Antibody to the capsular polysaccharide/adhesin protects rabbits against catheter-related bacteremia due to coagulase-negative staphylococci.

A rabbit model of catheter-related bacteremia was developed to study immunity to the capsular polysaccharide/adhesin (PS/A) of coagulase-negative staphylococci. Catheters colonized by coagulase-negative staphylococci were inserted into the right jugular vein and attached to a subcutaneous osmotic pump, and blood cultures were obtained over 14 days. Nonimmune rabbits were bacteremic for 6-8 days after infection, hypoglycemic, and hyperlipidemic and had strong immune responses to teichoic acid but not to PS/A. PS/A immunization, but not teichoic acid immunization, reduced the number of bacteremic days by approximately 60%, diminished the hypoglycemia and hyperlipidemia, and ablated the immune responses to teichoic acid. Passive infusion of PS/A-specific polyclonal and monoclonal antibodies using a separate, noninfected catheter-pump combination implanted in the left jugular protected against both bacteremia and hematogenous colonization of this contralateral catheter.