Bacterial surveillance of apheresis platelets in South Africa (January 2011 to December 2016)

Abstract

BackgroundGlobally, bacterial contamination of platelets remains the major transfusion‐related infectious risk. Limited data are available from low‐middle income countries. The South African National Blood Service routinely tests a percentage of apheresis platelets for bacterial contamination. We report on contamination rates from January 2011 to December 2016.MethodsA retrospective analysis of the surveillance data from apheresis platelets was performed. Two to 4 ml of each apheresis product was collected aseptically and divided equally into an aerobic and anaerobic culture bottle using the BacT/ALERT (bioMerieux) or BACTEC™ (Beckton Dickinson) systems. Bacterial identification was done using the MicroScan (Beckman Coulter) system.ResultsA total of 87 841 apheresis platelets were collected between 2011 and 2016 of which 18% were tested. The average positive culture rate was 2·7%, ranging between 0·6% (2011) and 5·22% (2015). Gram‐positive bacteria constituted 94% of all isolates (269/285), ten (4%) gram‐negative bacteria and 6 (2%) fungi were detected. The most common bacterial isolates were Cutibacterium acnes (35%), coagulase‐negative Staphylococci (26%), Bacillus spp. (8%), Corynebacteria spp. (8%). A total of nine highly pathogenic bacteria were isolated: two Acinetobacter spp, one each of Enterobacter spp., Serratia spp., Klebsiella spp., one Staphylococcus aureus and three Listeria spp. Average time to positivity for bacteria was 5·9 days. No cases of sepsis or death were reported during this time.ConclusionBacterial contamination rates, mostly due to gram‐positive bacteria, increased since 2011. Bacterial screening must be aligned with international recommendations, and novel technologies should be explored to reduce the residual risk.