Hatefi Atousa, Siavoshi Farideh, Khalili-Samani Saman
Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran.
Arch Microbiol. 2025 Mar 10;207(4):82. doi: 10.1007/s00203-025-04281-8.
Detection of Helicobacter pylori, Staphylococcus, Nocardia and Cyanobacteria inside the yeast Candida tropicalis raised the question whether treating yeast with antibiotics mix (ABM) eliminates intracellular bacteria. Live/Dead staining showed occurrence of viable bacteria inside the vacuole of C. tropicalis. Amplification of bacterial 16S rRNA genes from yeast DNA with the size of 521, 750, 606 and 450 bp were similar to those from control H. pylori, Staphylococcus, Nocardia and Cyanobacteria, respectively. To eliminate intracellular bacteria yeast cultures in yeast-glucose (YG) broth were treated with 32-1024 μg/mL of ABM (amoxicillin, ciprofloxacin, rifampin and metronidazole) for up to 24 h. Viability of treated yeast cells and their intracellular bacteria was assessed by colony count, Live/Dead staining and detection of bacterial 16S rRNA genes. Colony count of C. tropicalis exposed to 32-256 μg/mL of ABM (4.39-9.63) or 512-1024 μg/mL (9.67-9.77) were similar to their respected controls (p > 0.05). Amplification of similar bacterial genes from treated yeasts and controls confirmed persistent occurrence of intracellular bacteria. Micrographs of yeasts treated with 32-256 μg/mL of ABM showed intact yeasts and intracellular bacteria, however those treated with 512 and 1024 μg/mL showed occurrence of < 10% and > 10% yellow damaged yeasts, respectively that accumulated yellow rifampin. Fluorescence microscopy showed that both intact and damaged yeasts carried live bacteria inside their vacuole. Culture of treated yeasts on YG agar produced colonies with totally intact yeasts and intracellular bacteria. Yeast extruded antibiotics and reduced their effective concentration for killing intracellular bacteria. Establishment of bacteria inside the fungal vacuole cannot be disrupted with antibiotics.
在热带假丝酵母内检测到幽门螺杆菌、葡萄球菌、诺卡氏菌和蓝细菌，这引发了一个问题，即使用抗生素混合物（ABM）处理酵母是否能消除细胞内细菌。活/死染色显示热带假丝酵母液泡内存在活细菌。从酵母DNA中扩增出大小为521、750、606和450 bp的细菌16S rRNA基因，分别与对照幽门螺杆菌、葡萄球菌、诺卡氏菌和蓝细菌的基因相似。为了消除细胞内细菌，将酵母 - 葡萄糖（YG）肉汤中的酵母培养物用32 - 1024μg/mL的ABM（阿莫西林、环丙沙星、利福平和甲硝唑）处理长达24小时。通过菌落计数、活/死染色和检测细菌16S rRNA基因来评估处理后酵母细胞及其细胞内细菌的活力。暴露于32 - 256μg/mL ABM（4.39 - 9.63）或512 - 1024μg/mL（9.67 - 9.77）的热带假丝酵母的菌落计数与其各自的对照相似（p>0.05）。从处理后的酵母和对照中扩增出相似的细菌基因，证实细胞内细菌持续存在。用32 - 256μg/mL ABM处理的酵母的显微照片显示酵母和细胞内细菌完整，然而用512和1024μg/mL处理的酵母分别显示出<10%和>10%的黄色受损酵母，这些酵母积累了黄色的利福平。荧光显微镜显示完整和受损的酵母在其液泡内都携带活细菌。处理后的酵母在YG琼脂上培养产生的菌落中，酵母和细胞内细菌完全完整。酵母排出抗生素并降低了它们杀死细胞内细菌的有效浓度。真菌液泡内细菌的定植不能被抗生素破坏。
