Silva Carolina S O, Oliveira Sílvia D, Proenca Audrey M, Abati Eduarda V, Marconatto Letícia, Moura Cássio S, Medina-Silva Renata
Geobiology Group, Laboratory of Immunology and Microbiology, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, PUCRS, Porto Alegre, Brazil.
Environ Microbiol. 2025 Jun;27(6):e70115. doi: 10.1111/1462-2920.70115.
The contamination of water bodies by pesticides and antibiotics is a concerning environmental problem on a global scale. We investigated the impact of commonly used herbicides and antibiotics on bacterial isolates from the Guarani Aquifer System (GAS), the second largest aquifer in the world, in agriculture-intensive regions in southern Brazil. A total of 23 isolates were exposed to 2,4-D and glyphosate-based herbicides. Among these, 19 were tolerant (some presenting increased survival) to at least one herbicide. The collection site had a significant effect on isolates' maximum survival (MS), and a strong cross-tolerance between the two chemicals was detected, whereas seven out of 13 isolates (genera Bacillus, Lysinibacillus, Pseudomonas or Enterococcus) were resistant to at least one antibiotic. Isolates with the highest index of antibiotic resistance showed high MS values to herbicides, suggesting cross-resistance. We present the first characterisation of herbicide and antibiotic susceptibility of bacteria isolated from a deep aquifer. Herbicide tolerance was high and common, showing correlation with antibiotic resistance. The results suggest herbicides may impact microbial communities in aquifers, particularly concerning GAS-which spans four countries in South America-highlighting the importance of studying environmental microbes as potential remediators of contaminants, in line with the One Health principle.
农药和抗生素对水体的污染是一个全球范围内令人担忧的环境问题。我们调查了常用除草剂和抗生素对来自巴西南部农业密集地区的瓜拉尼含水层系统（GAS，世界第二大含水层）中细菌分离株的影响。总共23株分离株暴露于2,4 - D和草甘膦基除草剂中。其中，19株对至少一种除草剂具有耐受性（有些表现出存活率增加）。采集地点对分离株的最大存活率（MS）有显著影响，并且检测到两种化学物质之间有很强的交叉耐受性，而13株分离株（芽孢杆菌属、赖氨酸芽孢杆菌属、假单胞菌属或肠球菌属）中有7株对至少一种抗生素具有抗性。抗生素抗性指数最高的分离株对除草剂表现出高MS值，表明存在交叉抗性。我们首次对从深层含水层分离出的细菌的除草剂和抗生素敏感性进行了表征。除草剂耐受性高且普遍，与抗生素抗性相关。结果表明，除草剂可能会影响含水层中的微生物群落，特别是对于跨越南美洲四个国家的GAS而言，这凸显了根据“同一健康”原则将环境微生物作为污染物潜在修复剂进行研究的重要性。
