 491 blood culture samples were collected from Xiamen Zhongshan hospital clinical laboratory,including 362 cases of positive blood cultures and 129 cases of negative blood cultures.Samples were analyzed by PCR/MCA and the results were compared with the results used in clinical microbiology diagnostic laboratories,if the results of the same samples were discordant,we would have the original samples polymerase chain reaction test(PCR)for validation.Results1.Three hundred and eighty-seven organisms were isolated from culture-positive sepsis,71.06% were gram negative,26.87% were gram positive,and 2.07% were yeasts.The main pathogenic bacteria were Escherichia colibacillus(34.63%),Klebsiella pneumoniae(20.41%),and Staphylococcus aureus(10.34%),respectively.2.Among the gram-positive bacteria,the penicillin resistance rate to Staphylococcus aureus was up to 87.5%,and no Staphylococcus aureus strain was found resistant to vancomycin,macrodantin and teicoplanin.Other Staphylococcus aureus strains had relatively high resistance to penicillin,benzoxazole and erythromycin,and were sensitive to rifampicin,linnazole,vancomycin and nitrofurantoin.The prevalence of erythromycin-resistant Streptococcus spp.and clindamycin-resistant Streptococcus spp.was high to 80%;the strains of Streptococcus spp.were still highly sensitive to penicillin,cefotaxime,linazolamide and vancomycin.Among the gram-negative bacteria,the sensitive rate of Escherichia colibacillus to cefuroxime was 100%,the sensitive rate to amikacin and piperacillin/tazobartan thiazole was above 95%.To Klebsiella pneumoniae,the rate of piperacillin-resistant Klebsiella pneumoniae was highest,and the sensitive rate to amikacin was 96.2%.The sensitive rates of amikacin to Pseudomonas aeruginosa and gentamycin to Pseudomonas aeruginosa were 100%;its overall drug resistant rates were relatively low.The overall drug resistance rate of Acinetobacter baumannii was relatively high,and the sensitive rate of amikacin to Acinetobacter baumannii was 53.3%.3.In blood culture positive patients,the levels of CRP and PCT in the sepsis group were significantly higher than those in non-sepsis(P<0.001).According to the ROC curve,the area under the curves(AUCs)of CRP,PCT and their combination in the diagnosis of sepsis were 0.85(95% CI,0.80~0.89),0.90(95%CI,0.88~0.94)and 0.92(95%CI,0.89~0.95),respectively.When the cutoff value of CRP was 97.05mg/L,the sensitivity and specificity were 77.8% and 80.7%,respectively.When the cutoff value of PCT was 1.34ng/mL,the sensitivity and specificity were 86.5% and 79.5%,respectively.The combination of CRP and PCT for the diagnosis of sepsis was 84.3% and 87.5%,respectively.According to pairwise comparison of ROC curve,the diagnostic value of PCT was higher than CRP(P=0.016).The levels of CRP and PCT in the severe sepsis and septic shock group were significantly higher than those in sepsis.The AUCs of CRP and PCT were 0.67(95% CI,0.62~0.73)and 0.98(95% CI,0.96~1.00),when their cutoff values were 197.01mg/L and 28.55ng/mL,respectively.The sensitivity and specificity of CRP were 50.5% and 79.7%,respectively;the sensitivity and specificity of PCT were 92.8% and 96.1%,respectively.4.In blood culture negative patients,the levels of CRP and PCT in the sepsis group were significantly higher than those in non-infection SIRS(P<0.001).According to the ROC curve,the area under the curves(AUCs)of CRP,PCT and their combination in the diagnosis of sepsis were 0.76(95% CI,0.73~0.79),0.97(95% CI,0.96~0.98),and 0.96(95% CI,0.96~0.98),respectively.When the cutoff value of CRP was 130.70mg/L,the sensitivity and specificity were 64.1% and 73.2%,respectively.When the cutoff value of PCT was 1.51ng/mL,the sensitivity and specificity were 93.7% and 88.6%,respectively.The sensitivity and specificity of combination CRP and PCT for diagnosis of sepsis were 91.3% and 91.5%,respectively.5.A total of 370 clinical isolates from 362 samples were cultured and identified.All 491 blood culture samples were analyzed by PCR/MCA assay and clinical microbiology test.Specifically speaking,the positive agreement for Escherichia colibacillus is 95.9%(117/122),93.4%(57/61)for Klebsiella pneumoniae,94.4%(51/54)for Staphylococcus spp.,100%(22/22)for Streptococcus spp.,93.8%(15/16)for fungus,86.7%(13/15)for Acinetobacter baumannii,100%(12/12)for Enterococcus spp.,100%(11/11)for Pseudomonas aeruginosa.The specificity is 100%,and the consistency between two detection methods is quite good.Conclusions1.CRP and PCT have a grater clinical value for early diagnosis of sepsis and reflect the severity of sepsis.Comparing with CRP,PCT shows a higher accuracy in the early diagnosis of sepsis.2.Our results demonstrate that the PCR/MCA assay has good consistency with respect to clinical test and it conform to high throughput,accuracy and low cost.The PCR/MCA assay offers a rapid and reliable identification of pathogens for the diagnosis of sepsis,which shortens the turnaround time.