<i>Pseudomonas</i> Infections: Nuancing the Use of Antibiotics

Marin Hristos Kollef, MD: I’m always worried and nervous when people use the term “culturing” a lot because that often drives antibiotic use. If it’s culturing in response to a syndrome that looks like an infection, I’m all for it. The other comment I’d make, and I use this analogy all the time with the residents on rounds, is that the ICU is basically like a funnel. We’ve got, at the bottom of the funnel, the intensive care unit, and it’s a collecting bin for resistance genes. At the top, we’ve got long-term care, nursing homes, the floor, and other hospitals, especially in a system like ours. And so, all those resistance genes make their way into the intensive care unit.

Interestingly, one of the things we haven’t brought up yet is this issue of health care-associated infections that are community acquired. All that means is that those are infections that occur outside of the hospital that come in, but they’re still due to antibiotic-resistant pathogens.

Peter L. Salgo, MD: Because they got the antibiotics somewhere else.

Andrew Shorr, MD: Correct.

Marin Hristos Kollef, MD: Or they had contact with the health care system. They were back out there, and then they came back. And that makes up a large significant pool, even more so in the pneumonia patients that we see than ventilator-associated pneumonia. Those are now hospital-acquired pneumonias and health care-associated pneumonias in our intensive care units.

Peter L. Salgo, MD: We go back to something that I heard when I was a medical student. This is not new. Patients demand antibiotics from their primary care physicians. “I’ve got a cold, I’ve got an earache, I stubbed my toe. Can’t you give me a tertiary antibiotic of some sort?” The doctor says, “Sure, here’s a script,” and the next thing you know, send us your tired, your poor, your pseudomonas.

Andrew Shorr, MD: I think it’s a little more nuanced than that. I think the point about antibiotic abuse in the community has a lot to do with resistance to traditionally utilized community-focused antimicrobials, like levofloxacin or what have you. I think what Marin is really alluding to, and what he’s published extensively on, are these patients who are in the iron triangle of health care. They go from the hospital ICU to the floor, to the LTAC (long-term acute care), and then back, and while they’re at the LTAC, someone is treating them with antibiotics because they can do something.

There’s this cognitive bias that doing is better than watching in medicine, which is actually clearly harmful. What happens is that this person is never actually in the community, and so they’re continuing to be exposed to health care. They’re probably in an environment where there’s poor infection control, they’re getting antibiotics, and when they get sick, they show up to the emergency room and the original prescribers in the emergency room are saying, “Oh, well they came from the community, so it must be pneumococcus.” They’re missing the fact that this patient has actually never been in the community.

Peter L. Salgo, MD: This goes to your point. You’re worried that people culture for the sake of culturing. But if they were to culture in the LTAC and treat specifically with some laser-focused antibiotic, that might be better.

Marin Hristos Kollef, MD: I think it would be better if clinicians were focused on treating infections. But too often, the patient has a mild temperature spike and the trigger reaction is just to go right to the antibiotics as opposed to really thinking it through and maybe just watching that patient for a period of time.

Peter L. Salgo, MD: Oh, that’s hard to do though.

Yoav Golan, MD: Just to connect the adequate use of antibiotics or not using antibiotics when not needed to the culture question. First of all, I think it’s really important to differentiate surveillance cultures. You really want to know what the patient carries for when the patient gets sick, and we don’t do a lot of that. I think they do much more of that in Europe and so forth. I think we have to talk about, how do you know what kind of bacteria is causing this severe infection? How do you use the right antibiotics? I think that we’re going to be using more surveillance cultures, because we find that these are helpful.

I think it’s also important to understand that people have to, not for surveillance’s sake, diagnose an infection for guidance and management. People have to make sure that patients qualify for an infection from a clinical perspective first. In the ICU, we see a lot of patients who are suspected of having pneumonia, for example, who don’t really meet the clinical criteria of actually having pneumonia. And so, any culture that will drive treatment may be driving the unnecessary use of antibiotics. Those patients are at high risk for infections, so a future infection where they actually do need the antibiotic may be harder to treat.