Antibodies to cell wall peptidoglycan of Staphylococcus aureus in patients with serious staphylococcal infections.

An enzyme-linked immunoassay was used to detect antibodies to the cell wall peptidoglycan of Staphylococcus aureus in human sera. All 170 sera from donors and patients with staphylococcal and nonstaphylococcal infections contained IgG antibodies to peptidoglycan; antibody levels varied with age, and transplacental transfer occurred. IgM antibodies to peptidoglycan were not found in donors and were present in only one patient with serious staphylococcal infection. Significantly elevated levels of IgG antibodies to peptidoglycan were observed in 20 (80%) of 25 patients with deep tissue infection with S. aureus but in only two (9%) of 22 patients with superficial staphylococcal infection. An increase in levels of antibodies to peptidoglycan generally coincided with an increase in level of IgG antibodies to teichoic acid. No cross-reactivity between peptidoglycan and teichoic acid was observed. Thus, staphylococcal peptidoglycan is immunogenic in humans, and testing for IgG antibodies to peptidoglycan may be useful in the diagnosis and follow-up of serious staphylococcal infections.