Procalcitonin and macrophage inflammatory protein-1 beta (MIP-1β) in serum and peritoneal fluid of patients with decompensated cirrhosis and spontaneous bacterial peritonitis

Emergency medicine updates: Spontaneous bacterial peritonitis

INTRODUCTION

Spontaneous bacterial peritonitis (SBP) is a common infection in patients with cirrhosis and ascites and is associated with significant risk of mortality. Therefore, it is important for emergency medicine clinicians to be aware of the current evidence regarding the diagnosis and management of this condition.

OBJECTIVE

This paper evaluates key evidence-based updates concerning SBP for the emergency clinician.

DISCUSSION

SBP is commonly due to Gram-negative bacteria, but infections due to Gram-positive bacteria and multidrug resistant bacteria are increasing. The typical presentation of SBP includes abdominal pain, worsening ascites, fever, or altered mental status in a patient with known liver disease; however, some patients may be asymptomatic or present with only mild symptoms. Paracentesis is the diagnostic modality of choice and should be performed in any patient with ascites and concern for SBP or upper gastrointestinal bleeding, or in those being admitted for a complication of cirrhosis. Ultrasound should be used to optimize the procedure. An ascites absolute neutrophil count (ANC) ≥ 250 cells/mm³ is diagnostic of SBP. Ascitic fluid should be placed in blood culture bottles to improve the culture yield. Leukocyte esterase reagent strips can be used for rapid diagnosis if available. While many patients will demonstrate coagulation panel abnormalities, routine transfusion is not recommended. Management traditionally includes a third-generation cephalosporin, but specific patient populations may require more broad-spectrum coverage with a carbapenem or piperacillin-tazobactam. Albumin infusion is associated with reduced risk of renal impairment and mortality.

CONCLUSIONS

An understanding of literature updates can improve the care of patients with suspected SBP.

Mid-Infrared Spectroscopy as a New Tool for Ruling Out Spontaneous Bacterial Peritonitis: A Proof-of-Concept Study

Background and aims: A highly sensitive and specific point-of-care method for diagnosing spontaneous bacterial peritonitis (SBP) is currently lacking. The objective of the present study is to evaluate the diagnostic value of a rapid, easy-to-use, mid-infrared fiber evanescent wave spectroscopy (MIR-FEWS) method for ruling out SBP. Patients and Methods: Cirrhotic patients (n = 256) at five centers in France were included for suspected SBP or for the scheduled evacuation of ascites fluid. The mid-infrared spectrum of 7 µL of an ascites fluid sample was recorded using a MIR-FEWS system. To define a model for the diagnosis of SBP, the patients were divided into a calibration group (n = 170) and a validation group (n = 86). Results: Most of the patients were male (71%). The mean age was 60.25 years. Alcohol-related liver disease was the most common cause of cirrhosis. SBP was observed in 18% of the patients. For the diagnosis of SBP in the calibration and validation groups, respectively, the model gave areas under the receiver operating characteristic curves of 0.87 and 0.89, sensitivities of 90% and 87%, specificities of 78% and 80%, positive predictive values of 48% and 50%, negative predictive values of 97% and 96%, positive likelihood ratio of 4.09 and 4.35, negative likelihood ratio of 0.13 and 0.16, Youden index of 0.68 and 0.67, and correct classification rates of 80% and 81%. Conclusion: The results of this proof-of-concept study show that MIR-FEWS is a highly sensitive diagnostic method for ruling out SBP. The method warrants further investigation.

Neutrophil to Lymphocyte Ratio and Spontaneous Bacterial Peritonitis among Cirrhotic Patients: A Systematic Review and Meta-analysis

BACKGROUND

The goal of this systematic review and meta-analysis was analyzing published studies on the role of neutrophil to lymphocyte ratio (NLR) in infection and spatially spontaneous bacterial peritonitis (SBP) among cirrhotic patients.

METHODS

PubMed, Web of Science, and Scopus were searched until May 24, 2022. The Newcastle-Ottawa scale was used for quality assessment.

RESULTS

Of 14 studies included in our study, six studies were on infection with 2786 hospitalized cirrhotic patients, of whom 934 developed an infection. Other studies were on SBP with 1573 cirrhotic patients with ascites, of whom 557 developed SBP. The pooled results showed that there was no difference in NLR levels between hospitalized cirrhotic patients who developed infection compared to those who did not (random-effects model: SMD = 0.63, 95% CI = -0.01-1.27, p=0.054). However, cirrhotic patients with ascites who developed SBP had elevated levels of NLR compared to those who did not (random-effects model: SMD = 1.05, 95% CI = 0.52-1.57,p < 0.001). This difference remained significant in prospective studies (SMD = 0.94, 95% CI = 0.51-1.38,p < 0.001) but not in retrospective studies (SMD = 1.37, 95% CI = -0.56-3.29,p=0.165), in the subgroup analysis according to the study design. The pooled sensitivity of NLR was 92.07% (95% CI = 74.85%-97.84%) and the pooled specificity was 72.58% (95% CI = 57.72%-83.69%). The pooled positive likelihood ratio, negative likelihood ratio, DOR of NLR were 3.35(95%CI = 2.06-5.46), 0.10 (95%CI = 0.03-0.38), and 30.78 (95%CI = 7.01-135.04), respectively.

CONCLUSION

Our results support NLR to be a valid biomarker that can be readily integrated into clinical settings to help in the prevention and prediction of SBP among cirrhotic patients.

MCP1, CRP and Procalcitonin as Novel Diagnostic Markers in Cirrhotic Patients with Spontaneous Bacterial Peritonitis

Background & Aims:

The aim of the study was to evaluate serum c-reactive protein (CRP), ascitic procalcitonin (PCT) and monocyte chemotactic protein-1 (MCP-1) in the diagnosis of spontaneous bacterial peritonitis (SBP) in cirrhotic patients.

Methods:

A cross-sectional analytic study that included 199 patients with decompensated cirrhosis (101 with SBP and 98 without SBP). Patients were classified according to Child-Pugh criteria. Ascitic PCT and MCP-1 were measured by enzyme-linked immunosorbent assay. Serum CRP, liver and renal functions were assessed.

Results:

Three markers are significantly elevated in SBP patients than those without ascites. Using the ROC curve at AUC 0.883 and a cut-off value of >186 ng/ml, the diagnostic performance of ascitic MCP-1 level was higher than CRP (AUC 0.562) and ascitic fluid procalcitonin (AUC 0.751) in the diagnosis of SBP. The sensitivity and specificity were 86.15% and 79.59% at the cutoff of 186 ng/ml for MCP-1, 65.4 and 75.5 at ≥ 1 ng/ml for PCT, and 52.5 and 64.3, respectively for at 11.2 mg/dl CRP.

Conclusion:

Ascitic MCP-1 has a better diagnostic value with higher sensitivity and specificity in diagnosis SBP compared to CRP and procalcitonin which has higher diagnostic accuracy than CRP. Further studies with a large number will be necessary to evaluate the usefulness of these markers in diagnosis, follow-up and relation to morbidity and mortality of SBP patients.

Plasticity of monocytes and macrophages in cirrhosis of the liver

Cirrhosis of the liver is a systemic condition with raising prevalence worldwide. Patients with cirrhosis are highly susceptible to develop bacterial infections leading to acute decompensation and acute-on-chronic liver failure both associated with a high morbidity and mortality and sparse therapeutic options other than transplantation. Mononuclear phagocytes play a central role in innate immune responses and represent a first line of defence against pathogens. Their function includes phagocytosis, killing of bacteria, antigen presentation, cytokine production as well as recruitment and activation of immune effector cells. Liver injury and development of cirrhosis induces activation of liver resident Kupffer cells and recruitment of monocytes to the liver. Damage- and pathogen-associated molecular patterns promote systemic inflammation which involves multiple compartments besides the liver, such as the circulation, gut, peritoneal cavity and others. The function of circulating monocytes and tissue macrophages is severely impaired and worsens along with cirrhosis progression. The underlying mechanisms are complex and incompletely understood. Recent 'omics' technologies help to transform our understanding of cellular diversity and function in health and disease. In this review we point out the current state of knowledge on phenotypical and functional changes of monocytes and macrophages during cirrhosis evolution in different compartments and their role in disease progression. We also discuss the value of potential prognostic markers for cirrhosis-associated immuneparesis, and future immunotherapeutic strategies that may reduce the need for transplantation and death.

Spontaneous bacterial peritonitis: update on diagnosis and treatment

Spontaneous bacterial peritonitis (SBP) is a common complication in patients with liver cirrhosis, with an increased risk of mortality. For this reason, a diagnostic paracentesis should be performed in all patients with ascites and clinical features with high diagnostic suspicion. Although literature data abound in identifying new diagnostic markers in serum or ascites, they have not yet been validated. The final diagnosis requires the analysis of ascites and the presence of > 250 mm³ neutrophil polymorphonuclear (PMN) in ascites. If previous data showed that the most common microorganisms identified were represented by gram-negative bacteria, we are currently facing an increase in gram-positive bacteria and multi-drug resistant bacteria. Although prompt and effective treatment is required to prevent outcomes, this becomes challenging as first-line therapies may become ineffective leading to worsening prognosis and increased inhospital mortality. In this paper we will make a brief review of existing data on the diagnosis and treatment of SBP.

Macrophages in Chronic Liver Failure: Diversity, Plasticity and Therapeutic Targeting

Chronic liver injury results in immune-driven progressive fibrosis, with risk of cirrhosis development and impact on morbidity and mortality. Persistent liver cell damage and death causes immune cell activation and inflammation. Patients with advanced cirrhosis additionally experience pathological bacterial translocation, exposure to microbial products and chronic engagement of the immune system. Bacterial infections have a high incidence in cirrhosis, with spontaneous bacterial peritonitis being the most common, while the subsequent systemic inflammation, organ failure and immune dysregulation increase the mortality risk. Tissue-resident and recruited macrophages play a central part in the development of inflammation and fibrosis progression. In the liver, adipose tissue, peritoneum and intestines, diverse macrophage populations exhibit great phenotypic and functional plasticity determined by their ontogeny, epigenetic programming and local microenvironment. These changes can, at different times, promote or ameliorate disease states and therefore represent potential targets for macrophage-directed therapies. In this review, we discuss the evidence for macrophage phenotypic and functional alterations in tissue compartments during the development and progression of chronic liver failure in different aetiologies and highlight the potential of macrophage modulation as a therapeutic strategy for liver disease.

The Role of Serum Procalcitonin Level as an Early Marker of Ascitic Fluid Infection in Post Hepatitic Cirrhotic Patients

AIMS & BACKGROUND

The early diagnosis of spontaneous bacterial peritonitis (SBP) has been considered important in the overall patient's survival. Ascitic fluid culture examination performance, in the emergency setting, is time-consuming and not always available, so there is a need for easy to apply, rapid and reliable markers for diagnosis of patients with ascites. The present prospective study aimed to determine the early diagnostic value of serum procalcitonin (PCT) levels in decompensated cirrhotic patients (DCPs) with SBP.

METHODS

47 HCV cirrhotic patients with ascites were enrolled for this prospective study. The severity of cirrhosis was classified based on the Child-Pugh criteria. All patients were subjected to paracentesis and ascitic fluid (AF) culture. Serum PCT levels were measured using enzyme-linked fluorescence analysis (ELFA).

RESULTS

The diagnostic value of serum PCT levels and WBC/PLT ratios for detecting infections were serum PCT levels (3.63 ± 3.47 ng/mL) in DCPs with infections which were significantly higher than in DCPs without infections (0.505 ± 0.230 ng/mL); p < 0.05. The cut-off value for serum PCT levels was 0.7 ng/mL for the diagnosis of infections in DCPs, for which the sensitivity and specificity were 93.1% and 73.2%, respectively. The AUC was 0.91 (95% CI: 0.83-0.99).

CONCLUSION

Serum procalcitonin seems to provide satisfactory diagnostic biomarkers in SBP.

Ascitic calprotectin for the diagnosis of spontaneous bacterial peritonitis: a systematic review and meta-analysis

Calprotectin is a promising diagnostic biomarker for spontaneous bacterial peritonitis (SBP) among cirrhotic patients, but published studies report a wide variation of its diagnostic accuracy. We systematically searched six databases for eligible studies (i.e., all original studies that reported ascitic calprotectin as a diagnostic marker for SBP in cirrhotic patients), and assessed their quality with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. We calculated the pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), and diagnostic odds ratio (DOR) using the bivariate mixed-effect model. We constructed the summary receiver operating characteristic and determined the area under the curve (AUC). We registered the study protocol in PROSPERO (CRD42019125476). Our search retrieved 102 studies, of which 10 were included in the analysis. The overall risk of bias of these studies ranged from low to moderate. There was no heterogeneity from the threshold effect (Spearman correlation coefficient = 0.100, P value = 0.770). The pooled estimates [95% confidence intervals (CIs)] for ascitic calprotectin were as follows: sensitivity 0.91 (95% CI: 0.88-0.94), specificity 0.87 (95% CI: 0.68-0.96), PLR 7.18 (95% CI: 2.52-20.43), NLR 0.10 (95% CI: 0.07-0.15), DOR 71.91 (95% CI: 19.42-266.34), and AUC 0.92 (95% CI: 0.90-0.94). The sensitivity analysis did not detect outliers, and the model had a robust goodness of fit. There was no significant publication bias detected (Deeks test of asymmetry, P value = 0.79). Ascitic calprotectin is a promising diagnostic biomarker for SBP in cirrhotic patients.

Diagnostic and prognostic role of ascitic fluid calprotectin level: six-month outcome findings in cirrhotic patients

AIM

To assess the role of ascites calprotectin in early detection of SBP in patients with cirrhosis and to investigate its prognostic value in determination of the 6-month outcome. Methods and material: In this cross-sectional study, patients with liver cirrhosis who were consecutively referred to Imam Reza hospital, tertiary referral center in the northwest of Iran, underwent abdominal paracentesis. The samples were collected for measurement of calprotectin, albumin, total protein, WBCs, and PMNs.

RESULTS

The mean age of a total of 87 included patients was 56.86 (SD 16.05) years old with over half of the subjects (55.2%) being female. About 28.7% of performed paracenteses tested positive for SBP. Ascitic calprotectin was positively correlated to the PMN counts. Patients with SBP were found to have higher levels of ascites albumin, total protein, and calprotectin. Only 51 individuals survived the 6-month follow-up period and mortality outcomes were significantly related to the levels of aforementioned biochemical markers (p-value <.05).

CONCLUSION

Alongside with standard PMN counts, calprotectin measurement in the ascitic fluid could be used as an available test for early diagnosis of SBP. Calprotectin can also serve as a valuable prognostic marker in the evaluation of cirrhotic patients.

Recurrence of spontaneous bacterial peritonitis in cirrhosis: novel predictors

BACKGROUND AND AIMS

Recurrence of spontaneous bacterial peritonitis (SBP) is still a matter of debate. We conducted this study to evaluate the probable factors that predict the recurrence of SBP in patients who recovered from the first episode of SBP and the long-term outcomes of SBP recurrence.

METHODS

One hundred twenty-four patients diagnosed with liver cirrhosis, SBP and did not receive secondary prophylaxis either with norfloxacin or other antibiotics were included in this prospective cohort pilot study. Clinical, biochemical and ascitic fluid analysis parameters were evaluated. Ascitic fluid interferon-γ-induced protein (IP-10), calprotectin, interleukin-6 and tumor necrosis factor-α were measured by ELISA.

RESULTS

Of these, 76 patients survived with an in-hospital mortality rate of 38.7%. The survivors were classified into two groups according to recurrence and nonrecurrence of SBP and survival time, clinical parameters and cause of death were investigated. Thirty-one participants had one or more attacks of SBP, with a recurrence rate of 40.8% within one-year follow-up. Before discharge, multivariate analysis showed that ascitic IP-10 (≥1220 pg/ml), ascitic calprotectin (≥550 ng/ml), serum albumin (≤2.5 g/dl), nonuse of prophylactic β-blockers and use of proton-pump inhibitors (PPIs) were the independent variables in predicting recurrent SBP. Sepsis-related organ failure was the most common etiology of mortality in the recurrent SBP group within 3 and 6 months.

CONCLUSION

Increased ascitic calprotectin and IP-10, hypoalbuminemia, nonuse of prophylactic β-blockers and use of PPI were independently associated with increased SBP recurrence rate. Sepsis-related organ failure was the most common etiology of mortality.

A novel serum index for accurate diagnosis of spontaneous bacterial peritonitis in cirrhotic patients without other infections

Background

The accurate non-invasive diagnosis of spontaneous bacterial peritonitis (SBP) in patients with decompensated liver cirrhosis has not been achieved yet. The aim of the study was to obtain an unmistakable diagnosis of SBP using a new simple serum bioscore, made by combined measurement of procalcitonin (PCT), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), which we called the PEC index. This cross-sectional analytic study comprised 178 cirrhotic patients with ascites (60 patients with SBP and 118 patients with sterile ascites), after excluding non-SBP infection, during the period from March 2019 until September 2019. In all participants, serum levels of PCT, ESR, and CRP were measured, and PEC index was calculated [PEC index = PCT × (ESR + CRP)].

Results

Patients with SBP (n = 60) had significantly higher serum PEC index than those with sterile ascites (n = 118) (41.0/31.2–93.0 vs. 9.9/5.9–15.0, P < 0.001). PEC index distinguished culture positive cases significantly (P < 0.001). Using receiver operating characteristic (ROC) statistics, the sensitivity and specificity of PCT, at a cutoff value of 0.590 ng/mL, for SBP diagnosis, were 81.67% and 93.33%, respectively (area under the curve [AUC] = 0.879; 95% confidence interval [CI] 0.809–0.948). The sensitivity and specificity of ESR, at a cutoff value of 27.0 mm/hour, were 73.33% and 61.67%, respectively (AUC = 0.679; 95% CI 0.581–0.776). The sensitivity and specificity of CRP, at a cutoff value of 21.0 mg/L, were 93.33% and 51.67%, respectively (AUC = 0.736; 95% CI 0.639–0.833). While, the sensitivity and specificity of PEC index, at a cutoff value of 20, were highest (98.33% and 96.67%, respectively, AUC = 0.977; 95% CI 0.940–0.996).

Conclusion

Serum PEC index makes an accurate noninvasive diagnosis of SBP, after excluding other infections.

Mansoura simple scoring system for prediction of spontaneous bacterial peritonitis: lesson learnt

BACKGROUND AND OBJECTIVE

Spontaneous bacterial peritonitis (SBP) is a common bacterial infection with life-threatening sequelae in cirrhotic ascites. The purpose of this retrospective cohort study was to recognize the predictors of SBP to build up a noninvasive system to exclude or establish an episode of SBP.

PATIENTS AND METHODS

Of 1194 consecutive patients with cirrhotic ascites, only 966 patients were enrolled in this study. SBP was diagnosed once polymorphonuclear count was at least 250 cells/mm and/or there was a positive ascitic fluid culture result. Biochemical and clinical parameters were evaluated as predictors of SBP. A scoring system was established in the training group of 682 and validated in a second group of 284 participants.

RESULTS

The incidence of SBP was 12.3 and 12% in the training and validation groups, respectively. Age of at least 55 years, mean platelet volume (MPV) of at least 8.5 fl, neutrophil-to-lymphocyte ratio (NLR) of at least 2.5, and C-reactive protein (CRP) of at least 40 mg/l were identified as independent predictors of SBP. A scoring system including these four variables (age, MPV, and NLR with 1 point each, whereas CRP with 2 points) achieves a specificity of 98.2% with a positive predictive value for the diagnosis of SBP of 88.1% (score≥4). At a threshold of 1 point, the negative predictive value is 97.5% with a sensitivity of 92.9%. SBP is not associated with a high Model for End-stage Liver Disease score (P=0.135).

CONCLUSION

The combination of age, MPV, NLR, and CRP in a simple scoring system, Mansoura simple scoring system, supports quick and accurate exclusion or diagnosis of SBP.

Biomarker Guided Diagnosis of Septic Peritonitis in Dogs

Septic peritonitis (SP) is common in dogs and is associated with high mortality. Early recognition is essential to maximizing survival and may be aided by biomarker measurement. The present study aimed to evaluate the ability of biomarkers to discriminate septic peritonitis from non-septic ascites (NSA). Eighteen dogs with SP and 19 age-matched controls with NSA were enrolled. Contemporaneous blood and peritoneal effusion samples were obtained. Concentrations of cell-free DNA (cfDNA), cytokines, glucose, lactate, N-terminal pro-C-type natriuretic peptide (NT-proCNP), nucleosomes, and procalcitonin (PCT) were measured using commercial reagents and assays. Paired biomarker concentrations were compared with the Wilcoxon matched-pairs signed rank test, and biomarker concentrations between groups were compared with the Mann-Whitney U-test. P-values were adjusted for multiple comparisons using the Bonferroni correction. Receiver operating characteristic curves were generated to assess the ability of the above biomarkers to discriminate SP from NSA. Dogs with SP had significantly greater blood CCL2 concentrations than dogs with NSA (P = 0.032). Dogs with SP had significantly greater effusion CCL2, IL-6, IL-10, and lactate concentrations than dogs with NSA (P ≤ 0.0121). Blood-effusion concentration gradients of CCL2, glucose, IL-6, IL-10, and lactate were significantly different in dogs with SP compared to dogs with NSA (P ≤ 0.0165). Effusion lactate concentration had the highest AUROC value (0.866, 95% CI 0.751–0.980, P = 0.0001), although other biomarkers performed similarly. An effusion lactate concentration of 4.2 mmol/L was 72.2% (95% CI 46.5–90.3%) sensitive and 84.2% (95% CI 60.4–96.6%) specific for the diagnosis of SP.

Suitability of serum cytokine profiling for early diagnosis of implant-associated infections after orthopaedic surgery: A preliminary prospective study

The C-reactive protein (CRP) is still the conventional marker used to diagnose implant-associated infections (IAI) after orthopaedic surgery. However, the CRP level can lead to misdiagnosis since it is up-regulated not only during bacterial infection. In this prospective study, we evaluated the serum cytokine profile before (pre-OP) and after orthopaedic surgery (post-OP) as well as after confirmation of a developed infection (COI) to identify candidate biomarkers for diagnosis of IAI. Sera from 10 controls 7 to 1 days pre-OP and 0 to 22 days post-OP as well as from 5 patients who developed IAI 5 to 1 days pre-OP, 0 to 197 days post-OP and after COI were analyzed for 27 different cytokines using a multiplex cytokine assay. In addition to CRP, 14 cytokines IL-1ra, IL-4, IL-5, IL-6, IL-8, IL-12(p70), IL-13, IL-17, eotaxin, G-CSF, IFN-γ, IP-10, MCP-1, and MIP-1β were significantly altered (P ≤ 0.05) during the study although some differences were low-fold elevations compared to the pre-OP levels. IL-6 as well as IL-12(p70) were consistently elevated in infected patients. Surgery influenced cytokine production with some overlap of cytokines in both groups, implying that the use of cytokines is maximized when the cytokines are not or no longer affected by surgical trauma. To lend more robustness to the selection of candidate cytokines, in addition to the statistical differences, we applied a threshold cut-off of approximately 2-fold elevations when comparisons were made. This resulted in the selection of 8 cytokines, namely IL-6, IL-1ra, IL-8, IL-12(p70), eotaxin, IP-10, MCP-1, and MIP-1β, which may be used in a multiplex assay for detection of IAI after surgery. Furthermore, IL-1ra and IL-8 may be used as prognostic cytokines prior to surgery. The present results imply that the use of cytokines may be a suitable alternative to CRP for IAI diagnosis.

Accuracy of calprotectin using the Quantum Blue Reader for the diagnosis of spontaneous bacterial peritonitis in liver cirrhosis

AIM

We aimed to evaluate the accuracy of the dosage of calprotectin in ascitic fluid (AF) using the Quantum Blue assay, for the prompt diagnosis of spontaneous bacterial peritonitis (SBP).

METHODS

We prospectively collected 236 AF samples from 119 cirrhotic patients hospitalized in two French centers between May 2016 and May 2017. Bloody and chylous/cloudy AF, and secondary peritonitis were excluded. SBP was diagnosed if neutrophils in AF were >250/mm³ using standard cytology. The Quantum Blue Reader selectively measured the calprotectin antigen (MRP8/14) in 12 min within the measurable range from 0.18 to 1.80 μg/mL; values outside this range were registered as 0.17 and 1.81 μg/mL.

RESULTS

A total of 36 AF were considered as SBP (15.2%). SBP had higher median levels of calprotectin than non-SBP (1.81 vs. 0.25 μg/mL, P < 0.001). Calprotectin levels were positively correlated with neutrophils in AF (r = 0.57, P < 0.001) and C-reactive protein (r = 0.43, P < 0.001), but not with the Child-Pugh and Model for End-Stage Liver Disease scores. The optimal threshold of calprotectin to diagnose SBP was set at 1.51 μg/mL (80th percentile of calprotectin), yielding sensitivity, specificity, and positive and negative predictive values of 86.1%, 92.0%, 65.9%, and 97.3%, respectively. Only one asymptomatic patient with SBP had a low calprotectin level, but a high serum C-reactive protein level that strongly suggested an ongoing infection. We also showed that intraclass correlation coefficients for inter- and intra-observer agreement were excellent, with 0.95 and 0.89, respectively.

CONCLUSIONS

The dosage of calprotectin in AF using the Quantum Blue assay is a rapid and reliable method of ruling out SBP in hospitalized cirrhotic patients.

Bacterial translocation in patients with liver cirrhosis: physiology, clinical consequences, and practical implications

The gut liver axis is an operative unit that works to protect the human body against potentially harmful substances and microorganisms, maintaining the homeostasis of the immune system. Liver cirrhosis profoundly alters this complex system. The intestine becomes more permeable allowing the translocation of bacteria, bacterial products and fragments into the portal circulation, triggering an abnormal local and systemic inflammatory response and a condition of perpetual immunologic alarm. This immune-inflammatory disorder related to dysbiosis is involved in the development of liver damage and liver cirrhosis complications and increases intestinal permeability in a vicious circle. Areas covered: The most relevant studies on bacterial translocation, the mechanism of intestinal barrier dysfunction and its consequences in patients with liver cirrhosis have been revised through a PubMed search. Data have been discussed with particular regard to their significance in clinical practice. Expert commentary: The assessment of bacterial translocation and intestinal permeability is not currently used in clinical practice but may be useful to stratify patients' prognosis.

Homocysteine: a new diagnostic marker in spontaneous bacterial peritonitis

BACKGROUND AND AIMS

The diagnosis of spontaneous bacterial peritonitis (SBP) depends primarily on a polymorphonuclear leukocyte cell count more than 250/mm. This method is invasive, and not diagnostic in all variants of SBP; we aimed to assess serum homocysteine as a precise indicative marker for the diagnosis of all variants of SBP.

PATIENTS AND METHODS

A total 323 consecutive ascitic patients were registered in this prospective work. Serum and ascitic fluid of homocysteine were evaluated utilizing an enzyme-linked immunosorbent assay.

RESULTS

Participants were classified into a non-SBP group, including 262 participants and 61 patients with SBP. Serum and ascitic homocysteine were considerably elevated in the SBP group than in the non-SBP group (17.94±7.57 vs. 11.75±5.68 μmol/l; P<0.001 and 14.70±5.45 vs. 9.75±4.55 μmol/l; P<0.001). At a cutoff value of 17.79 μmol/l, serum homocysteine had 89.3% specificity and 95.1% sensitivity for distinguishing SBP (area under the curve: 0.932) and, at a cutoff value of 16.1 μmol/l, ascitic homocysteine had 84.4% specificity and 92.7% sensitivity for distinguishing SBP (area under the curve: 0.901). Both were positively correlated with the polymorphonuclear count, C-reactive protein, Child-Pugh score, and Model For End-Stage Liver Disease score as well as negatively correlated with the protein content in the ascitic fluid and estimated glomerular filtration rate. After SBP therapy, there was a marked reduction in serum and ascitic homocysteine levels.

CONCLUSION

This study demonstrates that serum and ascitic homocysteine are considerably higher in SBP participants versus non-SBP patients. Serum homocysteine may provide a reliable and noninvasive diagnostic marker for all variants of SBP.

Spontaneous bacterial and fungal peritonitis in patients with liver cirrhosis: A literature review

Spontaneous bacterial (SBP) and spontaneous fungal peritonitis (SFP) can be a life-threatening infection in patients with liver cirrhosis (LC) and ascites. One of the possible mechanisms of developing SBP is bacterial translocation. Although the number of polymorphonuclear cells in the culture of ascitic fluid is diagnostic for SBP, secondary bacterial peritonitis is necessary to exclude. The severity of underlying liver dysfunction is predictive of developing SBP; moreover, renal impairment and infections caused by multidrug-resistant (MDR) organism are associated with a fatal prognosis of SBP. SBP is treated by antimicrobials, but initial empirical treatment may not succeed because of the presence of MDR organisms, particularly in nosocomial infections. Antibiotic prophylaxis is recommended for patients with LC at a high risk of developing SBP, gastrointestinal bleeding, or a previous episode of SBP, but the increase in the risk of developing an infection caused by MDR organisms is a serious concern globally. Less is known about SFP in patients with LC, but the severity of underlying liver dysfunction may increase the hospital mortality. SFP mortality has been reported to be higher than that of SBP partially because the difficulty of early differentiation between SFP and SBP induces delayed antifungal therapy for SFP.

Novel applications for serum procalcitonin testing in clinical practice

INTRODUCTION

Procalcitonin has emerged as a reliable marker of acute bacterial infection in hospitalized patients and the assay has recently been incorporated into several clinical algorithms to reduce antimicrobial overuse, but its use in patients with end-organ dysfunction is controversial. Areas covered: In this review, the authors examine what is known about procalcitonin testing in patients with organ dysfunction, including those with end-stage renal disease, congestive heart failure, chronic obstructive pulmonary disease, and cirrhosis, and explore how the assay is now being used in the management of non-infectious diseases. Expert commentary: Procalcitonin holds tremendous promise to identify a diverse set of medical conditions beyond those associated with acute bacterial infection, including post-surgical anastomotic leaks, acute kidney injury, and complications after intracerebral hemorrhage. The authors review recent studies examining procalcitonin in these areas and explore how the assay might be used to guide diagnosis and prognosis of non-infectious diseases in the near future.

Bacterial translocation markers in liver cirrhosis

Bacterial translocation (BT) is an important mechanism in the development of infection in liver cirrhosis. The migration and colonization of bacteria and/or bacterial products from the bowel to mesenteric lymph nodes is a controlled process in healthy persons. Increased intestinal permeability, bacterial overgrowth and defect of gut-associated lymphatic tissue promote impaired BT in cirrhotics. We reviewed the reports on markers used for the evaluation of BT published between 1987 and 2016. We focused on the clinical consequences of BT in cirrhosis, as indicated by the values of the BT markers. Patients with cirrhosis are reported to have elevated levels of surrogate markers associated with BT compared with controls. The most widely used BT parameters are C-reactive protein, procalcitonin, bacterial DNA, endotoxin or lipopolysaccharide, lipopolysaccharide binding protein, calprotectin, and bactericidal/permeability increasing protein. High levels of these factors in serum and/or ascitic fluid in humans may be associated with advanced liver disease, hemodynamic instability, high levels of proinflammatory cytokines, susceptibility to the development of severe or recurrent infections, acute-on-chronic liver failure, hepatic encephalopathy, hepatorenal syndrome and poor prognosis during follow up. In conclusion, high levels of BT markers are associated with a high inflammatory response, increased complications of liver cirrhosis and occasionally high fatality rates.

Ascitic Fluid Calprotectin and Serum Procalcitonin as Accurate Diagnostic Markers for Spontaneous Bacterial Peritonitis

Background/Aims

The diagnosis of spontaneous bacterial peritonitis (SBP) is based on a polymorphonuclear leukocytes (PMNs) exceeding 250/μL in ascitic fluid. The aim of the study was to evaluate serum procalcitonin and ascitic fluid calprotectin as accurate diagnostic markers for detecting SBP.

Methods

Seventy-nine patients with cirrhotic ascites were included. They were divided into a SBP group, including 52 patients, and a non-SBP group of 27 patients. Serum procalcitonin, ascitic calprotectin, and serum and ascitic levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) were measured using an enzyme-linked immunosorbent assay.

Results

Serum procalcitonin and ascitic calprotectin were significantly higher in SBP patients than in non-SBP patients. Significant increases in both serum and ascitic levels of TNF-α and IL-6 were observed in SBP patients versus non-SBP patients. At a cutoff value of 0.94 ng/mL, serum procalcitonin had 94.3% sensitivity and 91.8% specificity for detecting SBP. In addition, at a cutoff value of 445 ng/mL, ascitic calprotectin had 95.4% sensitivity and 85.2% specificity for detecting SBP. Both were positively correlated with ascitic fluid proteins, PMN count, TNF-α, and IL-6.

Conclusions

According to our findings, determination of serum procalcitonin levels and ascitic calprotectin appears to provide satisfactory diagnostic markers for the diagnosis of SBP.

Ascitic Calprotectin is a Novel and Accurate Marker for Spontaneous Bacterial Peritonitis

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a known complication of advanced cirrhosis and presents a high mortality rate. A polymorphonuclear (PMN) cell count >250/μl in the ascitic fluid is the current gold standard for diagnosing SBP.

AIM

We evaluated the accuracy of a point-of-care test (POCT) for ascitic calprotectin in diagnosing patients with SBP.

METHODS

Eighty-eight patients admitted with decompensation of liver cirrhosis were studied including 41 patients (46.6%) with SBP. Ascitic calprotectin was measured using a quantitative POCT developed by Bühlmann^® .

RESULTS

Calprotectin levels correlated with PMN cell count and other inflammatory markers and were significantly higher in patients with SBP. An optimal cutoff of calprotectin above 1.57 μg/ml presented high sensitivity (87.8%), specificity (97.9%), and positive (97.3%) and negative (90.2%) predictive values for diagnosing SBP. Using calprotectin selectively in patients with a serum albumin-ascites gradient above 11 g/l further increased the sensitivity and negative predictive values of the test.

CONCLUSION

Ascitic calprotectin appears to be a reliable method for diagnosing SBP in patients with liver cirrhosis. It may present an alternative to other conventional diagnostic methods.

Reactive oxygen species measure for rapid detection of infection in fluids

BACKGROUND

Early detection of infection is critical to rapidly starting effective treatment. Diagnosis can be difficult, particularly in the intensive care unit (ICU) population. Because the presence of polymorphonuclear neutrophils in tissues is the hallmark of inflammatory processes, the objective of this proof of concept study was to determine whether the measurement of reactive oxygen species (ROS) could be an efficient diagnostic tool to rapidly diagnose infections in peritoneal, pleural and bronchoalveolar lavage (BAL) fluids in ICU patients.

METHODS

We prospectively included all patients hospitalized in the 21-bed surgical ICU of a teaching hospital from June 2010 to February 2014 who presented with systemic inflammatory response syndrome with suspicion of a peritoneal or pleural fluid or pulmonary infection needing a BAL. Instantaneous basal ROS production was measured in fluids and after phorbol 12-myristate 13-acetate (PMA) stimulation. We compared patients with infected fluids to those with non-infected fluids.

RESULTS

The overall ICU mortality rate was 34 %. A majority of patients were sampled following a delay of 5 days (2-12) after ICU admission, with most receiving antibiotics at the time of fluid sampling (71 %). Fluids were infected in 21/65 samples: 6/17 peritoneal fluids, 8/28 pleural fluids and 7/20 BALs. ROS production was significantly higher in the infected than in the non-infected group at baseline and after PMA stimulation in the peritoneal and pleural fluids but not in BAL.

CONCLUSION

Assessing instantaneous ROS production appears as a fast and reliable diagnostic method for detecting peritoneal and pleural fluid infection.

Diagnostic Accuracy of Serum Procalcitonin for Spontaneous Bacterial Peritonitis Due to End-stage Liver Disease: A Meta-analysis

Early diagnosis and prompt treatment of spontaneous bacterial peritonitis (SBP) due to end-stage liver disease is vital to shorten hospital stays and reduce mortality. Many studies have explored the potential usefulness of serum procalcitonin (PCT) in predicting SBP. The aim of this study is to evaluate the overall diagnostic accuracy of PCT levels for identifying SBP due to end-stage liver disease.After performing a systematic search of the Medline, Embase, and Cochrane databases for studies that evaluated the diagnostic role of PCT for SBP, sensitivity, specificity, and other measures of accuracy of PCT concentrations in serum for SBP diagnosis were pooled using random-effects models. A summary receiver operating characteristic curve was used to summarize overall test performance.Seven publications met the inclusion criteria covering 742 episodes of suspected SBP along with 339 confirmed cases. The summary estimates for serum PCT in the diagnosis of SBP attributable to end-stage liver disease were: sensitivity 0.82 (95% CI 0.79-0.87), specificity 0.86 (95% CI 0.82-0.89), positive likelihood ratio 4.94 (95% CI 2.28-10.70), negative likelihood ratio 0.22 (95% CI 0.10-0.52), and diagnostic OR 22.55 (95% CI 7.01-108.30). The area under the curve was 0.92. There was evidence of significant heterogeneity but no evidence of publication bias.Serum PCT is a relatively sensitive and specific test for the identification of SBP. However, due to the limited high-quality studies available, medical decisions should be carefully made in the context of both PCT test results and other clinical findings.

Inflammatory status in human hepatic cirrhosis

This review focuses on new findings about the inflammatory status involved in the development of human liver cirrhosis induced by the two main causes, hepatitis C virus (HCV) infection and chronic alcohol abuse, avoiding results obtained from animal models. When liver is faced to a persistent and/or intense local damage the maintained inflammatory response gives rise to a progressive replacement of normal hepatic tissue by non-functional fibrotic scar. The imbalance between tissue regeneration and fibrosis will determine the outcome toward health recovery or hepatic cirrhosis. In all cases progression toward liver cirrhosis is caused by a dysregulation of mechanisms that govern the balance between activation/homeostasis of the immune system. Detecting differences between the inflammatory status in HCV-induced vs alcohol-induced cirrhosis could be useful to identify specific targets for preventive and therapeutic intervention in each case. Thus, although survival of patients with alcoholic cirrhosis seems to be similar to that of patients with HCV-related cirrhosis (HCV-C), there are important differences in the altered cellular and molecular mechanisms implicated in the progression toward human liver cirrhosis. The predominant features of HCV-C are more related with those that allow viral evasion of the immune defenses, especially although not exclusively, inhibition of interferons secretion, natural killer cells activation and T cell-mediated cytotoxicity. On the contrary, the inflammatory status of alcohol-induced cirrhosis is determined by the combined effect of direct hepatotoxicity of ethanol metabolites and increases of the intestinal permeability, allowing bacteria and bacterial products translocation, into the portal circulation, mesenteric lymph nodes and peritoneal cavity. This phenomenon generates a stronger pro-inflammatory response compared with HCV-related cirrhosis. Hence, therapeutic intervention in HCV-related cirrhosis must be mainly focused to counteract HCV-immune system evasion, while in the case of alcohol-induced cirrhosis it must try to break the inflammatory loop established at the gut-mesenteric lymph nodes-peritoneal-systemic axis.

Markers of bacterial translocation in end-stage liver disease

Bacterial translocation (BT) refers to the passage of viable bacteria or bacterial products from the intestinal lumen, through the intestinal epithelium, into the systemic circulation and extraintestinal locations. The three principal mechanisms that are thought to be involved in BT include bacterial overgrowth, disruption of the gut mucosal barrier and an impaired host defence. BT is commonly observed in liver cirrhosis and has been shown to play an important role in the pathogenesis of the complications of end stage liver disease, including infections as well as hepatic encephalopathy and hepatorenal syndrome. Due to the importance of BT in the natural history of cirrhosis, there is intense interest for the discovery of biomarkers of BT. To date, several such candidates have been proposed, which include bacterial DNA, soluble CD14, lipopolysaccharides endotoxin, lipopolysaccharide-binding protein, calprotectin and procalcitonin. Studies on the association of these markers with BT have demonstrated not only promising data but, oftentimes, contradictory results. As a consequence, currently, there is no optimal marker that may be used in clinical practice as a surrogate for the presence of BT.