Spontaneous bacterial peritonitis (SBP) is a clinical syndrome in which ascitic fluid becomes infected in the absence of a recognizable cause of peritonitis. The diagnostic criterion for SBP is a polymorphonuclear cell (PMN) count greater than or equal to 250 cells/ml in the ascitic fluid. Lysis of PMNs could occur during transport to the laboratory, leading to false-negative results. Therefore, there has been considerable interest in the development of a bedside test that can diagnose SBP rapidly. Presence of lactoferrin (LAF) in body fluids is proportional to the flux of neutrophils. LAF also has been shown to be remarkably stable and resistant to degradation when left at room temperature for extended periods of time. In patients with cirrhosis and ascites, LAF concentration in ascitic fluid represents a potential new parameter for diagnosing SBP.Aim
This study aimed to evaluate the utility of ascitic fluid LAF for the diagnosis of SBP (isolate the main aerobic causative organisms of SBP and identify the antibiotic sensitivity patterns of an isolated organism to detect possible resistance to antimicrobials).Patients and methods
Sixty patients with cirrhosis who were clinically suspected to have SBP and who were admitted to the Medical Department of Ain Shams University Hospitals and Yassin Abd El Gaffar Charity Center for liver disease and research for suspicion of SBP were included in the study.Results
The majority of isolates were Escherichia coli (66%). The least isolated organisms were methicillin-resistant Staphylococcus aureus (2%) and Pseudomonas spp. (2%). Imipenem was the only drug that could be used for treatment because all isolates related to the Enterobacteriaceae family were sensitive to it. The LAF concentration was significantly elevated (191.7 ng/ml) in the cases in this study compared with controls (42.2 ng/ml). This study showed that LAF in ascitic fluid could discriminate between SBP and non-SBP samples. The highest combined sensitivity and specificity of LAF in ascitic fluid to detect SBP was achieved at the level of 88 ng/ml (sensitivity of LAF at a cutoff point of 88 ng/ml is 100.0% and specificity is 91.7%).Conclusion
LAF level in ascitic fluid is a promising diagnostic parameter that could serve as a sensitive and specific initial screening test for detection of SBP in cirrhotic patients with ascites, especially in those with culture-negative results. Ascitic fluid LAF level correlates positively with the polymorphonuclear leukocyte count, which makes this parameter invaluable because it is not operator dependent and is not destroyed at room temperature. At a cutoff value of 88 ng/ml LAF showed a very high sensitivity and specificity of 100 and 91.7%, respectively.