Bactericidal function of neutrophils from patients with acute bacterial infections and from diabetics

Killing of Staphylococus aureus by neutrophils from untreated patients with acute bacterial infection was increased compared with neutrophils from uninfected controls or the same patients after antibiotic treatment. In contrast, neutrophils from diabetics failed to increase their bactericidal activity in response to infection to the same degree as neutrophils from nondiabetic subjects. The latter abnormality was pronounced in poorly controlled (plasma glucose level, greater than 130 mg/100 ml), but was also present in well-controlled (plasma glucose levels, less than 130 mg/100 ml), diabetics. In parallel studies neutrophils from poorly controlled, uninfected diabetics did not kill S. aureus to the same degree as neutrophils from normal subjects or controlled diabetics. Finally, neutrophils from two diabetics who underwent controlled insulin withdrawal developed a bactericidal defect that was corrected by treating the patients with insulin or by preincubating their neutrophils with insulin in vitro. These results support the possibility that defective neutrophil bactericidal activity may contribute to the proposed increased susceptibility to bacterial infection of diabetics.