Department of Health Sciences, Università degli Studi di Milano, via A di Rudinì, 8, 20142 Milan, Italy.
Future Microbiol. 2013 Jun;8(6):799-805. doi: 10.2217/fmb.13.36.
We investigated the pathogenic role of biofilm and the therapeutic efficacy of anidulafungin in experimental infections of the wax moth Galleria mellonella by Candida albicans clinical strains.
MATERIALS & METHODS: On the basis of the in vitro propensity to form biofilm, five biofilm-producer (BP) and four nonproducer (NP) C. albicans clinical strains were used in this study. For each strain, we assessed the virulence by infecting G. mellonella larvae and observing survival. Anidulafungin was administered 2 h after yeast inoculum at 0.6 µg, according to the therapeutic dose recommended for humans.
Biofilm-forming ability highly influenced the larva-killing rate. A significant (p < 0.0001) survival decrease was observed in the BP group, with 80% of the infected larvae dying within 72 h. NP isolates did not reach the same killing rate, even at the end of experiments (216 h). Larval survival was enhanced (p < 0.0001) by anidulafungin administration in both groups. Survival rate at 72 h was similar in both groups (BP 78.5% and NP 87.5%); whereas there were still differences at the end of the experiments, with a higher survival in the NP group (75 vs 48%).
Our data confirm the pathogenic role of biofilm in C. albicans infections. Its importance was further enhanced by a lack of contribution from extracellular enzymes, detected in both NP and BP strains. In addition, we demonstrated anidulafungin efficacy in treating biofilm-related invasive candidiasis.
我们研究了生物膜的致病作用以及棘白菌素在白色念珠菌临床株感染蜡螟幼虫的实验性感染中的治疗效果。
基于体外形成生物膜的倾向，本研究使用了 5 株生物膜产生菌（BP）和 4 株非产生菌（NP）的白色念珠菌临床株。对于每种菌株，我们通过感染蜡螟幼虫并观察存活情况来评估其毒力。在接种酵母 2 小时后，根据推荐给人类的治疗剂量，以 0.6μg 的剂量给予棘白菌素。
生物膜形成能力高度影响幼虫致死率。BP 组的幼虫存活率显著下降（p<0.0001），80%的感染幼虫在 72 小时内死亡。NP 分离株即使在实验结束时（216 小时）也未达到相同的致死率。在两组中，给予棘白菌素均可增强幼虫的存活（p<0.0001）。72 小时时的存活率在两组之间相似（BP 为 78.5%，NP 为 87.5%）；然而，在实验结束时仍存在差异，NP 组的存活率更高（75%比 48%）。
我们的数据证实了生物膜在白色念珠菌感染中的致病作用。在 NP 和 BP 菌株中均检测到细胞外酶缺乏，这进一步增强了生物膜的重要性。此外，我们证明了棘白菌素在治疗生物膜相关侵袭性念珠菌病方面的疗效。
