Q&A: Dr. Samira Mubareka

Samira Mubareka

Dr. Samira Mubareka is a clinician-scientist investigating microbiology and infectious diseases.

This article originally appeared in the 2010 issue of Sunnybrook Research Institute Magazine.

Dr. Samira Mubareka is a scientist at Sunnybrook Research Institute in the Veterans & Community Research Program, and a microbiologist and infectious diseases consultant at Sunnybrook Health Sciences Centre. She is also an assistant professor at the University of Toronto. She spoke with Dilys Chan about her research.

What’s the connection among Staphylococcus aureus, bacterial pneumonia and influenza?

In recent years, about 30% of cases of severe influenza have been associated with bacterial pneumonia, which in the past was associated with Streptococcus pneumoniae and Haemophilus influenzae. Since the 1950s, we’ve seen more bacterial pneumonia that is due to Staphylococcus aureus. We don’t know why this is—it may be due to vaccination programs for Streptococcus pneumoniae and Haemophilus influenzae; or the emergence of MRSA [methicillin-resistant Staphylococcus aureus], which wasn’t present decades ago.

Our research question is: ‘Are people colonized with Staphylococcus aureus more likely to transmit influenza than people who are not?’ If we find this is true, then we could reduce transmission of influenza in patients who are colonized with Staphylococcus aureus. The potential secondary outcome would be the reduction of bacterial pneumonia after influenza virus infections.

What do researchers know about influenza compared to 10 years ago?

There has been an amazing amount of new information, thanks to a reverse genetic system. Essentially, you can clone the virus and look at how each segment contributes to viral pathogenesis. We know more about how viruses evade the immune system.

The generation of the 1918 virus has given us insight into virulence factors, mechanisms of disease, and how they differ from one strain to another. We also have a better understanding of modes of transmission. We’re also gaining an appreciation for different strains of influenza in animals—characteristics of swine or avian influenza virus—and how those can reassort (mix genetic material into new combinations) with human influenza viruses. In addition, with sequencing and surveillance now available globally, we’re getting a better sense of which parts of the virus have evolved.

What’s been your most interesting finding?

During my fellowship, we looked at aerobiology of viruses and noted that some strains transmit better than others. The more transmissible a virus, the more likely we were to recover it from the air. This an area I intend to pursue as a research project.

How do you measure the transmission in the air?

We use a liquid impactor, which is a pump that sucks air into a sampler. Then you can culture a virus from that sampler. There are also dry impactors, where you can do polymerase chain reaction assays on sampled air and look for viral RNA [ribonucleic acid, the influenza virus genetic material].

How do your research projects relate to your clinical work?

It’s important to me that our work has clinical impact. I think the more clinical work I do, the more our research will be based on clinical questions. It’s nice to go from the bedside to the bench, and ultimately back to the bedside with a solution. That’s thinking long-term, because it happens over years and years of research. Ultimately, we want to be able to say, ‘These are the differences that we’ve made.’

In addition, understanding the biology of the virus for the sake of advancing our knowledge of the natural world is also important. There are direct and indirect benefits to this, including gaining insight into how other RNA viruses are transmitted, and what the molecular and environmental determinants for transmission are. Understanding the interactions among host, pathogen and environment will allow us to develop approaches to stop transmission and disease.

Sunnybrook Research Institute provided start-up funding for Mubareka’s research. She also received a grant from the Canadian Institutes of Health Research.