Procalcitonin as a marker of Candida species detection by blood culture and polymerase chain reaction in septic patients

The Diagnostic Accuracy of Procalcitonin and Its Combination with Other Biomarkers for Candidemia in Critically Ill Patients

Background: The aim of this study was to investigate the usefulness of serum procalcitonin (PCT), C-reactive protein (CRP), neutrophil to lymphocyte count ratio (NLR), and their combination, in distinguishing candidemia from bacteremia in intensive care unit (ICU) patients. Methods: This is a retrospective study in ICU patients with documented bloodstream infections (BSIs) and with both serum PCT and CRP measurements on the day of the positive blood sample. Illness severity was assessed by sequential organ failure assessment (SOFA) score on both admission and BSI day. Demographic, clinical, and laboratory data, including PCT and CRP levels and NLR on the day of the BSI, were recorded. Results: A total of 63 patients were included in the analysis, of whom 32 had bacteremia and 31 had candidemia. PCT, CRP, and NLR values were all significantly lower in candidemia compared with bacteremia (0.29 (0.14-0.69) vs. 1.73 (0.5-6.9) ng/mL, p < 0.001, 6.3 (2.4-11.8) vs. 19 (10.7-24.8) mg/dl, p < 0.001 and 6 (3.7-8.6) vs. 9.8 (5.3-16.3), p = 0.001, respectively). PCT was an independent risk factor for candidemia diagnosis (OR 0.153, 95%CI: 0.04-0.58, p = 0.006). A multivariable model consisting of the above three variables had better predictive ability (AUC-ROC = 0.88, p < 0.001), for candidemia diagnosis, as compared to that of PCT, CRP, and NLR, whose AUC-ROCs were all lower (0.81, p < 0.001, 0.78, p < 0.001, and 0.68, p = 0.015, respectively). Conclusions: A combination of routinely available laboratory tests, such as PCT, CRP, and NLR, could prove useful for the early identification of ICU patients with candidemia.

Clinical utility of procalcitonin and its association with pathogenic microorganisms

In this review, we summarize the relationship of PCT with pathogens, evaluate the clinical utility of PCT in the diagnosis of clinical diseases, condition monitoring and evaluation, and guiding medical decision-making, and explore current knowledge on the mechanisms by which pathogens cause changes in PCT levels. The lipopolysaccharides of the microorganisms stimulate cytokine production in host cells, which in turn stimulates production of serum PCT. Pathogens have different virulence mechanisms that lead to variable host inflammatory responses, and differences in the specific signal transduction pathways result in variable serum PCT concentrations. The mechanisms of signal transduction have not been fully elucidated. Further studies are necessary to ascertain the PCT fluctuation range of each pathogen. PCT levels are helpful in distinguishing between certain pathogens, in deciding if antibiotics are indicated, and in monitoring response to antibiotics.

Procalcitonin levels in candidemia versus bacteremia: a systematic review

Background

Procalcitonin (PCT) is a biomarker used to assess systemic inflammation, infection, and sepsis and to optimize antimicrobial therapies. Its role in the in the differential diagnosis between candidemia and bacteremia is unclear. The aim of this systematic review was to summarize the current evidence about PCT values for differentiating candidemia from bacteremia.

Methods

PubMed and EMBASE were searched for studies reporting data on the diagnostic performance of serum PCT levels in intensive care unit (ICU) or non-ICU adult patients with candidemia, in comparison to patients with bacteremia.

Results

We included 16 studies for a total of 45.079 patients and 785 cases of candidemia. Most studies claimed to report data relating to the use of PCT values for differentiating between candidemia and bacteremia in septic patients in the intensive care unit. However, the studies identified were all retrospective, except for one secondary analysis of a prospective dataset, and clinically very heterogeneous and involved different assessment methods. Most studies did show lower PCT values in patients with candidemia compared to bacteremia. However, the evidence supporting this observation is of low quality and the difference seems insufficiently discriminative to guide therapeutic decisions. None of the studies retrieved actually studied guidance of antifungal treatment by PCT. PCT may improve diagnostic performance regarding candidemia when combined with other biomarkers of infection (e.g., beta-d-glucan) but more data is needed.

Conclusions

PCT should not be used as a standalone tool for the differential diagnosis between candidemia and bacteremia due to limited supporting evidence.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2481-y) contains supplementary material, which is available to authorized users.

Multiplex polymerase chain reaction to diagnose bloodstream infections in patients after cardiothoracic surgery

Background

Sepsis and other infectious complications are major causes of mortality and morbidity in patients after cardiac surgery. Whereas conventional blood culture (BC) suffers from low sensitivity as well as a reporting delay of approximately 48–72 h, real-time multiplex polymerase chain reaction (PCR) based technologies like “SeptiFast” (SF) might offer a fast and reliable alternative for detection of bloodstream infections (BSI). The aim of this study was to compare the performance of SF with BC testing in patients suspected of having BSI after cardiac surgery.

Methods

Two hundred seventy-nine blood samples from 169 individuals with suspected BSI were analyzed by SF and BC. After excluding results attributable to contaminants, a comparison between the two groups were carried out. Receiver operating characteristic (ROC) curves were generated to determine the accuracy of clinical and laboratory values for the prediction of positive SF results.

Results

14.7% (n = 41) of blood samples were positive using SF and 17.2% (n = 49) using BC (n.s. [p > 0.05]). In six samples SF detected more than one pathogen. Among the 47 microorganisms identified by SF, only 11 (23.4%) could be confirmed by BC. SF identified a higher number of Gram-negative bacteria than BC did (28 vs. 12, χ² = 7.97, p = 0.005). The combination of BC and SF increased the number of detected microorganisms, including fungi, compared to BC alone (86 vs. 49, χ² = 13.51, p < 0.001). C-reactive protein (CRP) (21.7 ± 11.41 vs. 16.0 ± 16.9 mg/dl, p = 0.009), procalcitonin (28.7 ± 70.9 vs. 11.5 ± 30.4 ng/dl, p = 0.015), and interleukin 6 (IL 6) (932.3 ± 1306.7 vs. 313.3 ± 686.6 pg/ml, p = 0.010) plasma concentrations were higher in patients with a positive SF result. Using ROC analysis, IL-6 (AUC 0.836) and CRP (AUC 0.804) showed the best predictive values for positive SF results.

Conclusion

The SF test represent a valuable method for rapid etiologic diagnosis of BSI in patients after cardiothoracic surgery. In particular this method applies for individuals with suspected Gram-negative blood stream. Due to the low performance in detecting Gram-positive pathogens and the inability to determine antibiotic susceptibility, it should be used in addition to BC only (Pilarczyk K, et al., Intensive Care Med Exp ,3(Suppl. 1):A884, 2015).

Ability of serum procalcitonin to distinguish focus of infection and pathogen types in patients with bloodstream infection

Background

Serum procalcitonin (PCT) is a widely recognized inflammatory marker which can distinguish systemic bacterial infection from other types of infections. The ability of PCT levels to distinguish different pathogens from different focus of infection is contradictory.

Methods

This study included 551 patients with bloodstream infection (BSI) diagnosed with positive blood culture (BC) during Jan 2013 and May 2018. The patients were divided into two groups with or without definite focus of infection. In this study, we analyzed PCT levels induced by Gram-positive bacteria, Gram-negative bacteria and fungal infection. Relationship of time between PCT peak and BC collection, and the impact of antibiotics usage on PCT peak distribution were examined.

Results

For patients without definite focus of infection, the serum PCT values of Gram-negative bacteria were higher than that of Gram-positive bacteria (P<0.05). A cut-off value of 7.54 ng/mL for PCT showed a sensitivity of 88.3%. For patients with definite focus of infection, the serum PCT values of Gram-negative bacteria were significantly higher than Gram-positive bacteria in patients with lower respiratory tract (P=0.003), abdominal (P=0.039), urinary tract infection (P=0.025), but not in patients with upper respiratory tract infection (P=0.664). The PCT values between multidrug-resistant organism (MDRO) and sensitive bacteria were not statistically significant (P>0.05) among all patients. Moreover, among patients who use antibiotics before BC collection, the longer antibiotics used, the higher trend of the proportion for PCT peak distribution after BC collection. The higher proportion of antibiotics combined before BC collection, the lower proportion of PCT peak distribution appeared before BC collection, and the higher the proportion of PCT peak distribution appeared after BC collection.

Conclusions

PCT value is determined by many factors. PCT value is related to not only Gram-positive bacteria or Gram-negative bacteria, but also related to specific pathogens, and specific of infection sites etc. The use of Antibiotics is also an important factor of PCT value.

Management of patients with septic shock due to Candida infection

Septic shock represents a serious complication occurring between 6% and 30% of all hospitalized patients; Candida septic shock represents a challenge for clinicians due to the absence of specific risk factors, diagnostic tests, and management. Identification of specific risk factors and use of biomarkers are useful tools considering that differentiation of Candida from bacterial septic shock is demanding. Early effective antifungal treatment, preferably with echinocandins with an adequate source control, represents the best approach for improving survival of patients with septic shock due to Candida. Given the importance of adequate therapy and source control in septic shock attributable to Candida clinical strategies and pathways are needed. This review will focus on epidemiology of septic shock in patients with invasive candidiasis with special attention to diagnostic pathways and treatment strategies.

Procalcitonin as Biomarker of Infection: Implications for Evaluation and Treatment

Procalcitonin (PCT) is a quickly measurable marker, assumed to have high sensitivity and specificity for sepsis and infection. A literature search was conducted to evaluate PCT ability as a diagnostic and prognostic tool in infectious processes and its ability to monitor the antibiotic therapy. PCT level is increased in bacterial and fungal infections, but not in viral infections, with a significantly higher level in patients with bacteremia compared with uninfected patients (2.5 vs. 0.3 ng/mL; P < 0.0001). A PCT value of ≤0.1 ng/mL discards bacteremia and microbiological tests (negative predictive value of 96.3%), >0.1 ng/mL needs microbiological tests, and >1.0 ng/mL is indicative of bacteremia. Antibiotic treatment algorithms guided by PCT decreased the need for antibiotic treatment in approximately 50%. PCT is a promising test in clinical practice to decide the introduction of antibiotic therapy in addition to the existing tools, without neglecting the clinical assessment, with a significant decrease in costs.

Use of 1,3-β-D-glucan in invasive fungal diseases in hematology patients

INTRODUCTION

Invasive fungal diseases (IFD) remain a leading cause of morbidity and mortality in hematology patients. Within a diagnostic-driven approach, the use of the serum (1,3)-ß-D-glucan (BDG) test represents a valid tool for the early diagnosis and treatment of IFD. Areas covered: The available literature on the use of BDG in hematology patients was systematically retrieved. Then, it was reviewed and discussed, to identify key issues pertaining to a clinically-oriented narrative presentation of the topic. Expert commentary: The use of BDG in hematology patients at risk for invasive aspergillosis (IA) is secondary to the use of galactomannan. However, since BDG is not specific for IA, it offers an advantage of diagnosing also other IFD, such as candidiasis and pneumocystosis. The limitations of BDG include high costs and lower sensitivity in hematology patients compared to other cohorts. The risk of false positive results is possibly lower in real life than in theory, since glucan-free equipment is available and modern dialysis membranes and blood products usually do not release BDG. Thus, in experienced hands and selected clinical situations, BDG is a useful diagnostic tool, particularly due to short turnover time to results and versatility in diagnosing different IFD.

Procalcitonin for the diagnosis of invasive candidiasis: what is the evidence?

Procalcitonin is a widely used marker for the evaluation of infection and sepsis and to guide antibiotic therapy. During the last decade, several studies evaluated its role and diagnostic performance as a surrogate marker for the identification of Candida spp. in suspected invasive candidiasis. A low serum level and a favorable negative predictive value are the main findings for procalcitonin in this setting. The aim of this report is to provide an updated brief summary of the evidence supporting the use of PCT for the management of invasive candidiasis.

Usefulness of procalcitonin in differentiating Candida and bacterial blood stream infections in critically ill septic patients outside the intensive care unit

We aimed to explore the role of procalcitonin (PCT) for the diagnosis of Candida spp. bloodstream infections in a population of critically ill septic patients admitted to internal medicine units. This is a retrospective case-control study considering all cases of candidemia identified in three internal medicine units, from January 1st 2012 to May 31st 2016. For each case of candidemia, two patients with bacteremic sepsis were included in the study as control cases. The end point of the study was to evaluate the diagnostic performance of PCT for the diagnosis of Candida spp. blood stream infections in patients with objectively documented sepsis. Sixty-four patients with candidemia and 128 controls with bacteremia were enrolled. Median and interquartile range (IQR) PCT values are significantly lower in patients with candidemia (0.73; IQR 0.26-1.85 ng/mL) than in those with bacteremia (4.48; IQR 1.10-18.26 ng/mL). At ROC curve analysis, values of PCT greater than 2.5 ng/mL had a negative predictive value (NPV) of 98.3% with an AUC of 0.76 (0.68-0.84 95% CI) for the identification of Candida spp. from blood cultures. At multivariate analysis, a PCT value <2.5 ng/mL showed an odds ratio of 8.57 (95% CI 3.09-23.70; p < 0.0001) for candidemia. In septic patients at risk of Candida infection, a PCT value lower than 2.5 ng/mL should raise the suspicion of candidemia, adding value for considering prompt initiation of antifungal therapy.

Combined use of serum (1,3)-β-D-glucan and procalcitonin for the early differential diagnosis between candidaemia and bacteraemia in intensive care units

Background

This study aimed to assess the combined performance of serum (1,3)-β-d-glucan (BDG) and procalcitonin (PCT) for the differential diagnosis between candidaemia and bacteraemia in three intensive care units (ICUs) in two large teaching hospitals in Italy.

Methods

From June 2014 to December 2015, all adult patients admitted to the ICU who had a culture-proven candidaemia or bacteraemia, as well as BDG and PCT measured closely to the time of the index culture, were included in the study. The diagnostic performance of BDG and PCT, used either separately or in combination, was assessed by calculating the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios (LR+ and LR–). Changes from pre-test probabilities to post-test probabilities of candidaemia and bacteraemia were inferred from Fagan’s nomograms.

Results

One hundred and sixty-six patients were included, 73 with candidaemia (44%) and 93 with bacteraemia (56%). When both markers indicated candidaemia (BDG ≥80 pg/ml and PCT <2 ng/ml) they showed higher PPV (96%) compared to 79% and 66% for BDG or PCT alone, respectively. When both markers indicated bacteraemia (BDG <80 pg/ml and PCT ≥2 ng/ml), their NPV for candidaemia was similar to that of BDG used alone (95% vs. 93%). Discordant BDG and PCT results (i.e. one indicating candidaemia and the other bacteraemia) only slightly altered the pre-test probabilities of the two diseases.

Conclusions

The combined use of PCT and BDG could be helpful in the diagnostic workflow for critically ill patients with suspected candidaemia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1763-5) contains supplementary material, which is available to authorized users.

Intra-abdominal Candida spp infection in acute abdomen in a quality assurance (QA)-certified academic setting

AIMS

To evaluate the contribution of light microscopy to detecting Candida spp infection in patients with complicated intra-abdominal infections (IAIs) admitted for acute abdomen to a quality assurance (QA)-certified surgical emergency ward.

METHODS

We conducted a retrospective study (2008-2012) of 809 abdominal intraoperative or biopsy tissue specimens obtained from patients admitted with acute abdomen and microbiological samples positive for Candida spp. Demographic data, mortality, comorbidities, specimen type, microscopy results, special histological staining performed, antimicrobial therapy were collected and analysed. Any comments at the multidisciplinary team meeting was recorded in minutes of and approved.

RESULTS

Sixty-six patients with complicated IAIs due to Candida spp were identified (39 male, 27 female, mean±SD age 75±20 years). Candida albicans was isolated in 35 cases and Candida non-albicans spp in 31 cases. Candida spp were isolated from blood in 50% of all selected microbiological specimens. Patients were stratified according to Candida spp (albicans vs non-albicans), underlying cancer disease and no previous antimicrobial administration, and a positive correlation with C. albicans isolation was found (p=0.009 and p=0.048, respectively). Out of 41 cases with microscopic evaluation, we identified yeast forms, pseudohyphae or both, indicative of Candida spp, in 23. Identification of Candida spp in histological specimens was higher in C. albicans cases than in C. non-albicans cases (73% vs 37.5%). Microscopy allowed prompt treatment of all patients.

CONCLUSIONS

Light microscopy still has great diagnostic significance, being a solid QA step. It provides rapid information and clues in patients who may harbour impaired defence mechanisms, concurrent chronic conditions and/or cancer.

Does serum procalcitonin aid in the diagnosis of bloodstream infection regardless of whether patients exhibit the systemic inflammatory response syndrome?

BACKGROUND

Physicians frequently rely on the systemic inflammatory response syndrome (SIRS) criteria to detect bloodstream infections (BSIs). We evaluated the diagnostic performance of procalcitonin (PCT) in detecting BSI in patients with and without SIRS.

METHODS

We tested the association between BSI, serum PCT levels, contemporaneous SIRS scores and serum lactate using logistic regression in a dataset of 4279 patients. The diagnostic performance of these variables was assessed.

RESULTS

In multivariate regression analysis, only log(PCT) was independently associated with BSI (p < 0.05). The mean area under the curve (AUC) of PCT in detecting BSI (0.683; 95% CI 0.65-0.71) was significantly higher than serum lactate (0.615; 95% CI 0.58-0.64) and the SIRS score (0.562; 95% CI 0.53-0.58). The AUC of PCT did not differ significantly by SIRS status. PCT of less than 0.1 ng/mL had a negative predictive value (NPV) of 97.4 and NPV of 96.2% for BSI in the SIRS-negative and SIRS-positive patients, respectively. A PCT of greater than 10 ng/mL had a LR of 6.22 for BSI in SIRS-negative patients. The probability of BSI increased exponentially with rising PCT levels regardless of SIRS status.

CONCLUSION

The performance of PCT for the diagnosis of BSI was not affected by SIRS status. Only PCT was independently associated with BSI, while the SIRS criterion and serum lactate were not. A low PCT value may be used to identify patients at a low risk for having BSI in both settings. An elevated PCT value even in a SIRS negative patient should prompt a careful search for BSI.

COMPARISON BETWEEN FOUR USUAL METHODS OF IDENTIFICATION OF Candida SPECIES

Infection by Candidaspp. is associated with high mortality rates, especially when treatment is not appropriate and/or not immediate. Therefore, it is necessary to correctly identify the genus and species of Candida. The aim of this study was to compare the identification of 89 samples of Candida spp. by the manual methods germ tube test, auxanogram and chromogenic medium in relation to the ID 32C automated method. The concordances between the methods in ascending order, measured by the Kappa index were: ID 32C with CHROMagar Candida(κ = 0.38), ID 32C with auxanogram (κ = 0.59) and ID 32C with germ tube (κ = 0.9). One of the species identified in this study was C. tropicalis,which demonstrated a sensitivity of 46.2%, a specificity of 95.2%, PPV of 80%, NPV of 81.1%, and an accuracy of 80.9% in tests performed with CHROMagar Candida;and a sensitivity of 76.9%, a specificity of 96.8%, PPV of 90.9%, NPV of 91%, and an accuracy of 91% in the auxanogram tests. Therefore, it is necessary to know the advantages and limitations of methods to choose the best combination between them for a fast and correct identification of Candidaspecies.

Evolution of procalcitonin, C-reactive protein and fibrinogen levels in neutropenic leukaemia patients with invasive pulmonary aspergillosis or mucormycosis

Unlike bacterial infections, the value of procalcitonin (PCT) in detecting fungal infections in leukaemia patients is not clear. To determine whether the monitoring of PCT coupled with C-reactive protein (CRP) and fibrinogen (Fib) could be helpful in the management of pulmonary aspergillosis (IPA) or mucormycosis (PM), we retrospectively analysed the evolution of PCT, CRP and Fib levels in 94 leukaemia patients with proven/probable IPA (n = 77) or PM (n = 17) from D-12 to D12 relative to IFI onset defined as D0. Overall, 2140 assays were performed. From D-12 to D0, 12%, 5% and 1.4% of patients had PCT >0.5, 1 and 1.5 μg l(-1) , respectively, while CRP was >50, 75 and 100 mg l(-1) in 84%, 70% and 57% and Fib was >4, 5 and 6 g l(-1) in 96%, 80% and 61% of cases respectively (P < 10(-7) ). The same trends were observed from D1 to D12. Overall, between D-12 and D12, only 6.4% of patients had PCT >1.5 μg l(-1) , while CRP >100 mg l(-1) and Fib >6 g l(-1) were observed in 80% and 75% of cases respectively (P < 10(-7) ). In leukaemia patients, IPA or PM was accompanied by a significant increase in CRP and Fib while PCT remained low.

Utility of blood procalcitonin concentration in the management of cancer patients with infections

Diagnosis of infections in cancer patients is usually problematic since differentiating between infection and fever of unknown origin is often a considerable clinical challenge. In general, increase concentration of blood procalcitonin (PCT) is associated with severe bacterial infection. PCT with an optimal cutoff level of 0.5 ng/mL seems to be the most helpful biochemical parameter in detecting severe infections, mainly bloodstream infection, in patients with hematological cancers. In all clinical situations, the elevated level of PCT should be carefully analyzed, always with a thorough physical examination and an appropriate microbiological assessment.

Diagnostic Accuracy of Procalcitonin for Predicting Blood Culture Results in Patients With Suspected Bloodstream Infection: An Observational Study of 35,343 Consecutive Patients (A STROBE-Compliant Article)

Previous studies have suggested that procalcitonin is a reliable marker for predicting bacteremia. However, these studies have had relatively small sample sizes or focused on a single clinical entity. The primary endpoint of this study was to investigate the diagnostic accuracy of procalcitonin for predicting or excluding clinically relevant pathogen categories in patients with suspected bloodstream infections. The secondary endpoint was to look for organisms significantly associated with internationally validated procalcitonin intervals. We performed a cross-sectional study that included 35,343 consecutive patients who underwent concomitant procalcitonin assays and blood cultures for suspected bloodstream infections. Biochemical and microbiological data were systematically collected in an electronic database and extracted for purposes of this study. Depending on blood culture results, patients were classified into 1 of the 5 following groups: negative blood culture, Gram-positive bacteremia, Gram-negative bacteremia, fungi, and potential contaminants found in blood cultures (PCBCs). The highest procalcitonin concentration was observed in patients with blood cultures growing Gram-negative bacteria (median 2.2 ng/mL [IQR 0.6-12.2]), and the lowest procalcitonin concentration was observed in patients with negative blood cultures (median 0.3 ng/mL [IQR 0.1-1.1]). With optimal thresholds ranging from ≤0.4 to ≤0.75 ng/mL, procalcitonin had a high diagnostic accuracy for excluding all pathogen categories with the following negative predictive values: Gram-negative bacteria (98.9%) (including enterobacteria [99.2%], nonfermenting Gram-negative bacilli [99.7%], and anaerobic bacteria [99.9%]), Gram-positive bacteria (98.4%), and fungi (99.6%). A procalcitonin concentration ≥10 ng/mL was associated with a high risk of Gram-negative (odds ratio 5.98; 95% CI, 5.20-6.88) or Gram-positive (odds ratio 3.64; 95% CI, 3.11-4.26) bacteremia but dramatically reduced the risk of PCBCs or fungemia. In this large real-life setting experience with more than 35,000 patients, procalcitonin was highly effective at excluding bloodstream infections regardless of pathogen categories. The results from our study are limited by its cross-sectional design and deserve to be validated in prospective longitudinal studies.

Procalcitonin is a marker of gram-negative bacteremia in patients with sepsis

Background:

Prediction of the species of pathogen among patients with sepsis within hours would be helpful in accelerating proper treatment. As a potential method of shortening the time to identification, this study considered the usefulness of measuring procalcitonin (PCT) to predict blood culture (BC) results.

Methods:

The authors retrospectively analyzed the data of patients with a diagnosis of sepsis in their hospital from December 2012 to December 2013. The authors analyzed all diagnostic episodes consisting of BC and PCT concentration. The diagnostic performance of PCT to predict gram-negative bacteremia was tested using a receiver operative characteristic curve. Logistic regression was constructed using the presence of gram-negative bacteria as the dependent variable.

Results:

A total of 262 diagnostic episodes met the inclusion criteria. According to BC classifications, a significantly higher value of PCT was observed in bloodstream infections caused by gram-negative bacteria (26.7 ng/mL, 0.09–188.3) than that in bloodstream infections caused by gram-positive bacteria (0.84 ng/mL, 0.05–18.79) or Candida spp. (1.12 ng/mL, 0.07–49.68). A cutoff value of ≥3.39 ng/mL for PCT showed a sensitivity of 80%, a specificity of 71%, a positive predictive value of 35%, a negative predictive value of 91% and an area under the curve of 0.73 for gram-negative bacteremia identification by BC. Among the 122 diagnostic episodes with positive BC results, a cutoff value of ≥6.47 ng/mL for PCT yielded a sensitivity of 74%, a specificity of 81%, a positive predictive value of 82%, a negative predictive value of 75% and an area under the curve of 0.81 for gram-negative bacteremia identification.

Conclusions:

PCT may represent a useful tool for differentiating gram-positive from gram-negative bloodstream infection with a significantly higher PCT level indicating gram-negative bacteremia.

Sepsis: From Pathophysiology to Individualized Patient Care

Sepsis has become a major health economic issue, with more patients dying in hospitals due to sepsis related complications compared to breast and colorectal cancer together. Despite extensive research in order to improve outcome in sepsis over the last few decades, results of large multicenter studies were by-and-large very disappointing. This fiasco can be explained by several factors, but one of the most important reasons is the uncertain definition of sepsis resulting in very heterogeneous patient populations, and the lack of understanding of pathophysiology, which is mainly based on the imbalance in the host-immune response. However, this heroic research work has not been in vain. Putting the results of positive and negative studies into context, we can now approach sepsis in a different concept, which may lead us to new perspectives in diagnostics and treatment. While decision making based on conventional sepsis definitions can inevitably lead to false judgment due to the heterogeneity of patients, new concepts based on currently gained knowledge in immunology may help to tailor assessment and treatment of these patients to their actual needs. Summarizing where we stand at present and what the future may hold are the purpose of this review.