Recurrent and relapsing peritonitis: causative organisms and response to treatment.

BACKGROUND The clinical behavior and optimal treatment of relapsing and recurrent peritonitis episodes in patients undergoing long-term peritoneal dialysis are poorly understood. STUDY DESIGN Retrospective study over 14 years. SETTING & PARTICIPANTS University dialysis unit; 157 relapsing episodes (same organism or culture-negative episode occurring within 4 weeks of completion of therapy for a prior episode), 125 recurrent episodes (different organism, occurs within 4 weeks of completion of therapy for a prior episode), and 764 control episodes (first peritonitis episode without relapse or recurrence). PREDICTORS Exit-site infection, empirical antibiotics. OUTCOME MEASURES Primary response (resolution of abdominal pain, clearing of dialysate, and peritoneal dialysis effluent neutrophil count < 100 cells/mL after 10 days of antibiotic therapy), complete cure (resolution by using antibiotics without relapse/recurrence), catheter removal (for any cause while on antibiotic therapy), and mortality. RESULTS Compared with the control group, more relapsing episodes were caused by Pseudomonas species (16.6% versus 9.4%) and were culture negative (29.9% versus 16.4%); recurrent infections commonly were caused by Enterococcus species (3.2% versus 1.2%) or other Gram-negative organisms (27.2% versus 11.1%) or had mixed bacterial growth (17.6% versus 12.7%). There were significant differences in primary response, complete cure, and mortality rates among groups (P < 0.001 for all comparisons). Compared with the control and relapsing groups, post hoc analysis showed that the recurrent group had a significantly lower primary response rate (86.4%, 88.5%, and 71.2%, respectively), lower complete cure rate (72.3%, 62.4%, and 42.4%, respectively), and higher mortality rate (7.7%, 7.0%, and 20.8%, respectively). LIMITATIONS Retrospective analysis. CONCLUSION Relapsing and recurrent peritonitis episodes are caused by different spectra of bacteria and probably represent 2 distinct clinical entities. Recurrent peritonitis episodes had a worse prognosis than relapsing ones.