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.

Emergence of resistance in staphylococci after long-term mupirocin application in patients on continuous ambulatory peritoneal dialysis.

In the present study, we evaluated the effects of once-weekly mupirocin application to catheter exit sites on Staphylococcus aureus and coagulase-negative staphylococcus (CNS) colonization and investigated the resistance of those bacteria to methicillin (MeR) and mupirocin (MuR). We enrolled 36 continuous ambulatory peritoneal dialysis (CAPD) patients (mean age: 55.1 +/- 1.4 years) into the study. The patients (men/women: 21/15) had been applying mupirocin to the catheter exit site once weekly before the start of the study (mupirocin treatment duration: 3.1 +/- 2.0 years). During the study period, swabs were taken monthly from the nares, axillae, inguinal area, and catheter exit site. The swabs were inoculated on blood plates. Methicillin and mupirocin susceptibility were tested by disc diffusion according to the interpretative criteria of the National Committee for Clinical Laboratory Standards. We evaluated a total of 144 cultures. Among CNS isolates, the MuR was 66%, and the MeR was 38.8%. At the start of the study period, 3 patients were S. aureus nasal carriers. In nasal swabs, no MeR S. aureus was identified, and only 1 MuR S. aureus was found. Once-weekly application of mupirocin at the exit site in CAPD patients led to comparable rates of colonization by MuR S. aureus as did thrice-weekly or more frequent application. Clinical results showing high mupirocin and methicillin resistance in CNS are controversial.

The effects of weekly mupirocin application on infections in continuous ambulatory peritoneal dialysis patients.

Application of mupirocin to the nares or catheter exit site and frequency of mupirocin administration in continuous ambulatory peritoneal dialysis (CAPD) patients remain controversial. The objective of our study was to evaluate, using a historical control group, the efficacy on CAPD-related infections of once-weekly application of mupirocin at the catheter exit site. We instructed 18 CAPD patients, who did not initially use prophylactic antibiotic treatment, about once-weekly application of mupirocin ointment to the exit site as part of their exit-site care. We recorded the incidence of catheter-related infections, the causative micro-organisms, and the rate of catheter loss. We observed 17 acute exit-site infections (AESIs: 0.45 episodes/patient-year) before mupirocin treatment and 2 AESIs (0.06 episodes/patient-year) after treatment. The relative rate of AESI reduction was 86%. Before application of mupirocin, 52% of AESIs were attributable to Staphylococcus-aureus; after mupirocin administration, no AESIs were staphylococcal. Peritonitis episodes were also reduced from 21 before mupirocin treatment (0.56 episodes/patient-year), to 9 after mupirocin administration (0.29 episodes/patient-year). The relative rate of peritonitis reduction was 48%. Once-weekly application of mupirocin to the exit site resulted in a reduction in exit-site infections and peritonitis episodes comparable to those obtained with daily application.

Report of a case with polymicrobial endocarditis related to multiresistant strains.

We present a patient with polymicrobial endocarditis who had been operated on previously for a mycotic aneurysm and was seen at the cardiology clinic because of palpitations related to effort. A transesophageal echocardiogram revealed a 15-mm vegetation on his aortic valve. Staphylococcus epidermidis and Corynebacterium striatum were isolated from the blood cultures. Both strains were multiresistant (susceptible to 3 antibiotics at most) against chemotherapy in vitro. Microbiological eradication was not achieved from blood cultures even after applying antimicrobial therapy with effective antibiotics as determined with an antibiotic susceptibility test. For this reason, the patient underwent valve replacement. He was discharged from hospital in fairly good health.