Bacterial contamination of platelets concentrates in a lower middle-income country: Data from a single tertiary care hospital

Background

Transfusion of bacterially contaminated platelets may cause life threatening sepsis in the recipients. Cost of platelet screening is a major challenge for low middle income countries (LMICs). In this study, we evaluated the frequency of bacterial contamination in the platelet units (PUs) and the outcome of transfusing such platelets to the patients in a single institute at Pakistan.

Material and methods

During 2018–2022, whole blood-derived (WB-PU) and apheresis platelets (AP) were screened by BacT-ALERT® automated system. Single sample from each AP and samples from ≤ 5 WB-PUs were pooled and cultured within 24 h-post collection. An initial positive signal was followed by re-culture, Gram’s staining, pool resolution and bacterial identification. Results were interpreted as ‘confirmed positive’ or ‘indeterminate’ and ‘confirmed negative’ based on differences in initial-reactive and final results.

Results

A total of 84246 PUs (476 AP and 83770 WB-PU) was screened, and 239 (0.28 %) culture bottles were positive on day one. Individual cultures were performed on 1378 PUs (239 bottles) for pool resolution. Seven of 1378 (0.5 %) PUs were ‘confirmed positive’ while 1371 (99.4 %) were ‘indeterminate’. No bacterial growth was observed in 82868 (82392 WB-PU and 476 AP) of 84246 (98.3 %). Overall bacterial contamination rate was low at 1 in 12000 PUs approximately. Seven patients were transfused with contaminated PUs but no transfusion reaction was observed.

Conclusion

An insignificant risk of bacterial contamination was observed in this study but remains a concern for patient safety. LMICs need cost effective but efficient techniques to screen platelets for the presence of bacteria.