<i>Pseudomonas</i> Infections in the ICU Versus on the Floor

Peter L. Salgo, MD: When you take a look at pseudomonas infections, as you pointed out, they’re everywhere. They’re in the hospital. Some patients come to your ICU with pseudomonas. How common are they, all-comers into the ICU versus those developing pseudomonads in situ in the ICU de novo? That’s a lot of Latin.

Marin Hristos Kollef, MD: I think it depends on the infection that you’re looking at. At least within our ICUs, pneumonia is quite common when we’re talking about pseudomonas. On the other hand, when you look at all our urinary tract infections in the intensive care unit, Enterobacteriaceae probably would make up the vast majority.

Peter L. Salgo, MD: Right.

Marin Hristos Kollef, MD: The thing about pseudomonas I would like to add is that it also is very proficient at forming a biofilm. It can stay hidden for a period of time. That echoes some of the other comments that people have made. If you’ve got a device in place in an endotracheal tube—or even within abnormal mucosa within the lung, within the airways&mdash;it can essentially hide there for long periods of time in patients who are placed on antibiotics, who may have other stress factors, and who are not getting adequate nutrition. It just allows that infection to come forward.

Peter L. Salgo, MD: You mean a biofilm is a very gentle way of saying it forms this yuck.

Andrew Shorr, MD: Well, it makes it concrete.

Peter L. Salgo, MD: It’s concrete, right, and human antibodies have trouble getting through it.

Andrew Shorr, MD: Exactly.

Peter L. Salgo, MD: It’s a very successful adaptation.

Andrew Shorr, MD: And it does quorum sensing, so it doesn’t even reproduce. If an antibiotic penetrates, it’s hiding from it.

Yoav Golan, MD: There’s actually very good literature, particularly for pseudomonas, showing that in bathrooms it almost develops in a community sense.

Marin Hristos Kollef, MD: Correct, absolutely.

Yoav Golan, MD: There is communication within this community. And as you know, when bacteria is self-dividing, they become far less susceptible to antibiotics and can actually send messages to each other: “There may be an antibiotic in the area.”

Peter L. Salgo, MD: I just had this picture of Pseudomonas on social media: “Watch out, they’re coming this way.”

Andrew Shorr, MD: If Far Side was still doing cartoons, this would be ripe material.

Peter L. Salgo, MD: Ripe material. But that does bring up something that you pointed out, which is the institution. Does every institution need a biogram? This is our pseudomonas, this is what we see, and this is how we need to treat it.

Andrew Shorr, MD: Absolutely. You can argue that you don’t have a multidrug-resistant pseudomonas problem, but hospitals that do that, when I speak with them, have what I call a WNL issue. And WNL doesn’t stand for “within normal limits.” It stands for “we never look.” They don’t look. They don’t think they have a problem. When we look and break out our ICU antibiogram, especially comparing it to our ward or non-ICU antibiogram, that information is usually insightful. There is a lot of MDR Pseudomonas in the ICU among the isolates we collect.

There’s a lot on the floor as well, and that process and that conclusion allowed people to realize that we needed a system-wide approach and paradigms in terms of protocols as opposed to saying, “Well, let’s just target the ICU because it’s geographically constrained.” That makes you miss a lot of what’s underneath the tip of the iceberg.

Jason Pogue, PharmD, BCPS-AQID: Yes, I think that floors/ICU observation is absolutely true. But I also think we tend to culture those patients.

Peter L. Salgo, MD: The ICU patients or the floor patients?

Jason Pogue, PharmD, BCPS-AQID: The ICU patients get cultured more, so we see it more. It’s the same thing as looking and seeing it from that standpoint. But I totally agree, and I totally believe them. I see specific antibiograms. They’ve been shown to improve on empiric therapy. But they come with a lot of asterisks that people need to be aware of from that standpoint.

Peter L. Salgo, MD: Like what?

Jason Pogue, PharmD, BCPS-AQID: You need to know patient-specific risk factors. I can look at day 1. If I look at my ICU antibiogram on day 1 of admission and it’s still pretty nasty, it’s because they’re coming from long-term care facilities. They have history of all these previous antibiotic exposures and ventilation. If that patient goes to the floor, they have the same risk of having pseudomonas. Actually, they’re just not as sick. But I think that patient-specific factors, as we learn more and more, are even a bigger determinant than ICU versus non-ICU.

Peter L. Salgo, MD: I want to take your point about patients not being cultured, which is to say that if you culture enough patients, you can develop an antibiogram anywhere, right? The lab’s got the data; the lab’s got the sensitivities. Are you saying that we need to culture more on the floor?

Jason Pogue, PharmD, BCPS-AQID: I would, as a stewardship pharmacist. I would love the floor patients to be cultured more because then I can actually do antibiotic modifications. When they’re not cultured, they get started on empiric therapy and then we’re stuck with those therapies. But yes, we would understand that microbiology better and we’d also have the ability to modify therapy accordingly.