One of today’s top global health crisis is the threat stemming from the rise of antibiotic resistance. Antibiotic resistance refers to the ability of potentially harmful microorganisms to be unresponsive to, or unaffected by, the effects of antibiotics. 1 Modern uses of antibiotics (including in livestock as growth promotion) have generated resistance in many of our antibiotics. 2
Brought about primarily by exposure to sub-lethal doses of antibiotics, antibiotic resistance occurs because microorganisms adapt and change in order to survive. In the face of hostile environments, these pathogens are able to alter themselves rapidly in order to reduce the effectiveness of our antibiotics. If you like, sub lethal doses of antibiotics act like vaccines for micro-organisms.
One of the most interesting of resistance mechanisms is something called “horizontal gene transfer”, a process by which bacteria are able to swap genetic material. Antibiotics kill only the susceptible bacteria. Resistant strains of bacteria that survive these antibiotics multiply, replacing the susceptible bacteria, and communicate important survival mechanisms to neighbouring bacteria. In this manner, bacteria can become resistant to multiple drugs, and in some cases, all antibiotics. Patients who are regularly subjected to multiple doses, sub lethal doses or even long term doses of antibiotics can find themselves over time, unresponsive to many of today’s antibiotic arsenal, and therefore vulnerable to infection. With so few new classes of antibiotics under development, the prospect of developing multiple antibiotic resistance is truly worrisome.
- Tiwari R, Tiwari G. Use of antibiotics: From preceding to contemporary. Scho Res J [serial online] 2011 [cited 2014 Jan 15];1:59-68. Available from: http://www.scholarsjournal.in/text.asp?2011/1/2/59/99659