Colonization of the oropharynx with pathogenic microorganisms--a potential risk factor for infection in compromised patients.

The indigenous oropharyngeal microflora is complex and consists of many different aerobic and anaerobic microorganisms. Nonindigenous pathogenic microorganisms do not normally colonize the oropharynx due to several different defense mechanisms such as cell specific bacterial attachment, secretion of antibacterial substances and immunoglobulins. Also microbial interactions play an important role in the prevention of new colonization of the oropharynx. Suppression of the indigenous flora by antibiotics promote new colonization. Patients that are severely compromised by disease may be infected by colonizing microorganisms. At special risk are patients with low neutrophil count and patients that are prone to aspiration pneumonia. Thus new colonization should be prevented in such risk patients. Careful monitoring of systemic antimicrobial therapy is essential and decontamination of oropharynx with local antimicrobial agents may be of value.