ASCRS 2023: Antibiotic resistance of intraocular bacterial pathogens

Penny Asbell, MD, FACS, MBA, sat down with David Hutton, Managing Editor, Ophthalmology Times®, to discuss her presentation on the ARMOR study and the antibiotic resistance of intraocular bacterial pathogens at the ASCRS annual meeting in San Diego

Video transcript

Editor’s note: This transcript has been edited for clarity.

David Hutton:

I'm David Hutton of Ophthalmology Times. The American Society of Cataract and Refractive Surgery is holding its annual meeting in San Diego. Joining me today is Dr. Penny Asbell. She will discuss her presentation titled "In Vitro Antibiotic Resistance of Intraocular Bacterial Pathogens From The ARMOR Surveillance Study." Thank you so much for joining us today Dr. Asbell. Tell us about your presentation.

Penny Asbell, MD, FACS, MBA:

Thanks, David. Glad to join Ophthalmology Times and talk about the ARMOR study. This is the only surveillance study done in the United States collecting eye isolates from, I think it's 42 sites and over 20 states. And looking at antibiotic resistance from these ocular isolates. In this particular data set, we're looking specifically at the isolates that were collected from the aqueous or vitreous.

Well, you know, if you're sending a sample like that to a laboratory for culture, we're talking about a really serious infection, typically endophthalmitis. And that's important. Obviously, that's the most dreaded infection you can get in an eye disease. And we certainly want to get our hands around the antibiotic resistance and best treatments.

So here we're looking at isolettes over the last decade. And what's interesting is that we still see a lot of methicillin resistance. Nearly 40 to 50%, whether it's Staph aureus, or coagulase-negative Staph. But the real take home message is when you look at the methicillin resistant staph organisms, they're typically, many of them are going to be multi-drug resistance. So resistance to methicillin but then they're often resistant to three or more other antibiotic classes, and that's over 80% of them. So it's actually going to be a problem. Yes, we know that with eye treatment, we can put a lot of drops on the eye. But when you have a resistant organism, you're still going to have a tough time treating it.

I think it's interesting to look at one of the particular antibiotics that we use frequently Ciprofloxacin. When you look at the Staph organisms there, maybe about 40% are resistant to moxifloxacin. And if it's methicillin-resistant Staph aureus, it's over 80%. And it's true with the coagulase-negative organisms as well. Much higher resistance if it's methicillin-resistant, and we're talking about moxifloxacin.

If there's some good news around, when you look at the MICs, which is a laboratory way of testing potency, we still do pretty well with vancomycin. And one of the available drops besifloxacin, also does pretty well in the MIC measuring potency. So it's good to know there's some things out there that look pretty good in terms of possible treatment for resistant organisms.

The other thing I looked at was Pseudomonas. Fortunately, this is a relatively rare organism for endophthalmitis, but it can be a serious one as we well know. It's good to remember that Polymyxin B, all the Pseudomonas were resistant to Polymyxin B. We don't put that intraocular but we do use it topically sometimes. And a couple of them were also resistant to moxifloxacin as well. So we see resistance there even with the moxifloxacin, which is we know frequently used as an intraocular on antibiotic at the end of ocular surgery. So something to keep in mind.

Even those that we consider a broad spectrum are not 100% against all organisms. So antibiotic resistance is alive and well if you will, and something we need to think about.

And I think the ARMOR study is a good opportunity in terms of picking your first antibiotic before you have those laboratory cultures and resistance information available for treating the patient. It gets you going and hopefully we'll end up with a better result for the patient because that's what we all want. So thank you for joining me today – ARMOR study, we like to share whatever information we have with you. Thank you