Influence of faeces on the activity of antimicrobial agents used for decontamination of the alimentary canal.

The influence of faeces on the activity of 9 antibiotics currently used for selective decontamination of the digestive tract was studied. These in vitro findings showed that the antimicrobial activity is differently affected by the presence and concentration of faeces. Great differences in loss of activity were observed on different microorganisms. Decontaminating drugs which were found to be minimally inactivated in vitro by the presence of faeces are proven to be superior in clinical studies too.