Don’t look now, but you are full of germs. Billions and billions and billions of them. Bacteria, viruses, and fungi of all kinds are at this moment cavorting in your saliva, on your skin, and in your bowels. Just your intestines contain about a thousand billion germs per gram of matter; a number greater than the total number of cells in your body. And if you really want to be impressed, just consider that the combined weight of germs in the world is greater than the combined weight of all plants and animals. It’s hard to imagine such an astounding presence, because you can look for germs and not see a single one. Not without a microscope, anyway. But you can imagine the shock and awe when, in the seventeenth century, Antonie van Leeuwen hoek managed to build a microscope that magnified some 200 times! In his own saliva, he saw “many very little living animalcules, very prettily moving. The biggest sort had a very strong and swift motion, and shot through the spittle like a pike does through the water.” This was the first description of the antics of bacteria! Van Leeuwenhoek had no idea of the role his “animalcules” played in life, and would undoubtedly have been shocked to learn that diseases attributed to microbes are the number-one killer of people in the world.
Possibly, Girolamo Fracastoro, an Italian physician who lived 100 years before van Leeuwenhoek, would have interpreted the observation correctly. He had theorized that diseases were transmitted by “seminaria,” tiny particles that were way too small to be seen. But Fracastoro’s theory and van Leeuwenhoek’s observations would not coalesce until the brilliant French chemist Louis Pasteur became interested in why French wines sometimes soured. He investigated numerous wines with his microscope, and found that when the wine was up to snuff, the only microbes present were yeasts from the grape, but when it became cloudy and foul smelling, there were various bacteria present. Where did they come from? Pasteur quickly proved that the source of bacteria was the air. He devised fermentation vessels that prevented contact between the wine and the air and showed that the wine did not sour. Now he began to wonder whether, if microbes could make wine sick, they could do the same to people.
The fact that certain diseases were contagious had long been evident, but nobody knew exactly how they were transmitted. Some clues had, however, been uncovered. Anthrax, an animal disease, could be transmitted if blood from a sick animal was injected into a healthy one, and it was assumed that some chemical in the blood was responsible. Pasteur did not believe this was so. He had observed tiny rod-shaped bacteria in the blood and thought these were the culprits. To prove his point, he devised a clever experiment. Pasteur took a drop of fresh blood from a sheep that had just died from anthrax, and placed it in a flask with a culture medium in which bacteria could multiply. After allowing the microbes to proliferate, he transferred a drop to a second flask, diluted it with water, and again allowed the microbes to multiply. He did this a dozen times, until he was sure that none of the original blood present remained. Still, an animal injected with a sample from the twelfth flask died of anthrax! The disease was not caused by blood, but rather by the bacteria it harbored.
Pasteur’s idea that specific germs caused specific diseases was not immediately accepted. One disbelieving surgeon even challenged him to a duel! Today we know that Pasteur was correct, and that germs are responsible for a great deal of misery. Clostridium difficile, so called because at first it was very difficult to culture in the laboratory, is a particularly nasty microbe. It can cause terrible diarrhea, and is usually acquired in a hospital after a patient has had antibiotic therapy. The hundreds of varieties of bacteria that live in our digestive tract usually do so in harmony; they compete for food and keep each other in check. But antibiotic therapy can wipe out some of the “good” bacteria and allow C. diff to multiply and produce toxins that cause diarrhea or, in severe cases, even permanently damage the large bowel. Infection with this bacterium rarely causes any significant problem for people who are in good health and who have not been on antibiotics.
Usually just stopping antibiotic therapy, if possible, resolves the problem. If not, oral metronidazole or vancomycin is tried. A promising treatment makes use of oral doses of lactobacillus GG (“Culturelle”), a “good” bacterium that can survive the journey through the stomach and suppresses the growth of disease-causing bugs like C. diff. Another fascinating possibility is the insertion of fecal bacteria from a healthy donor into the bowel of a patient with hopes of reestablishing a balance between the good and bad bacteria.
Without a doubt, though, the best way to deal with C. diff is through proper hygiene. The bacterium forms “spores” that can live outside the body for months. Alcohol gels are ineffective against spores, but washing the hands with soap for thirty seconds gets rid of them. Cleaning floors, sinks, and toilets with bleach also destroys the spores. Remember that the ten worst sources of contagion are our fingers. If only hands were washed properly, and repeatedly, the Clostridium difficile problem would not be so difficult to deal with.