17 Feb 2021
Dr. Romney Humphries, Professor of Pathology, Microbiology and Immunology at Vanderbilt University Medical Centre, discusses the effects of COVID-19 on antimicrobial resistance and explains the impact of supply chain shortages in clinical labs. Romney discusses the varying benefits of different forms of COVID-19 testing and explains how they help scientists understand the immune response of the disease.
My name is Romney Humphries, and I am a clinical microbiologist. So what that means is, day-to-day, I direct the activities of the diagnostic clinical lab that performs testing for infectious diseases at Vanderbilt University Medical Center. In addition, I have a small research lab.
And what I'm particularly interested in is antibiotic resistance. My research really falls into two buckets. So the first is really assessing antibiotic resistance, and so understanding the genetic basis for how bacteria become resistant to antibiotics, how that evolves, and developing methods and tasks that clinical labs can use to detect resistant infections in patients that we serve.
The other real bucket is developing new tests for the diagnosis of infectious diseases. So we partner in my lab with a variety of companies to help them develop their tests and get them through the FDA clearance process or other regulatory bodies for other countries, such that those can be used for patient testing.
So one thing that we are particularly interested in is understanding how the COVID-19 pandemic has impacted microbial resistance ratings. And the reality is we don't fully understand that yet. There's a lot of things that suggest that maybe it could go down. There are also some things that suggest that resistance rates might go up. The last thing I would say that is concerning with COVID-19 is the supply chain for clinical labs and testing.
This is something that maybe on the surface, isn't obvious, but it can impact antibiotic resistance because clinical labs don't always have the test supplies or tools readily available to them to do testing to determine if a patient who does have an infection has been caused by an antibiotic-resistant bacteria or by one that's pretty susceptible or sensitive to antibiotics.
One of the good news stories out of COVID-19 is, if you look at other viral pandemics, people often would develop a viral infection first, for example, with flu in 1918. But what really caused a lot of mortality was the secondary bacterial infection they had then acquired. So essentially, the influenza virus roughed up the lungs and provided an environment that allowed bacterial infections an easy entry to the body.
And so a lot of patients developed these bacterial infections. In contrast with COVID-19, this is really not something that we're seeing, which is good news, because it really helps us manage these patients. You're really focused in on the COVID-19, the viral part of the infection, and don't have to worry about secondary bacterial infections to the same extent as we did with other viruses.
When we look at the different array of tests for COVID-19, they fall into a couple of different buckets. So we have tests that detect the actual virus and so these might be antigen tests. They might also be molecular or PCR-based tests. And then we also have tests that look at the human response to the virus, so your antibodies that you may have generated.
So antibody tests are not good tests to tell if you actively have an infection or an acute event. But they can help us understand who's been exposed to the virus. And so this is useful clinically, for example, if we have a patient who has developed some syndromes that are associated with COVID-19.
The other places that it may be of value is to understand vaccine conversion rates for patients, as well as helping us to triage who may need to be vaccinated as a higher priority, i.e. those that don't have any existing antibodies and those that don't. As we entered the pandemic with COVID-19.
you know, you would hear clinicians talk about antibiotic stewardship with the secondary consideration to just managing patients with COVID-19, and I think that's very true. As we've learned more on how to treat patients with COVID-19 and we've better understood their risks for developing secondary infection caused by bacteria, I think that antibiotic stewardship has really come back into play.
And so we are seeing antibiotic stewardship programs continue their activities and their efforts to really make sure that patients are treated appropriately with antibiotics in the hospital. I'm really hopeful that the work we do in my research lab and in the clinical lab can help push microbiology testing, sort of, into the next phase. Currently, we wait for bacteria to grow on plates.
We subject them to tests. And it's a pretty lengthy process. Typically between the time you have the patient sample collected and the results are finalized, it's between three to five days. And so my goal is really, or dream, I suppose I should say, is that we can speed this process up and provide, you know, as near to the point of care or as near to that patient result as possible.
Vanderbilt University Medical Centre
Dr. Romney Humphries received her Ph.D. in medical microbiology and bacteriology from The University of Calgary. Since then, Romney has become a Professor of Pathology, Microbiology and Immunology at Vanderbilt University Medical Centre, where her particular focus is on rapidly identifying antimicrobial resistance bacteria in a clinical setting.