Heparin-Binding Protein (HBP), Neutrophil Gelatinase-Associated Lipocalin (NGAL) and S100 Calcium-Binding Protein B (S100B) Can Confirm Bacterial Meningitis and Inform Adequate Antibiotic Treatment

Cerebrospinal Fluid Neutrophil Gelatinase-Associated Lipocalin as a Novel Biomarker for Postneurosurgical Bacterial Meningitis: A Prospective Observational Cohort Study

BACKGROUND AND OBJECTIVES

Postneurosurgical bacterial meningitis (PNBM) was a significant clinical challenge, as early identification remains difficult. This study aimed to explore the potential of neutrophil gelatinase-associated lipocalin (NGAL) as a novel biomarker for the early diagnosis of PNBM in patients who have undergone neurosurgery.

METHODS

A total of 436 postneurosurgical adult patients were enrolled in this study. Clinical information, cerebrospinal fluid (CSF), and blood samples were collected. After the screening, the remaining 267 patients were divided into the PNBM and non-PNBM groups, and measured CSF and serum NGAL levels to determine the diagnostic utility of PNBM. Subsequently, patients with PNBM were categorized into gram-positive and gram-negative bacterial infection groups to assess the effectiveness of CSF NGAL in differentiating between these types of infections. We analyzed the changes in CSF NGAL expression before and after anti-infection treatment in PNBM. Finally, an additional 60 patients were included as an independent validation cohort to further validate the diagnostic performance of CSF NGAL.

RESULTS

Compared with the non-PNBM group, CSF NGAL was significantly higher in the PNBM group (305.1 [151.6-596.5] vs 58.5 [30.7-105.8] ng/mL; P < .0001). The area under the curve of CSF NGAL for diagnosing PNBM was 0.928 (95% CI: 0.897-0.960), at a threshold of 119.7 ng/mL. However, there was no significant difference in serum NGAL between the 2 groups (142.5 [105.0-248.6] vs 161.9 [126.6-246.6] ng/mL, P = .201). Furthermore, CSF NGAL levels were significantly higher in patients with gram-negative bacterial infections than those with gram-positive bacteria (P = .023). In addition, CSF NGAL levels decrease after treatment compared with the initial stage of infection (P < .0001). Finally, in this validation cohort, the threshold of 119.7 ng/mL CSF NGAL shows good diagnostic performance with a sensitivity and specificity of 90% and 80%, respectively.

CONCLUSION

CSF NGAL holds promise as a potential biomarker for the diagnosis, early drug selection, and efficacy monitoring of PNBM.

The diagnostic utility of heparin-binding protein among patients with bacterial infections: a systematic review and meta-analysis

BACKGROUND

Bacterial infections are considered a leading cause of hospitalization and death globally. There is still a need for a rapid and feasible biomarker for bacterial infections. Heparin-binding protein (HBP) was shown to be related to bacterial infections. The objective of the study is to investigate the diagnostic accuracy of HBP in bacterial infections.

METHODS

Articles were screened in PubMed, SCOPUS, Web of Science, and Cochrane to recognize eligible studies. We included studies investigating the diagnostic accuracy of HBP and reported the necessary data to construct 2 × 2 tables. A univariate analysis was conducted to determine the pooled sensitivity and specificity, and a bivariate diagnostic random-effects model was used to calculate the optimal cut-off point.

RESULTS

The analysis comprised sixteen studies in total. Plasma HBP showed a sensitivity of 0.90 (95% CI: [0.79, 0.96]) and a specificity of 0.87 (95% CI: [0.66, 0.96]) in diagnosing bacterial infections using blood samples. Pooling data from seven studies revealed that HBP in cerebrospinal fluid (CSF) has sensitivity and specificity of 96% (95% CI: [0.85, 0.99]), and 95% (95% CI: [0.89, 0.97]), respectively, for the diagnosis of bacterial meningitis. In urinary tract infections (UTI), urine-HBP was revealed to have a high diagnostic value in discriminating bacterial from non-bacterial UTI infection at a cut-off value of 32.868 ng/ml with sensitivity and specificity of 87%.

CONCLUSION

HBP has shown a high diagnostic accuracy of bacterial infections, including UTI and meningitis. Further studies are needed to determine its prognostic value and whether it could guide antibiotic therapy.

The Role of Cerebrospinal Fluid Levels of Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Electroencephalography in the Assessment Of Impaired Consciousness in the Context of Infection

Introduction: The sepsis syndrome is potentially affecting several organs and systems irrespectively of the primary source of the infection. Alterations of the brain function in sepsis patients may result either from a primary central nervous system (CNS) infection or could be part of the sepsis-associated encephalopathy (SAE), a common complication of sepsis, characterized by a diffuse dysfunction of the brain due to an infection elsewhere in the body without overt CNS infection. Aim of the study was to evaluate the usefulness of electroencephalography and the biomarker Neutrophil gelatinase-associated lipocalin (NGAL) when measured in the cerebrospinal fluid (CSF) in the management of these patients. Methods: Patients presenting at the emergency department with altered mental status and signs of infection were included in this study. Among initial assessment and treatment of the patients based on the international guidelines for treating sepsis, NGAL was measured in the cerebrospinal fluid (CSF) using ELISA technique. Electroencephalography was performed when possible within 24 hours after admission and EEG abnormalities were recorded. Results: 32 of 64 patients included in this study were diagnosed with central nervous system (CNS) infection. CSF NGAL was significantly higher in patients with CNS infection compared to patients without CNS infection (18.1 [5.1-71.1] vs 3.6 [1.2-11.6]; p<0.001). There was a trend for higher CSF NGAL in patents with EEG abnormalities, that did not reach statistical significance (p=0.106). CSF NGAL levels were similar between survivors and non-survivors (medians: 7.04 vs 11.79). Conclusion: In patients presenting at the emergency department with altered mental status and signs of infection, CSF NGAL was significantly higher in patients with CSF infection. Its role in this acute setting should be evaluated further. CSF NGAL could be suggestive of EEG abnormalities.