Indian Council of Medical Research (ICMR), Delhi, India.
Department of Microbiology, Institute of Bioresources and Sustainable Development, A National Institute of Department of Biotechnology, Government of India, Imphal, Manipur, India.
PLoS One. 2021 Oct 14;16(10):e0258607. doi: 10.1371/journal.pone.0258607. eCollection 2021.
Staphylococcus aureus and Methicillin-resistant S. aureus (MRSA) remains one of the major concerns of healthcare associated and community-onset infections worldwide. The number of cases of treatment failure for infections associated with resistant bacteria is on the rise, due to the decreasing efficacy of current antibiotics. Notably, Acrophialophora levis, a thermophilous fungus species, showed antibacterial activity, namely against S. aureus and clinical MRSA strains. The ethyl acetate extract of culture filtrate was found to display significant activity against S. aureus and MRSA with a minimum inhibitory concentration (MIC) of 1 μg/mL and 4 μg/mL, respectively. Scanning electron micrographs demonstrated drastic changes in the cellular architecture of metabolite treated cells of S. aureus and an MRSA clinical isolate. Cell wall disruption, membrane lysis and probable leakage of cytoplasmic are hallmarks of the antibacterial effect of fungal metabolites against MRSA. The ethyl acetate extract also showed strong antioxidant activity using two different complementary free radicals scavenging methods, DPPH and ABTS with efficiency of 55% and 47% at 1 mg/mL, respectively. The total phenolic and flavonoid content was found to be 50 mg/GAE and 20 mg/CAE, respectively. More than ten metabolites from different classes were identified: phenolic acids, phenylpropanoids, sesquiterpenes, tannins, lignans and flavonoids. In conclusion, the significant antibacterial activity renders this fungal strain as a bioresource for natural compounds an interesting alternative against resistant bacteria.
金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌（MRSA）仍然是全球与医疗保健相关和社区获得性感染的主要关注点之一。由于当前抗生素的疗效下降，与耐药菌相关的感染治疗失败的病例数量正在上升。值得注意的是，嗜热真菌 Acrophialophora levis 表现出抗菌活性，即对金黄色葡萄球菌和临床耐甲氧西林金黄色葡萄球菌菌株具有活性。培养滤液的乙酸乙酯提取物对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌显示出显著的活性，最低抑菌浓度（MIC）分别为 1 μg/mL 和 4 μg/mL。扫描电子显微镜照片显示，代谢产物处理的金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌临床分离株的细胞结构发生了剧烈变化。细胞壁破裂、膜溶解和细胞质可能泄漏是真菌代谢产物对耐甲氧西林金黄色葡萄球菌抗菌作用的标志。乙酸乙酯提取物还通过两种不同的互补自由基清除方法，DPPH 和 ABTS 显示出很强的抗氧化活性，在 1 mg/mL 时的效率分别为 55%和 47%。总酚和类黄酮含量分别为 50 mg/GAE 和 20 mg/CAE。从不同类别中鉴定出十多种代谢产物：酚酸、苯丙素、倍半萜、单宁、木脂素和类黄酮。总之，显著的抗菌活性使该真菌菌株成为天然化合物的生物资源，是一种有前途的针对耐药菌的替代物。
