Treatment Time Can Contribute to Resistance

If drug concentration drops below the MIC before infection is cleared, residual pathogens may regrow and cause disease relapse. During regrowth, spontaneous errors in DNA replication generate new resistant mutants, and the resulting mutant subpopulations will be enriched when antibiotic therapy is restarted. Successive rounds of treatment and relapse with the same type of antibiotic contribute to the emergence of resistant pathogen populations. Traditional treatment strategy calls for antibiotic therapy to be long enough to eliminate most, if not all, of the susceptible pathogen population. Whether the usual 10-day period is long enough or too long is not known. Longer treatment places more selective pressure on commensal bacteria, and in ....