Safety Bites!

An important thing to bear in mind, as a person begins studying microbiology and realizes just how ubiquitous germs are, is that a healthy sense of perspective is always a good thing to have.

This mischievious little creature here is a jackdaw (Corvus monedula). Like its fellow corvids, the crows and the ravens, jackdaws are intelligent, social birds. They are great thiefs with a penchant for shiny objects, and have the smarts to get what they want from man-made environments.

This mischievious little creature here is Campylobacter jejuni, a bacteria that causes a diarrheal disease. C. jejuni is found on many different kinds of birds - if you were enough of a gourmand that you like to lick raw chickens or something, you’ll soon be very familar with this little guy.

In other words, one of the fastest ways of being infected with C. jejuni is to simply eat undercooked chicken. Or, you could also be an English person in an area full of jackdaws, and who drinks home-delivered milk!

A case-control study showed that there was a strong association between patients who contracted Campylobacter and drinking pecked milk. In other words, the chain of infection went like this:

1) A jackdaw, being as smart as any bird can be, figures out that those bottles carry wonderful, wonderful milk.

2) This jackdaw then punches its beak into the foil milk cap, effectively injecting the milk of some poor person with an infectious dose of C. jejuni.

3) The owner of the milk drinks it, and gets sick.

Epidemiology in a nutshell. Easy, right?***

The solution, in the case, of course, is to use hard plastic or metal caps so that the jackdaws cannot contaminate the milk. But realizations like these are often made on hindsight - it’s not really obvious that a bottle of milk would get contaminated by clever birds unless one observed or thought about it.

The point is, illnesses can come from the most unexpected sources. Proper precautions can be taken, but in the end, you’d never know.. illnesses can just come flying down on you, just like that. This is where a sense of perspective comes in handy - most people don’t get sick from cases like these, and most of us have healthy immune systems that resist the frequent microbial challenges our bodies face every day. So, why overworry?

Today’s thought is - take proper precautions, but don’t sweat the microscopic stuff!

*** Actually, it’s not.

It’s really hard to think of good things to say about flesh-eating bacteria, in general, except this – it really, really gets the attention of people otherwise disinterested in microbiology. It’s not easy to be all blasé when you read a newspaper with a headline screaming stuff like:

OH, NO, FLESH EATING BACTERIA STRIKES AGAIN!!!!

And:

FLESH EATING BACTERIA DEVOURED ELVIS AT A GAS PUMP IN BAKERSFIELD, CALIFORNIA!!!

The media do love their flesh-eating bacteria, you know. And who can blame them, really? The effects of so-called flesh-eating bacteria are as graphic as you might imagine – the bacteria, once they’ve introduced into the deeper layers of your flesh, start tearing you apart from the inside out. I’ve seen photos of red, raw flesh hanging off an arm bone belong to a victim of this disease. There’s been a case, recently, of a new-born baby contracting the disease – to save her life, surgeons had to amputate all of her limbs.

And for this ghastly disease, there is an equally ghoulish scientific name: necrotizing fasciitis, which in Latin, roughly means “cell-destroying inflammation of the connective tissue,” and also means, more precisely, “Hoo, boy, are you screwed now, (sad face).”

I should point out, though, that there are a couple of things that are often missed when it comes to flesh-eating bacteria. First, it’s not just one kind of bacteria that causes necrotizing fasciitis. Streptococcus pyogenes, and Staphylococcus aureus are just some of the little jerks running around, having a field day in your body. If your body is a temple, then these guys are like ruthless savages, pulling down your connective tissues like so many supporting columns and buttresses. If your body is a frat house, well, you probably needed that trip to the doctor’s anyhow. (Kidding, kidding!).

But it’s also unfair to place all of the blame on the bacteria. See, the other thing that often goes unmentioned is the fact that while the bacteria do start the party, your own immune system is complicit in this bacterial bacchanalia as well.

That’s right – your own immune cells, usually macrophages, are also degrading your flesh. Streptococcus bacteria, in particular, release a toxin that acts as a superantigen. An antigen, very quickly, is something that activates the immune system. A superantigen not only activates the immune system, it also tells the immune system, “Hark, there are demonic hosts in the larder, your fortress is falling apart, and God hates you.” The immune system then overreacts, so to speak, causing a hyper-immune response. This hyper-immune response, in turn, destroys cells. Tiny blood vessels are also damaged or clogged, depriving tissue of oxygen and causing even more tissue damage.

But those of you worried about imminent zombification – rest easy! Although necrotizing fasciitis is some really bad stuff, the actual occurrence of the disease is pretty rare. Two of the pathogens most frequently implicated in necrotizing fasciitis, S. aureus and S. pyogenes, are fairly common bacteria – the former colonizes as many as 20% of all humans, and maybe more, depending on who you ask. The fact that the disease is so rare even when its causative organisms are so common points to how infrequently the disease strikes.

So stand tall, and tell the S. aureus on your skin – today’s not the day! (No, not out loud. If anyone caught you talking with the bacteria on your skin, you’d be in the hospital for an entirely different reason).

Moral of the Story:

Flesh-eating bacteria may destroy you, but only if you have like, major bad luck. Also, having necrotizing fasciitis may be one of the very few justified reasons for massive bouts of self-pity, so emo song-writers, take heed, and start writing!

In 1865, a young man named Robert Koch published his report, full of long Teutonic words like Menschlichen, about the effects of eating a half-pound of butter every day.

With that auspicious start, Koch embarked on a remarkable career in the sciences – among other things, the good German doctor discovered the causative agents for anthrax and tuberculosis, and invented pure culture technique. Along the way, he developed a bitter rivalry with Louis Pasteur, dumped his wife for a 17-year old girl, killed several people with a non-miraculous miracle cure – and eventually, claimed a Nobel Prize. All in all, a fine, eventful career!

But first, let’s turn back the clock several decades — Koch, then a young(ish) doctor, was milling around the countryside, doing doctor-y things, and developing an interest in that old warhorse, anthrax. Quiz time, folks – what is anthrax?

Is anthrax :

i) Scary white stuff that turns up in the US Postal Service when the planets align right?
ii) HAIR GODS OF HEAVY METAL?
iii) A deadly bacteria-borne disease that can spread by infectious spores?

The answer, folks, is all of the above, of course! However, at the time, anthrax was more associated with sheep and farmers than with white powder in envelopes and metal bands, so Koch, being a countryside doctor, made it his business. And yes, I realize that HEAVY METAL GODS are more associated with goats then they are with sheep, but the less I say about that, the less I’m going to worry that Pat Robertson is going to walk out of my closet and do the cha-cha on my back, so I’m moving on.

In any case, our intrepid hero set forth with his weapons of choice, wooden splinters dipped in anthrax-infested sheep’s blood, and stabbed several terrified mice with them. History does not record what the mice had to say about their working relationship with Koch, but it is safe to assume that they just could not stand up to the man. It’s hard to stand up in general when infected with anthrax, I hear.

Koch, in a move that was as much ingenious as it was downright creepy, then drained a cow’s eye and used the liquid to grow, for the first time in human history, pure cultures of bacteria. Not satisfied with just that, Koch inoculated mice with this pure culture, giving them anthrax. By doing so, Koch had taken germs from mice, cultured the germs and then reinfected the mice, showing a chain of transmission. This is the Circle of Life, and it moves us all. (Not really.)

This discovery proved Louis Pasteur’s Germ Theory, which according to some accounts, pissed the French scientist off to no end because he had wanted to prove it himself. Other accounts indicate that Koch severely criticized Pasteur in his anthrax writings, targeting Pasteur’s later success in devising an anthrax vaccine based on Koch’s findings. In truth, both men had it out for each other, and accused each other of using impure cultures in their discoveries, as seen in this transcript of a heated debate between them :-

PASTEUR : Mousieur, your methods do not ensure purity as mine do. Please go home and cry.

KOCH: I think not. I submit that my methods produce cultures that are purer than your mother. I also submit that you fail at life.

A bitter rivalry soon sprung up between the two great scientists, stoked by nationalism. It was a veritable microbiology boxing match between France and Germany, with Koch and Pasteur facing off against each other. Very much like Rocky Balboa and Ivan Drago, except without the flying droplets of sweat and machismo.

In the next installment of Cow Eye Koch, Intrepid Microbiologist – Fun With Cholera!