An initiative to improve effluent culture detection among pediatric patients undergoing peritoneal dialysis through process improvement.

BACKGROUND: Peritonitis is a significant cause of morbidity and healthcare cost among pediatric patients undergoing peritoneal dialysis. Culture-negative peritonitis has been associated with an increased risk of technique failure. Known risk factors for culture-negative peritonitis are related to the process of collection and sample processing for culture, but additional studies are needed. A culture detection rate of 16.7% was identified among our patients undergoing peritoneal dialysis, which is below the national benchmark of ≥ 85%. Our primary objective of this quality improvement project was to improve culture detection rates. METHODS: Interventions were developed aimed at standardizing the process of effluent collection and laboratory processing, timely collection and processing of samples, and addressing other modifying risk factors for lack of bacterial growth from culture. These interventions included direct inoculation of effluent into blood culture bottles at bedside and use of an automated blood culture system. Two Plan-Do-Study-Act cycles were completed prior to moving to the sustain phase. RESULTS: The culture detection rate improved from 16.7% (pre-intervention) to 100% (post-intervention). A decrease in the median process time also occurred from 83 min (pre-intervention) to 53 min (post-intervention). An individual and moving range chart identified a decrease in both the centerline (mean) and upper control limit, indicating that the process became more reliable during the sustain phase. CONCLUSIONS: An improvement in process time and culture positivity rate occurred following standardization of our PD fluid culture process. Future studies should be aimed at the impact of the components of collection and processing methods on the effluent culture yield. A higher resolution version of the Graphical abstract is available as Supplementary information.

Matrix Metalloproteinase-8 Augments Bacterial Clearance in a Juvenile Sepsis Model.

Genetic ablation or pharmacologic inhibition of matrix metalloproteinase-8 (MMP8) improves survival in an adult murine sepsis model. Because developmental age influences the host inflammatory response, we hypothesized that developmental age influences the role of MMP8 in sepsis. First, we compared sepsis survival between wild type (WT, C57BL/6) and MMP8 null juvenile-aged mice (12-14 days) after intraperitoneal injection of a standardized cecal slurry. Second, peritoneal lavages collected at 6 and 18 hours after cecal slurry injection were analyzed for bacterial burden, leukocyte subsets, and inflammatory cytokines. Third, juvenile WT mice were pretreated with an MMP8 inhibitor prior to cecal slurry injection; analysis of their bacterial burden was compared to vehicle-injected animals. Fourth, the phagocytic capacity of WT and MMP8 null peritoneal macrophages was compared. Finally, peritoneal neutrophil extracellular traps (NETs) were compared using immunofluorescent imaging and quantitative image analysis. We found that juvenile MMP8 null mice had greater mortality and higher bacterial burden than WT mice. Leukocyte counts and cytokine concentrations in the peritoneal fluid were increased in the MMP8 null mice, relative to the wild type mice. Peritoneal macrophages from MMP8 null mice had reduced phagocytic capacity compared to WT macrophages. There was no quantitative difference in NET formation, but fewer bacteria were adherent to NETs from MMP8 null animals. In conclusion, in contrast to septic adult mice, genetic ablation of MMP8 increased mortality following bacterial peritonitis in juvenile mice. The increase in mortality in MMP8 null juvenile mice was associated with reduced bacterial clearance and reduced NET efficiency. We conclude that developmental age influences the role of MMP8 in sepsis.