Analysis of microbiological trends in peritoneal dialysis–related peritonitis from 1991 to 1998

Abstract

The microbial cause of peritoneal dialysis–related peritonitis is an important determinant of clinical outcome and the basis of widely used treatment guidelines. Five hundred forty-six cases of peritonitis in 374 patients from 1991 to 1998 were analyzed. The rate of peritonitis declined significantly from 1.37 episodes/patient-year in 1991 to 0.55 episode/patient-year in 1998 (P = 0.02). The rate of Gram-positive peritonitis decreased significantly from 0.75 to 0.28 episode/patient-year during the same period (P = 0.02). Conversely, the occurrence of Gram-negative peritonitis remained constant at approximately 0.16 episode/patient-year (P = 0.28). Staphylococcus epidermidis and Staphylococcus aureus were the most common causes of peritonitis, isolated in 27.8% and 19.3% of the culture-positive cases, respectively. A distinct decrease in peritonitis caused by S epidermidis was observed, with 0.40 episode/patient-year in 1991 compared with 0.11 to 0.20 episode/patient-year during subsequent years. The rate of infections caused by S aureus decreased significantly over time from a high of 0.21 episode/patient-year in 1992 to a low of 0.04 episode/patient-year in 1998 (P = 0.01). Pseudomonas aeruginosa, Escherichia coli, and Klebsiella species were the most common causes of Gram-negative peritonitis, identified in 7.1%, 6.8%, and 5.2% of culture-positive cases, respectively. The most dramatic increase in antibiotic resistance was seen among S epidermidis. From 1991 and 1992 to 1997 and 1998, resistance to ciprofloxacin increased from 5.4% to 47.8% (P = 0.003), and resistance to methicillin increased from 18.9% to 73.9% (P = 0.03). Our study showed significant trends in the causative pathogens of peritoneal dialysis–related peritonitis and dramatic increases in antibiotic resistance. These data support further study and warrant reevaluation of current treatment practices.