Due to the unawareness of physiological parameters in Venezuela, such as the growth kinetic
and the importance that such parameter involves, the main purpose of this work was to determine
the growth kinetic of five autochthonous isolates (two from books, one from the environment, two
clinical) and one reference strain of the
Aspergillus
section
Fumigati in liquid Sabouraud (LS) by
spectrophotometry. For this, each three days cultures were seeded in agar Sabouraud and LS.
The inoculum was prepared from the third subculture in LS, then homogenized to obtain an O.D.
of 0.024 (540nm), incubated under mechanical agitation at 28 ºC and reading at different times.
The parameters of generation time (GT) and growth velocity (k)) were calculated and each phase
was microscopically observed using lactophenol cotton blue. The growth curves lasted for 39 and
60 h, where the latency phase was observed during the first 24 h of growth, the exponential
phase was of 21-42 h and the stationary phase started at 39 and 60 h. The GT fluctuated
between 9.4- 26.5 h (half: 17.3 h) and k was from 0.026 to 0.074 h-1 (half: 0.047 h-1). A similar
behaviour was noted between the books and environmental isolates whereas the clinical isolates
showed some differences. The isolates coming from books were more rapid in all aspects. The
micromorphological characteristics of each growth phase were similar for the studied fungi. The
results here obtained show the importance of knowing the growth kinetic of
Aspergillus section
Fumigati, since evidenced the kinetic variability in a fungal species.
