临床分离角膜致病曲霉菌的生长特性研究

Growth characteristics of Aspergillus isolated from clinical infective cornea

目的通过体外培养方法比较眼部临床分离曲霉菌与曲霉菌标准菌株生长特性的异同,研究真菌致病的关键点。方法配制液态和固态形式的3种培养基:综合马铃薯葡萄糖(PDA)培养基、沙氏培养基和酵母浸膏(YG)培养基,分别接种临床分离的曲霉菌株L和菌株W以及曲霉菌标准菌株,在29℃下培养96 h,分别于培养后0、4、8、12、24、36、48、60、72和96 h测定液态培养基上的吸光度(OD),绘制生长曲线,并在固态培养基上观察记录真菌生长情况。结果在综合PDA液体培养基上,菌株L和菌株W的生长曲线与标准菌株比较,差异均无统计学意义(均P<0.05);在YG和沙氏液体培养基上,临床分离菌株L和菌株W生长曲线与标准菌比较,差异均有统计学意义(均P<0.05),临床分离的2株曲霉菌更早进入显著生长期,生长速率明显快于标准菌株。固体培养基上,同一菌株在综合PDA培养基上菌落范围大、菌丝密度高;在沙氏培养基上菌落范围小、菌丝密度低;YG培养基上菌落介于另外2种培养基之间,菌落颜色变化最晚。同种固体培养基上,临床分离曲霉菌较标准菌株菌落范围更大、颜色变化更早、颜色变化范围更广。结论较标准菌株而言,临床分离曲霉菌在营养条件较差时表现出更强的环境适应能力,使得临床分离菌株在复杂的临床环境中得以生存,进而致病。

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.