The activity of Aspergillus terreus ICMP 477 against antibiotic-sensitive and resistant strains of E. coli, K. pneumoniae, and S. aureus by zone of inhibition assay

To perform zone of inhibition (ZOI) testing, potato dextrose agar (PDA) plates were inoculated with a lawn of either antibiotic-sensitive <em>E. coli</em> (ATCC 25922) or resistant clinical isolates (CTX-M-9, CTX-M-14, CTX-M-15, NDM-1) or antibiotic-resistant <em>K. pneumoniae</em> (ATCC 700603, produces SHV-18). Similarly, Mueller-Hinton agar plates were inoculated with a lawn of either antibiotic-sensitive <em>S. aureus</em> (ATCC 29213) or antibiotic-resistant <em>S. aureus</em> (ATCC 33593). ICMP 477 was obtained from Manaaki Whenua - Landcare Research and grown on PDA plates for 36 days and fungal plugs removed using a 6 mm punch biopsy tool (Amtech Medical, New Zealand). Fungal plugs were placed onto the bacterial lawns, alongside PDA plugs containing no fungus as a control. Plates were incubated inverted at 37°C for 24 h before measuring any zones of inhibition (in mm) produced. A zone of 6 mm = no inhibition. Experiments were performed using three biological replicates with three technical replicates each.

为开展抑菌圈（zone of inhibition, ZOI）试验，我们将抗生素敏感型大肠杆菌（E. coli）ATCC 25922、耐药临床分离株（CTX-M-9、CTX-M-14、CTX-M-15、NDM-1）及产SHV-18的耐药肺炎克雷伯菌（K. pneumoniae）ATCC 700603均匀涂布接种于马铃薯葡萄糖琼脂（potato dextrose agar, PDA）平板。同理，将抗生素敏感型金黄色葡萄球菌（S. aureus）ATCC 29213与耐药金黄色葡萄球菌（S. aureus）ATCC 33593分别均匀涂布接种于穆勒-欣顿琼脂（Mueller-Hinton agar）平板。菌株ICMP 477由Manaaki Whenua - Landcare Research提供，于PDA平板上培养36天后，使用6mm打孔器（Amtech Medical, 新西兰）制备真菌菌塞。将真菌菌塞与不含真菌的PDA琼脂塞（空白对照）分别放置于涂布有细菌的平板表面。随后将平板倒置置于37℃培养24小时，之后测量所形成抑菌圈的直径（单位：mm），当抑菌圈直径为6mm时代表无抑菌作用。本实验设置3次生物学重复，每次生物学重复包含3次技术重复。