• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services

Animal & Veterinary

  • Print
  • Share
  • E-mail

Epidemiology of Campylobacter in Animals

Dr. Paula J. Fedorka-Cray

DR. FEDORKA-CRAY: My fast food expertise is dependent upon which toy is out.

(Laughter.)

Well, it looks like I have to re-boot the computer. It put itself to sleep. So I will take a moment to say that I will stick with the thought that Andy gave earlier that developing gray hair is a result of a antimicrobial resistance. I keep trying to tell my children now that this is the professional look.

And I caught them on a telephone conversation recently telling my mother that a bottle of her Clairol would fit really well in my stocking this year. I am not sure where that is going to leave me. I hope it is a good color. I guess I could get purple to match my computer, too. I saw a few of those in Paris last week.

(Laughter.)

Well, with this modern technology, I had modern technology glitches in -- this week when I left my power cord on Monday at home and found out that you just can't plug your finger into the socket.

(Slide.)

I will start by saying that some of the production statistics, just to give you a background on where we are coming from, 8.25 billion chickens were -- are estimated to be in production for 1999. And more than 29 billion pounds of ready-to-cook chicken is produced. This results in an economic impact of 22 billion dollars for the wholesale value of these shipments.

We eat it is projected more than 79 pounds of chicken per year per individual. This is increased from 28 pounds per person in 1996. And our estimated expenditure for these products is 40 billion dollars. A retail price for chicken has increased from really a minuscule amount to $1.02 per pound.

However, it is supposed to be 44 percent less than it was many years ago, though I don't seem to think that the IRS has much thought about that. And I know my sons who consume vast quantities of food have no consideration for what anything costs anymore.

(Slide.)

There are top states for producing chickens which sometimes results in a regional analysis. And broiler companies directly employ 300,000 Americans. Now, if we look at Campylobacter itself, I was pleased to see that Kirk really gave a lot of the epidemiologic aspects. So I will concentrate a little bit more on the microbiologic aspects.

It is a fastidious organism. And really, it is fairly fragile compared to something like Salmonella which can survive in the environment for years at a time and survive in many different means and states.

However, it has been demonstrated that Campylobacter can survive for weeks in soil and water. I don't think that it has been clearly demonstrated that Campylobacter can survive for a very long period of time on surfaces. And we don't find that surface survival even in the laboratory is very high. And I can assure you that OSHA doesn't want to come on a daily basis to the lab and check the bench tops.

It is a gram negative organism which makes it one of the more popular organisms. It has a motile nature which helps us in identification. And it has special oxygen requirements in that it requires a low oxygen, a micro-aerobic environment for growth. So this confounds and compounds our problems in the laboratory as we try to propagate it.

It often requires special media including the addition of blood and blood products, iron and other compounds for growth. Over-growth is highly likely, in fact almost -- most often observed on a daily basis regardless of what one puts into the broth media for selection. And this confounds our selection of Campylobacter.

And often it is missed. So I will still comment from Dave Nesbitt who gave a comment at our USDA/FSIS meeting earlier this week when he said that they noticed 80 percent prevalence in swine. And someone said, "Oh, you are doing well. You only missed 20 percent."

So the range for prevalence estimates go anywhere from zero to 100 percent. And I think that a lot of that has to do with selection methods and skill of the lab itself. Antibiotics are often required to minimize the overgrowth in the media.

And this may effect recovery of some of the organisms. And --- gas that is used in media often as a selector. And it may select specifically for jejuni and coli populations which may minimize the prevalence of some of the other serotypes.

(Audio missing due to technical malfunction.)

--- you will find halviticus coming from cattle --- is why don't we see it for three weeks. Okay. Why is it so difficult then if it is there and we have the genetic relationship from the breeders to say that, in fact, it went from the breeders to the chicks but we don't see it for three weeks? What is happening?

And we have a lot of different theories about that, but that is a hot and heavy topic right now for scientific pursuit.

Now, one of the things though that we do observe is that within a single bird, we can see mixed species. And they are often recovered in varying numbers. We can have coli and jejuni, lari, maybe some --- all coming from the same bird. And it is hard to predict in what population it is going to be, although of course most often it will be jejuni or coli predominating over the other lesser species.

Mixed species have also been recovered from human fecal samples. And this then puts the question of our selection criteria for any one colony on a plate. If we are looking on a plate, typically -- because I have my nice new little purple computer, I failed to put all of my nice little pictures on here.

But if we look at a plate of microbiologic media and we have, in fact, the opportunity to pick multiple colonies from a plate, which one are we going to select. And this can be confounded by the culture methods and by the fact that we have this mixed population and it is difficult to predict exactly what is coming from any one individual source.

(Slide.)

Now, although we have this mis-population, it is often confounded by our culture methods, as we said. And if we look to genetic identification to do rapid PCR tests, for example, while it can provide us with information about the mixture, it doesn't provide us with an isolate to do any further characterization. So that's what limitations we would have in using genetics to identify what is in a population.

So then if we finish us looking at slaughtered, all of our populations are, in fact, mixed then in the chill tank in particular. And there is a high probability that, in fact, the carcasses will acquire other strains while mixed in this fecal soup. And we are the premiere lab for ---

(Audio missing due to technical malfunction.)

And these mixed populations that are observed in slaughter samples then, we have to ask ourselves from the scientific standpoint what are these differences between the strains that might be coming from any --- of each individual isolate and with respect to the resistance profiles that may or may not be identified from the selected isolate.

And then we have to ask ourselves then how do we facilitate selecting an isolate. Many members from the laboratory are in the back. To them I owe great deal of thanks. We have had many pizzas over the year, increasing from 1,000 to 5,000 colonies is to integrate my budget there along the pizza lines. So the Pizza Hut will be happy.

So these are some of the questions I think that we have to ask ourselves scientifically. If we look at some of our information, we see that just by random chance, 33 percent of our isolates that we selected over the course of the year were coli as opposed to jejuni which suggests that there is a higher population of coli actually going into the human population.

(Audio missing due to technical malfunction.)

--- associated with jejuni. We do see a much higher resistance with coli compared to jejuni for both the human and poultry isolates. And I will leave you with that.

(Applause.)

DR. BEAULIEU: I quick question for Paula?

MS. : In Europe, we see the same seasonal peaks that you have shown in your material in the U.S. But you also see the same seasonal peaks in the poultry. The thing is that the human peaks ---

(Audio missing due to technical malfunction.)

DR. FEDORKA-CRAY: What we do is seasonal association with Campylobacter also in the poultry production, although this may, in fact, be confounded by region in that we have different climactic areas that we would be dealing with. So the prevalent --- region for any number of reasons.

And then we can -- we have observed some studies which we have been involved with in which there really wasn't much of a seasonal analysis or, in fact, we do find times that it shifts. And those may be due to climactic reasons.

One of the things that Norman Stern has reported on is that when there is a more -- more rain or humid conditions, then the prevalence of Campylobacter increases. So even though you see you may have an off season when you shouldn't be seeing it, say winter, if it a rainy winter that is a little bit warmer, then I would guess that the prevalence of Campylobacter, in fact, may be higher at that point in time. So --

DR. BEAULIEU: One last quick question.

(Away from microphone.)

MR. : A comment. Relative to chillers and in poultry processing plants, the additive of fecal soup, as a veterinarian working in this industry, I feel that that is the thing. That the chillers are mostly after ---, after the food separation of the carcasses, after at least one, two, three --- antimicrobial compounds.

And I might add that there is a zero tolerance for fecal material in chillers established by USIS. And I know of plants --- chillers. If you think this is a small task for simply a chiller that holds thousands of gallons of ice water, let me tell you it is not. So I am taking some exception.

DR. FEDORKA-CRAY: And you are right --- for colony on that. And I should not have mentioned it as fecal soup. I think that when you look into that, you will see a lot of carcasses. And a better description would be that all the carcasses are in close contact with one another and have the ability -- a lot of the Campylobacter contamination does occur on the skin and skin surfaces.

And so the opportunity for mixing and rubbing is there. I meant in no way to imply that they were standing in a lot of fecal soup.

(Away from microphone.)

MR. : Well, even as a --- chiller --- agitated ----.

DR. FEDORKA-CRAY: Yes.

MR. : --- by air. Yes, their contact where there is also separation where the ice and the warmth completely surround the carcasses. But the question I have -- and I saw this in the document that you have just given us. I see here it is referenced where we ---

DR. FEDORKA-CRAY: Right.

MR. : --- as literally an enrichment for growing Campylobacter. Now, when do you do that? Aren't we actually selecting the first stage of development of resistance for ---?

DR. FEDORKA-CRAY: There is a debate about that. And we have talked about that with CDC. We are looking at some of those mechanisms. I think that -- let's see, Nina, do you want to speak to Gerald's -- I think Gerald feels that there is no selection, is that correct, as far as there is no genetic selection ---

(Audio missing due to technical malfunction.)

--- for isolates that are more prone to that first step because they will have to have some resistance to the nalidixic acid to propagate. And there is a disparity in methods in how isolates are selected. And that --- you know, and if that is in fact the case, then all of these graphs and everything have to have a disclaimer associated with it.

We don't use it for our selection purposes. It is an identification tool. But other labs will.

DR. BEAULIEU: Thanks, Dr. Cray. I am sure Dr. Cray will be around for your other questions. I am sure she will be happy to answer those one on one. There is also time set aside this afternoon for additional questions. Go ahead, David.

Our next speaker is David Vose. David is an independent risk analysis consultant currently located in France which I think falls into the category of it is a tough job, but somebody has got to do it. He is an expert in --- risk analysis with ten years experience in simulation modeling. He has applied his expertise to a wide range of problems from oil and gas production to banking to epidemiology all over the world. And David is going to take us through the risk assessment.