BACKGROUND: The failure of new, innovative, and often expensive tests to show the presence of intraabdominal infection caused us to reexamine the value of an inexpensive and almost forgotten one. Lysozyme is a bacteriolytic enzyme located within the lysosomes of phagocytic cells including leukocytes. METHODS: We measured serum concentrations of lysozyme by a standard turbidimetric method in both a murine model of intraabdominal infection and in trauma patients with intraabdominal abscesses or other acquired infections. RESULTS: In mice with intraabdominal abscess secondary to cecal ligation and puncture (n = 35) serum lysozyme activity increased compared with sham-operated controls (n = 20; p < 0.001). In trauma patients with intraabdominal abscess after injury and surgery (n = 19), there was also an increase in serum lysozyme activity compared with controls (n = 15; p < 0.001) or with patients with lung infection (n = 21; p < 0.001). The increase of serum lysozyme activity occurred before intraabdominal sepsis was clinically apparent. CONCLUSIONS: In this study, serum lysozyme concentration has a high specificity related to the presence of an intraabdominal abscess and is an indirect measure of the sequestration of leukocytes to the site of an established or developing collection of intraabdominal pus. The estimation of serum lysozyme may be an aid to differentiate critically ill patients with a potential occult intraabdominal abscess.
BACKGROUND: The failure of new, innovative, and often expensive tests to show the presence of intraabdominal infection caused us to reexamine the value of an inexpensive and almost forgotten one. Lysozyme is a bacteriolytic enzyme located within the lysosomes of phagocytic cells including leukocytes. METHODS: We measured serum concentrations of lysozyme by a standard turbidimetric method in both a murine model of intraabdominal infection and in traumapatients with intraabdominal abscesses or other acquired infections. RESULTS: In mice with intraabdominal abscess secondary to cecal ligation and puncture (n = 35) serum lysozyme activity increased compared with sham-operated controls (n = 20; p < 0.001). In traumapatients with intraabdominal abscess after injury and surgery (n = 19), there was also an increase in serum lysozyme activity compared with controls (n = 15; p < 0.001) or with patients with lung infection (n = 21; p < 0.001). The increase of serum lysozyme activity occurred before intraabdominal sepsis was clinically apparent. CONCLUSIONS: In this study, serum lysozyme concentration has a high specificity related to the presence of an intraabdominal abscess and is an indirect measure of the sequestration of leukocytes to the site of an established or developing collection of intraabdominal pus. The estimation of serum lysozyme may be an aid to differentiate critically illpatients with a potential occult intraabdominal abscess.