Israel Medical Association Journal

Objective: To reexamine the impact of prolonged nasogastric tube feeding on the oral microbiota and to explore the salivary flow and composition in elderly patients in long-term care.

Methods: We compared a group of elderly patients fed by nasogastric tube with a control group of elderly patients in long-term care who are fed orally. Bacteriologic studies were performed by culturing samples from the oropharynx. Saliva studies included quantitative and biochemical analysis of basal and stimulated salivary flow.

Results: Bacteriologic studies performed in 90 patients revealed a significantly higher prevalence of gram-negative bacteria in nasogastric tube-fed patients (73% vs. 13%, P < 0.001). It is emphasized that Pseudomonas aeruginosa and Klebsiella pneumoniae were commonly and exclusively isolated from the oral flora of the nasogastric tube-fed patients (P < 0.001, P < 0.05). In the saliva studies performed on 23 nasogastric tube-fed and 21 control patients, basal and stimulated salivary flow was not significantly different in the two groups, however the ratio of stimulated to basal flow was reduced in the nasogastric tube-fed group (P < 0.05). Significant differences were also found in the concentrations of sodium, amylase, phosphor and magnesium. Noteworthy was the concentration of uric acid, the main non-enzymatic antioxidant of saliva, which was significantly lower in nasogastric-tube fed patients (P < 0.002).

Conclusions: These findings suggest that prolonged nasogastric tube feeding is associated with pathologic colonization of the oropharynx and with alterations in the saliva that are related to the risk of aspiration pneumonia. Further research is called for, as well as a thorough revision of the existing oral cleansing procedures in these patients.

Background: Factors influencing the oral flora of premature infants have not been adequately investigated.

Objective: To investigate the effects of gestational age and of anti-bacterial therapy on the oral flora of premature infants.

Methods: Oral cultures were obtained at age 1 day and age 10 days from 65 premature infants, divided into three groups: a) 24 neonates of 30-34 weeks gestation who did not receive ABT, b) 23 neonates of 30-34 weeks gestation who received ABT, and c) 18 neonates < 30 weeks gestation who received ABT.

Results: Oral bacterial colonization increased from day 1 to day 10 of life. In 24-34 week neonates, gestational age did not affect early bacteremia or oral colonization at birth. Neither gestational age nor ABT affected late bacteremia or oral colonization at day 10. In 30-34 week neonates with ABT, the oral flora consisted mainly of non-Escherichia coli gram-negative bacteria, whereas those who did not receive ABT grew mainly alpha-hemolytic streptococci, Klebsiella pneumoniae and E. coli in neonates < 30 weeks who received ABT the oral flora were mainly coagulase-negative staphylococci. Oral colonization with anearobes was zero and colonization with fungi was minimal.

Conclusions: Acquistion of oral bacteria rose from day 1 to day 10 of life, regardless of gestational life or ABT. On day 10 of life, the spectrum of oral bacterial flora changed following ABT and consisted mainly of coagulase-negative Staphylococcus and non E. coli garm-negative bacteria. Oral colonization showed few fungi but no anaerobes. These microbiologic observations merit attention when empirical anti-microbial therapy is considered in premature infants suspected or having late-onset sepsis.