Microbial detection in peritonitis may be faster by automated molecular methods, but less sensitive, which also depends on cause of peritonitis

Background Bacterial peritonitis is a serious infection, associated with high mortality in cirrhosis. Outcome is better the faster appropriate antibiotic treatment is given, but a wide variety of bacteria, antibiotic resistance and time consuming conventional microbiological work-up hamper rapid treatment. We aimed to clarify if a commercial automated multiplex PCR application (Unyvero IAI) might improve microbial diagnosis.

Methods We retrospectively analyzed patients with bacterial peritonitis on the background of cirrhosis or peritoneal dialysis (PD), in whom both conventional microbiological culture and the Unyvero IAI PCR application were performed, with respect to sensitivity and time to positive result.

Results Our patient cohort comprised 43 patients with peritonitis, n=24 and n=19 on the background of peritoneal dialysis (PD) and cirrhosis, respectively. Conventional culture was more sensitive compared to PCR in PD patients (71 versus 38%; p=0.04), which was less pronounced in cirrhosis (42% versus 32%; p=0.74). While patterns of Gram-negative versus Gram-positive infection was comparable in PD and cirrhosis (35% and 65% in PD versus 29% and 64% with 7% of Candida in cirrhosis), the main Gram-positive bacteria were coagulase-negative staphylococci in PD (35%) while enterococci were frequent (21%) in cirrhosis. Among the 11 pathogens not detected by PCR, 45% were coagulase-negative staphylococci. Time to final positive result was 19 hours by PCR and 61 hours by conventional culture in real life (&quot;p<0.001&quot;).

Conclusion The automated multiplex PCR method yielded significantly faster, but less sensitive results, which was more relevant in peritonitis related to peritoneal dialysis than related to cirrhosis.

Publication History

Article published online:
20 January 2025