# Bacterial contaminants in stored blood and blood products at Zomba Central Hospital Blood Bank: assessing the possible risk of post-transfusion sepsis in a resource-limited setting

## TL;DR

This study found that nearly 18% of stored blood products at a hospital in a resource-limited setting were contaminated with bacteria, posing a risk of post-transfusion sepsis.

## Contribution

The study provides new data on bacterial contamination rates and types in stored blood products in a resource-limited setting.

## Key findings

- 18.3% of blood products were contaminated with gram-positive bacteria.
- Most contaminated products had exceeded two weeks of storage.
- Bacillus spp and Listeria spp were the most common contaminants.

## Abstract

National Blood Transfusion Services have done a commendable job in reducing transfusion-related fatalities from viruses, syphilis, and malaria through the vigilant screening of blood donors and donated blood. Bacterial contamination of blood products remains the commonest cause of transfusion-associated fatalities, but it remains unaddressed in resource-limited countries. Up-to-date knowledge of the prevalence and causes of bacterial contamination of blood products is necessary to ensure safe blood transfusion. This study investigated the rate and spectrum of bacterial contaminants in stored blood products at the Zomba Central Hospital from October to November 2022.

in this cross-sectional study, a total of 115 blood products (whole blood, packed red blood cells, and platelets) were randomly and aseptically collected into Tryptic Soy Broth and then incubated for 7 days. After overnight incubation, all samples were subcultured onto BA, CA, and MAC. Colony morphology, gram staining, and biochemical tests were used for identification. Descriptive, correlation, and regression statistics were used, and results with p ≤ 0.05 were considered significant.

out of the 115 samples, 21 (18.3%, CI: 11.7%-26.6%) were contaminated with various gram-positive bacteria. The contaminants were Bacillus spp (33.33%), Listeria spp (33.33%), coagulase-negative Staphylococcus (19.05%), S. aureus (9.52%), and Enterococcus sp (4.76%). 90.5% of all the contaminated products had exceeded 2 storage weeks.

bacterial contamination of stored blood products is common at the study site presenting a significant risk of post-transfusion sepsis to the recipients. This study emphasizes the need to implement hemovigilance projects aimed at reducing bacterially contaminated blood products.