Low antibiotic concentration increases antimicrobial resistance

Existing antimicrobial resistance may become increasingly prevalent on its own -- with no interference from antibiotics -- in compact bacterial communities known as biofilms, or when protozoa hunt bacteria for food. Even weak antibiotic concentrations are sufficient to cause a rise in the prevalence of antimicrobial resistance in bacterial populations cultured in laboratory conditions.

Antimicrobial resistance is a trait that can spread within a bacterial species or even across the species barrier. Resistance will expand and become increasingly prevalent when bacteria that survive in an environment containing antibiotics genetically pass on or otherwise distribute this trait to other bacteria.

Recent studies indicate that even weak antibiotic concentrations are sufficient to cause a rise in the prevalence of antimicrobial resistance in bacterial populations cultured in laboratory conditions. Such conditions are brought about when antibiotics used to treat both human and animal infections end up in sewage or elsewhere in the environment.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology