Culture-negative peritoneal dialysis-associated peritonitis rates are decreased with water lysis but not 16S rRNA gene sequencing

Objectives A successful peritoneal dialysis (PD) programme should aim to have low peritoneal dialysis-associated peritonitis (PDAP) rates. Identification of the microbial organism enables targeted antibiotic treatment and allows for a root cause analysis to be performed. Culture-negative (CN) peritonitis presents a more challenging scenario whereby empirical treatment for Gram-positive and Gram-negative organisms is commenced for 14 days, with Gram-negative cover discontinued based upon clinical response. In accordance with ISPD recommendations, we conducted a clinical quality improvement project in 2018 to decrease our culture-negative PDAP. Methods From 2018 to 2021, our department had 336 cases of PDAP. The introduction of a water-lysis step and the application of 16S rRNA gene sequencing were implemented to reduce culture-negative PDAP. Results There were 336 cases of PDAP between 2018 and 2021. In total, 135 cases occurred prior to the initiation of the water lysis step and 201 cases occurred after the introduction of the water lysis step and 16S rRNA sequencing. The rate of culture-negative PDAP prior to our change in PD effluent culture methodology was 33% (45/135); following changes to include a water lysis step and an increase in sample volume, the rate of culture-negative PDAP significantly fell to 20% (41/201) ( p < 0.01). 16S rRNA, using Sanger sequencing of culture-negative samples, did not significantly increase pathogen detection. Five out of 6 samples remained CN in the pre-water lysis step group, and 17 out of 23 samples also remained CN in the post-water lysis group ( p = 0.61). Conclusions Introduction of water lysis of peritoneal effluent significantly decreased culture-negative peritonitis rates, thus increasing organism identification and allowing for targeted antimicrobial therapy.