Deanna Buehrle, PharmD: Bloodstream Infections in Solid Organ Transplant Recipients

Segment Description: Deanna Buehrle, PharmD, infectious diseases clinical pharmacist in the Department of Medicine, at VA Pittsburgh Healthcare System, discusses her study on bloodstream infections in solid organ transplant recipients.

Interview transcript (modified slightly for readability):

Contagion®: Can you describe your study on bloodstream infections and patients who received a solid organ transplant?

We studied over 3000 patients who received a solid organ transplant at our institution over the last 9 years. We were particularly interested in transplant recipients who had a bloodstream infection after their transplant. And about 500 patients had at least 1 episode of bloodstream infection after their transplant. We saw that liver transplant recipients and pancreas transplant recipients were at increased risk as compared to other transplanted organs for bloodstream infections within 30 days of transplant. So those 2 specifically, liver and pancreas transplants, were at the highest risk to develop bloodstream infection within 30 days.

As far as organisms that caused infection in the early period, which is within 30 days of transplant, we saw that gram-negatives, or Enterobacteriaceae were the most common. And then in the intermediate and late post-transplant times, which is 2-6 months or more greater than 6 months post-transplant, and Enterococcus and other gram positives became more common.

As far as the breakdown, the bacteria that were causing bloodstream infections differed greatly by organ transplanted as you would expect. And, we're going to use that so that we can make antibiograms and know what specific organisms affect which specific organ transplant.

And then we also have antimicrobial susceptibility of bloodstream infections and we saw that our rates of MRSA are decreasing, as are our rates of carbapenem-resistant Enterobacteriaceae over that 9-year period.

But our rates of VRE, and drug-resistant Pseudomonas are staying pretty stagnant. And then lastly, we looked at mortality, and as you would expect, patients with at least 1 episode of bloodstream infection post-transplant, were at higher risk for mortality than those who never had an episode of bloodstream infection.

Contagion®: Why is this patient population particularly susceptible to these infections?

Solid organ transplant patients are a particularly vulnerable population. Some things that make them vulnerable to infection are the fact that they just had recent surgeries, and these are usually major surgeries that include transplanted organs. They also can have indwelling lines and other indwelling devices which put them at risk for infection. And then they're also on immunosuppressive medications which put them at risk for infection as well.

Contagion®: How can clinicians work to cut mortality associated with these bloodstream infections in solid organ transplant patients?

Clinicians should have a high index of suspicion for infection in solid organ transplant patients because they may not have the same signs or symptoms as non-organ transplant patients. And it's very important to use early active and microbial therapy in this population as that has been shown to improve outcomes. A multidisciplinary team that includes infectious diseases providers, infectious diseases, pharmacists and microbiology can help to tailor appropriate empirical antibiotic therapy depending on institutions specific antibiograms.

Contagion®: Why was this an interesting avenue of research for you?

I was very interested in looking at antimicrobial susceptibility patterns over time at our institution. Particularly in transplant patients, there's not a ton of literature describing antimicrobial susceptibility over time so that's why I chose to look at this population. We also do quite a large number of transplants, so we had a lot of patients to look through. The hope of this project is to figure out what are the antimicrobial susceptibility patterns are, which type of organisms affect transplant patients, and hopefully devise organ-specific antibiograms so that we know how to do direct antimicrobial therapy.

The abstract, Nine-year Survey of Bloodstream Infections (BSIs) across Six Types of Solid Organ Transplant (SOT) at a Large University Medical Center, was presented in a poster session on Thursday, October 3, 2019, at IDWeek 2019 in Washington DC.