[The microbial pattern of the catheter exit-site infection in peritoneal dialysis: A non-diphtheria Corynebacteria emergence?]

Abstract

Background: A prospective cohort study was undertaken to compare the rates of the infecting microorganisms of the peritoneal catheter exit-site in three periods of the prophylactic protocol of a peritoneal dialysis program. All patients treated for more than one month on Peritoneal Dialysis were included: Fourty-eight in Period 1 (P1), 48 in Period 2 (P2), and 54 in Period 3 (P3). Each period was of 3 years.

Methods: Infection prophylaxis protocol: P1: hydrogen peroxide or povidone iodine and non-occlusive dressing; P2: sterile water (boiled water) instead of antiseptic agents, semi-permeable dressing for taking showers, and nasal mupirocine prophylaxis for Staphylococcus aureus carriers; P3: equal to P2, plus local application of antibiotics in equivocal exit-site for infection and argentic nitrate in granulation tissue.

Main outcome measure: The rates of catheter infection and microorganisms causing infection were analysed by means of the Poisson regression method. Chi-square and ANOVA when appropriate.

Results: The proportion of catheters implanted by nephrologist or surgeon (p<0.01) and modality treatment by CAPD or CCPD (p<0.0001) were significantly different in the three periods, while the Staph. Aureus carrieres was in the limit of significance (p=0.048). Throughout the three periods, a significantly decreasing rate of total (P=0.0035) and acute infections (P<0.001), Staph. aureus (P=0.003) and peritonitis (P=0.0025) were found. The Pseudomonas aer. (P=0.006) and Gram negative Bacteria (P=0.023) decreased significantly in P2. The multiple factor analysis included eight factors: sex, age group, ESRD, DM, catheter implantation (nephrologist, surgeon), modality treatment (CAPD, CCPD), manufacturer and prophylaxis period as possible predictors of the catheter infections, the specific microorganisms and the peritonitis. That analysis revealed the prophylaxis period as the main predictive factor of the improvements found (p<0.02,- p<0.001). In contrast, the Corynebacteria spp. increased significantly (P=0.008) throughout the three periods. One half of the Corynebacteria in each period could be considered colonisers. The other half caused true infections, but not one of those episodes required catheter intervention. The non-diphtheria Corynebacteria increase was found related with the continuous cycling Peritoneal Dialysis treatment in multiple factor analysis (p=0.0023) and in the proportion analysis (P=0.039, c2).

Conclusion: The progressive protocol applied obtained good results, without the continued use of local antiseptics or antibiotics at the exit-site. However, the non-diphtheria Corynebacteria sp. infection increment favours the consideration of an antiseptic agent for the exit-site care.