Comparison of limulus amebocyte lysate assay for detection of endotoxin with blood culture in patients undergoing chronic hemodialysis

Infection is a common complication in patients undergoing hemodialysis. Despite the improvement of dialysis techniques, infection especially by bacteria remains the primary cause of death in these patients. Laboratory diagnosis is made by blood culture, the result of which may not be available for several days and during this period endotoxemia may lead to septic shock. Therefore, attempts at developing simple and rapid diagnostic tests are underway. In the present study, the Limulus Amebocyte Lysate [LAL] assay was used to detect endotoxin and compare its results with that of blood culture in hemodialysis patients. This study involved 278 chronic hemodialysis patients. LAL assay and blood culture were performed and the results were compared. 38 blood cultures were positive and the types of bacteria were determined with biotyping and serotyping methods. LAL assay was used to determine the presence of endotoxin in positive blood cultures. Endotoxin was detected in 15 patients. The sensitivity and specificity of LAL assay for Gram-negative bacteria were 88% and 95%, respectively. The frequency of bacteremia in patients was 13.6%. The prevalence of Gram-negative bacteremia [GNB] was 44.7%. Escherichia coli accounted for the majority of pathogenic microorganisms and Staphylococcus aureus was the most commonly encountered Gram-positive bacterium. Results of present study demonstrated that LAL assay is a rapid, sensitive and simple method. An excellent correlation was found between results of LAL assay and the presence of GNB. Gram-negative bacteria accounted for approximately 50% of documented infections. Endotoxin originating from Gram-negative bacteria was found to contribute to the inflammatory responses of patients with sepsis

[Measurement of endotoxin levels in blood of hemodialysis patients by 'LAL' test and comparision of its efficacy with blood culture]

Presently, bacteremia is the principal cause of morbidity in patients undergoing hemodialysis. Gram-negative bacteria account for approximately 50 percent of documented infections. Endotoxins released during lysis of gram negative bacteremia result in inflammatory and defense response by the body and if not treated promptly result in septic shock and ultimately death of the patient. This study describes the detection of endotoxins in blood of patients with bacteremia due to gram-negative bacteria by LAL test. Blood samples of 278 hemodialysis patients were analyzed in this study and pathogens were isolated from blood culture samples. Then, their antibiotic sensitivity was determined. In patients with positive blood culture, endotoxin levels were measured by LAL-test. Frequency of bacteremia in patients was 13.6%. The prevalence of gram-negative bacteremia was 44.7%. E coli were the major pathogens, while staphylococcus aureus was the most common gram positive bacterium. Endotoxin was detected in 15 patients [3.8 +/- 1.08 EU/ml]. The sensitivity and specificity of endotoxins for gram-negative bacteremia were 88% and 95%, respectively. The results indicate that the LAL method is a fast, sensitive and simple method. There was no significant difference between the results of blood culture and LAL-test [P>0.05]

Comparison of salivary anti helicobacter pylori IgG serum IgG with and bacteriological tests in detecting helicobacter pylori infections

This study was conducted to compare the efficacy of enzyme-linked immunosorbent assay [ELISA] for detecting anti-Helicobacter pylori [H. pylori] specific IgG antibodies in specimens of oral fluid and serum with bacteriological tests. Antral biopsy specimens, as well as serum and oral fluid samples were collected from 97 patients who underwent upper gastrointestinal endoscopy. The presence or absence of current H. pylori infection was determined by culture, histology and urease detection. Anti-H. pylori specific IgG was detected in serum and oral fluid, using an established lab-made, and a commercial ELISA kit. The obtained data were compared with results of bacteriological tests. In all, 62 [64%] of 97 patients were positive for H. pylori by one or more of the gold standard tests [culture, histology and urease detection]. Lab-made enzyme-linked immunoassay of oral fluid had a sensitivity and specificity of 92% and 83% respectively. A sensitivity and specificity of 87% and 83%, respectively, was obtained with the commercial kit. Lab-made enzyme-linked immunoassay of serum samples had a sensitivity and specificity of 90% and 88%, respectively. A sensitivity of 86% and specificity of 86% was obtained with the commercial kit. Detection of anti-H. pylori specific IgG in oral fluid by ELISA is comparable in sensitivity and specificity with serum based methods. Oral fluid based ELISA could provide a reliable, non-invasive method for the diagnosis of H. pylori infection. Saliva testing may have a role in epidemiological studies