Bacterial contamination and sepsis associated with transfusion: current status in Latin America

In 2016 and 2017, eighteen Latin American countries transfused 21,808,541 blood components, 55.9% corresponded to red blood cells and 20.1% to platelet concentrates. In the same period, only Brazil reported to the Pan American Health Organization (PAHO) six cases of sepsis due to bacterial contamination (BC; four in 2016 and two in 2017). These data represent a frequency of one case per 3,634,756 transfused blood components. These results contrast with those notified by the haemovigilance reports from North America, Europe, Africa, and Oceania, where transmitted-transfusion bacterial infection (TTBI) frequency range 1:14,515 to 1:384,903 in transfused platelets, and 1:96,850 to 1:3,448,275 in transfused erythrocytes. Today’s frequency of TTBI is higher than viral infections. Although strategies such as diversion of the first aliquot, bacterial detection during storage, and pathogen reduction technologies (PRT) reduce the risk of TTBI, they do not eliminate it. This review aims to establish the strategies implemented to reduce TTBI in Latin American countries and know the number of cases recorded. Likewise, we determined the limitations that prevent TTBI notification. Finally, we estimated the number of events that should be presented based on more experienced haemovigilance programs. TTBI mitigation strategies vary within each country and throughout the Latin American region. There are blood banks that have not yet implemented the diversion 18 ^ ORCID: 0000-0001-9637-8937. Annals of Blood, 2021 Page 2 of 18 © Annals of Blood. All rights reserved. Ann Blood 2021 | http://dx.doi.org/10.21037/aob-20-92 Introduction Blood transfusion is one of the therapeutic strategies employed in clinical practice (1). However, its use carries not only benefits but also potential risks. Transfusiontransmitted infections (TTIs) comprise several biological agents (viruses, parasites, bacteria, fungi, and prions) transmitted during the administration of whole blood or blood components (2). To date, there are more than 68 potentially causative agents of TTI (3,4). However, currently, the spread of viruses transmitted by transfusion has been substantia l ly reduced, so that bacteria l contamination (BC) of blood components is today the most frequent cause of TTI (5). Sepsis associated with red blood cell transfusion has decreased rapidly in the last twenty years, possibly due to the more widespread application of leukoreduction filters (6). Therefore, most cases of posttransfusion sepsis today involve platelet components stored at room temperature. With the introduction of better skin disinfection, first aliquot diversion techniques, and bacterial detection in platelets, the rate of clinically significant septic reactions has decreased but not eliminated. Today it is known that the severity of a septic reaction will depend on various factors related to bacteria (gram-positive or gramnegative, the type of strain) and receptors (comorbidities, immune status, use of antibiotics), as well as the bacterial concentration at the time of transfusion (7,8). Multiple aerobic culture surveillance studies have shown BC frequencies of 1: 1,000 to 1: 3,000 in platelet units (PT) (6). Despite contamination estimates, actual rates of septic adverse transfusion reactions (ADRs) are lower, approximately 1 in 25,000 units of PT (range 1:13,000 to 1:100,000) (6). Underreport of sepsis caused by the transfusion is frequent. Jacobs et al. found that during periods of active culture screening, contaminated platelet components and sepsis were 32.0 and 10.6 times more likely to be documented than during a period based solely on clinical recognition reports (9). Likewise, other authors have shown that the active search for transfusionassociated sepsis could be 35.9 times greater than passive surveillance (10). Hong et al. performed active and passive surveillance for bacterially contaminated platelets between 2007-2013 at the University Hospitals Case Medical Center. The authors showed no reports of the five cases of transfusion-associated sepsis during a seven-year study period. Documentation of these cases was the result of an active surveillance program (8). Between January 2010 and December 2016, the United States of America’s haemovigilance system reported 111 cases of TTI in 7.9 million blood components transfused. Babesia spp was identified in 16 cases in red blood cell units (14.4%), while Staphylococcus aureus was the most frequent microorganism isolated from PT units (10.8%). A TTI rate = 1.95 per 100,000 transfused PT units and a rate of 0.53 TTI per 100,000 units of red blood cells transfused were estimated (5). In 2017, the Food and Drug Administration (FDA) reported five mortality cases related to transfusion, with definite or probable imputability, associated with BC (Staphylococcus epidermidis, Klebsiella pneumoniae, and Clostridium perfringens) (11). To date, the primary sources of transmitted-transfusion bacterial infection (TTBI) are of the first aliquot. In general, no country performs microbiological culture screening of 100% of its collected platelet units. PRT are used only in some private and public blood banks. Between 2018–2020, Brazil reported 29 TTBI (7 definitive, 10 probable, and 12 possible), while Colombia registered four in 2020 (three definitive and one probable). Other Latin American countries have not reported cases. We identified several causes of low notification of adverse transfusion reactions (ADRs), not only those related to TTBI. We estimated that the underreporting of TTBI in Latin American countries ranges from 7 to 29-fold compared to data of robust haemovigilance programs. Importantly, several countries lack national coordination to collect, analyze, and provide feedback to stakeholders. Finally, there is no external audit to guarantee the adoption of standard definitions and processes related to haemovigilance in Latin American countries.