Abstract：
The simultaneous development of antibiotic resistance in bacteria due to metal exposure poses a significant threat to the environment and human health. This study explored how exposure to both arsenic and antibiotics affects the ability of an arsenite oxidizer, Achromobacter xylosoxidans CAW4, to transform arsenite and its antibiotic resistance patterns. The bacterium was isolated from arsenic-contaminated groundwater in the Chandpur district of Bangladesh. We determined the minimum inhibitory concentration (MIC) of arsenite, cefotaxime, and tetracycline for A. xylosoxidans CAW4, demonstrating a multidrug resistance (MDR) trait. Following this determination, we aimed to mimic an environment where A. xylosoxidans CAW4 was exposed to both arsenite and antibiotics. We enabled the strain to grow in sub-MIC concentrations of 1 mM arsenite, 40 µg/mL cefotaxime, and 20 µg/mL tetracycline. The expression dynamics of the arsenite oxidase (aioA) gene in the presence or absence of antibiotics were analyzed. The findings indicated that simultaneous exposure to arsenite and antibiotics adversely affected the bacteria\'s capacity to metabolize arsenic. However, when arsenite was present in antibiotics-containing media, it promoted bacterial growth. The study observed a global downregulation of the aioA gene in arsenic-antibiotic conditions, indicating the possibility of increased susceptibility through co-resistance across the entire bacterial population of the environment. This study interprets that bacterial arsenic-metabolizing ability can rescue the bacteria from antibiotic stress, further disseminating environmental cross-resistance. Therefore, the co-selection of metal-driven antibiotic resistance in bacteria highlights the need for effective measures to address this emerging threat to human health and the environment.
摘要：
由于金属暴露，细菌中抗生素耐药性的同时发展对环境和人类健康构成了重大威胁。这项研究探讨了暴露于砷和抗生素如何影响亚砷酸盐氧化剂的能力，木氧化无色杆菌CAW4，转化亚砷酸盐及其抗生素抗性模式。该细菌是从孟加拉国昌德布尔地区砷污染的地下水中分离出来的。我们确定了亚砷酸盐的最小抑制浓度（MIC），头孢噻肟,和四环素用于木氧喜散杆菌CAW4，表现出多药耐药（MDR）特征。在这个决定之后，我们的目的是模拟一种环境,在该环境中,木氧氧化A.CAW4暴露于亚砷酸盐和抗生素.我们使菌株能够在亚MIC浓度的1mM亚砷酸盐中生长，40µg/mL头孢噻肟，和20微克/毫升四环素。分析了在存在或不存在抗生素的情况下亚砷酸盐氧化酶（aioA）基因的表达动力学。研究结果表明，同时接触亚砷酸盐和抗生素会对细菌代谢砷的能力产生不利影响。然而,当亚砷酸盐存在于含抗生素的培养基中时，它促进了细菌的生长。该研究观察到aioA基因在砷抗生素条件下的全球下调，表明通过环境中整个细菌群体的共抗性增加易感性的可能性。这项研究解释了细菌的砷代谢能力可以拯救细菌免受抗生素应激，进一步传播环境交叉抗性。因此,细菌中金属驱动的抗生素耐药性的共同选择凸显了需要采取有效措施来应对这种对人类健康和环境的新威胁。
