Methicillin resistant Staphylococcus aureus, or MRSA, is a bacterial infection that is becoming increasingly resistant to the antibiotics designed to treat it. According to a new report by the Centers for Disease Control, or CDC, MRSA now kills more people in the United States than AIDS. In 2005, the death toll from MRSA reached 16,000 in the U.S. alone.

MRSA first showed up as a nosocomial (institution-acquired) infection targeting older adults or people with weakened immune systems. More recently, it has graduated to community-acquired MRSA, or CA-MRSA, and widened its scope to attack the young and healthy. This form of MRSA causes serious skin and soft tissue infections, sometimes known as "flesh-eating" bacteria. It can also cause a highly virulent form of pneumonia. Several newly discovered strains of MRSA show antibiotic resistance even to third-generation, intravenous antibiotics like vancomycin and teicoplanin.

The first case of MRSA in a human occurred in 1961. The first reported outbreak of MRSA happened in 1968 in a Boston hospital. It is only in the last month that scientists in the U.S. started studying pigs, which were first identified as MRSA carriers in 2003, when researchers in the Netherlands identified MRSA strain number ST398 and linked it to several human deaths from pneumonia in the region.

In June, a study conducted by the University of Iowa showed MRSA strains in more than 70 percent of the 209 pigs tested on 10 farms in Iowa and Illinois. The researchers, led by Tara Smith, also found MRSA in almost half the 20 workers employed at those locations.

According to Abby Harper, one of Smith's graduate students, there are indications that the antibiotics routinely used in pig farming - specifically tetracycline - may be the cause of the spread of MRSA. Other researchers have also noted the synchronous rise of CA-MRSA in humans in the 1990s and the simultaneous introduction of antibiotic regimens on pig farms.

The agent (of disease) may not be tetracycline itself, but the fact that pigs regularly treated with it develop an immunity to it, just like humans, and this immunity can then be transferred, along with the bacteria, to the pig's human caretakers. If so, the routine use of antibiotics in pig farming, coupled with the indiscriminate use of those same antibiotics in human populations, may be a recipe for a pandemic to rival the 1918 Spanish Flu that swept the world, killing 50 to 100 million people before it disappeared. 

So far, no one has tested MRSA patients in hospitals to see if they carry the strain (ST398) now found in pigs. The US Department of Agriculture (USDA) is responsible for testing imported meat for pathogens, but doesn't have a test for MRSA. Even if it did, processing or cooking meat kills bacteria, so the testing is likely to provide little benefit.

The US Food and Drug Administration, or FDA, is nominally responsible for testing meat produced locally, but so far has not taken the initiative. An industry group, the National Pork Board, also says it intends to start testing for the germ in the near future, but this is the same group that formerly lobbied against testing for fear the discoveries would lead to reduced pork sales. The American Association of Swine Veterinarians, at its 2008 annual meeting, did collect nasal swabs from 150 volunteers, and the results show an MRSA prevalence of 7 percent among American veterinarians, even though this sampling is far from the rigorous protocols essential to a scientific study.

The most interesting part of this epidemic is a second strain, USA100, which was discovered in Ontario, Canada, in 2007 among both pigs and their human caretakers. Since this strain is most often associated with humans, researchers concluded that MRSA transmission goes both ways - from pigs to humans and from humans to pigs.

The transmission isn't all that surprising. Pigs are known for their ability to harbor bacteria and transmute them into new, and even more dangerous, diseases. This awareness - of the uncleanness of pig flesh - has been part of human culture for centuries and is the historic reason behind Jewish and Muslim taboos against eating pork (the religious tradition came later). Pigs are also very similar to humans in anatomical terms, so the bacteria they mutate pass easily to their caretakers, and from them to the population at large.

Smith intends to continue her research, working with associates in Minnesota, Ohio and North Carolina to examine more pig farms, both free-range (organic) and conventional operations using antibiotics. In the UK, where three people not associated with pig farming or meat handling have come down with MRSA ST398, there is an immediate need to discover if MRSA has entered the food chain.

Because the 398 strain is resistant to tetracyclines, the most commonly used antibiotic, it becomes more difficult for doctors to isolate it as the cause and then select appropriate, affordable remedies in a timely manner. This could make having the strain a matter of life and death, according to the UK's Department for Environment, Food and Rural Affairs policy advisor Richard Young.

The bad news is, pork eaters in every nation may already be infected. MRSA, which usually lives in nasal passages and does not always sicken its carrier, is nonetheless one of the new "superbugs" that shows the potential to affect large portions of the population rather quickly if it develops additional resistance, or mutates.  

The good news is that researchers in the UK have found that plain old garlic is more effective against MRSA than any antibiotic currently on the market. University of East London scientists found that the ingredient in garlic that makes it smell so offensive (allicin) is also a potent weapon, and a new, stable, aqueous extract has been used to treat even the most persistent strains of MRSA.

The reason you haven't heard more about this is because the drug companies don't want you to know. They don't have a patent on garlic, or allicin, so they prefer that doctors continue to prescribe prohibitively expensive and sometimes ineffective third-generation antibiotics that can only be delivered via intravenous solution. This way, both the drug companies and the hospitals make money.

Nonetheless, if you can tolerate the odor and the taste, this humble herb is apparently the newest cure for stubborn strains of deadly MRSA. Just don't stand too close to your fellow subway riders.