The Silent Role of Biofilms in Chronic Disease › Forums › Biofilm Community › Expert Interviews › Dr. Garth Ehrlich – Microbiologist, Geneticist (Video & Interview Excerpt Available) › Reply To: Dr. Garth Ehrlich – Microbiologist, Geneticist (Video & Interview Excerpt Available)
Excerpts from our on-camera interview are below. Minor edits were made for brevity and clarity.
Arthroplasty Patient Foundation: Please tell us a bit about yourself any major developments here.
Dr. Garth Ehrlich: I serve as the Executive Director for the Center for Genomic Sciences and our primary mission is to understand how bacteria cause disease, specifically, how bacteria cause chronic disease. Weve been doing this type of research for nearly 20 years. We started at the University of Pittsburgh in 1990, and then moved to the Allegheny-Singer Research Institute in 1997.
I think that the major epiphanies, if you will, metanoic moments, that weve had scientifically was the recognition that chronic bacterial infections are usually caused by biofilms and one of the things that occurs during biofilm infections is continual gene rearrangements.
Arthroplasty Patient Foundation: Can you differentiate between an acute and chronic bacterial infection?
Dr. Garth Ehrlich: Acute bacterial infections and chronic bacterial infections are very different. Acute bacterial infections are caused by planktonic bacteria, that is, bacteria that are swimming freely, each bacteria is essentially a single-celled organism. Chronic infections, for the most part, are caused by bacterial biofilms, and a bacterial biofilm is, in essence, a multicellular organism, so that each individual bacterium within the biofilm is analogous to each individual cell in your body. And so they are actually functioning as a single, single organism, and its the adoption of the biofilm mode of growth that provides for, what we say, chronicity, or persistence.
And, so, when you get an acute infection anywhere in your body when you have a medical device implanted, there is a finite risk that some of those planktonic bacteria that are associated with acute infection will land on the implanted medical device. And, if they do, they can form a biofilm on that device, uh and then you end up with a chronic infection resulting from that. You can think of bacteria as having a life cycle, because, once the bacteria are on the device as a biofilm, theres always a certain percentage of the biofilm bacteria that are shed as planktonic bacteria, and we call these showers.
And so, when a shower of planktonic bacteria occurs, then that can cause an acute exacerbation. So you go from chronic to acute, chronic to acute. Now the acute, you can treat with antibiotics, so you can treat somebody, and youll stop the acute infection, but you wont get rid of the nidus, the mother biofilm, which keeps spewing them out over time. And so, thats why, if you hear about somebody who has something like a central line or something like that (e.g. a catheter) in their vein, and they become episodically febrile, (they have a fever) that means theyve had a planktonic shower. You treat the planktonic shower with antibiotics then it kills the planktonic bacteria, but the mother biofilm stays intact. So theyre no longer acutely ill, but they still have that chronic infection and that chronic infection will produce subsequent showers again. So the only way to actually stop that showering is to take that device out, pull the catheter out and start over again.
Arthroplasty Patient Foundation: Can you elaborate on this a bit more the bacterial infections process?
Dr. Garth Ehrlich: There are two different ways, basically, that a medical device inside someones body can become infected. The first way is actually associated with the procedure that put the device in, so that there was a break in sterility. Generally, we try to do surgery under sterile conditions, but its not perfect. And, so, at some low percentage, bacteria will be introduced into the wound site at the time of infection and these are called acute infections because it happens with the surgery. The second type is one where the infection occurs much, much later. It can occur years later, when somebody has what we call septic or bacteremic effect, where, for some reason theres bacteria in the bloodstream. So, perhaps you had a dental procedure or something like that; if you disrupt the biofilm bacteria you know, that are associated with gum disease, and its very easy for them to get into the blood. So, essentially you have a planktonic shower and then those planktonic bacteria if some of them land on the plates in somebodys spine or their artificial joint in their in their leg, then they can become infected. They can have their implant infected years after it was put in.
And those late-occurring infections are by no means are a result in a loss in sterility during the surgical process. So, basically, if somebody you know is out more than six months from the time of surgery before they have any symptoms, then its a fairly good guess that the infection occurred post-surgically, as opposed to intra-operatively.
Arthroplasty Patient Foundation: Are there any other things you wanted to mention that you feel as though patients should learn from you or from the Institute?
Dr. Garth Ehrlich: One of the things that I would recommend to any patient who is going to have any sort of procedure done, if they already have an implantable device anywhere in their body, is that, before the procedure is done, is that they prophylactically take antibiotics to prevent a planktonic shower to prevent what we call bacteremia — which is simply bacteria in the blood. .
So, whereas I dont think people should overdose with the antibiotics, if youre going to have a procedure and you already have some sort of prosthetic device, then I think its very wise to be treated prophylactically with antibiotics you have that procedure. Thats one thing you could really do to cut down the risk of developing a chronic biofilm infection. The other thing that Id like patients to know is that there is now a community of scientists which recognize that chronic infections are associated with biofilms.
And biofilms act profoundly differently than planktonic bacteria and it is only a matter of time before we do have effective therapies for biofilms. The analogy I would use is, when people first really understood the bacterial nature of disease in the middle of the 19th century, some of the work that was done by Louis Pasteur, Robert Koch and Paul Ehrlich. It took decades from the discovery of planktonic bacteria, really, to the development of the first antibiotics and nearly a century before the antibiotics became widely available in usage. So its only been within the past.