Dr. Sandra Ramirez-Arcos

Dr. Sandra Ramirez

Development Scientist

Canadian Blood Services

Adjunct Professor

University of Ottawa

Degrees:

MSc, Universidad de los Andes, Colombia (1994)
PhD, Universidad Autónoma de Madrid, Spain (1997)

Contact info:

Office: Canadian Blood Services
1800 Alta Vista Drive
Ottawa, ON K1G 4J5
Phone: 613-739-2169

Email: sandra.ramirez@blood.ca

http://www.bloodservices.ca/

Dr. Ramirez personal web page at CBS

Research Interests: 

We have built a strong team with expertise on bloodborne bacteria. Our applied research projects include the development of validation and implementation protocols for bacterial screening of blood components. Our basic research interests are focussed on two main areas:

  1. Detection of bacterial contamination in blood components
  2. Dynamics of bacterial growth and biofilm formation during platelet storage

Contamination of blood products with bacteria poses a major transfusion-associated infectious risk and platelet concentrates (PCs) are the blood product most susceptible to contamination. Several measures, including sensitive screening systems, have been implemented to reduce the risk of transfusing bacterially-contaminated PCs. However, tainted units still escape detection. We have developed a highly-sensitive and specific RT-PCR assay targeting the cell division divIVA gene and the biofilm icaA gene that detects the most common platelet contaminant, Staphylococcus epidermidis.

Studies focused on the role of S. epidermidis as a platelet contaminant revealed that it is able to form surface-attached communities of bacterial cells known as biofilms, under simulated platelet storage conditions. S. epidermidis has the ability to adhere to platelet aggregates and to the plastic surfaces of platelet bags, which might account for reported missed detection with sensitive routine screening methods. Surprisingly, characterization of skin flora isolated from contaminated PCs in Canada revealed that some of these presumably harmless bacteria possess biofilm-associated genes and display slime formation. Studies aimed to decrease bacteria-platelet attachment have revealed that modification of the platelet surface with polyethylene glycol results in significant reduction of biofilm formation by S. epidermidis. More recently, we demonstrated that biofilm formation by S. epidermidis and the Gram negative Serratia liquefaciens is also reduced in PCs suspended in the platelet additive solutions.

Current and future research in the Ramirez lab is focussed on:

  1. Investigation of the link between biofilm formation during platelet storage and missed bacteria detection
  2. Optimization of assays to determine whether red blood cell storage conditions support bacteria biofilm formation and whether this contributes to survival in this environment
  3. Comparison among the different blood product storage containers for the ability to support bacterial adhesion
These investigations will provide a useful framework for developing novel approaches toward improved detection and/or reduction of blood product bacterial contaminants.

Selected Publications:

  • Greco, C., Zhang, J., Kalab, M., Yi, Q-L., Ramirez-Arcos, S., and Gyongyossy-Issa, M. Effect of platelet additive solution on bacterial dynamics and their influence on platelet quality in stored platelet concentrates. Transfusion. Published Online: 10 Jun 2010. DOI 10.1111/j.1537-2995.2010.02726
  • Mastronardi, C., Perkins, H., Derksen, P., denAdmirant, M., and Ramirez-Arcos, S. (2010) Evaluation of the BacT/ALERT® 3D system for the implementation of in-house quality control sterility testing at Canadian Blood Services. Clin Chem Lab Med. 48:1179-87
  • Ramirez-Arcos, S., and Goldman, M. (2010) Skin disinfection methods: prospective evaluation and postimplementation results. Transfusion. 50:59-64
  • Martincic, I., Mastronardi, C., Chung, A., and Ramirez-Arcos, S. (2008) Unexplained agglutination of stored red blood cells in Alsever’s solution caused by the gram-negative bacterium Serratia liquefaciens. Immunohematology. 24:39-44
  • Greco, C., Mastronardi, C., Pagotto, F., Mack, D., Ramirez-Arcos, S. (2008) Assessment of biofilm-forming ability of coagulase-negative staphylococci isolated from contaminated platelet preparations in Canada. Transfusion. 48:969-977
  • Cameron Mastronardi, C., and Ramirez-Arcos, S. (2007) Quantitative PCR for detection and discrimination of the bloodborne pathogen Staphylococcus epidermidis in platelet preparations using divIVA and icaA as target genes. Can J Microbiol. 53:1222-1231
  • Greco, C., Martincic, I., Gusinjac, A., Kalab, M., Yang, A-F, and Ramirez-Arcos, S. (2007) Staphylococcus epidermidis forms biofilms under simulated platelet storage conditions. Transfusion. 47:1143-1153
  • Ramirez-Arcos S., Jenkins, C., Dion, J., Bernier, F., Delage, G., and Goldman, M. (2007) Canadian experience with detection of bacterial contamination in apheresis platelets. Transfusion; 47:421-429
  • Mastronardi, C, Martincic, I, and Ramirez-Arcos, S. (2007) Implementation of a Proficiency Testing Program for Bacterial Screening in Platelet Preparations in Canada. Vox Sanguin. 93-131-138
  • Ramirez-Arcos, S., Chin-Yee, I., Hume, H., Fearon, M., Goldman, M., Eckert, K.,  Martincic, I., Peters, G. and Richardson, S.  (2006) A fatal septic shock case associated with transfusion-transmitted Serratia marcescens. Transfusion. 46:679-681
  • Ramirez-Arcos, S., and Goldman, M. (2005) Evaluation of pool cultures for bacterial detection in whole-blood-derived platelets. Transfusion. 45:1275-1279
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Last updated: 2010.09.22