Peritoneal dialysis-associated peritonitis caused by Brevundimonas aurantiaca

Brevundimonas aurantiaca is an aerobic, non-fermenting Gram-negative bacillus traditionally regarded as an environmental organism within the genus Brevundimonas. Although this species had long been known microbiologically, human infection caused by B. aurantiaca was not reported until 2022, and peritoneal dialysis-associated peritonitis due to this organism had not been previously described. We report a case of peritoneal dialysis (PD)-associated peritonitis in a 55-year-old man with end-stage kidney disease receiving continuous ambulatory peritoneal dialysis. B. aurantiaca was isolated from two consecutive PD effluent cultures during the initial episode. The isolate could not be reliably identified by routine matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and species-level identification was achieved by 16S rRNA gene sequencing. The effluent cultures became negative during antimicrobial treatment. One week after completion of therapy, cloudy effluent developed again. One of two blood cultures grew Streptococcus agalactiae, while CAPD effluent and catheter cultures were negative. The PD catheter was subsequently removed, after which the patient improved without further episodes of peritonitis.