Measurement of serum procalcitonin levels for the early diagnosis of spontaneous bacterial peritonitis in patients with decompensated liver cirrhosis

Application of metagenomic next-generation sequencing in optimizing the diagnosis of ascitic infection in patients with liver cirrhosis

BACKGROUND

Metagenomic next-generation sequencing (mNGS) is an emerging technique for the clinical diagnosis of infectious disease that has rarely been used for the diagnosis of ascites infection in patients with cirrhosis. This study compared mNGS detection with conventional culture methods for the on etiological diagnosis of cirrhotic ascites and evaluated the clinical effect of mNGS.

METHODS

A total of 109 patients with ascites due to cirrhosis were included in the study. We compared mNGS with conventional culture detection by analyzing the diagnostic results, pathogen species and clinical effects. The influence of mNGS on the diagnosis and management of ascites infection in patients with cirrhosis was also evaluated.

RESULTS

Ascites cases were classified into three types: spontaneous bacterial peritonitis (SBP) (16/109, 14.7%), bacterascites (21/109, 19.3%) and sterile ascites (72/109, 66.1%). In addition, 109 patients were assigned to the ascites mNGS-positive group (80/109, 73.4%) or ascites mNGS-negative group (29/109, 26.6%). The percentage of positive mNGS results was significantly greater than that of traditional methods (73.4% vs. 28.4%, P < 0.001). mNGS detected 43 strains of bacteria, 9 strains of fungi and 8 strains of viruses. Fourteen bacterial strains and 3 fungal strains were detected via culture methods. Mycobacteria, viruses, and pneumocystis were detected only by the mNGS method. The mNGS assay produced a greater polymicrobial infection rate than the culture method (55% vs. 16%). Considering the polymorphonuclear neutrophil (PMN) counts, the overall percentage of pathogens detected by the two methods was comparable, with 87.5% (14/16) in the PMN ≥ 250/mm3 group and 72.0% (67/93) in the PMN < 250/mm3 group (P > 0.05). Based on the ascites PMN counts combined with the mNGS assay, 72 patients (66.1%) were diagnosed with ascitic fluid infection (AFI) (including SBP and bacterascites), whereas based on the ascites PMN counts combined with the culture assay, 37 patients (33.9%) were diagnosed with AFI (P < 0.05). In 60 (55.0%) patients, the mNGS assay produced positive clinical effects; 40 (85.7%) patients had their treatment regimen adjusted, and 48 patients were improved. The coincidence rate of the mNGS results and clinical findings was 75.0% (60/80).

CONCLUSIONS

Compared with conventional culture methods, mNGS can improve the detection rate of ascites pathogens, including bacteria, viruses, and fungi, and has significant advantages in the diagnosis of rare pathogens and pathogens that are difficult to culture; moreover, mNGS may be an effective method for improving the diagnosis of ascites infection in patients with cirrhosis, guiding early antibiotic therapy, and for reducing complications related to abdominal infection. In addition, explaining mNGS results will be challenging, especially for guiding the treatment of infectious diseases.

A randomized study of ceftriaxone for the prevention of infections in hospitalized patients with advanced cirrhosis

BACKGROUND

Infections frequently complicate hospital admission among patients with cirrhosis and are associated with adverse outcomes. In specific settings, administration of prophylactic antibiotics has been shown to improve outcomes. In this pilot study, we aimed to assess the feasibility of a randomized study of whether prophylactic ceftriaxone (CTX), administered to hospitalized patients with advanced cirrhosis (Model for End-Stage Liver Disease-Sodium ≥ 18) without known infection, could reduce the incidence of infection. We also sought to determine whether we could identify patients most likely to benefit through the use of clinical and laboratory parameters.

METHODS

Hospitalized patients with cirrhosis, with Model for End-Stage Liver Disease-Sodium ≥ 18 and no known infection after evaluation, were randomly assigned in a double-blinded fashion to receive either CTX 1 gr/day or placebo for up to 7 days. Subjects were monitored for incident infection and other outcomes of interest, including adverse reactions such as the development of C. difficile infection. Biomarkers of interest, including C-reactive protein and procalcitonin, were measured before initiation of treatment.

RESULTS

Thirty subjects were enrolled and received CTX or placebo (15 subjects each) per protocol. There were no observed statistically significant differences between groups in incidence of infection, mortality, length of stay, or key laboratory parameters, including C-reactive protein and procalcitonin. Adverse events related to treatment were rare and clinically of minor significance.

CONCLUSIONS

Overall, enrollment of subjects proved feasible, and results from this pilot study, while inadequate for confirmation of the potential efficacy of CTX, provide evidence of study feasibility for future, more definitive clinical trials.

[Prognosis and risk factors for mortality in cirrhotic patients with probable spontaneous bacterial peritonitis]

OBJECTIVE

To investigate the survival outcomes and risk factors for mortality in cirrhotic patients with probable spontaneous bacterial peritonitis (SBP).

METHODS

We retrospectively analyzed the clinical data of 323 cirrhotic patients with ascites admitted from June 2021 to May 2022, including 115 patients with SBP [ascites polymorphonuclear leucocyte (PMN) count ≥250/mm3], 52 patients with bacterascites (PMN count < 250/mm3 with positive microbiological finding in ascites), 67 patients with probable SBP (PMN count < 250/mm3 with negative microbiological finding in ascites but clinical symptoms of SBP) and 89 patients without infection (PMN count < 250/mm3 with negative microbiological finding without clinical symptoms of SBP). The clinical characteristics, laboratory data and 90-day mortality of the patients were compared among the 4 groups. Cox proportional hazard model and propensity score matching (PSM) in a 1∶1 ratio were used to analyze the risk factors for mortality in patients with probable SBP.

RESULTS

The patients with probable SBP had a 90-day mortality rate of 43.28%, similar to those of patients with SBP (46.95%, P=0.121) and bacterascites (48.07%, P=0.805) but significantly higher than that of non-infected patients (11.23%, P < 0.001). In the 46 pairs of patients matched using PSM, the 90-day mortality rates were higher in probable SBP group than in non-infected group both before (43.28% vs 11.23%, P < 0.001) and after PSM (34.78% vs 15.21%, P=0.038). Cox regression analysis indicated that probable SBP was an independent predictor of 90-day mortality in cirrhotic patients with ascites (HR=1.539, 95% CI: 1.048-2.261, P=0.028). A Model for End-Stage Liver Disease (MELD) score > 15 (HR=1.943, 95% CI: 1.118-3.377, P=0.018) and procalcitonin level > 0.48 ng/mL (HR=1.989, 95% CI: 1.111-3.560, P=0.021) at diagnostic paracentesis were both independent risk factors for 90-day mortality in patients with probable SBP.

CONCLUSION

Cirrhotic patients with probable SBP have poor survival outcomes, and their management should be further optimized based on their MELD score and procalcitonin level.

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.

Amyloid A in Serum and Ascitic Fluid as a Novel Diagnostic Marker of Spontaneous Bacterial Peritonitis

Background: Diagnosis of Spontaneous Bacterial Peritonitis (SBP) depends mainly on ascetic fluid culture which may be negative in spite of the clinical suggestion of SBP and high ascetic fluid neutrophilic count.

Aims: This study aimed to evaluate the biological importance of amyloid A biomarker in both serum and ascetic fluid to diagnose SBP as early as possible and to compare it to other markers (C-reactive protein (CRP), and the neutrophil-to-lymphocyte ratio (NLR)).

Methods: This study included 37 patients with hepatic ascites; twenty-two of them had SBP, and 15 patients did not have SBP. Serum and ascetic fluid amyloid A, ascetic fluid neutrophil, C-reactive protein, and neutrophil-to-lymphocyte ratio were measured in all subjects before the start of antimicrobial chemotherapy to the infected ones.

Results: Both the serum and ascetic fluid amyloid and also, CRP were significantly higher in patients infected with ascetic fluid than others. The cut-off point of serum amyloid A for early detection of SBP was 9.25ug/ml with the high sensitivity and specificity. For ascetic amyloid A, the sensitivity and specificity were 90.09% and 60% at cut-off point 2.85ug/ml, respectively.

Conclusion: Amyloid A in serum and ascitic fluid can be considered as a good biomarker for early diagnosis of SBP.

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.

Procalcitonin and Liver Disease: A Literature Review

Procalcitonin (PCT) is a widely used biomarker for the diagnosis of bacterial infections. It is produced by various organs and the liver is considered to be the most important site of production. Severe liver dysfunction has been shown to influence PCT levels. Patients with no sources of infection who have liver disease are observed to have increased serum levels of PCT, thereby reducing the diagnostic utility and value within this particular patient subset. Here, we have summarized the relationship between PCT and liver disease, including liver cirrhosis, liver failure, and liver transplantation.

Adjusted Intensive Care Infection Score (ICISΔ)-A new approach for prediction of ascitic fluid infection in patients with cirrhosis

BACKGROUND

Early and accurate diagnosis is the key to improving survival in cirrhotic patients with ascitic fluid infection.

AIMS

To investigate the usefulness of adjusted Intensive Care Infection Score (ICIS_Δ) for diagnosis of ascites infection in cirrhotic patients.

METHODS

Cirrhotic patients with ascites (n = 125) were enrolled, and the efficacy of ICIS and ICIS_Δ for predicting ascites infection was evaluated. ICIS_Δ was created by using the weighted variation of each ICIS parameter.

RESULTS

The area under the curves (AUCs) of ICIS for the diagnosis of ascites infection were 0.90 (95% CI: 0.84-0.95), 0.85 (95% CI: 0.79-0.90), and 0.87 (95% CI: 0.81-0.93), for SBP, culture-negative SBP, and combined SBP/culture-negative SBP, respectively. ICIS was optimized and diagnostic accuracy was obviously improved. ICIS_Δ had high AUCs of 0.99 (95% CI: 0.93-1.00) for SBP, 0.98 (95% CI: 0.83-1.00) for culture-negative SBP, and 0.98 (95% CI: 0.94-1.00) for the combination group. The optimal cutoff was identified as ICIS_Δ > 2, which had >97.8% sensitivity and 100% specificity for diagnosis of both SBP and culture-negative SBP. The ICIS_Δ had significantly higher AUCs than PCT and CPR in both groups (P = 0.002-0.008). ICIS_Δ kinetics could differentiate between SBP and culture-negative SBP patients. From sterile ascites, through culture-negative SBP to SBP, three ICIS_Δ parameters showed an increasing trend.

CONCLUSIONS

ICIS and ICIS_Δ are simple, rapid, accurate and cost-effective methods for the diagnosis of ascites infection in cirrhotic patients.

Combination of PCT, sNFI and dCHC for the diagnosis of ascites infection in cirrhotic patients

BACKGROUND

It is difficult to diagnose ascites infection early in cirrhotic patients. The present study was to create and evaluate a new bioscore combined with PCT, sNFI and dCHC in the diagnosis of ascites infection in cirrhotic patients.

METHODS

Two hundred and fifty-nine consecutive patients were enrolled; of which 51 patients were culture-positive spontaneous bacterial peritonitis (culture-positive SBP) and 58 patients were culture-negative SBP. The efficacy of procalcitonin(PCT), c-reactive protein (CRP), white blood cell (WBC), mean fluorescence intensity of mature neutrophils(sNFI) and difference in hemoglobin concentration between newly formed and mature red blood cells(dCHC) for diagnosing ascites infection was examined. These parameters were used to create a scoring system. The scoring system was analyzed by logistic regression analysis to determine which parameters were statistically different between ascites infection and non-ascites infection patients. Receiver operating characteristic curve (ROC) was used to analyze the diagnostic ability of bioscore for ascites infection.

RESULTS

In ROC analysis, the area under the curves (AUC) for PCT was 0.852 (95% CI 0.803-0.921, P < 0.001), dCHC 0.837 (95% CI 0.773-0.923, P < 0.001), CRP 0.669 (95% CI 0.610-0.732, P = 0.0624), sNFI 0.838 (95% CI 0.777-0.903, P < 0.001), and WBC 0.624 (95% CI 0.500-0.722, P = 0.0881). Multivariate analysis revealed PCT, dCHC and sNFI to be statistically significant. The combination of these three parameters in the bioscore had an AUC of 0.937 (95% CI 0.901-0.994, P < 0.001). A bioscore of ≥3.40 was considered to be statistically significant in making a positive diagnosis of ascites infection. In different groups of ascites infection, bioscore also shown a high diagnostic value of AUC was 0.947(95% CI 0.882-0.988, P < 0.001) and 0.929 (95% CI 0.869-0.974, P < 0.001) for culture-positive SBP and culture-negative SBP group respectively.

CONCLUSION

The composite markers of combining PCT, dCHC and sNFI could be a valuable diagnostic score to early diagnose ascites infection in patients with cirrhosis.

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.

Spontaneous Bacterial Peritonitis by Burkholderia cepacia Complex: A Rare, Difficult to Treat Infection in Decompensated Cirrhotic Patients

INTRODUCTION

Burkholderia cepacia complex (Bcc) is non-fermenting Gram-negative bacillus and has been rarely reported to cause spontaneous bacterial peritonitis (SBP) in decompensated cirrhosis.

OBJECTIVE

This study was done to evaluate the clinical presentation of cirrhotic patients with SBP due to Bcc and to determine its impact on clinical outcome.

METHODS

This is a retrospective, observational study conducted during the period from 1st January 2013 through 31st March 2015. Medical records and microbiology laboratory files were reviewed to identify all cases of Bcc associated SBP among patients hospitalized at the liver intensive care unit and analyzed.

RESULTS

During the study period, out of 252 SBP patients, 11 (4.3%) patients with a positive ascitic fluid culture for Bcc were identified. Pain abdomen was the predominant symptom present in 9 (81%) patients followed by hepatic encephalopathy in 7 (63%) patients. Acute kidney injury (AKI) was universally present, seen in 6 (54%) patients at the time of presentation and 4 (36%) patients developed AKI during hospital stay. The mean CTP score was 11.2 ± 1.1 (10-13), and the mean MELD was 24.3 ± 5.9 (14-35). The mean SOFA and APACHE II score at presentation were 11 ± 4.2 (4-18) and 19.4 ± 5.2 (11-28), respectively. A total of 8 (72%) patients (6-ACLF, 2-NASH) succumbed to the illness during hospitalization due to severe sepsis and multiorgan dysfunction and 3 (27%) patients are doing well on follow-up after 3 months.

CONCLUSION

SBP caused by Bcc has been rarely reported in cirrhotic patients. This organism is intrinsically resistant to third generation cephalosporins, which are the initial antibiotic of choice for SBP patients, hence associated with multi organ failure and high mortality rates.

Serum Procalcitonin in Patients with Acute Liver Failure

BACKGROUND

Procalcitonin (PCT) is a known diagnostic marker of bacterial infection. There are no previous reports of PCT concerning acute liver failure (ALF). We evaluated the clinical value of serum PCT levels in patients with ALF.

METHODS

Forty-four patients with acute hepatitis (19 men and 25 women; median age, 40 years; range, 20-79 years) were retrospectively enrolled from January 2001 and June 2015. PCT levels were measured by saved serum samples obtained within 3 days after admission. ALF was defined as prothrombin time (PT) < 40% regardless of hepatic encephalopathy.

RESULTS

Serum PCT levels were significantly higher in the patients with ALF (n = 16) than in those with non-ALF (n = 28) [0.25 (0.13-2.66) ng/mL vs. 0.165 (0.03-1.08), P = 0.00967]. Creatinine, total bilirubin, and direct bilirubin were positively correlated, and PT was negatively correlated with PCT. Receiver operating characteristic curve analysis showed an area under the curve of 0.74 for detecting ALF. With a PCT cut-off value of 0.5 ng/mL, the presence of ALF could be demonstrated with low sensitivity (37.5%) and high specificity (96.5%) with high positive (85.7%) and negative (72.9%) predictive value. Multivariate analysis showed that PCT was an independent factor associated with the presence of ALF. The cumulative survival rate was also significantly lower in patients with PCT ≥ 0.5 ng/mL (P = 0.0314), but it was not an independent prognostic factor.

CONCLUSION

Serum PCT level was significantly higher in patients with ALF.

Procalcitonin-guided diagnosis and antibiotic stewardship revisited

Several controlled clinical studies have evaluated the potential of the infection biomarker procalcitonin (PCT) to improve the diagnostic work-up of patients with bacterial infections and its influence on decisions regarding antibiotic therapy. Most research has focused on lower respiratory tract infections and critically ill sepsis patients. A clinical utility for PCT has also been found for patients with urinary tract infections, postoperative infections, meningitis, and patients with acute heart failure with possible superinfection (i.e., pneumonia). In these indications, PCT levels measured on hospital admission were found to substantially reduce the initiation of antibiotic treatment in low-risk situations (i.e., bronchitis, chronic obstructive pulmonary disease exacerbation). For more severe infections (i.e., pneumonia, sepsis), antibiotic stewardship by monitoring of PCT kinetics resulted in shorter antibiotic treatment durations with early cessation of therapy. Importantly, these strategies appear to be safe without increasing the risk for mortality, recurrent infections, or treatment failures. PCT kinetics also proved to have prognostic value correlating with disease severity (i.e., pancreatitis, abdominal infection) and resolution of illness (i.e., sepsis). Although promising findings have been published in these different types of infections, there are a number of limitations regarding PCT, including suboptimal sensitivity and/or specificity, which makes a careful interpretation of PCT in the clinical context mandatory. This narrative review aims to update clinicians on the strengths and limitations of PCT for patient management, focusing on research conducted within the last 4 years.

The role of serum procalcitonin and C-reactive protein levels in predicting spontaneous bacterial peritonitis in patients with advanced liver cirrhosis

OBJECTIVE

To determine the role of serum procalcitonin (PCT) and C-reactive protein (CRP) in predicting spontaneous bacterial peritonitis (SBP) in patients with advanced liver cirrhosis.

METHODS

A total of 88 patients with advanced liver cirrhosis were enrolled for this study, which included 40 cases with SBP and 48 cases with CNNA. Bacterial cultures, ascitic fluid (AF) leukocyte, C-reactive protein (CRP) and serum PCT measurements were carried out prior to the use of antibiotics. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of procalcitonin levels.

RESULTS

Serum PCT levels in advanced liver cirrhotic patients with SBP were significantly higher than those with CNNA. We used PCT 0.78 ng/mL as optimal cutoff value to diagnose SBP, for which the sensitivity and specificity was 77.5% and 60.4%. The area under the curve (AUC) was 0.706 (95% confidence interval: 0.576-0.798). The PCT level was significantly correlated with the AF WBC count (rs=0.404, P<0.01). However, there was no significant difference between SBP and CNNA patients in serum CRP levels.

CONCLUSION

According to our findings, serum PCT levels seem to provide an early diagnostic accuracy in advanced liver cirrhotic patients with SBP.

Diagnostic value of serum PCT and CRP for spontaneous bacterial peritonitis in patients with liver cirrhosis

AIM: To assess the value of serum procalcitonin (PCT) and C-reactive protein (CRP) for ascites spontaneous bacterial peritonitis (SBP) in patients with liver cirrhosis and ascites.

METHODS: The clinical data for 168 patients with liver cirrhosis and ascites treated at our hospital from January 2011 to January 2016 were retrospectively analyzed. According to the presence of SBP or not, the patients were divided into two groups: SBP group and non-SBP group. Factors that can predict the development of SBP were evaluated. The receiver operating characteristic (ROC) curves for significant parameters were generated to assess their sensitivities and specificities for diagnosis of SBP.

RESULTS: Serum ALT, AST and white cell count did not differ significantly between the SBP group and non-SBP group (P > 0.05). Serum PCT and CRP in the SBP group were significantly higher than those in the non-SBP group (P < 0.05). The ROC curve analysis showed that the areas under the ROC curves of PCT and CRP were 0.951 and 0.868, respectively. Using the cut-off values of 1.9 ng/mL and 22.6 mg/L, the sensitivities were 89.1% and 86.3%, and specificities were 81.7% and 80.6%, respectively.

CONCLUSION: Abnormally elevated serum PCT and CRP are of significant value for predicting SBP in patients with liver cirrhosis and ascites.

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.