Dr. Sandra Ramirez-Arcos

Biography

Research Interests

We have built a strong team with expertise on bloodborne bacteria. Our research interests are focused on two main areas:

Reducing Bacterial Contamination in Blood Components: Our team regularly tests the methods used for routine screening of blood and stem cell components for contamination at Canadian Blood Services and works with industry partners to evaluate new technologies for the detection of bacterial contamination. Our group is involved in investigations of adverse reactions due to transfusion of contaminated blood components. We have developed and patented a rapid, highly sensitive and specific assay to discriminate Staphylococcus epidermidis from other staphylococcal species in platelet concentrates, an important advance as this blood product is at particular risk of being contaminated with S. epidermidis, a skin contaminant. We are also participating in a World Health Organization-endorsed international study to develop a panel of bacterial strains suitable for validation and comparison assessments.

Our current research is focused on:

1. Develop a method to detect bacteria in cord blood units that contain antibiotics.
2. Assess bacterial survival during buffy coat platelet production and storage.
3. Evaluate the effectiveness of pathogen reduction technologies on biofilm-forming bacteria.

Dynamics of Bacterial Growth and Biofilm Formation in Blood Products: We have developed extensive expertise around bacteria forming surface-attached aggregates known as biofilms. The formation of such biofilms is associated with increased pathogenicity and might explain instances of missed bacterial detection in blood components. Our team screened skin flora bacteria isolated from contaminated platelet concentrates in Canada for their biofilm-forming ability and surprisingly found that some of these presumable harmless bacteria display a virulent phenotype. Importantly, we have recently shown that these biofilm‐forming skin microflora bacteria are resistant to the bactericidal action of disinfectants used during blood donation. Our group has also shown that anaerobic bacteria cannot replicate during platelet storage, but can survive in the presence of oxygen, likely as a result of the formation of biofilms. Investigation of preventive measures to control biofilm formation in platelet concentrates has resulted in the development of a patent showing that polyethylene glycol-modification of the platelet surface results in significant reduction of bacterialbiofilm formation.

Our current research is focused on:

1. Determine the contribution of the platelet storage environment and plastic material of platelet containers to bacterial biofilm formation.
2. Assess biofilm resistance to synthetic and platelet-derived antimicrobial peptides and natural oils.
3. Conduct comparative studies of the expression, at the mRNA level, of S. epidermidis genes when grown in media and PCs.

Selected Publications

• Kou Y, Pagotto F, Hannach B, Ramirez-Arcos S. (2015) Fatal false-negative transfusion infection involving a buffy coat platelet pool contaminated with biofilm-positive Staphylococcus epidermidis: a case report. Transfusion. 55:2384-9.
• Ramirez-Arcos S, Alport T, Goldman M. (2015) Intermittent bacteremia detected in an asymptomatic apheresis platelet donor with repeat positive culture for Escherichia coli: a case report.Transfusion. 2015; 55:2606-8.
• Ramirez-Arcos S, Kou Y, Yang L, Perkins H, Taha M, Halpenny M, Elmoazzen H. (2015)Validation of sterility testing of cord blood: Challenges and results. Transfusion. 55:1985-92.
• Ramirez-Arcos S, Kou Y, Perkins H. (2014) Evaluation of a universal point-of-issue assay for bacterial detection in buffy coat platelet components. Vox Sang.;107:192-195.
• Ali H, Greco-Stewart VS, Jacobs MR, Yomtovian RA, Rood IG, de Korte D, Ramírez-Arcos SM (2014) Characterization of the growth dynamics and biofilm formation of Staphylococcus epidermidis strains isolated from contaminated platelet units. J Med Microbiol;63(Pt 6):884-89.
• Taha M, Kalab M, Yi Q, Landry C, Greco‐Stewart V, Brassinga AK, Sifri CD, Ramirez‐Arcos S (2014) Biofilm‐forming skin microflora bacteria are resistant to the bactericidal action of disinfectants used during blood donation. Transfusion  54:2974-2982.
• Kumaran D, Kalab M, Rood IG, de Korte D, Ramirez-Arcos S (2014)Adhesion of anaerobic bacteria to platelet containers Vox Sang 107(2):188-91.
• Ali H, Greco-Stewart VS, Jacobs MR, Yomtovian RA, Rood IGH, de Korte D, Ramírez-Arcos SM (2014) Characterization of the growth dynamics and biofilm formation of Staphylococcus epidermidis strains isolated from contaminated platelet units. J Med Microbiol; 63:884-891
• Hodgson SD, Greco-Stewart V, Jimenez CS, Sifri CD, Brassinga AKC, Ramirez-Arcos S (2014) Enhanced pathogenicity of biofilm-negative Staphylococcus epidermidis isolated from platelet preparations. Transfusion 54:461-70.
• Ramirez-Arcos S, Perkins H, Kou Y, Mastronardi C, Kumaran D, Taha M, Yi Q, McLaughlin N, Kahwash E, Lin Y, Acker J (2013) Bacterial growth in red blood cell units exposed to uncontrolled temperatures: challenging the 30-minute rule. Vox Sang 105:100-107 (Highlighted in the American Blood Centers Newsletter in February 2013; Received Vox Sanguinis Best Paper Prize2013).