Microbiological Screening of Bacterial contamination of Platelet Concentrates units: a single center observational study.

Abstract

Background: Bacterial contamination of donated platelets is a major issue in transfusion medicine. Platelet concentrates (PCs) are highly susceptible to bacterial contamination due to their storage conditions at room temperature, which offers a suitable environment for bacterial proliferation. Therefore, the aim of the study is to determine the prevalence of bacterial contamination in the donated platelets units and to identify the isolated microorganisms in samples collected in blood bank services at King Abdullah Medical City (KAMC) in Makkah, Saudi Arabia.

Material and methods: A total of 4,318 PCs units including random and pooled platelets were screened for bacterial contamination in the microbiology laboratory. All PCs units were inoculated into blood bottles and loaded into the BacT/ALERT microbial detection system to screen for any suspected bacterial growth over five days. Positive platelet units were subcultured on nutrient agar and incubated overnight at 37°C. The microbiological identification of contaminated PCs units was then performed using the Microscan WalkAway system.

Results: Six positive bacterial isolates were recovered and isolated from the screened PCs units. Most of the microorganisms isolated from contaminated platelets were coagulase-negative staphylococci (CoNS), including Staphylococcus capitis (50%), Staphylococcus epidermidis (17%), and Corynebacterium species (33%) among the isolates.

Conclusion: Microorganisms isolated from PCs units were mainly skin contaminants related to procedures used during donor phlebotomy or lab processing techniques. However, the rate of bacterial contamination of the donated PCs units subjected to screening was low in this study. The continuous improvement of safety precautions, protocols, and quality assurance of blood collection and storage procedures is essential to reduce the risk of contaminating donated units and any potential post blood transfusion reactions.