"Bugs" and Drugs

While I was Twittering away I came across this cool articles about drug resistant bacteria from National Geographic http://news.nationalgeographic.com/news/2012/04/120411-drug-resistance-bacteria-caves-diseases-human-health-science/ Articles about drug-resistant bacteria are fairly common, and we’ve all been told don’t overuse antibiotics because you’ll create a “superbug” that will be resistant to all available antibiotics. In fact, there are some isolated cases that suggest this is already happening for TB, and antibiotics not used properly have taken the blame.

This article could change all that. Microbiologists have found close to 100 types of bacteria that are resistant to modern antibiotics in the Lechuguilla cave system in New Mexico. What is really interesting is that this cave has been completely isolated from humans – a thick dome of rock isolated the cave 4-7 million years ago. The cave was untouched until cavers unveiled it in 1986. Entrance to the cave is strictly restricted, but microbiologist Hazel Barton and her team have been in the cave to sample microbial life. The samples were sent to Gerry Wright at McMaster (Yay Mac!) and tested for signs of antibiotic resistance. The Wright lab was able to grow 93 types of bacteria for testing, and 70% of the bacteria were resistant to 3-4 classes of antibiotics! This is amazing because it suggests that the bacteria naturally have resistance to antibiotics, and the medicinal use of antibiotics hasn’t created the resistance that’s seen now. These bacteria have never “seen” the antibiotics we use. It may be possible that other bacteria that hasn’t been isolated from humans also naturally contained antibiotic resistance, which they passed to pathogenic bacteria. Bacteria that are growing nearby are able to undergo conjugation, which is an exchange of non-essential DNA called plasmids. These plasmids usually contain DNA that codes for antibiotic resistance. Bacteria that were already antibiotic resistance could have given their plasmids to pathogenic bacteria, making them antibiotic resistant too.

Like almost all science, there are some concerns about this research. It’s not known how the antibiotic resistance genes get into the hospital, where they can causes disease like MRSA. It is also possible that what they are observing from the cave looks like antibiotic resistance but is actually something else. Finally, it’s not known how the resistance occurred – did the bacteria generate antibiotics and then the resistance developed, or was the resistance always there and it was just observed when we started using antibiotics? In any case, this finding is pretty cool and leaves open lots of room for future investigations in this cave. Please note – just because these findings suggest new origins for antibiotic resistance in bacteria doesn’t mean you need to change how you take antibiotics. Not all “bugs” need drugs! And if your bug does need some drugs, make sure you take them as prescribed – don’t stop, even if you feel better! Not all bacteria die at the same rate, so you might feel better but could have a little lingering around so make sure you finish your antibiotics course!

C