A model of bacterial-antimicrobial interactions: the case of oropharyngeal and gastrointestinal microflora.

The normal human oropharyngeal and gastrointestinal microflora is a complex ecosystem in a symbiotic relationship with the host. The microflora helps to prevent invasion of pathogens and participates in several metabolic processes. On the other hand, under certain conditions members of the normal microflora can cause serious infections. Administration of antimicrobial agents may cause severe alterations in the normal microflora. Suppression of the anaerobic flora has been associated with decreased colonization resistance, i.e. the resistance of the normal host to the implantation of exogenous microorganisms.