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  • Pathology and Treatment of Polymicrobial Infection
  • Lecture Transcript
  • Male Speaker: Has been a friend of podiatry for many years, Dr. Steve McClain. He’s very animated speaker, likes a warm welcome like jumping out of your seat clapping very strongly for him. He’s a dermatopathologist.

    [Applause]

    Male Speaker: Look at this. Look at this. And specializes in malignant melanoma, wound healing, pathology informatics. Great friend of ours, great informer of information, provider. He’s going to talk on 10 reasons why surgical antiseptics are simpler and more practical than antibiotics for clinical use in healing chronic wounds. Please welcome Dr. McClain.

    Steve McClain: Come on. It was a warm welcome, come on. Let’s hear it. Okay, it is my pleasure to be here today and this is a great meeting and a great group. You’ll notice under the adjunct professor’s SUNY at Stony Brook, I’ve been there for 22 years now and had the good fortune to have Richard A.F. Clark who was mentioned by Dr. Frykberg. And so, I have studied wound healing for quite a while and we have been trying to uncover the extracellular matrix. I’m not going to show you much of that work today however. But it is complicated and there’s a lot that the animal wound models can teach us but there’s a lot that it can’t teach us. There are no animal models for chronic wounds, almost none. I’ve been working on this problem for at least five years now with very little progress. But we have made progress on the human wounds. I’m a pathologist, I study human wounds every day and I was fortunate enough to have some podiatrist to send me their debridements. It was only with great difficulty that in a disease that kills 30% of its patients in five years, that we could get podiatrist to actually send debridements to the laboratory. If this were a cancer, you’d be sued for not biopsying. And yet, here is what I’ve learned about these chronic wounds and that mainly it’s a polymicrobial infection and it’s not just one organism, it’s a whole host of organisms. I like to focus a little bit on treatment and focusing on antiseptics because they are simpler and they’re more practical than antibiotics. Now, antiseptics have a long history. We go back almost 200 years of using antiseptics in wounds and I’ll present some of that for you. They’ve gotten a bad name that they’re cytotoxic and they’re this and they’re that. All the nurses don’t want you to use these things and yet it’s very practical and there’s good reasons why you should. Let’s see, I have no disclaimers or conflicts. I work for myself in my own laboratory and I have a great staff. Let’s see. Let’s see if we can get this to advance. Okay, for the residents, write down these four names, Alexis Carrel, Robert Kirsner, Fumal, F-U-M-A-L, and Keisha Finley [Phonetic]. These are four critical references that you should know about. They’re all available free. You say, “McClain, are you a nut? 1917? What are you talking about?” This book is available, you go to Google Search, Advanced Book Search and you can find the whole text that’s available to PDF. Some of what I’m going to show you was pretty well-worked out in World War I. Okay, in general, the same chemicals can be called [indecipherable] [04:15], an antiseptic, a disinfectant, a preservative and basically they’re chemical agents that either inactivate or killed vegetative microbes. But the chemical has to diffuse in. This is from Alexis Carrel’s book in 1917, chemical diffusion must reach the microbes. They must get in. This is a wound at the mid-thigh level, complicated, through and through injury during the war and you can see that there’s three tubes instilling hypochlorous acid. Okay, this was done six times a day. Probably the master wound healers I’ve learned was Dr. Paul Brand.

    [04:56]

    His recipe for ulcer was pretty simple and it was pretty much identical whether we’re talking about leprosy and the neuropathy of leprosy or diabetes and its neuropathy. It goes like this, neuropathy plus some kind of injury which you don’t really perceive of that gets infected. People say, “Well, Paul Brand showed it was the neuropathy.” Yes, but Paul Brand was treating infection if you look at his methods. Many people like to ignore the infection so let’s call it a dragon instead of an infection. But Paul Brand was treating infection. He would say, take out every bit of the dragon, the house and the part that’s going down, the root cellar, chemically disinfect using one’s cells, suppress reinfection with gentian violet and/or iodine. Then around the wounds, you would have them soak every night and cleanse in oil nightly to keep the flakes down. We’ve known since Hippocrates that bed rest was a key. Just putting someone to bed can heal many of these wounds. The stress of walking on it and repeated trauma are a real problem. The total contact cast method which he became known for really goes back a long ways. But the key is to get it offloaded. Here’s an example of a problematic one and we see all the flakes around those fairly cleaned out ulcer on the heel and a little biopsy site. I began giving out gentian triple dye about three years ago now. This is a compound, triple dye was given to more than 4 billion U.S. babies over 40 years time and yet the FDA says it needs more animal testing. I don’t know how much more animals you’re going to test in 4 billion U.S. babies. This is still considered a category 2 agent. But the key is to put enough on, load it up. Six or seven coats is what Robert Aldrich described, he was a Harvard surgeon and he used this stuff on burns up to 65% of the body surface area, sprayed it on. They said spray it on, it helps if you’re going to spray on 65% body surface to warm it up a little bit. Here’s the recipe for ulcer again, neuropathy and then some kind of injury, repetitive trauma, pressure, Chilblains fissure. And then there’s a symbiotic fungal infection often in the nails. You look at these nails in patients with ulcers, they almost all have toe fungus and tinea. Many of them have a dermatitis that goes all the way up to about three fingers. I don’t know why three fingers but it’s about three fingers below the patella. You’ll see these repeatedly again and again. Well, you’ll see it right now. This was a picture on YouTube on Stacey’s dermatitis and you can see the flakes on the left leg and the break down. The erythema comes up to a certain point. Many fungal infections have an allergy component that goes along with it. This is a toe that came into the lab a few weeks ago. Most amazing specimen. We soften the whole thing, we decalcified it and looked at it, took a slice through it. You can see the distal, you can see the brown, black of the infected toenail on top. The black dot distally which is out at the point of where it ulcerated overlying the distal phalanx, the cartilage at the IP joint there has degenerated. This is a slice all the way through it. There’s three areas I’m going to show you. One is the nail, one is the bone, and one is the skin, distally. I know that candidal onychomycosis has been out logged. But yet there is Candida loaded in that nail. What was more amazing was the bone. If you see them, the upper right where the two arrows are, those vessels are jam full of cornified cells. Around the cornified cells, again, loaded with Candida, just the pressure of walking, has driven those cornified cells all the way in the bone. The bottom right is a immunoperoxidase stain. Red is specific for Candida albicans. We can prove that Candida albicans inside the bone marrow in the end of the toe. And that it would heal up and then it would break down. It would heal up and it would break down. Finally, they underwent an amputation. In the callus distally, PAS on the left showing the Candida. Candida albicans antibody stain in red on the right.

    [09:58]

    We can prove there’s Candida in the nail in the callus on the tip of the toe and also in the bone, okay. There is a mechanism, just the pressure of walking could drive these flakes into a bony tissue and they’ll break down and they don’t heal well. Okay, let’s get on to the ten reasons. Now for this part, we got about 20 minutes left. I advise you to put your seatbelts on, your tray tables up in the full upright position because we’re going to rock now. Microbes and chronic wounds inhibit wound healing. Okay, I don’t know why people don’t talk more about this but what I learned only recently and I learned it from a 98-year-old book was it doesn’t take very many of them. Foot and ulcer microbes include fungi. Almost all the wound healing literature keeps talking about the bacterial component and nobody talks about the fungus. And yet the fungi are really important in this. Now to the point about antiseptics, antiseptics have broad effects where antibiotics are quite selective. Antiseptics are active against fungi and most antibacterials don’t have much of an effect on fungi. Antiseptics reduce antibacterial resistance. Some antiseptics, in particular, povidone promotes wound healing. Cadexomer iodine, for example, is marketed by the company as a cicatrizant promoting wound healing. But it’s more than just scarring when it’s forming, I’ll show you in a minute. Antibiotics don’t usually promote wound healing. There’s one antibiotic that has some effect on wound healing and that’s the tetracyclines, especially doxycycline because it inhibits tissue metalloproteinases or MMPs, okay. It does solve specifically by binding the calcium and zinc which are needed for the serine proteases that have their effect. You bind the zinc, the serine proteases don’t break down the tissue. It does so at a very low dose and you can compound that Christopher [Phonetic] into a topical if you want. One percent doxycycline is a pretty effective metalloproteinase inhibitor. Okay, many antiseptics are much longer lasting. You can use them in a contact cast. They also reduce biofilm. Here’s a key, way less contact allergy with antiseptics, cell culture cytotoxicity. Now, this is complicated but I’ll show you a picture. Povidone is one of the least cytotoxic. Okay, we’re done. We can go home, right? I think I have another 18 minutes, so let’s use it up. Alexis Carrel, 1917. The first part of the wound healing curve is often called the inflammatory stage. It’s also known as the lag phase. The cells are proliferating and growing in there. The second part, the lower part. Thank you, Kimberly. The second part is called the contraction phase and this is repeatable. In the guinea pigs, rats, monkeys, pigs, humans, all pretty much the same. Lag phase, contraction phase. Let’s look at microbes in chronic wounds. They do inhibit wound healing and it doesn’t take very many of them. Two bacteria per oil field was enough to prevent wound closure. How do we know that? We know that from Alexis Carrel. These guys really did a Nobel Prize winning effort. He didn’t win the Nobel Prize for this work but he was a Nobel Prize winner. He graph wound bacteria, that’s the bottom curve that I’m showing you. You see it’s high. It’s at infinity up until the red cross. Then they began treating and they treated with Dakin’s solution, full strength six times a day. Immediately the bacteria fell. At the same time, if you graph wound area over that same time period when the bacteria were high, the wound got larger, it actually increased in area up to the point they began treating. Again, it assumes a geometric curve and starts falling or starts closing down almost immediately. At the same time, the bacteria are low. If there’s a spike in the bacteria, the curve flattens out. Two bacteria per oil field, not very many bacteria at all. If we graph a human wound after or while you’re treating with Dakin’s solution, two hours a day, they would instill this.

    [15:01]

    This is during World War I. They didn’t have antibiotics. They just had Dakin’s, okay. Six times a day, this was put in. The cytotoxicity, at least, based on the World War I data is pretty minimal, at least we don’t see it with this. Foot and foot microbes include fungi. I love this work here because this is kind of the mystery. This is the dragon in all of us. Most people don’t talk about the fungi in these foot wounds. This is Keisha Finley’s work in Nature and it’s available free. On the left axis is the one TSI median richness. The vertical scale there, 80, 60, 40, those are relative scale and it shows that the most fungal species anywhere on the body are to be found on the plantar heel more than the toe web, surprisingly to me, and greater than the toenail. All of those were way more than the palm, the volar forearm and the antecubital fossa which are next. Those were all more bacteria. But the feet are loaded with fungi. Feet also have bacteria as well, not as much. And so they graph the two of these and I don’t know how to interpret these but basically all the blue are the foot, okay. Those are considered a dry area or, excuse me, a moist area on the bacteria on the right and the blue is fungal on the left and they’re all over the map. Okay, many different types of fungi make their home normally in the human foot. Where do they live? They can live in eccrine ducts, in the cornified layer. This is from a callus adjacent to an IPK. Let’s start talking about wounds though. This is often called putrefaction, colonization, but rarely is it called infection. We have trouble defining what a polymicrobial infection is where there’s many different types of microbes. In fact, many of the soil microbes that you would grow that would be found normally on a foot or around the foot that’s been walking in a shoe, that’s been in contact with the soil, most people would call normal flora, okay. Streptomyces, Nocardia, Actinomyces, all those don’t grow very well in culture. But the purple there is all the bacteria and all the grunge that’s on top of these and the edematous or pale zone in the middle, which is a fair amount of water. But you see all the red and all the red are vessels and the microbes are actually growing right down in the vessels and you see fibrin of these stalled blood vessels. It’s also called the vasculitic by some and I’ll show you a little bit of work on that. But these are the vessels that one sees in stalled healing. Over and over again, when I get a biopsy of these wound basis, this is what we see, we see vessels plugged with fibrin. Sometimes, we can identify a bacteria in them, sometimes we can identify fungi in them and sometime we just can’t tell but it’s the pattern of an infected wound. Okay, antiseptics have broad effects. This is the spectrum for iodine, okay. Now if you treat it with an antibiotic, it might get gram-positives or it might be directed towards gram-negatives. But iodine here has an effect on gram-positives, gram-negatives, fungi, protozoans, algae, spirochetes, viruses including herpes, including polio, including an AFP. Broad spectrum event, when you don’t know what the organism is, it makes sense to treat it with something that’s fairly broad spectrum. Okay, this is a quote from Frontiers in Microbiology just this year, “Unlike antibiotics which usually have a specific target, disinfectants are multi-target agents.”

    [20:02]

    They may have an attack on the cell wall on denaturing proteins, DNA, RNA. But the ultimate endpoint is to disrupt the microbial cell membrane and inactivate it completely, meaning kill it, prevent it from reproducing. Okay, antiseptics are active against fungi in foot ulcer. Well, let’s show you about the fungi in foot ulcer or fungi in any skin condition. Say you have a child with widespread eczema, you can go on the Mayo Clinic site or this is from the AAD, American Academy of Dermatology, bleach bath therapy. We’re talking dilute bleach, one half a cup of bleach in a full bath tub of water or a teaspoon in a gallon of water. Very dilute regular strength bleach. I think the cytotoxicity for many of the chlorinated ones is overrated but it’s there. If you have too high of a concentration, you can inhibit wound healing. Now the next one is gross, if you’re grossed out by war pictures and stuff, just close your eyes. This is a transfemoral amputation in a soldier in Iraq. Okay, explosive device. The brown areas, the dark brown areas are places of muscle necrosis. These are due to advancing fungal infections. These are angioinvasive, they tend to grow in blood vessels and what was amazing to me, first line treatment by the army, even before they’ve identified an organism, before they do anything else, 0.0025% meaning Dakin’s solution, 5 cc’s in a liter of saline. That’s really dilute. You can dilute it out quite a bit and it still has an effect. Okay, this is in Military Medicine. It was published two years ago. Okay, what about the fungus and foot ulcers, Steve? This is more like what we see. Look at those toenails. I can see four fungal toenails from right here. The callus around those ulcers is fungal, it’s a fungal product, it’s kind of like wood. It’s a combination of weird human cornified cells interlaced with weird fungi. But the ulcer callus, you remember this, is just as fungal as a mycotic nail and it’s why you have to debride all that away. You can’t just mess around with it. You have to take that down at the living tissue. If you send it to the lab, you can just put it in formalin. Between the lytic clefts, there’s all kinds of fungi. This pattern is sometimes known as fungal parakeratosis, the entire callus is infected including the fungal parakeratosis. Those purple, they almost look black in this picture, giant hyphae, all kinds of forms. These things are growing like a jungle. They love living there. They have lots of moisture. Right in the center of the wound, that glop that you sometimes scoop out, you notice those thread-like things, those reddish purple things, this is a PAS and alcian blue stain. Fungi growing luxuriantly. Okay, pyocytes have multiple targets, we’ve kind of already talked about it, but that’s why there’s less antimicrobial resistance to antiseptics. Not that there isn’t resistance to antiseptics but by having multiple targets, we see less of this. Where you see multi-antiseptic resistance is primarily in hospitals where they use a single agent over and over and over again. Okay, I’ll skip that. This work really goes back, hypochlorite became commercially available and immediately was given to a surgeon by the name of Lisfranc. I’ve thought this quote of his, “Henceforward, there will no longer be any gangrene in hospitals, thanks to Monsieur Labarraque,” 1825. Well, it didn’t quite work out that way but this was his miracle drug. Semmelweis, I know a lot of you had been getting the red, the Riot Act on hand washing and stuff and they’re mostly talking about alcohol hand cleansers and stuff but Semmelweis was talking about chlorinated compounds to disinfect the hands, he wasn’t talking about alcohols. Brief word on fungal osteomyelitis, this is a case I saw about three years ago. Someone sent me a proximal hallux phalanx and the bone was all necrotic.

    [25:03]

    It looked like what I would call driftwood bone. Obvious septate hyphae in the bottom left two pictures and then these grains that were PAS positive, that were gram-positive, some of them were gram-negative. I didn’t really realize how close this was but it’s the description is like mycetoma. It’s amazing that a disease that’s quite similar to mycetoma might be found in my county in Suffolk County. I went back and read the work on mycetoma which was originally described by Henry Vandyke Carter. In his second publication, I was astounded to read on the second page, I have a notion hospital gangrene is caused or aggravated by fungus. This is not what we teach today, I know, but this is what they saw 154 years ago. You will notice as we zoom in, he was quite the anatomist. He did all the drawings in the original Grey’s anatomy, the septate hyphae and then those grains. He saw it all in the 1860. Okay, Lister used antiseptics, he used phenol and he was the master at diluting it out. He didn’t just use one size fits all because he would dilute out the phenol to make sure it didn’t injure the skin and it would protect the skin. He said the same thing, that hospital gangrene may said to have been banished by the antiseptic system. Okay, promoting wound healing. Let’s say I got five minutes and I got five subjects. I’m really going to have to speed up now. Povidone has been known as this cicatrizant promoting healing. What I didn’t know was that the same ointment has been shown to stimulate epidermal regeneration at least in animals. Many antiseptics are longer acting, meaning less frequent dressing changes and you can use it with a contact cast. Now Brand tended to use gentian violet, hydrogen peroxide and iodine were his methods. But it’s also been shown that antiseptics can reduce biofilm. Biofilm forms because there’s an interaction of multiple microbes. It’s not just one microbe forming the biofilm. Use of cleansers, use of antiseptics on top of them are the preferred method for reducing biofilm. Okay, a little bit of word on contact allergy. Every year, the dermatologist published the top contact allergens and for the past 20 years, neomycin and bacitracin, two of the components in triple antibiotic are in the top 10 or 12 causes, 7.7% are causes of hand dermatitis and 7.4. Okay. Now, does this mean they’re bad? No. But recognize that so many people have either allergies are related to neomycin and bacitracin. Or that almost anything you put on a wound long enough, you can get tape allergies for example. Anything you put on the skin, after a while, people will become allergic to it. You can even become allergic to antiseptics, although it’s rare enough as to be a case report. When was this published? 2005, it’s a French publication, 75 cases, 68 were work-related, excuse me, therapy-related and six cases work-related in healthcare workers, and one in a cattle farmer who used povidone iodine. Another case in women who developed reactions to the preservatives in their cosmetics, especially hexamidine or PHMD. Among those, chlorhexidine, almost any of them including Mercurochrome, people will become allergic to. If you put it on long enough, you’ll probably develop it. But right now, people have fewer allergies to antiseptics because we haven’t been using them as much. Okay, this is one of my favorites and this is the paper by Fumal. It was a pathologic study. They studied 17 patients and they did biopsies before in the middle and they studied wound area closure. Now the key was each of the patients had two ulcers. They had a control on one side or maybe a little higher up on the leg and one that was treated. They were treated with either silver sulfadiazine or chlorhexidine or povidone.

    [29:59]

    Each patient served as their own control. An entry into the study, fibroblast, macrophages, neutrophils and vessels were all studied. In addition, they noted the focal necrotizing vasculitis that was related to the microbiological load. Meaning this, what I showed you earlier, the infected vessels of stalled wound healing. Now, all of them improved. No matter which are the ones they used, they were all better than the control, okay. That means that they just used, I think it was a hydrocolloid dressing, did not do any further antimicrobials, just the hydrocolloid dressing on the other side, there’s a control. The silver and the chlorhexidine were not significant statistically. But the povidone iodine significantly improved the healing rate and the time to healing was reduced compared to the hydrocolloid by two to nine weeks. Again, statistically significant. What was interesting was that the difference, there was cytotoxicity in the SSD and the chlorhexidine treated ones, okay. Whereas, povidone iodine did not alter the microvessels, did not significantly reduce density of dendrocytes, meaning the dermal antigen presenting cells and fibroblast. Okay. They concluded that the toxicity on the host cells was different. The main reason the nurses give why we don’t use antiseptics in these wounds is supposedly the cytotoxicity. But most cytotoxicity data is based on cell culture work, not actual human. In contrast, the povidone iodine appeared to be an efficient compound in these respects. Okay, so last point, people asked me what to do, I say, send all your debridements in formalin to pathology and we’ll look at them. Let’s look at what’s in these wounds. If you want to do a stain, fine, we’ll do a gram stain or send it to the lab and do a gram stain. Or do a culture, but you can expect to see a host of things coming out of a culture. Okay, I’m going to stop there because some of these infections are pretty wild and I’m not going to go any further onto the infections. Thank you for your time. I appreciate it.