COMPARATIVE STUDY OF MICROCALORIMETRIC BEHAVIOR OFESCHERICHIA COLI, PROTEUS MIRABILIS AND KLEBSIELLAPNEUMONIAE
Natividad Lago Rivero, José L. Legido, Isaac Arias Santos, Lidia M. Casás Pol J Microbiol 2012; 61 (3): ICID: 1014507 Article type: Original article IC™ Value: 10.00
Abstract provided by Publisher
Purpose: To analyze the microcalorimetric behaviour of Escherichia coli, Proteus
mirabilis and Klebsiella pneumoniae, to study the contribution of
microcalorimetry in the early diagnosis of infections by enterobacteria.
Methods and materials: We started of pure bacterial of E. coli, P. mirabilis
and K. pneumoniae. Its concentration was adjusted to a turbidity of 0.5 on the
Mcfarland scale, and diluted it with physiological saline solution to obtain final
concentrations of 106,105,103, and 10 CFU/ml.
As experimental equipment we used a Calvet microcalorimeter, inside which a
constant temperature of 309 K was maintained.
Results: Using the experimental difference of heat power generated by the cells
over time, we obtained growth graphs of the three enterobacteria at different
concentrations. The curves obtained have a characteristic form that repeats for
each bacteria species at all the concentrations studied. Furthermore, we observed
an inversely proportional relationship between inoculum size and the time until
signal detection; with this reducing on increasing the concentration of the culture.
In any case, even at low concentrations (10 CFU/ml), we can identify bacterial
growth in the sample within 8 hours.
Conclusions: Microcalorimetry is an efficient technique in the early detection and
identification of enterobacteria in a culture medium.