Tongue Microbiota Is Disturbed In Elderly Adults Fed By Tube

Objectives: Enteral tube feeding is widely used to maintain nutrition for elderly adults with eating difficulties but has become associated with worse prognosis. We examined the oral microbiota composition of the tube-fed elderly adults, which is the primary source of aspiration pneumonia. Methods: The bacterial community structure on tongue surface of 98 institutionalized elderly adults aged 65 and over was investigated by analyzing 16S rRNA gene. The terminal restriction fragments length polymorphism (T-RFLP) profiles of the 44 tube fed subjects were compared with those of the 54 orally fed subjects. To characterize the differences in more detail, the 454-based pyrosequencing data were also obtained in the 17 subjects of each group. Additionally, we observed the health outcome for the following six months after sample collection. Results: The T-RFLP profiles demonstrated that the microbiota composition of tube-fed subjects was distinct from that of orally fed ones. The pyrosequencing data further revealed that Corynebacterium, Fusobacterium, Peptostreptococcus, Parvimonas and Porphyromonas accounted for markedly high proportions in tube-fed subjects, whereas dominant genera in orally fed ones were much less predominant. The opportunistic pathogens rarely detected in normal oral microbiota, such as Streptococcus agalactiae and Corynebacterium striatum were often found in unexpectedly high proportions. The mortality and incidence of pneumonia or fever were significantly higher than the orally fed subjects. Conclusion: The oral indigenous microbiota is disturbed in the use of enteral feeding, allowing health-threatening bacteria to thrive. It may lead to poor outcome of this intervention.