ISOLATION OF ENTEROBACTERIACEAE FROM THE MOUTH AND POTENTIAL ASSOCIATION WITH MALODOR

Bad breath is a common phenomenon, usually the result of bacterial met abolism in the oral cavity. It is generally accepted that Gram-negativ e bacteria are responsible for this problem, largely through degradati on of proteinaceous substances. In initial experiments, screening of m alodorous isolates following outgrowth of samples obtained from saliva , periodontal pockets, and the tongue dorsum yielded enterobacterial i solates. Clinical studies were conducted to examine the prevalence of such bacteria in four different populations: orthodontic patients, mal odor clinic patients, complete-denture wearers, and a healthy young po pulation. The prevalence of Enterobacteriaceae in the oral cavities of the denture-wearing population was very high (48.0%) as compared with the other groups: 27.1% in the malodor clinic patients, 16.4% in the normal population, and 13% among orthodontic patients. Isolates of Kle bsiella and Enterobacter emitted foul odors in vitro which resembled b ad breath, with concomitant production of volatile sulfides and cadave rine, both compounds related to bad breath. When incubated on a steril e denture, enterobacterial isolates produced typical denture foul odor . Isolates exhibited cell-surface hydrophobic properties when tested f or adhesion to acryl and aggregation with ammonium sulphate. The resul ts, taken together, suggest that Klebsiella and related Enterobacteria ceae may play a role in denture malodor.