CASE REPORT : PERITONEAL DIALYSIS-ASSOCIATED PERITONITIS DUE TO S. AUREUS VS P. AERUGINOSA IN DIFFERENT PATIENTS

Background: Peritoneal dialysis–asscociated peritonitis (PDAP) is a serious complication in PD patients, which remains the leading cause of patient drop out from continuous ambulatory peritoneal dialysis (CAPD). This case report highlights the difference of management, and outcome of PDAP due to Staphylococcus aureus (a common gram-positive skin pathogen) and Pseudomonas aeruginosa (a notoriously resistant gram-negative pathogen).

Case illustration: We report two cases of PDAP in different patients. Case one:  A 48-year-old woman who had been on CAPD for 8 years, presented with mild abdominal pain and cloudy dialysate effluent. There was a history of prior PD catheter leakage. Dialysate culture was positive for methicillin-susceptible S. aureus (MSSA). She is given intra peritoneal (ip) ceftriaxone and gentamycin for 14 days, followed by oral ciprofloxacin for 7 days. The patient responded well and did not require catheter removal. Case two: A 44-year-old man had been on CAPD for 10 months, presented with moderate to severe abdominal pain, fever, and cloudy effluent. Dialysate culture was positive for P. aeruginosa. He had peritonitis 3 weeks before, and also had previous exit-site infection (ESI) due to the same pathogen 5 months before. 5 days after being given ip ceftazidime and gentamycin, the patient showed no clinical or effluent turbidity improvement. We decided to remove the peritoneal catheter, and the patient was permanently transferred to haemodialysis (HD).

Discussion: PADP can be secondary to ESI, touch and wet contamination. When ESI is caused by P. aerigosa, it can be serious complication. Around 20% of patients develop P.aeruginosa peritonitis several months after the resolution of ESI. P.aeruginosa has ability to form dense biofilm that shield bacterial colonies on the catheter surface. Thus causes recractory or relapsing infection, has tendency to exhibit multi-drug resistance, and is also associated with high risk of catheter loss. MSSA peritonitis also leads to serious risks, but its outcomes are generally better than those of Pseudomonas. On case one, patient has a history of PD catheter leakage that cause wet contamination due to MSSA. She has no history of peritonitis and ESI before. On case two, he has a relapsing peritonitis and history of ESI due to P. aruginosa 5 months before.  ISPD 2022 suggest that S.aureus be treated with effective antibiotic for 3 weeks. Meanwhile Pseudomonas be treated with 2 antibiotics with different mechanisms of action for 3 weeks. Peritoneal catheter should be removed if PD effluent does not clear after 5 days of appropriate antibiotic therapy defining the episode as refractory. We gave 14 days of ip ceftriaxone and gentamycin, followed by oral ciprofloxacin for 7 days to patient one. She responded well and did not require catheter removal. On patient two, after 5 days of being given ip ceftazidime and gentamycin,  he showed refractory response. Therefore, the peritoneal catheter was removed.

Conclusion: When comparing MSSA with P. aeruginosa peritonitis in CAPD patients, Pseudomonas is associated with a significantly worse prognosis. It leads to higher rates of treatment failure, catheter removal, and transfer to HD.