Multiplex PCR for Microbiological Testing in Patients with Peritoneal Dialysis- and Liver Cirrhosis-Related Peritonitis: Faster, but Less Sensitive

<b>Background:</b> We analyzed the performance of a multiplex PCR application (Unyvero IAI) in comparison to culture in a cohort of peritonitis patients undergoing peritoneal dialysis or with liver cirrhosis. <b>Methods:</b> We performed a single-center study of 47 patients with clinically suspected peritonitis and compared pathogen detection rates of culture and PCR. The main outcome of interest was a comparison of accuracy and time to final positive result. <b>Results:</b> In the total cohort, the pathogen detection rate in culture was 58.14% versus 34.88% in PCR (<i>p</i> = 0.03). Detection rates of bacteria in peritoneal dialysis patients were even higher by culture (70.83%) but comparably low by PCR (37.50%; <i>p</i> = 0.04). The majority of discordant results were in the Gram-positive spectrum (81.82%). Differential time to final positive result was 37.39 ± 16.75 h. <b>Conclusion:</b> Time gains by using PCR diagnostic have to be weighed against lower detection rates, mainly in Gram-positive infections.