The week of October 6th is antibiotic resistance week. We will explore how pathogens evolve resistance to antimicrobial agents and how medical professionals and researchers can develop strategies to reduce the evolution of resistance.
On tuesday we will discuss 4 strategies for reducing bacterial evolution of resistance.
1) Limiting use of antibiotics to proven bacterial infections and making sure that patients take their full course. This is what the CDC recommends. Some doctors are valiantly trying to make this a reality. Will they be successful?
2) Designing new antibiotics as the old ones become obsolete. Pharmacologists are screening thousands of plant and insect and other organisms for antimicrobial activity. There can be great financial reward in inventing a new antibiotic. Therefore the free market and the impressive capabilities of modern biotechnology should meet the needs of people into perpetuity. (Right?)
3) Cycling antibiotics. If you have 4 classes of antibiotics, you would use only one class for a certain period of time, then switch to the next, and so on over a predetermined period of time. The idea would be that just when bacteria might start to develop resistance, you switch to another. By the time you return to any given antibiotic in a cycle, hopefully the bacterial population would be sensitive to it. The rationale for persistence of sensitivity is that in between the times that antibiotic #1 is used, the bacterial population would have been selected for resistance to different antibiotics (#2, 3, 4)and they would lose resistance to the antibiotic #1. Seems logical doesn’t it?
4) Holding some antibiotics in reserve. Because much of the time resistance is incomplete, sometimes doctors can get some benefit from increasing dosages or increasing the schedule of older drugs. Then when necessary we pull the bigger guns off the shelf.
It turns out that some of these have been tested. Some work better than others, and there is an interesting quirk of bacterial biology that gives promise to strategy #4.
Tuesday’s discussion will borrow heavily from the work of Miriam Barlow PhD (of UC Merced, California), who gave a lecture at UNM last spring. I will present some evidence of hers to the group for discussion.
See you then,
Joe Alcock MD
Emergency Physician, Educator, Researcher, interested in the microbiome, evolution, and medicine