What is the appropriate initial empiric antibiotic therapy for Peritoneal Dialysis catheter exit site infection?
Staphylococcus aureus , coagulase-negative staphylococcus , and other gram-positive organisms are the most frequent causes of exit site infection, followed in frequency by Pseudomonas aeruginosa and other gram-negative organisms. As with peritonitis, however, knowledge of both the epidemiology of exit site/tunnel infections and the local antibiotic sensitivities in each PD unit is imperative to guide therapy in that unit. After identification of an exit site or tunnel infection, empiric antibiotic therapy may be initiated, or therapy can be deferred until the results of the culture of the exit site drainage can guide the choice of agent. Empiric therapy should always cover S. aureus and consider P. aeruginosa , because these are common causes of infection and are associated with peritonitis. An oral Penicillinase- resistant penicillin (i.e., dicloxacillin 500 mg four times a day) or a first-generation cephalosporin (i.e., cephalexin 500 mg twice a day) provide good gram-positive coverage, and oral quinolones can provide gram-negative (including antipseudomonal) and some gram-positive coverage. Documented P. aeruginosa may require two antipseudomonal drugs, given its relative resistance to therapy. Antimicrobial agents should be continued for 2 weeks or until the exit site appears normal, whichever is longer. Ultrasound may be helpful in determining the presence, response, and duration of therapy in the case of a tunnel infection. Failure to adequately eradicate the infection should prompt replacement of the PD catheter. Dosing recommendations of other commonly used antibiotics and details useful in the treatment of exit site and tunnel infection can be found at www.ISPD.org .