Department of Nutrition and Food Science, Wayne State University, Detroit, MI, USA.
Department of Food Science and Nutrition, Illinois Institute of Technology, Summit, IL, USA.
Int J Antimicrob Agents. 2018 Aug;52(2):241-250. doi: 10.1016/j.ijantimicag.2018.05.016. Epub 2018 May 30.
Urban agricultural soils can be an important reservoir of antibiotic resistance, and have great food safety and public health indications. This study investigated antibiotic-resistant bacteria and antibiotic resistance genes in urban agricultural soils using phenotypic and metagenomic tools. In total, 207 soil bacteria were recovered from 41 soil samples collected from an urban agricultural garden in Detroit, MI, USA. The most prevalent antibiotic resistance phenotype demonstrated by Gram-negative bacteria was resistance to ampicillin (94.2%), followed by chloramphenicol (80.0%), cefoxitin (79.5%), gentamicin (78.4%) and ceftriaxone (71.1%). All Gram-positive bacteria were resistant to gentamicin, kanamycin and penicillin. Genes encoding resistance to quinolones, β-lactams and tetracyclines were the most prevalent and abundant in the soil. qepA and tetA, both encoding efflux pumps, predominated in the quinolone and tetracycline resistance genes tested, respectively. Positive correlation (P<0.05) was identified among groups of antibiotic resistance genes, and between antibiotic resistance genes and metal resistance genes. The data demonstrated a diverse population of antibiotic resistance in urban agricultural soils. Phenotypic determination together with soil metagenomics proved to be a valuable tool to study the nature and extent of antibiotic resistance in the environment.
城市农业土壤可能是抗生素抗性的重要储存库，对食品安全和公共健康具有重要意义。本研究采用表型和宏基因组学工具研究了城市农业土壤中的抗生素抗性细菌和抗生素抗性基因。总共从美国密歇根州底特律市一个城市农业园区采集的 41 个土壤样本中回收了 207 株土壤细菌。革兰氏阴性菌表现出的最普遍的抗生素耐药表型是对氨苄青霉素的耐药性（94.2%），其次是对氯霉素（80.0%）、头孢西丁（79.5%）、庆大霉素（78.4%）和头孢曲松（71.1%）。所有革兰氏阳性菌均对庆大霉素、卡那霉素和青霉素耐药。土壤中存在的基因编码对喹诺酮类、β-内酰胺类和四环素类抗生素的耐药性最为普遍和丰富。在测试的喹诺酮类和四环素类抗生素耐药基因中，qepA 和 tetA 分别编码外排泵，占主导地位。抗生素耐药基因组与金属耐药基因组之间以及抗生素耐药基因组之间存在正相关（P<0.05）。数据表明城市农业土壤中存在多样化的抗生素抗性群体。表型测定与土壤宏基因组学相结合被证明是研究环境中抗生素抗性性质和程度的有效工具。
