Tempo para positivar cultura de bactérias no líquido de diálise peritoneal : avaliação de diferentes técnicas laboratoriais

Abstract

Chronic kidney disease patients on peritoneal dialysis therapy are susceptible to infections, with peritonitis being the primary cause of technique failure. Peritoneal fluid culture is one of the essential elements for proper diagnosis and treatment of peritonitis. The aim of this study was to compare the time required to obtain a positive culture using different laboratory methods. An in vitro cross-sectional study comparing different laboratory techniques for preparation and culture of bacteria in peritoneal fluid. The research was conducted with 21 sterile dialysis fluid bags with 1.5% glucose concentration, and 21 peritoneal dialysis bags containing peritoneal fluid drained from patients without peritonitis, assisted at the Nephrology Unit from HSL-PUCRS. Fluids from the 42 peritoneal dialysis bags were contaminated by injecting a coagulase-negative Staphylococcus suspension and then prepared for culture using four distinct techniques - A (direct culture), B (post-centrifugation culture), C (direct culture after 4h sedimentation), and D (culture after 4h sedimentation and centrifugation) – followed by seeding. In the 21 contaminated sterile bags, the mean times to obtain a positive culture with techniques D (19.6 h ±2.6) and C (19.1 h ±2.3) were longer in comparison to A (15.8 h ±3.0; p<0.01), but not statistically different from group B mean (19.0 h ±3.2). The same occurred in the 21 bags drained from patients, with mean times for techniques D (14.0 h ±1.9) and C (14.5 h ±1.7) being longer than technique A (12.22 h ±1.94; p<0.05), however not statistically different from technique B (13.2 h ±1.3). The sedimentation and centrifugation steps were unnecessary and may delay antibiotics sensitivity test result by approximately 8 hours.