Korea Food Research Institute, Wanju, Jeolla-buk, 55365, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon, 34113, South Korea.
Korea Food Research Institute, Wanju, Jeolla-buk, 55365, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon, 34113, South Korea.
Microb Pathog. 2024 Nov;196:106974. doi: 10.1016/j.micpath.2024.106974. Epub 2024 Sep 21.
This study investigated the acid adaptation and antimicrobial resistance of seven pathogenic Escherichia coli strains and one commensal strain under nutrient-rich acidic conditions. After acid adaptation, three pathogenic E. coli survived during 100 h incubation in tryptic soy broth at pH 3.25. Acid-adapted (AA) strains showed increased resistance to antimicrobials including ampicillin, ciprofloxacin and especially polymyxins (colistin and polymyxin B), the last resort antimicrobial for multidrug-resistant Gram-negative bacteria. Enterotoxigenic E. coli strain (NCCP 13717) showed significantly increased resistance to acids and polymyxins. Transcriptome analysis of the AA NCCP 13717 revealed upregulation of genes related to the acid fitness island and the arn operon, which reduces lipopolysaccharide binding affinity at the polymyxin site of action. Genes such as eptA, tolC, and ompCF were also upregulated to alter the structure of the cell membrane, reducing the outer membrane permeability compared to the control, which is likely to be another mechanism for polymyxin resistance. This study highlights the emergence of antimicrobial resistance in AA pathogenic E. coli strains, particularly polymyxin resistance, and the mechanisms behind the increased antimicrobial resistance, providing important insights for the development of risk management strategies to effectively control the antimicrobial resistant foodborne pathogens.
本研究调查了七种致病性大肠杆菌菌株和一种共生菌株在营养丰富的酸性条件下的酸适应和抗微生物耐药性。在酸性适应后，三种致病性大肠杆菌在 pH 值为 3.25 的胰蛋白酶大豆肉汤中孵育 100 小时后仍能存活。酸适应（AA）菌株对包括氨苄西林、环丙沙星和特别是多粘菌素（黏菌素和多粘菌素 B）在内的抗生素的耐药性增加，多粘菌素 B 是治疗多药耐药革兰氏阴性菌的最后手段。肠致病性大肠杆菌菌株（NCCP 13717）对酸和多粘菌素的耐药性显著增加。AA NCCP 13717 的转录组分析显示，与酸适应岛和 arn 操纵子相关的基因上调，这降低了脂多糖在多粘菌素作用部位的结合亲和力。eptA、tolC 和 ompCF 等基因也上调，改变了细胞膜的结构，与对照相比，外膜通透性降低，这可能是多粘菌素耐药的另一种机制。本研究强调了 AA 致病性大肠杆菌菌株，特别是多粘菌素耐药性的出现以及增加的抗微生物耐药性背后的机制，为制定有效的风险管理策略提供了重要的见解，以有效控制食源性病原体的抗微生物耐药性。
