Growth characteristics of Aspergillus isolated from clinical infective cornea

Objective To analyze the growth characteristics of the clinical isolates of Aspergillus compared to standard strains in vitro. Methods The sabourauds agar medium (SDA), yeast extract medium(YG) and potato dextrose agar medium (PDA) were used to test two clinical isolates and one standard strain.The strains were incubated at 29 ℃ for 96 hours.In liquid medium, the optical density (OD) values at 0 hour, 4, 8, 12, 24, 36, 48, 60, 72 and 96 hours after culture were recorded to generate growth curves for each strain and culture medium.Meanwhile, on solid medium, the features of colony morphology were recorded. Results In liquid medium, the growth curves were not significantly different between clinical isolates and standard strain in PDA medium (all at P<0.05), while the differences were obvious in SDA medium and YG medium (P<0.05). The clinical isolates showed shorter lag phase and higher growth rate than standard strain.On solid medium, all strains appeared the best growth state on PDA medium and the poorest state on SDA medium.Color change time was later on YG medium than that on the other medium.The clinical isolates performed better on the aspects of colony sizes and color change than standard strain when growed on the same medium, especially on SDA medium. Conclusions Compared with standard strain, the clinical isolates of Aspergillus have higher adaptive capacity to poor nutrition condition. Key words: Clinical isolates; Standard strain; Aspergillus; Growth characteristics