A near fatal septic transfusion reaction due to Streptococcus dysgalactiae subspecies equisimilis calls for novel safety measures

Two cases of Streptococcus dysgalactiae subspecies equisimilis infection transmitted through transfusion of platelet concentrate derived from separate blood donations by the same donor

BACKGROUND

Transfusion-transmitted bacterial infections (TTBIs) in Japan have been largely prevented due to a short shelf life of 3.5 days after blood collection for platelet concentrate (PC) and washed PCs (WPCs; PC in which 95% plasma is replaced by platelet additive solution).

CASE PRESENTATION

Case 1: In January 2018, a woman in her 50s with aplastic anaemia who received WPC transfusion and developed a fever the next day and Streptococcus dysgalactiae subspecies equisimilis (SDSE) was detected in the residual WPC. Case 2: In May 2018, a man in his 60s with a haematologic malignancy who received PC transfusion and developed chills during the transfusion. SDSE was detected in the patient's blood and residual PC. The contaminated platelet products were both manufactured from blood donated by the same donor. The multi-locus sequencing typing revealed that SDSE detected in case 1 was identical to that from case 2; however, whole blood subsequently obtained from the donor was culture negative.

CONCLUSION

WPC and PC produced from two blood donated 106 days apart by the same donor were contaminated with SDSE of the same strain and both caused TTBIs. Safety measures should be considered regarding blood collection from a donor with a history of bacterial contamination.

Infections in myelodysplastic syndromes

Myelodysplastic syndromes are associated with a risk of severe infections. While neutropenia is likely to be the main predisposing factor, several other immune defects have been reported, including impaired neutrophil function, B-, T- and NK-cell defects and the possible consequences of iron overload due to red blood cell transfusions. The advanced age of most patients, their frequent comorbidities, and the fact that drugs such as hypomethylating agents and lenalidomide, which are effective in myelodysplastic syndromes but can transiently worsen neutropenia, may increase the risk of infection and their severity in this context. The majority of infections in myelodysplastic syndromes are bacterial, while the incidence of fungal infections is not well known and viral infections seem to be rare. No prophylactic measures against infections have demonstrated efficacy in myelodysplastic syndromes. However, pending more data, we propose here some recommendations for the management of patients with myelodysplastic syndromes. In the future, an important contribution can be made by prospective trials testing the efficacy of prophylactic and therapeutic approaches to infection in these patients, especially in the context of the new drugs available for myelodysplastic syndromes.

[Acknowledged risks in transfusion and impact of taken measures on those risks]

Sur la base évidente, d’une part, de l’existence de risques (de différentes natures) en transfusion sanguine et, d’autre part, de l’attente d’une transfusion sans « vice » ni risque, trois niveaux de sécurisation ont pu être proposés ces dernières années : une politique d’analyse de risques généralisée ; des procédures de maîtrise des risques ; une politique généralisée de qualité. Ces constructions sécuritaires ont néanmoins des impacts multidirectionnels, sur les organisations, les coûts et l’économie en général, la disponibilité des produits, et – in fine – possiblement sur l’éthique. Ce sont ces points qui sont analysés dans le présent essai, ainsi que la place éventuelle dans ces dispositifs des procédés d’inactivation/réduction de pathogènes.

Invasive infection caused by Streptococcus dysgalactiae subsp. equisimilis: characteristics of strains and clinical features

Among clinically isolated β-hemolytic streptococci, Streptococcus pyogenes and S. agalactiae were considered the main pathogens in humans until recently. In 1996, S. dysgalactiae subsp. equisimilis (SDSE) was proposed as a novel taxon among human-derived streptococcal isolates. SDSE has Lancefield group C or G antigens, exhibits strong β-hemolysis, and exerts streptokinase activity upon human plasminogen and proteolytic activity upon human fibrin. Similarly to group A streptococci, SDSE possesses virulence factors including M protein, streptolysin O, streptolysin S, streptokinase, hyaluronidase, C5a peptidase, and others. SDSE may exist among the normal flora of the skin, oropharynx, and gastrointestinal and genitourinary tracts. In the twenty-first century, invasive SDSE infection (i.e., cellulitis, urosepsis, and pneumonia) leading to various disseminated diseases is being diagnosed increasingly in Japan, elsewhere in Asia, in Europe, and in America. Particularly, among elderly patients, these invasive diseases are encountered increasingly in Japanese hospital emergency departments. Analysis of the part of the emm gene encoding the amino acid sequence at the N-terminal end of the M protein is used to determine the molecular epidemiology of SDSE. The distribution of emm types from patients with invasive or noninvasive infections differs between surveillance results from different countries. In this review, we summarize the characteristics of phenotypes and virulence factors in SDSE strains; the review also focuses on emerging SDSE infectious disease and future vaccination research.