Hn. Williams et al., EVALUATION AND USE OF A LOW NUTRIENT MEDIUM AND REDUCED INCUBATION-TEMPERATURE TO STUDY BACTERIAL-CONTAMINATION IN THE WATER-SUPPLY OF DENTAL UNITS, Canadian journal of microbiology, 40(2), 1994, pp. 127-131
A low nutrient medium, dilute peptone, and reduced incubation temperat
ures (25 or 30 degrees C) were used to recover bacteria from dental un
it water supply. Significantly greater numbers of bacterial colony-for
ming units were recovered on the dilute peptone medium than on the enr
iched media, blood agar or trypticase soy agar. Lower incubation tempe
ratures yielded greater numbers of colony-forming units on all media.
The bacterial population in dental unit water supply following stagnat
ion in the supply lines and flushing of the lines was studied using di
lute peptone incubated at 25 degrees C. No significant differences in
the numbers of colony-forming units were found in stagnant water versu
s fresh water. Flushing the water lines for 10 min did not significant
ly reduce the numbers of colony-forming units.