A laboratory microcosm (artificial mouth) for the culture and continuous pH measurement of oral bacteria on surfaces

• Published in: Journal of applied bacteriology Vol. 60; no. 4; p. 301
• Main Authors: Hudson, D E, Donoghue, H D, Perrons, C J
• Format: Journal Article
• Language: English
• Published: England 01.04.1986
• Subjects: Bacteriological Techniques; Bicuspid - microbiology; Culture Media; Hydrogen-Ion Concentration; Lactates - biosynthesis; Lactic Acid; Mouth - microbiology; Saliva, Artificial; Streptococcus - growth & development; Streptococcus - metabolism
• ISSN: 0021-8847
• DOI: 10.1111/j.1365-2672.1986.tb01737.x

A laboratory microcosm has been designed for the cultivation of bacteria on surfaces subjected to an adjustable supply of fluids. Bacteria are grown as a microbial film on halved premolar teeth, mounted back to back. Synthetic saliva is dropped slowly over the teeth throughout experiments. A nutrient supplement is provided at regular intervals. The drops of fluid retained by the teeth can be sampled for metabolic end-products. Alternatively, a miniature glass electrode may be set into one half of a tooth assembly to monitor the pH continuously at the stagnation site between tooth segments. Up to six replicate culture flasks and six electrodes can be accommodated in a single experiment. Satisfactory electrode performance was maintained during 66 h experiments. In initial 48 h experiments, teeth were inoculated with Streptococcus rattus BHT or 'Streptococcus mitior' LPA-1 in pure culture and provided with 1% (w/v) glucose for 1 h every 6 h. Bacteria produced typical responses to glucose feeds leading to the formation of 'Stephan'-like curves of pH-fall. Under these conditions, 'Strep. mitior' was more acidogenic than Strep. rattus and the pattern of acid production was distinct for each organism.