Microbial Adhesion on Membrane Oxygenators in Patients Requiring Extracorporeal Life Support Detected by a Universal rDNA PCR Test

Abstract

Extracorporeal membrane oxygenation (ECMO) represents a temporary life-saving therapy for respiratory or circulatory failure, but infections during ECMO support are a life-threatening complication. Surface-related infections of ECMO are mentioned, but rarely described in the literature. A universal rDNA polymerase chain reaction (PCR) test was used to investigate the potential microbiological colonization of membrane oxygenators (MOs) in 20 patients undergoing ECMO. The overall patient-based positivity by PCR was 45%. Gram-positive bacteria (71%) represented the most abundant microorganisms on MO surfaces, followed by Gram-negative bacteria (22%) and fungi (7%). The most frequently detected causative pathogens were staphylococci (58%). Bacterial mixed infections represented 56% of all infections. In four PCR-positive cases, the pathogens detected on the MO surfaces were also found by blood culture or by culture of specimens obtained from the infectious focus. In conclusion, hollow fiber membranes of MOs can be colonized by microorganisms and appear to be a potential source of bacterial and fungal infections in ECMO patients. These infections may pose an increased risk for clinical worsening. As a consequence, persistent septic complications have to be discussed as an indication for MO exchange. The initial results suggest that the applied PCR assay is a valuable tool to investigate MOs.