Bacterial Contamination in Stored Blood for Transfusion and Associated Infectious Risks Among Patients with Cancer at Mbarara Regional Referral Hospital, in Uganda

Abstract

Background: Patients with cancer often require supportive transfusion therapy. However, this approach is undermined by the risk of bacterial contamination. This study assessed the bacterial contamination rate, identified the bacterial contaminants and their antimicrobial susceptibility patterns; and the associated infectious risk to patients with cancer at Mbarara Regional Referral Hospital, in southwestern Uganda. Materials and Methods: This prospective cohort study used a pre-transfusion aliquot of donor blood or components for blood culture. Positive cultures were identified and their antibiotic susceptibility testing was performed using the bioMerieux VITEK 2 compact system. Recipients were assessed for bacterial infection at 48 hours’ post-transfusion. Data were analyzed using R software and presented as proportions. Results: We evaluated 376 blood units, with 275 (73.1%) of these being red cell concentrates (RCC). The median storage times for RCC and whole blood (WB) were 23 days (IQR, 18–29 days) and 3 days (IQR, 1–5 days) for platelets (PLT), respectively. Four units (3RCC, 1PLT) had bacterial growth, yielding a contamination rate of 1.1% (95% confidence interval, 0.4–1.8%). Staphylococcus hominis and Bacillus subtlis were isolated from RCC, while Staphylococcus capitis was isolated from PLT. The isolates exhibited variable resistance to erythromycin, clindamycin, teicoplanin, vancomycin, tetracycline, nitrofurantoin, rifampicin, and trimethoprim sulfamethoxazole. There were 211 recipients whose mean age was 34.1 years (standard deviation: 2.84 years). Of these, 62 (29.4%) had received ≥3 donor units, and 146 had been on antibiotics. None of the investigated recipients had a positive bacterial blood culture. Conclusion: The study found a low bacterial contamination rate of stored blood components underscoring the importance of stringent blood collection precautionary measures. The four bacterial isolates were resistant to common antibiotics, which poses a risk of transmission of antibiotic-resistant strains to immunocompromised recipients with cancer. Notably, there was no infectious risk posed post-transfusion presumably due to the concurrent antibiotic therapy.