pet connection

This is the full text of my recent interview with Laura Stokking PhD., DVM, DACVD, on the subject of drug-resistant staph infections — methicillin-resistant staphylococcus intermedius, or MRSI, similar to human MRSA — in pets. Dr. Stokking is a diplomate of the American College of Veterinary Dermatology, and has published several book chapters and reviews in veterinary dermatology and has lectured veterinarians at national and local conferences. She is active in educating general practitioners in San Diego County on recognizing and treating resistant staph infections in companion animals.

I was referred to Dr. Stokking for this interview by one of her clients, Mary Ann Rose of San Diego, CA, whose Scottish Deerhound Angelina, like my Borzoi Kyrie, has been struggling with a drug resistant staph infection.

CHRISTIE KEITH: Are you seeing a lot of MRSI in your practice?

DR. LAURA STOKKING: I certainly am, and certainly more than I saw a year ago this time.

CHRISTIE KEITH: Do you think it’s being diagnosed more or do you think it’s more prevalent? And what do you suggest to general practitioners?

DR. LAURA STOKKING: I think it’s definitely a combination of both, being diagnosed more and also more prevalent.

I’m basically recommending to general practitioners that they do cultures if something does not respond the way we think it should. So if a pet has been on the standard antibiotics that have been working for years like cephalexin and clavamox and all those things that have worked for canine skin infections for decades, if they see a change where the pet is on those drugs and they’re not working, then a culture needs to be done so we can treat based on the culture result to know exactly what the issue is, what the organism is and what the best ways to treat that organism are.

CHRISTIE KEITH: Do you feel that a lot of drug resistant infections – or an increasing number I should say – are being misdiagnosed at the start because this isn’t in a general practitioner’s awareness yet?

DR. LAURA STOKKING: That’s a good question. I know the people that the practitioners down here are catching a lot of them. A lot of them I’m catching, but a lot of them they’re catching, and then they’re sending to me because they don’t have the comfort level yet to treat them.

We have a really highly-educated practitioner base in San Diego County. It’s really quite a treat to be a specialist, down here with them because they’re so good.

Then I get a lot of challenging cases because the easy ones, they’re getting, but also we’re trying to make the practitioners, aware too. I had a newsletter and a CE last summer already on the emergence of these infections, and a lot of the veterinarian literature that most vets throughout the country get is now talking about it.

So I think that a lot of them are being caught, so I think there isn’t a lot of misdiagnosis at this point because it’s kind of in everybody’s frame of reference or kind of in the back of everybody’s mind.

Definitely in dogs it’s an emerging problem. Up until recently, the bacteria that most commonly affected dogs didn’t tend to trade resistance information with other bacteria the same way that the staph in humans did. That’s recently changed, and that is why the incidence and the prevalence of the resistance are now spreading in companion animals.

And from what we know, the ultimate source of the resistance was from human forms of staph. Basically the genetic material jumped into the canine forms. That doesn’t mean that if a person has a dog that has a resistant staph [infection] that the dog got that from that family. It’s just that as a population the resistance developed in the bacteria affecting the human population, and then some of that genetic information jumped to the bacteria affecting the canine population.

CHRISTIE KEITH: One of the things that caused my veterinarians confusion is that my dog, my Borzoi, Kyrie, unlike Angelina, had not been hospitalized or even at the vet or anywhere that we could conceive of where she picked this up.

DR. LAURA STOKKING: That is also happening in humans. That’s because there are basically two different strains of resistant organisms, and back even as recently as three or four years ago when we saw resistant staph in humans it was the hospital-acquired resistance.

And now there’s another strain that’s a community-acquired resistance and they are genetically distinct. The community-acquired MRSA is actually what’s been hitting the news, because that’s the MRSA that’s affecting day care centers and college athletic teams and that people can pick up just anywhere.

So even though a few years ago when we saw the methicillin-resistant staph [in pets] we tried to go back to a link at a hospital. All bets are off now for that because there is the separate strain, the community-acquired MRSA that’s out there and right now at this point we don’t have a link with the MRSA or the MRSI – staph intermedius versus staph aureus.

We don’t usually see a link between hospitalization or veterinary visits and the acquisition of that strain. We do frequently see repeated use of antibiotics that in the past we didn’t have to worry about. When I was going through my residency we were perfectly comfortable saying oh, we don’t have to worry, we can use these drugs long-term – drugs like cephalexin and Clavamox. We can use those long-term because the staph in dogs doesn’t develop resistance to it. But that has now changed, and that is the reason we’re seeing so much more of the resistant bacteria found in dogs.

CHRISTIE KEITH: It was interesting in my Borzoi’s case, she’s nine years old and she’s only had antibiotics once and it was doxycycline, about five years ago. But she cultured out for both methicillin-resistant and multi-drug-resistant staph.

DR. LAURA STOKKING: Would you mind – just for curiosity would you mind at some point faxing me or e-mailing me a copy of her culture results? Because I do have a really strong interest in this.

CHRISTIE KEITH: Sure, I’ll be happy to. Have you been doing any education with vets?

DR. LAURA STOKKING: I have. I did a newsletter on it last August, and then I did a continuing education lecture at night, and I’m going to be doing the rounds and then another lecture on it.

CHRISTIE KEITH: And this is locally in San Diego?

DR. LAURA STOKKING: Yes, it’s in San Diego County.

CHRISTIE KEITH: One of the things I wanted to ask you was how to increase awareness of MRSI as a possible diagnosis. Even though I worked for the Veterinary Information Network for seven years and I’ve been a pet writer for 16 years and I have a background in human medical journalism as well, and I consider myself to be more aware than most people and more pushing for more testing, this still didn’t cross my mind at first. It looked to me like my dog had a hot spot, even though that was odd for the winter.

And when I took her in and the vet looked at it and she said wow, I think this is a spider bite, I accepted that. She put her on cephalexin, I took her home. When the antibiotic didn’t seem to help, and she was getting worse, I googled dog spider bites and discovered that number one, there aren’t any venomous spiders in San Francisco and number two, that usually this is a misdiagnosis of a drug-resistant staph infection, and the next day – after the cephalexin did absolutely nothing and it had tripled in size overnight – and I took her immediately to a specialist, and she immediately thought it was MRSI and we cultured it, we even still went wrong.

So I really wanted to ask you, while it sounds like in your area you’ve got a much higher level of awareness, I’m wondering if you’ve picked up any sense on a more national level.

DR. LAURA STOKKING: It was definitely a main topic at the national dermatology conference [the North American Veterinary Dermatology Forum], held in Denver in April, and that’s where Dan Morris from the University of Pennsylvania is actually starting a study. He’s been looking at it for a while and he’s starting a new study that I can’t really talk about , but there’s definitely a lot of awareness in the dermatology community and that definitely was a hot topic: how many cases are you seeing, what are you doing?

As regards the confusion with a spider bite, in humans, the CDC even has this little poster, “Looks like a spider bite but it isn’t? MRSA.” And that’s the community-acquired strain. Because of specific toxin that’s exuded by that specific strain of community acquired resistant staph causes necrosis, destruction of the skin.

That’s one of the little things that I have in my CE, that if it looks like a spider bite and you did not actually visualize, you don’t have evidence that a spider bit there, than culture for MRSI.

CHRISTIE KEITH: Is Angelina one of the worst cases that you’ve treated?

DR. LAURA STOKKING: Fortunately for her, no she isn’t, and she responded pretty well. I have some cases where there is a substantially higher amount of the body that’s affected and a lot more tissue necrosis and the dogs are really systemically ill and so far it’s been pretty fortunate with just aggressive therapy.

CHRISTIE KEITH: Good.

DR. LAURA STOKKING: And you know, it was easy with Angelina’s parents because they’re physicians so they know a lot more, but a lot of the other clients I give a packet of information from the CDC.

CHRISTIE KEITH: Is there anything else that you’ve noticed that you’d like to say – other than the if it looks like a spider bite, culture – any other suggestions for pet owners and general practitioners that could kick this into a higher level of awareness?

DR. LAURA STOKKING: It’s better to do a culture and then find out that it would have responded to cephalexin than not culture and let it go three weeks before realizing that you’re dealing with a methicillin-resistant strain. So if there is any doubt in anyone’s mind, get a culture.

I wish they’d do that in human hospitals. I have – when I have diagnosed it in dogs, I’ve had people tell me these horror stories about it not being diagnosed correctly in human hospitals, and not cultured.

CHRISTIE KEITH: Mary Ann told me about Angelina because I posted about what my dog was going through on the Deerhound email list. She wrote me about Angelina and sent me pictures and all this information, and I just sat there looking at it thinking, I can’t believe this is going on. I’m wondering if this isn’t just going on in the background with a lot of dogs right now.

DR. LAURA STOKKING: It is. It definitely is, all over the country because there was – I mean I can’t give you statistics but it definitely was one of the main emphases and with the national dermatology conference and then also a topic of discussion at the World Congress in to be held in November. Definitely [veterinary] dermatologists nationally and internationally are paying a lot of attention to it.

CHRISTIE KEITH: Any tips on people for avoiding it for their pets or do you think that at this point it’s just kind of everywhere and you can’t really avoid it?

DR. LAURA STOKKING: At this point I can’t say. I’d love to talk to you further about your own dog and try to figure out where your dog got it from but at this point we don’t know.

CHRISTIE KEITH: I don’t – I think she might have gotten it from her groomer. I don’t know.

DR. LAURA STOKKING: Okay. That’s a possibility, really.

CHRISTIE KEITH: I called the groomer, not in any accusatory way because I realized at that point it was ridiculous, she could have had it ages ago, but I wanted them to know for the safety of their other clients. And they really just shut me down and were very disinterested and they said there was no reason to even cancel her future appointments. I literally was speechless.

I thought, you want me to bring a dog with a diagnosed multi-drug resistant skin infection to be groomed by you? Are you out of your mind? My vet told me, don’t get her groomed anymore. She’s a risk to other dogs.

DR. LAURA STOKKING: Yeah, do it at home.

CHRISTIE KEITH: I’m grooming her myself now and I don’t like it – you know the long hair. It’s hard.

DR. LAURA STOKKING: And I like the chlorohexadine shampoos because chlorohexadine showers – or topical chlorohexadine – is one of the things that’s used to decrease the transmission in human carriers. Right now we don’t know if there is a link between human carriers and canine patients or not. It’s usually a different staph on humans than it is on dogs, and so far I don’t really see a correlation, but that is one of the things that’s being looked at.

That’s a shampoo that pretty much all dermatologists use, either by itself or mixed with miconazole or ketoconazole to stop also the yeast. I don’t want the Groomers Association of America to sue us but that’s –

CHRISTIE KEITH: No. I don’t want it to look like I am accusing anyone, because of course I have absolutely zero evidence or reason to believe she got it at the groomer –

DR. LAURA STOKKING: Yeah.

CHRISTIE KEITH: — other than it’s the only thing I can think of.

DR. LAURA STOKKING: But certainly look at contaminated water, contaminated soap bottles. It’s a possibility.

CHRISTIE KEITH: Yeah. Well, thank you so much for your time. I really appreciate it and I will send you a link when the article is published.

DR. LAURA STOKKING: Thank you!