Uptake and metabolization of antibiòtics in crops
The discovery of antibiotics (ABs) and their mass production brought a revolution in medicine worldwide during the middle of the XX century. Infectious diseases with high morbidity and mortality suddenly become treatable. In the years that followed ABs were widely (mis) used in human and veterinary...
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| Format: | Doctoral thesis |
| Status: | Published version |
| Publication date: | 2020 |
| Country: | España |
| Institution: | CBUC, CESCA |
| Repository: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/670291 |
| Online Access: | http://hdl.handle.net/10803/670291 https://dx.doi.org/10.5821/dissertation-2117-334954 |
| Access Level: | Open access |
| Keyword: | Àrees temàtiques de la UPC::Enginyeria agroalimentària 504 614 632 |
| Summary: | The discovery of antibiotics (ABs) and their mass production brought a revolution in medicine worldwide during the middle of the XX century. Infectious diseases with high morbidity and mortality suddenly become treatable. In the years that followed ABs were widely (mis) used in human and veterinary applications, consequently ABs become the victims of their own success. AB bacterial resistance, although an ancient phenomenon, become one of the biggest threats to global health and food safety. AB pollution has been reported worldwide and in different environmental compartments. The presence of ABs has been reported in wastewaters (WW), surface waters, groundwater, manure, agricultural soils, animal food (meat and dairy products) and more recently in vegetables. In recent years several studies conducted in greenhouse conditions showed that ABs can be taken up and translocated in crops. The base of this Thesis is analytical methodology development and its application for the determination of several classes of incurred antibiotics in crops. Namely, analysis of ABs is a challenging task due to the complexity of vegetable matrices that entangle their quantification, especially if they are present at a relatively low ng g-1 level. Thus Chapter II presents an analytical method for the target analysis of 10 ABs and 6 of their metabolites. The developed method relies on liquid chromatography coupled to mass spectrometry in combination with liquid extraction and cleanup workflows. Strikingly, in 73% of all samples analysed, the concentration of a transformation product (TP) was higher than the concentration of its parent compound. Despite the numerous studies reporting the uptake and translocation of ABs by vegetables in controlled conditions or simulated real field scale conditions, there is a lack of data regarding the occurrence of ABs and its transformation products in vegetables under real field-scale conditions to assess the potential risk associated with their consumption. Thus, holistic sampling campaigns were performed (Chapter III) where four different vegetable types were included. Moreover different agricultural practices were involved and all collected samples represent real, commercially available vegetables intended for human consumption. Farming plots where manure was applied as fertilizer and water from Llobregat River was used for irrigation showed the highest ABs loads. Crop type was another important factor that determined the level of ABs occurrence. In real agricultural environments variations of many different factors are creating complex and specific interactions, thus have to be observed as such. Another unknown and poorly studied area that draws attention is related to ABs bio transformation pathways in pore water-plant systems. An innovative workflow for non-target screening allowed us annotation and identification of 11 metabolites of ofloxacin (OFL), of which five metabolites were reported for the first time in plants, suggesting the need to be included in surveys if they possess antimicrobial activity and/or toxicity (Chapter IV). Major transformation pathways were tentatively proposed revealing the major OFL metabolization pathways in lettuce. Finally, in Chapters V and VI, general discussion of all results and conclusions is given summing up the main ideas and hypothesis validation. |
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