College of Life and Environmental Science, University of Exeter, Penryn, UK; UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
Biocatalysis Centre, University of Exeter, Exeter, UK.
Environ Int. 2019 Nov;132:105117. doi: 10.1016/j.envint.2019.105117. Epub 2019 Aug 29.
Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.
频繁和持续的重金属污染对微生物群落的组成和活性有深远的影响。重金属选择抗金属性，但也可以共同选择对抗生素的抗性，这是一个全球健康关注的问题。我们在这里记录了英国西北部一个池塘的沉积物档案中的金属浓度、金属抗性和抗生素抗性，该档案涵盖了一个多世纪的人为污染。我们特别关注锌，因为它是一种普遍存在且有毒的金属污染物，已知会共同选择对抗生素的抗性，以评估重金属污染的时间变化对微生物群落多样性的影响，并量化差异重金属暴露对抗生素抗性的选择效应。核心中的锌浓度和生物利用度被发现存在变化，这可能反映了 20 世纪中叶左右工业化的增加。锌浓度对细菌群落组成有显著影响，这反映在可培养细菌的锌耐受性水平与锌浓度之间存在正相关关系。锌抗性分离株的比例也与三种临床相关抗生素（苯唑西林、头孢噻肟和甲氧苄啶）的抗性呈正相关。用于人为污染物的 class 1 整合子-整合酶基因 intI1 的丰度与锌和头孢噻肟抗性的流行呈正相关，但与苯唑西林和甲氧苄啶抗性无关。我们的微生物古生物学方法揭示，在抗生素使用之前就已受到金属污染的沉积物中富含抗生素抗性细菌，这证明了金属-抗生素共同选择在环境中的普遍影响。
