Microbiological characteristics of peritoneal dialysis-related peritonitis in an Asian tertiary hospital 2011–2014

Background Peritonitis is the leading cause of technique failure among peritoneal dialysis (PD) patients. The study aimed to examine the microbiological characteristics of PD-related peritonitis in a tertiary hospital in Singapore. Methods A retrospective, cross-sectional study was performed at Singapore General Hospital (SGH). Data of patients diagnosed with PD-related peritonitis from January 2011 to December 2014 were collected. Microbiological characteristics of PD-related peritonitis were reported using descriptive statistics. Results A total of 377 episodes of peritonitis occurred in 247 patients. The average peritonitis rate in the centre was 0.23 episodes per patient year. There were 118 (31.2%) Gram-positive, 98 (26.0%) Gram-negative, 58 (15.4%) polymicrobial, 16 (4.2%) fungal, 2 (0.5%) mycobacterium and 85 (22.6%) culture-negative, PD-related peritonitis episodes. The three main Gram-positive micro-organisms isolated from peritoneal fluid cultures were Coagulase-negative Staphylococcus aureus (CoNS) (n=70, 17.6%), Streptococcus spp. (n=52, 13.1%) and Enterococcus spp. (n=28, 7.1%), while the three main Gram-negative isolates were Escherichia coli (n=50, 12.6%), Klebsiella spp. (n=46, 11.6%) and Enterobacter spp. (n=27, 6.8%). Candida parapsilosis (n=9, 1.9%) was the commonest fungus identified. Only 33 (47.1%) CoNS strains were sensitive to cefazolin, which was used in the institution for empiric coverage of Gram-positive micro-organisms in PD-peritonitis. All Streptococcus strains were sensitive to cefazolin (n=52). The majority of Escherichia coli (n=38, 76%), Klebsiella spp. (n=37, 80.4%) and Enterobacter spp. (n=18, 66.7%) strains were sensitive to gentamicin, the empiric antibiotic used for coverage of Gram-negative micro-organisms. Conclusions Our findings highlight the importance of regular monitoring of micro-organisms and their antimicrobial sensitivities in determining appropriate, centre-specific empirical antibiotics.