Volume 8, Number 4—April 2002
Perspective
Antimicrobial Use and Antimicrobial Resistance: A Population Perspective
Marc Lipsitch*
and Matthew Samore†
and Matthew Samore†Table
Mechanisms by which antimicrobial treatment has direct and indirect effects on resistance
| Mechanism (effect of treatment) | Relationship between selection for resistance and treatment success | Relationship between no./dose of antibiotics and selection | Examples | Figure |
|---|---|---|---|---|
| mergence of resistance during treatment (Da, Ib) | (−)c | (−) | TB, HIV, Pseudomonas aeruginosa, Enterobacter spp. | 1a |
| Reduced transmission of susceptible strains (I) | (+)d | (+) | May occur for nearly every infection | 1b |
| Increased susceptibility to colonization (D, I,) | ?e | ? | Commensals of skin, intestinal and respiratory tracts | 1c |
| Increased density of colonization in individuals already colonized with resistant organisms, by inhibiting competitors (D,I) | ? | (+)−? | VREf and antianaerobic treatments | 1d |
aD=direct.
bI=indirect.
c(-)=inverse relationship.
d(+)=positive relationship.
e?=relationship uncertain.
fVRE=vancomycin-resistant Enterococci.
