4. Antimicrobial drug resistance
Richard D Smith, Joanna Coast.
Antimicrobial resistance & its economic conceptualisation
- Micro-organisms are resistant to a drug when they multiply in concentrations higher than those achievable in humans receiving therapeutic doses
- AMR is a natural reaction to use of drugs
- There is uncertainty surrounding the development and spread of AMR
- Once AMR develops it is exacerbated by 'modern life'
Micro-organisms are said to be resistant to a specific antimicrobial drug when they are able to multiply in the presence of drug concentrations higher than those achievable in humans receiving therapeutic doses.
AMR is a natural biological phenomenon, caused by the selection of resistant micro-organisms as a direct consequence of the use of antimicrobial treatments.
There is considerable uncertainty surrounding the development and spread of resistance resulting from poor knowledge about basic scientific, clinical and epidemiological factors, with further uncertainties about the costs and benefits associated with treatment. Resistance may be acquired by previously sensitive isolates from the environment, from other organisms, from bacteriophages or through random mutation.
Although using antimicrobials exerts a selection pressure favouring the emergence of resistance, but for any specific antimicrobial the correlation between consumption and resistance is complicated by factors such as the relative fitness of resistant and sensitive strains and linked multiple resistances. However, once resistance has developed, its spread is exacerbated by a number of aspects of modern society including increasing international travel, ecosystem disturbances, war, the rapid growth of large cities and increasing numbers of people compromised immune systems.