Detection of bacterial contamination in platelet concentrates from Brazilian donors by molecular amplification of the ribosomal 16S gene

Objective The aim of our work was to establish a semi-automated high-throughput DNA amplification method for the universal screening of bacteria in platelet concentrates (PCs). Background Among cases of transfusion transmission of infectious agents, bacterial contamination ranks first in the number of events, morbidity and mortality. Transmission occurs mainly by transfused PCs. Automated culture is adopted by some blood banks for screening of bacterial contamination, but this procedure is expensive and has a relatively long turnaround time. Methods PCs were spiked with suspensions of five different bacterial species in a final concentration of 1 and 10 colony-forming units (CFU) per millilitre. After incubation, the presence of bacteria was investigated by real-time polymerase chain reaction (PCR) and by the Enhanced Bacterial Detection System (eBDS, Pall) assay as a reference method. Real-time PCR amplification was performed with a set of universal primers and probes targeting the 16S rRNA gene. Co-amplification of human mitochondrial DNA served as an internal control. Results Using the real-time PCR method, it was possible to detect the presence of all bacterial species tested with an initial concentration of 10 CFU mL(-1) 24 h after contamination, except for Staphylococcus hominis. The PCR assay also detected, at 24 h, the presence of Serratia marcescens and Enterobacter cloacae with an initial concentration of 1 CFU mL(-1). Conclusions The real-time PCR assay may be a reliable alternative to conventional culture methods in the screening of bacterial contamination of PCs, enabling bacterial detection even with a low initial concentration of microorganisms.