Effect of once-a-week vs thrice-a-week application of mupirocin on methicillin and mupirocin resistance in peritoneal dialysis patients: three years of experience.

INTRODUCTION: The application of mupirocin to the exit-site in peritoneal dialysis (PD) patients decreases peritonitis and exit-site infection (ESI) considerably. However, long-term application of mupirocin may result in the development of methicillin- and mupirocin-resistant strains. In this study, we aimed to investigate the effect of once-a-week vs. thrice-a-week application of mupirocin on mupirocin and methicillin resistance in PD patients.

PATIENTS AND METHODS: Thirty-six patients were divided into two groups based on frequency of weekly mupirocin application at the catheter exit-site. In group 1, patients were randomly assigned to apply mupirocin once a week (n = 18), while patients in group 2 applied mupirocin three times a week (n = 18). We obtained cultures from the nares, inguinal area, axillae, and the exit site. The microorganisms reproduced, and the resistance to mupirocin and methicillin were recorded. Three years of follow-up of these patients were also recorded.

RESULTS: During the three-year follow-up period, seven episodes (0.26 episodes/patient-years) of ESI and 13 episodes (0.36 episodes/patient-years) of peritonitis were determined in group 1, and one episode of ESI (0.11 episodes/patient-years) and six episodes (0.24 episodes/patient-years) of peritonitis were determined in group 2. The rate of peritonitis and ESI were, respectively, 56% and 92% lower in group 2 when compared to group I (p = 0.041 and p = 0.038, respectively). Throughout three years, a total of 1852 samples were analyzed. In group 1, S. aureus reproduction rate and mupirocin resistance were 2.11% and 0.2%, respectively. In group 2, S. aureus reproduction rate was 0.93%, and no mupirocin resistance was observed. Methicillin-resistant S. aureus was not observed in both groups. Coagulase-negative staphylococcus (CNS) reproduction rate was 70.56% (mupirocin resistance: 59.87% and methicillin resistance: 33.7%) and 72.56% (mupirocin resistance: 64.7% and methicillin resistance: 33.3%) in groups 1 and 2, respectively. No peritonitis and ESI secondary to S. aureus and fungal agents were observed in both groups.

CONCLUSION: The thrice-a-week application of mupirocin seems to be more efficient when compared to once-a-week application of mupirocin. Long-term application of mupirocin may cause the development of mupirocin- and methicillin-resistant strains, especially in CNS, which results in a difficulty for struggling against infections.