SO008STREPTOCOCCI NOW DOMINATE THE CLINICAL SPECTRUM OF PERITONEAL DIALYSIS (PD)-RELATED PERITONEAL INFECTIONS. AN ANALYSIS OF TRENDS DURING 30 YEARS

Abstract Background and Aims Peritoneal infections remain as a significant source of morbidity and mortality in PD patients. A steady decline of their incidence has been accompanied by changes in the etiologic spectrum of these infections, during the last decades. We have undertaken a review of trends in the compared incidence of PD-related peritonitis in our centre during a 30-year period, with a particular interest in streptococcal infections. Method Following an observational, retrospective design, we analyzed trends in the incidence and outcomes of peritoneal infections diagnosed in our centre between January 1990 and October 2019. We mainly focused on the incidence, risk factors and outcomes of streptococcal peritonitis. We excluded fungal peritonitis (very low incidence), surgical enteric infections and non-infectious peritonitis. Treatment failure was defined by transfer to hemodialysis for at least 3 months after the infection or death related to peritonitis. We applied Cox’s model to define clinical predictors of streptococcal infection, and stepwise logistic regression to investigate predictors of treatment failure. Results We recorded 1026 episodes of peritoneal infection in 878 patients, including 234 (22.8%) streptococcal infections, 57 (5.6%) infections by Staphylococcus aureus (SAu), 285 (27.8%) infections by coagulase-negative staphylococci (CNSt), 182 (17.7%) infections by gram-negative bacteria, 135 (13.2%) infections with 2 or more microorganisms and 133 (13.0%) culture-negative cases. Remarkably, streptococci were also main components in polimicrobial infections (present in 58.2% of cases). The incidence of peritonitis decreased during the observation period, from 0.91 (1990-94) to 0.47 episodes (2015-19) per patient and year This decline affected preferentially infections by SAu (0.068 to 0.006) and CNSt (0.361 to 0.067), while the incidence of infections by other etiologic agents remained essentially stable. As a consequence, the relative clinical spectrum moved to a predominance of streptococcal (10.7 to 23.3%), polimicrobial (8.0 to 15.7%) and culture-negative infections (4.7 to 16.2%). On multivariate analysis, patients suffering streptococcal infections were older (p=0.019), and presented lower albumin levels (p=0.004), than either patients suffering infections of other etiologies or presenting a peritonitis-free clinical course. After logistic regression analysis, older age, longer time on dialysis at the time of the infection, comorbidity, previous immunosuppression and plasma albumin were most consistent predictors of peritonitis-related mortality and treatment failure. Streptococcal peritonitis showed more benign outcomes than SAu (p<0,001) or gramnegative infections (p=0.032), with rates of treatment failure comparable to those observed for CNSt, non-enteric polimicrobial or culture-negative infections. Conclusion Streptococcal and polimicrobial (often including streptococci) infections have become dominant in the clinical spectrum of PD-related peritonitis, after the decline in the incidence of staphylococcal infections. The clinical aggressiveness of these infections appears intermediate between that observed in Staphylococcus aureus and CNSt infections.