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Published on: October 23, 2011
Multiplexed MALDI fingerprints for rapid detection of spontaneous bacterial peritonitis
Qiong Wu1, Bo Wei2, Han Zhang1
1School of Chemistry and Molecular Engineering and Shanghai Key Laboratory of Functional Materials Chemistry, and Research Centre of Analysis and Test, East China University of Science and Technology, Shanghai 200237, China.
Background:
The efficient diagnosis of spontaneous bacterial peritonitis (SBP) has been hindered by the low sensitivity of current clinical indicators. A rapid and accurate detection method for SBP is essential to enable early diagnosis and prompt intervention.
Methods:
Given the critical role of specialized metabolites in bacterial infections, we combined matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with partial least squares discriminant analysis (PLS-DA) to directly analyze intact protein and specialized lipid fingerprints in ascitic fluid, in order to effectively distinguish spontaneous bacterial peritonitis (SBP) from noninfected ascites.
Results:
MALDI-TOF MS delivers results in minutes to hours, far surpassing traditional culture-based methods that take 24-48 hours. Its capacity for rapid, direct pathogen detection in ascitic fluid is critical for prompt treatment and precise antibiotic selection. Unlike database-dependent approaches, PLS-DA serves as an independent statistical tool for SBP classification. MALDI-TOF MS enables direct analysis of lipid species (500-1000 Da) and intact proteins (2000-20,000 Da) without bacterial culture. Notably, α-defensins, particularly human neutrophil peptides (HNP-1, HNP-2), emerged as promising SBP biomarkers, while a novel peptide-SSSYSKQFTSSTSYNRGDSTFES (a fibrinogen fragment)-was associated with noninfected ascites. The combination of HNP-2 (P-3368) and this peptide (P-2550) achieved an AUC of 0.956, demonstrating outstanding diagnostic accuracy for SBP.
Conclusions:
MALDI-TOF MS advances SBP diagnosis by enabling the multiplexed detection of diverse lipids and proteins, offering crucial insights into the metabolic interplay of the host's response to infection.
