Department of Plant and Soil Sciences, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
Department of Science and Innovation, National Research Foundation Centre of Excellence in Food Security, Pretoria, South Africa.
J Appl Microbiol. 2022 Mar;132(3):2389-2409. doi: 10.1111/jam.15357. Epub 2021 Nov 29.
To investigate the microbiological quality, potential foodborne pathogen presence, and to phenotypically (antimicrobial resistance [AMR] profiles) and genotypically (DNA fingerprints and diarrhoeagenic genes) characterize Escherichia coli isolated throughout spinach production systems from farm-to-sale.
Samples (n = 288) were collected from two commercial supply chains using either river or borehole irrigation water. E. coli was enumerated throughout the chain where river water was directly used for overhead irrigation at levels between 0.00 and 3.22 log colony forming unit (CFU) g . Following enrichment, isolation and matrix-assisted laser desorption ionization time-of-flight mass spectrometry identification, E. coli was isolated from 22.57% (n = 65/288) of all samples. Salmonella spp. were isolated from 3% (n = 9/288) of river and irrigation water samples on one farm, and no Listeria monocytogenes was detected throughout the study. Of the 80 characterized E. coli isolates, one harboured the stx2 virulence gene, while 43.75% (n = 35) were multidrug resistant. Overall, 26.30% of the multidrug-resistant E. coli isolates were from production scenario one that used river irrigation water, and 17.50% from the second production scenario that used borehole irrigation water. A greater percentage of resistance phenotypes were from water E. coli isolates (52.50%), than isolates from spinach (37.50%). E. coli isolates from spinach and irrigation water clustered together at high similarity values (>90%) using enterobacterial repetitive intergenic consensus-polymerase chan reaction analysis.
This study reported the presence of multidrug-resistant environmental E. coli throughout spinach production from farm, during processing and up to retail. Furthermore, the similarity of multi-drug resistant E. coli isolates suggests transfer from irrigation water to spinach in both scenarios, reiterating that irrigation water for vegetables consumed raw, should comply with standardized microbiological safety guidelines.
Multidrug-resistant E. coli presence throughout spinach production emphasizes the necessity of increased surveillance of AMR in fresh produce and the production environment within a One Health paradigm to develop AMR mitigation strategies.
调查菠菜生产系统从农场到销售过程中整个过程的微生物质量、食源性病原体的存在情况，并进行表型（抗微生物药物耐药性[AMR]特征）和基因型（DNA 指纹和致泻基因）分析。
使用河水或井水对两条商业供应链中的 288 个样本进行了采集。在使用河水直接进行头顶灌溉的供应链中对 E. coli 进行了计数，水平在 0.00 到 3.22 对数集落形成单位（CFU）g 之间。在进行富集、分离和基质辅助激光解吸电离飞行时间质谱鉴定后，从 22.57%（n=65/288）的所有样本中分离出 E. coli。在一个农场，河水和灌溉水中的沙门氏菌从 3%（n=9/288）的样本中分离出来，整个研究过程中没有检测到李斯特菌。在所鉴定的 80 株 E. coli 分离株中，一株带有 stx2 毒力基因，而 43.75%（n=35）为多药耐药。总的来说，使用河水灌溉的第一个生产场景中，有 26.30%的多药耐药 E. coli 分离株来自生产场景，而第二个使用井水灌溉的生产场景中，有 17.50%来自生产场景。多药耐药表型的比例，从水 E. coli 分离株（52.50%）大于菠菜（37.50%）。使用肠杆菌重复基因间 consensus-聚合酶链反应分析发现，来自菠菜和灌溉水的 E. coli 分离株聚类在一起，相似度值大于 90%。
本研究报告了从农场到零售过程中，整个菠菜生产过程中存在多药耐药环境 E. coli。此外，多药耐药 E. coli 分离株的相似性表明，两种情况下都存在从灌溉水向菠菜的转移，这再次强调了食用生蔬菜的灌溉水应符合标准化微生物安全指南。
整个菠菜生产过程中存在多药耐药 E. coli，强调了在一个健康范围内，需要增加对新鲜农产品和生产环境中抗微生物药物耐药性的监测，以制定抗微生物药物耐药性缓解策略。
