OBJECTIVE: To evaluate the influence of neonatal malnutrition on the pattern and growth of aerobic bacteria of the normal bacterial flora of the oral cavity in adults Wistar rats. METHODS: In the present study, the material of the oral cavity was collected through swabs soaked in 40µL of sterile saline solution. After the collection, each swab was placed in a sterile tube containing 960µL of brain heart infusion. Later, the samples were homogenized. Then, from the 1.000µL, 1µL was collected with a gauged loop to be sowed in Petri dishes containing Agar-blood and Agar-Levine, for the isolation and identification of the Gram-positive and Gram-negative bacteria respectively. The plates were placed into a bacteriological incubator, 37ºC, for 48 hours and the colony-forming units that grew were counted and their percentages were calculated. For bacterioscopy, slides were stained with the Gram method. RESULTS: From the 5th to the 21st day of life, body weight of the undernourished group (33.6g:42.8g, standard deviation=27.2g) was smaller (p<0.001) than that of the nourished group (52.5g:56.3g, standard deviation=24.0g). From the 60th to the 120th days of life the body weight of the undernourished group (7.4.x.10(6) colony-forming units, standard deviation=1,0x10(6) colony-forming units bacteria/mL) decreased when compared to that of the nourished group (306.2g:319.4g, standard deviation=219.5g), Mann-Whitney test, p<0,05. The microbiota was composed of a smaller number of bacteria in the nourished group (4.2 x10(6) colony-forming units, standard deviation=1.2x10(6) colony-forming units bacteria/mL) when compared with the undernourished group (7.4x10(6) colony-forming units, standard deviation=1.0x10(6) colony-forming units bacteria/mL), Student's "t" test (p=0.026). From the bacteria isolated in cultures, a similar bacterial pattern was observed in both groups, with 70% of Gram-positive bacteria and 30% of Gram-negative bacteria. CONCLUSION: Neonatal malnutrition was effective in decreasing body weight and increasing bacterial growth. Although the bacterial pattern was not altered, the increase in bacterial growth may induce an imbalance of the oral microbiota, being a threat to the host.
bacteria; aerobic; mouth; neonatal malnutrition; rats Wistar
