Streptococcus bovis septic shock due to contaminated transfused platelets

INVESTIGATION OF BIOFILM FORMATION IN COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM PLATELET CONCENTRATE BAGS

Platelet Concentrates (PCs) are the blood components with the highest rate of bacterial contamination, and coagulase-negative staphylococci (CoNS) are the most frequently isolated contaminants. This study investigated the biofilm formation of 16 contaminated units out of 691 PCs tested by phenotypic and genotypic methods. Adhesion in Borosilicate Tube (ABT) and Congo Red Agar (CRA) tests were used to assess the presence of biofilm. The presence of icaADC genes was assessed by means of the Polymerase Chain Reaction (PCR) technique. With Vitek(r)2, Staphylococcus haemolyticus was considered the most prevalent CoNS (31.25%). The CRA characterized 43.8% as probable biofilm producers, and for the ABT test, 37.5%. The icaADC genes were identified in seven samples by the PCR. The ABT technique showed 85.7% sensitivity and 100% specificity when compared to the reference method (PCR), and presented strong agreement (k = 0.8). This study shows that species identified as PCs contaminants are considered inhabitants of the normal skin flora and they might become important pathogens. The results also lead to the recommendation of ABT use in laboratory routine for detecting biofilm in CoNS contaminants of PCs.

[Bacterial contamination on platelet concentrates: identification, antimicrobial susceptibility profile and transfusion-related sepsis]

INTRODUCTION

Bacterial sepsis associated with the transfusion of platelet concentrates (PCs) results in serious clinical implications for patients. Given these implications, certain procedures have been integrated into the preparation and quality control of blood components to reduce the risk of bacterial contamination. This article describes the prevalence of bacterial contamination on transfused PCs, the bacterial spectrum detected and their antimicrobial susceptibility profile and transfusion reactions in receptors.

METHODS

A total of 292 PCs (278 random and 14 per apheresis) from the Blood Center of the State of Rio Grande do Sul (HEMORGS), located in the city of Santa Maria, were tested. Quantities of 100 μL and 200 μL were collected from platelet bag tubing and seeded using two methodologies.

RESULTS

Using the qualitative methodology, bacteria were isolated in five units (1.7%; 5/292), while only one was isolated using the quantitative methodology. Staphylococcus epidermidis was the microorganism identified in all samples. Two patients died of transfusion-related sepsis.

CONCLUSIONS

Bacterial contamination due to PC transfusion is considered a major public health problem due to its association with high rates of morbidity and mortality. In this study only gram-positive microorganisms were isolated and none of the samples obtained by apheresis presented contamination.

Influence of harvest bacterial contamination on autologous peripheral blood progenitor cells post-transplant

Microbiological contamination of manipulated blood products, including hematopoietic progenitors obtained from peripheral blood, is an infrequent but persistent problem in transplant units. The relevance of such contamination in causing patient infection has been reported as insignificant, but the effect on the post-transplant course has not been well documented. We studied the incidence of bacterial contamination in autologous peripheral blood progenitor cell transplants in two of the bench processing steps, as well as the repercussions in the post-transplant course affecting incidence of infections, transfusion requirements and time to engraftment. A total of 365 aphereses performed on 152 patients were cryopreserved in 617 bags. In 31 of these bags (5.0%), bacterial cultures were positive for Coagulase-negative Staphylococcus (31.1%), S. epidermidis (21.9%), Corynebacterium sp. (6.3%), S. warneri (6.3%), Stenotrophomonas maltophilia (6.3%), Streptococcus sp. (9.4%), Viridans group Streptococcus (3.1%) and more than one bacteria (Coagulase-negative Staphylococcus plus Corynebacterium) (15.6%). Half of the bags were contaminated at the time of freezing and the others at the time of thawing. The 31 contaminated bags were infused into 17 patients. In five of these the same contaminating bacteria was found. No difference between the two groups of patients (contaminated and non-contaminated) was found on the day the fever started, length of fever, blood transfusion requirements and engraftment, but length of hospitalization was significantly greater in patients receiving contaminated transplants.