Clinical Evaluation of Digital PCR for Rapid Pathogen Detection in Suspected Bloodstream Infections.

Objective To discuss the clinical application value of serum procalcitonin(PCT) in patients with Candida bloodstream infection. Methods The data of 783 hospitalized patients of Tianjin Medical University General Hospital including blood culture and serum PCT test were retrospectively analyzed, and the medical records of patients with Candida or bacterial bloodstream infection were evaluated by univariate and multivariate logistic regression analysis. The comparison of PCT value were carried out among the different blood culture groups using the Mann-Whitney U test. A receiver operating characteristic(ROC) curve was used to determine the diagnostic performance of the PCT. Results The PCT was 0.21 (0.06, 1.02) ng/mL in the 510 patients with negative blood culture, but in 121 patients with Candida infection and 152 patients with bacteria infections, the PCT levels were 1.15 (0.38, 6.85) ng/mL and 2.34 (0.77, 15.12) ng/mL, respectively. There were statistically significant differences in PCT levels among three groups(P<0.05). According to ROC, when the value of PCT was 0.355 ng/mL, the sensitivity was 76.9%, and the specificity was 60.8% with 0.726 area under the curve (AUC) (P<0.01) for the identification of Candida infection by blood cultures. Conclusions Serum PCT levels have a certain diagnostic value for Candida bloodstream infection. In critically ill patients with factors associated with candidemia, the combination of clinical symptoms with PCT as an adjuvant diagnostic marker and other laboratory findings can be used to make a prompt and effective initiation of antifungal therapy. Key words: Procalcitonin; Blood culture; Candida; Blood stream infection

Early Quantitative Determination of Serum Procalcitonin Can Help Distinguishing Strains of Different Bloodstream Infections in Patients with Hematologic Diseases

Objective To evaluate the detection of membrane neutrophilic alkaline phosphatase (mNAP) by flow cytometry in diagnosis of bloodstream infection. Methods A total of 298 patients with suspected bloodstream infections admitted in the First People's Hospital of Lianyungang during June 2013 and October 2014 were enrolled; 80 healthy subjects in physical examination center were also enrolled as the control group. Bloodstream infection was diagnosed by blood culture and mNAP was detected by flow cytometry. Serum levels of procalcitonin (PCT) and C-reactive protein (CRP) were detected by electro-chemiluminescence (ECL) and immune scatter turbidimetry, respectively. The value of mNAP, PCT and CRP in diagnosing bloodstream infection was determined by receiver operating characteristic (ROC) curve. Results Among 298 patients, 109 were confirmed with bloodstream infections, including 43 patients with Gram-positive bacterial infections and 66 with Gram-negative bacterial infections. The median levels of CRP, PCT and mNAP in bloodstream infection group were 138.71 mg/L, 7.04 ng/mL and 13 929 AB/c, which were significantly higher than those in healthy control group (1.50 mg/L, 0.12 ng/mL, 1 831 AB/c; U=5.00, 48.50 and 65.01, P<0.01). The expression of mNAP in Gram-positive bacterial infection group was 9 598 (6 064-11 643) AB/c, which was significantly lower than that in Gram-negative bacterial infection group [16 512 (11 654-22 001) AB/c] (U=250.00, P<0.01). ROC curve analysis showed that, the areas under the curve (AUCs) of mNAP, PCT and CRP in diagnosing bloodstream infection were 0.987, 0.962 and 0.901. When 4 578AB/c, 0.90 ng/mL and 13.50mg/L were taken as optimal cut-off values, the sensitivities of mNAP, PCT and CRP in diagnosis of bloodstream infection were 95.8%, 93.0% and 90.3%; the specificities were 97.8%, 95.6% and 85.5%, respectively. Conclusion Among mNAP, PCT and CRP, mNAP is of the highest value in diagnosing bloodstream infection, and may be used as a biomarker for clinical diagnosis of bloodstream infection. Key words: Flow cytometry; Alkaline phosphatase; Neutrophilic alkaline phosphatase; Bloodstream infection; Procalcitonin; C-reactive protein

Objective To investigate the expression of procalcitonin (PCT) and C-reactive protein (CRP) , and endotoxin in bloodstream infection with different microorganisms, so as to assess the value of these inflammatory cytokines in early diagnosis of sepsis in bloodstream infections patients. Methods Data of 152 septic bloodstream infected patients with 90 male and 62 female aged from 62 to 102 years and 79.2±16.3 years in average admitted from January 2012 to December 2013 were analyzed retrospectively. According to the results of blood culture, the microorganisms could be categorized into gram-negative bacteria, gram-positive bacteria and fungus groups, and the levels of serum CRP, PCT, and endotoxin were compared among these groups of bloodstream infections patients within 24 hours after admission. Results (1) A total of 152 strains of microorganisms were surveyed including 92 gram-negative strains (61.18%) , 43 gram-positive strains (28.29%) , and 16 fungal strains (10.53%) . In the gram-negative strains, Klebsiella pneumoniae (n=29) , Acinetobacter baumannii (n=24) , Escherichia coli (n=23) , Burkholderia cepacia (n=9) and Pseudomonas aeruginosa (n=4) were the most common isolates. In the Gram-positive strains, 13 strains of Staphylococcus aureus were isolated. (2) In the gram-negative bacterial bloodstream infections group, there were 60 (64.52%) patients with endotoxin positive, and there were no endotoxin positive cases with detected gram-positive bacteria and fungal bloodstream infections. The median levels of PCT were significantly different among the three groups [gram-negative strains group: 7.760 (3.365, 28.585) ng/mL, gram-positive strains group: 0.705 (0.265, 3.225) ng/mL, fungal infection group: 1.245 (0.543, 1.998) ng/mL]. In the fungal bloodstream infection group, the mean level of CRP was higher than that in other two groups [gram-negative strains group: (126.01 ± 66.53) mg/L, gram-positive strains group: (77.58±54.21) mg/L, fungal infection group: (140.14±71.21) mg/L]. (3) The receiver operating characteristic (ROC) curve of inflammatory cytokines was made for the diagnostic value in bloodstream infections. ROC curve used to distinguish between gram-positive bacterial bloodstream infections group and fungal group showed that AUCPCT+ CRP=0.791. When PCT cut-off value was 0.92 ng/mL, and CRP cut-off value was 68.00 mg/L, the sensitivity was 50% and the specificity was 95.5%. ROC curve used to distinguish between the gram-negative bacterial bloodstream infections group and fungal group showed that AUCPCT+ CRP+ LPS=0.947. When PCT cut-off value was 2.16 ng/mL and CRP cut-off value was 94.10 mg/L, and endotoxin was positive, the sensitivity was 82.8% and the specificity was 100% . ROC curve used to distinguish between gram-negative bacterial bloodstream infections group and gram-positive bacterial group showed that AUCPCT+ CRP+ LPS=0.947. When PCT cut-off value was 2.68 ng/mL, CRP cut-off value was 106.5 mg/L, endotoxin was positive, the sensitivity was 74.2% and the specificity was 97.7% . Conclusions Gram-negative bacteria were the most common microorganisms in bloodstream infections in ICU patients. Compared with single inflammatory cytokine, the serum concentrations of PCT, CRP and endotoxin used together could provide more sensitivity and specificity for the early diagnosis of bloodstream infection with different microorganisms. Key words: Bloodstream infection; Sepsis; Gram-negative bacteria; Gram-positive bacteria; Fungal; Procalcitonin; C-reactive protein; Endotoxin

Introduction: Blood culture is considered as the gold standard for the diagnosis of bloodstream infection. Conventional blood culture system is less sensitive and takes longer duration for the detection of bloodstream infections whereas automated blood culture system is more sensitive and rapid in detecting causative organisms of bloodstream infections. This prospective study was undertaken to compare the automated blood culture system with the conventional blood culture system for the identification of microbial pathogens in bloodstream infections. Method: This prospective study was done in Department of Microbiology, Silchar Medical College &amp; Hospital, Silchar for a period of 7 months from November 2021 to May 2022. Blood samples from the patients were inoculated into BD BACTEC Plus Aerobic culture vials for automated blood culture system and Brain Heart Infusion broth for conventional blood culture system. Positive bottles flagged by the automated machine were isolated and identified by doing routine subcultures on Blood agar and MacConkey agar and necessary biochemical tests. The conventional blood culture bottles were processed as per standard protocols. Result: Out of 123 samples, 21(17.09%) showed culture positivity by automated blood culture method and 15(12.19%) showed culture positivity by conventional blood culture method. The most common isolate was Staphylococcus aureus followed by Escherichia coli in automated method whereas the most common isolate in conventional method was Staphylococcus aureus followed by Klebsiella pneumoniae. Conclusion: This study concluded that automated blood culture method is more sensitive than conventional method and detects the presence of microorganisms rapidly causing bloodstream infections. Keywords: Bloodstream infection, Automated blood culture, Conventional blood culture

Objective To search specific biomarkers of pathogenic bacteria in patients with sepsis so as to guide early using rationally antibiotic treatment. Methods Prospective survey of 147 patients with sepsis in ICU was carried out from Jan 2012 to Mar 2015. When patients blood culture was positive, clinical data including age, gender, vital signs, blood and, urine routine examination, DIC, blood biochemistry, c-reactive protein (CRP), procalcitonin (PCT), microbial detection, etc were recorded. Cultured blood samples were from central venous catheter and peripheral vessel. ELISA method was employed to detect soluble toll-like receptor 2 (sTLR2) and interleukin-8(IL-8), and the Acute Physiology and Chronic Health Evaluation Ⅱ (APACHEⅡ score) was calculated. The chi-square test and analysis of variance were performed where necessary. Receiver operating characteristic (ROC) curves were used to calculate cut-points (CP) and area under the curve (AUC). Results According to the results of blood culture, patients were divided into three groups: GP group [gram-positive bacteria (G+) group]; GN group [gram-negative bacteria (G-) group]; FG group (fungi group). There were no significantly statistical differences in age, APACHEⅡ score, vital signs and markers of inflammation among three groups (P> 0.05). Gram negative pathogenic bacterium was the most common microbe. Compared with GN group, the level of sTLR2 in the GP group was obviously higher ( P= 0.000); but there was no significant difference in sTLR2 level between GP group and FG group (P= 0.187). The amount of (1, 3)-beta glucan in the FG group was significantly higher than that in the GP group (P= 0.000). The sTLR2 level in FG group was obviously higher than that in the GN group (P= 0.000). There were no significantly statistical differences in PCT, CRP and IL-8 among the three groups (P> 0.05). For the diagnosis of gram negative bacteria infection, sTLR2 area under the curve was 0.768, and the sensitivity and specificity were 88.90% and 59.60%, respectively and the best cut-off point was 8.083 pg/mL. Namely, the diagnosis of gram negative bacteria infection was less likely, when level of sTLR2 was higher than 8.083 pg/mL. The markers of PCT, CRP, (1, 3)- beta glucan and IL-8 were less valuable for the diagnosis of Gram negative bacteria infection because the area under the curve was less than 0.5. Conclusions The combination of inflammatory indicators such as sTLR2 and (1, 3) - beta glucan etc, can imply the kind of pathogenic microorganisms partly. Key words: Sepsis; Bloodstream infections; Inflammatory markers; Soluble TOLL like receptor 2; (1, 3)-beta glucan; Calcitonin; C-reactive protein

Background Sepsis and its complications are one of the leading causes of mortality. Timely diagnosis and treatment are highly important in reducing morbidity and mortality. Serum biomarkers may aid in the early diagnosis of sepsis and therapeutic intervention. Procalcitonin (PCT) is a peptide precursor of the hormone calcitonin, and its primary trigger is infection. Increased serum PCT is associated with bacterial endotoxin and inflammatory cytokines. Therefore, PCT is widely used as a biomarker for bacterial infection and sepsis. Clinically, PCT greater than 2 ng/mL is associated with high risk of sepsis, and PCT less than 0.5 ng/mL is associated with low risk. We aimed to investigate the correlation between PCT and blood culture in the early diagnosis of sepsis in an unselected population with suspected bloodstream infections and evaluated the interpretative criteria helpful in diagnosis of systemic bacterial infection or sepsis. Methods We retrospectively analyzed medical records of 127 patients (72 (56.7%) males and 55 (43.3%) females) aged (X±SD(69.2±20.4) range (4-100 years) from different hospital departments who visited Dr. Sulaiman Alhabib Group of Hospitals (HMG) in Riyadh from January 2021 to December 2022. with suspected bloodstream infections who had PCT data and blood culture results. PCT was quantitatively determined by the BRAHMS PCT assay on the Abbott Allinity I System, which is a two-step chemiluminescent microparticle immunoassay (CMIA). Blood culture was done using BactAlert system (bioMérieux). Results Among study group blood culture was positive in 75 cases (59.1%) and negative in 52 cases (40.9), PCT was positive in 107 cases (84.3%) and negative in 20 cases (15.7%). Both tests were correlated (either positive or negative) in 71 cases (56%). PCT results were correlated to culture results (applying cutoff value 0.1 ng/ml) using Pearson Chi-Square test and results were insignificant (P value &amp;gt; 0.5). PCT found to have sensitivity of 84% (73.7% to 91.5%, 95% CI) and specificity of 15.4% (6.9 to 28.1%, 95% CI) To assess the significance of interpretative criteria, PCT results were classified into 3 groups (moderate risk for progression to sever sepsis (0.5-1.99 ng/ml), sever systematic response (2-9.99 ng/ml) and high likelihood of sever sepsis or septic shock (= 10ng/ml). One way ANOVA studies show Significant difference among the 3 subgroups of culture negative cases (F value =3.48, P= 0.38) and among culture positive cases (F value= 4.56, P= 0.14). However, the student T test shows insignificant results when each risk category was compared among culture positive and negative cases (p value of 0.73, 0.83, 0.75 respectively). Conclusion PCT elevated levels in study population may indicate sepsis (good screening assay with accepted sensitivity) but should be interpreted cautiously alongside with blood culture results. Further research is needed to establish the specificity of PCT. Test interpretative criteria may work as good predictor of inflammatory status rather than septic status

To compute diagnostic test properties of C-reactive protein (CRP) and serum procalcitonin (PCT) levels in bloodstream infections in children with cancer and suspected sepsis, in comparison with blood culture as the gold standard. Consecutive paediatric cancer patients, aged ≤14 years, with clinically suspected bloodstream infections were evaluated with blood culture and assay of PCT and CRP levels. Blood culture was taken as the gold standard for comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) and receiver operating characteristic (ROC) with area under ROC curve (AUC) were calculated to assess the diagnostic test performance for PCT and CRP.Results/Key findings. The ROC curve for PCT was better than that for CRP, with an AUC of 0.751 for PCT at a cut-off of 2.25 ng ml-1. The AUC for CRP was 0.638 at a cut-off of 8.0 mg dl-1. Among the three cut-off values of PCT selected from the ROC curve applicable to the patients under study, the cut-off value of ≥0.49 ng ml-1 had the maximum sensitivity of 81.4 % and an NPV of 94.67 %; ≥2.25 ng ml-1 had a sensitivity and specificity of 65.12 and 71.6 %, respectively, and ≥6.47 ng ml-1 had a maximum specificity of 82.10 %. For CRP, the cut-off value of ≥5.3 mg dl-1 had the maximum sensitivity of 72.09 %; ≥8.0 mg dl-1 had a sensitivity and specificity of 58.14 and 68.09 %, respectively, and ≥8.4 mg dl-1 had the maximum specificity of 70.04 %. PCT is a better serological marker for excluding bloodstream infections than CRP. The cut-off value of 0.49 ng ml-1 with a negative predictive value of 94.67 % will be ideal in a clinical setting of immune-compromised children with suspected sepsis.

Bloodstream infections (BSIs) are a major cause of morbidity and mortality worldwide, and impose considerable costs on healthcare systems. A key predictor of clinical outcomes in patients with BSIs is the early initiation of appropriate targeted antimicrobial therapy. However, with conventional blood culture methods, the gold standard, there is a significant time delay of approximately 2-3 days before clinical results are available, with many patients receiving inappropriate and/or unnecessary antimicrobial therapy in the interim. During the past two decades, the use of in vitro assays that utilize nucleic acid amplification-based detection of pathogen-associated molecular patterns has led to a significant reduction in the time (hours vs. days with blood culture) to detection and identification of several of the causative pathogens of BSIs and, potentially, earlier initiation of targeted antimicrobial therapy. This review focuses on the properties and clinical use of one of these molecular diagnostic assays, the Verigene(®) Gram-Positive Blood Culture Nucleic Acid Test (BC-GP), which detects many of the potentially pathogenic Gram-positive bacteria associated with BSIs, including Staphylococcus spp., Streptococcus spp., Listeria spp., and Enterococcus spp., and specific resistance markers (mecA, vanA, and vanB). Based on more than 1,600 samples, there was a high degree of agreement between BC-GP test results and those obtained using conventional blood culture and assay methods, irrespective of whether samples were fresh or frozen, and a high degree of agreement for identification of mecA-mediated meticillin resistance in S. aureus and S. epidermidis organisms and vanA- or vanB-mediated vancomycin resistance in E. faecalis and E. faecium organisms.

The ability of Procalcitonin, lactate, white blood cell count and neutrophil-lymphocyte count ratio to predict blood stream infection. Analysis of a large database.

Though droplet digital PCR (ddPCR) has emerged as a promising tool for early pathogen detection in bloodstream infections (BSIs), more studies are needed to support its clinical application widely due to different ddPCR platforms with discrepant diagnostic performance. Additionally, there is still a lack of clinical data to reveal the association between pathogen loads detected by ddPCR and corresponding BSIs. In this prospective study, 173 patients with suspected BSIs were enrolled. A multiplex ddPCR assay was used to detect 18 pathogens. The results of ddPCR testing were evaluated in comparison with blood cultures (BCs) and clinical diagnosis. Taking BC as the gold standard, receiver operating characteristic curve and Cohen's kappa agreement were used to investigate whether the pathogen load could predict a corresponding culture-proven BSI for the top five microorganisms detected by ddPCR. Of the 173 blood samples collected, BC and ddPCR were positive in 48 (27.7%) and 92 (53.2%) cases, respectively. Compared to BC, the aggregate sensitivity and specificity for ddPCR were 81.3% and 63.2%, respectively. After clinical adjudication, the sensitivity and specificity of ddPCR increased to 88.8% and 86.0%, respectively. There were 143 microorganisms detected by ddPCR. The DNA loads of these microorganisms ranged from 30.0 to 3.2×105 copies/mL (median level: 158.0 copies/mL), 72.7% (104/143) of which were below 1,000 copies/mL. Further, statistical analysis showed the DNA loads of Escherichia coli (AUC: 0.954, 95% CI: 0.898-1.000, κ=0.731, cut-off values: 93.0 copies/mL) and Klebsiella pneumoniae (AUC: 0.994, 95% CI: 0.986-1.000, κ=0.834, cut-off values: 196.5 copies/mL) were excellent predictors for the corresponding BSIs. The DNA loads of Pseudomonas aeruginosa (AUC: 0.816, 95% CI: 0.560-1.000, κ=0.167), Acinetobacter baumannii (AUC: 0.728, 95% CI: 0.195-1.000), and Enterococcus spp. (AUC: 0.282, 95% CI: 0.000-0.778) had little predictive value for the corresponding culture-proven BSIs. Our results indicate that the multiplex ddPCR is a promising platform as a complementary add-on to conventional BC. The DNA loads of E. coli and K. pneumoniae present excellent predictive value for the corresponding BSIs. Further research is needed to explore the predictive potential of ddPCR for other microorganisms.

Background: Procalcitonin (PCT) is a promising biomarker for predicting infection. Bloodstream infection (BSI) is usually a deteriorating stage of sepsis. The purpose of this study was to explore the predictive value of intense serial PCT assays for BSI in the intensive care unit (ICU).Methods: This study was a retrospective study based on a clinical database. We analyzed the data of critically ill patients from February 2016 to May 2020. The patients who received PCT assays and blood cultures (BCs) were classified into four groups according to the BCs: (i) BC negative, (ii) bacteria positive, (iii) fungi-positive, and (iv) combined-positive, and the patients with bacteremia were further subdivided into Gram+ and Gram– bacteremia.Results: The database included 11,219 patients. There were 3,593 patients who met the criteria for the analysis. The PCT concentration differed significantly across BC groups (p < 0.0001). The fluctuation of PCT significantly increased in the BC positive groups (p < 0.0001). According to the receiver operating characteristic (ROC), the optimum cutoff of the fluctuation of PCT was around 8 ng/ml for predicting BSI.Conclusion: Our study indicated that the fluctuation of PCT could be an indicator for screening BSI, but less accurate for Gram-positive infections. With a fluctuation of PCT less than 8 ng/ml, BSI should not be a rational cause for sepsis exacerbating.

Objective To investigate the diagnostic values of procalcitonin(PCT), high sensitive C-reactive protein(hs-CRP), white blood cell(WBC) and percentage of neutrocyte(NEU%) in Gram-negative and Gram-positive bacterial blood stream infection in early stage of sepsis in order to investigate the correlation between PCT and APACHEⅡ score as well as between PCT and SOFA score, and the prognostic value in assessment of Gram-negative and Gram-positive bacterial blood stream infection. Methods Clinical data of patients admitted to ICU from January 2012 through December 2014 were retrospectively analyzed. A total of 124 sepsis patients with blood stream infection were checked with PCT, hs-CRP, WBC and NEU% tests, and APACHEⅡ score and SOFA score were calculated. The differences in APACHEⅡ score and SOFA score were compared between Gram-negative group (n=41) and Gram-positive group (n=83). The correlation between PCT and APACHEⅡscore as well as between PCT and SOFA score was analyzed. The differences in diagnostic values of PCT, hs-CRP, WBC and NEU% between Gram-negative group and Gram-positive group were analyzed by using receiver operating characteristic (ROC) curve and it was plotted to assess the prognostic values of PCT, hs-CRP, WBC and NEU% for septic patients with blood stream infection. Results Compared with Gram-positive group, the levels of PCT [55.32(22.01, 97.11)vs. 2.13(0.27, 5.27)](P<0.01), hs-CRP[105.09(69.97, 186.12)vs. 70.54(42.37, 138.63)](P=0.508), NEU%[88.30(75.79, 93.52)vs.55.32(22.01, 97.11)](P=0.302)were higher but WBC was lower[13.59(10.74, 17.58)vs.13.73(11.32, 20.90)](P=0.058)in Gram-negative group.The ROC curve analysis of PCT showed the area under the curve (AUC) was 0.867 (95%CI: 0.789-0.946). When the optimal cutoff point of PCT was 17.48 ng/mL, the largest Youden’s index was found to be 0.661 with 76.9% sensitivity and 89.2% specificity. Between two groups, there were significant differences in APACHEⅡ score and SOFA score (27.46±9.60 vs.23.67±7.74, P=0.020; 8.05±3.38 vs.6.59±3.45, P=0.028). There was significant difference in diagnostic value between PCT and SOFA (r=0.536, P=0.036) in Gram-negative group but no significant difference in Gram-positive group. Conclusions Higher PCT levels are found in Gram-negative group and it can play a role in differntiation between the Gram-negative group and Gram-positive group rather than hs-CRP, WBC and NEU%. PCT can be a better indicator for evaluation of severity of sepsis as well as for prognosis of sepsis patients with Gram-negative bacterium infection. Key words: Procalcitonin; Gram-negative bacterium; Gram-positive bacterium; Blood infection

Objective To study the clinical values and implications for the prognosis of procalcitonin (PCT) combined with C-reactive protein (hs-CRP) in patients with bacterial bloodstream infection. Methods One hundred and twenty patients with infection hospitalized from Mar. 2020 to Jun. 2021 were chosen as subjects. All participants were tested for serum PCT, hs-CRP, and blood culture. According to the types of pathogenic bacteria, they were divided into the gram-negative bacteria bloodstream infection group (n = 53) and the gram-positive bacteria bloodstream infection group (n = 31). Depending on the prognostic outcome of the participants after 28 days, they were categorized into survival and fatality cohorts. The PCT and hs-CRP levels were compared to explore diagnostic value implications for the prognosis of the cases with bacterial bloodstream infection. Results Serum PCT and hs-CRP values in the positive cohort were higher than those in the negative cohort. The levels of serum PCT and hs-CRP in pulmonary infection were higher than those in the group with negative cases, and the difference was statistically significant (P < 0.05). There were 27 gram-positive participants and 9 gram-negative cases in the positive cohort. The serum PCT value of gram-negative bacterial infection was greater than that of gram-positive bacterial infection. The value of serum PCT in the gram-negative bacterial infection group was higher than that in the gram-positive bacterial infection group, and the difference was statistically significant (P < 0.05). The areas under the curve (AUCs) of PCT, combination of hs-CRP and PCT, and hs-CRP were 0.946, 0.783, and 0.991, respectively. The combined examination of PCT and hs-CRP was the largest, PCT was the second, and hs-CRP was the lowest. These results indicated that the accuracy of combined detection of PCT and hs-CRP in the diagnostic bloodstream infection was the highest (0.991), followed by PCT (0.946) and the lowest (0.783). The PCT and hs-CRP levels of the survival cohort were lower than those in the death cohort. AUCs of PCT, hs-CRP and PCT, and hs-CRP were 0.848, 0.826, and 0.934, respectively. The combined examination of PCT and hs-CRP was the largest, followed by PCT and hs-CRP. The accuracy of the combination of PCT and hs-CRP was the highest (0.934), followed by PCT (0.848), and the diagnostic accuracy of hs-CRP was the lowest (0.826). Conclusion There were significant differences in the levels of PCT and CRP between the gram-positive bacteria group and the gram-positive bacteria group. PCT and CRP have high diagnostic values in predicting the short-term prognosis of patients. PCT and CRP assist clinical diagnosis and guide treatment and play a positive role in early treatment and prognosis evaluation of patients.

Objective To investigate the value of inflammatory biomarkers such as procalcitonin (PCT),C-reactive protein (CRP),and endotoxin in early diagnosis of bacteriemia patients infected with gram-negative bacteria.Methods A cohort of 79 bacteriemia patients infected with gram-negative bacteria admitted from February 2011 to May 2013 were enrolled for retrospective study.Collected data for analysis included gender,age,disease severity (APACHE Ⅱ score),bacterial isolates from blood culture and other general information.The inflammatory biomarkers such as white blood cell (WBC),neutrophils (NEU),Creactive protein (CRP),procalcitonin (PCT),and endotoxin were assayed within 6 hours after admission.SPSS version 16.0 software was used for statistical analysis.The test of normality was used for analysis of continuous variables,t-test for inter-group comparison and non-parametric statistics for non-normal distribution variables.The AUC of ROC was calculated for determining the sensitivity and specificity of biomarkers for diagnosis of bacteriemia.Results (1) Statistically positive correlations were found among serum PCT,CRP,and endotoxin levels (PCT/CRP =0.916,PCT/endotoxin =0.496,Endotoxin/CRP =0.387),and between those and APACHE Ⅱ score were (PCT/APACHE Ⅱ =0.505,Endotoxin/APACHE Ⅱ =0.467,CRP/APACHE Ⅱ =0.278),respectively,in bacteriemia patients infected with gram-negative bacteria.(2) The receiver operating characteristic (ROC) curve indicated that AUC PCT =0.715 (sen 64.6％,spe 80.7％),AUC CRP =0.666 (sen 67.7％,spe 78.6％),AUC endotoxin =0.771 (sen 78.8％,spe 81.8％) in gram-negative bacteria bloodstream infection patients.(3) The AUC PCT =0.865 (sen 86.2％,spe 77.5％),AUC CRP =0.733 (sen 72.4％,spe 75.0％),AUCendotoxin =0.618 (sen 70.7％,spe 67.5％) in bacteriemia patients infected with gram-negative bacteria in severe sepsis and septic shock group.Conclusions The plasma PCT,CRP,and endotoxin have early predictive value in bacteriemia patients infected with Gram-negative bacteria.In sepsis stage,the level of serum endotoxin has the most significant value for diagnosis.In severe sepsis and septic shock stages,the PCT is the most value for diagnosis of bacteriemia.All biomarkers are positively correlated with severity of the disease. Key words: Procalcitonin (PCT) ; C-reactive protein (CRP) ; Endotoxin ; Gram-negative bacteria; Blood stream infection; Acute physiology and chronic health evaluation Ⅱ