Microbiologists from the University of Akron and McMaster University ( Canada) have recovered bacteria from the deepest recesses of Lechuguilla Cave in New Mexico’s Carlsbad Caverns National Park. Five hundred strains of bacteria were extracted from rock formations that have never been exposed to no more than a half-dozen humans. Of the recovered strains, only 93 survived in the scientists’ aboveground lab.
These hardy bacteria subsist on minimal water and only the nutrients they can extract from the subterranean rock. And they do it in total darkness. The microbiologists tested the bacteria against more than 25 different antibiotics, expecting these bacteria to succumb to these modern drugs. Instead, they found that all the microbes were resistant to at least one of the antibiotics. This surprising discovery suggests that bacteria have an ancient mechanism for evading toxic chemicals. Microbiologists have assumed that today’s antibiotic-resistance crisis was caused by increasing exposure of germs to antibiotics in the past 50 years. That is undoubtedly still true, but the newly discovered cave bacteria might give clues as to how germs evade drugs that they have never before confronted.
On Cloud Nine
The atmosphere is an inhospitable place for germs to live compared with soil and water. Dryness, cool temperatures, and excessive exposure to ultraviolet light are hard on a microbial cell. I have even pointed out in my books that the air is the last place a cell wants to spend time. But aeromicrobiologists (scientists who study the microbes in the atmosphere) are now showing that hundreds of trillions of bacteria and fungi probably live in clouds. Because these cells must absorb nutrients from the clouds to stay alive, they directly affect the chemistry of the atmosphere. The cells also act as tiny particles onto which moisture or ice crystals accumulate. When the accumulation grows large enough, it falls to Earth as precipitation, carrying the microbes with it. In this way microbes in the air affect our weather and can even make it rain.