Inhibition and Biotransformation Potential of Veterinary Ionophore Antibiotics under Different Redox Conditions

Sun, Peizhe; Huang, Ching-Hua; Pavlostathis, Spyros G.

doi:10.1021/es503005m

Cited by 11 publications

(6 citation statements)

References 38 publications

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“…While these results cannot be 290 verified from the data, they again demonstrate that screened and unscreened samples behave 291 similarly, and clearly show that aerated samples benefit from much faster monensin degradation. 292 This is similar to observations of monensin biotransformation in mixed cultures derived from 293 poultry litter and litter-amended soil, which demonstrated much faster transformation under 294 aerobic versus anoxic conditions (Sun et al, 2014). In addition to aeration resulting in shorter 295 half-lives, the potential for difference in reaction order (zero-versus first-order) will affect how 296 monensin degrades in each system.…”

Section: Aeration On Monensin Dissipation 265supporting

confidence: 70%

“…S2). The high pH of the aerated 273 samples indicates that hydrolysis is not a transformation pathway (Sun et al, 2014). The 274 13 decrease in DOC ( Fig.…”

Section: Aeration On Monensin Dissipation 265mentioning

confidence: 97%

“…Monensin concentrations in aerated samples are corrected for evaporation of water over 266 the time period, though final monensin concentration was greatly reduced in all aerated samples 267 regardless of correction. The reduction of monensin in aerated samples is likely due to 268 transformation, by either indirect oxidation or microbial transformations, as monensin has a very 269 low Henry's constant (low volatility) and is known to undergo biotransformation (Thiele-Bruhn, 270 2003;Sun et al, 2014). Monensin is also known to undergo hydrolysis in acidic conditions; 271 however, the pH in aerated samples increased to 7.5 and 8.3 (unscreened, screened) while non-272 aerated samples decreased to 6.4 and 6.5 after 5 wk (Fig.…”

Section: Aeration On Monensin Dissipation 265mentioning

confidence: 99%

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Effects of solid-liquid separation and storage on monensin attenuation in dairy waste management systems

Hafner

Watanabe²,

Harter³

et al. 2017

Journal of Environmental Management

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Environmental release of veterinary pharmaceuticals has been of regulatory concern for more than a decade. Monensin is a feed additive antibiotic that is prevalent throughout the dairy industry and is excreted in dairy waste. This study investigates the potential of dairy waste management practices to alter the amount of monensin available for release into the environment. Analysis of wastewater and groundwater from two dairy farms in California consistently concluded that monensin is most present in lagoon water and groundwater downgradient of lagoons. Since the lagoons represent a direct source of monensin to groundwater, the effect of waste management, by mechanical screen separation and lagoon aeration, on aqueous monensin concentration was investigated through construction of lagoon microcosms. The results indicate that monensin attenuation is not improved by increased solid-liquid separation prior to storage in lagoons, as monensin is rapidly desorbed after dilution with water. Monensin is also shown to be easily degraded in lagoon microcosms receiving aeration, but is relatively stable and available for leaching under typical anaerobic lagoon conditions.

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Section: Aeration On Monensin Dissipation 265supporting

confidence: 70%

“…S2). The high pH of the aerated 273 samples indicates that hydrolysis is not a transformation pathway (Sun et al, 2014). The 274 13 decrease in DOC ( Fig.…”

Section: Aeration On Monensin Dissipation 265mentioning

confidence: 97%

Section: Aeration On Monensin Dissipation 265mentioning

confidence: 99%

See 1 more Smart Citation

Effects of solid-liquid separation and storage on monensin attenuation in dairy waste management systems

Hafner

Watanabe²,

Harter³

et al. 2017

Journal of Environmental Management

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“…However, most of the studies focused on the degradation kinetics of MON and only to a lesser extent on the identification of TPs. A few studies investigated oxidative TPs, namely the conversion of MON with metalloporphyrins [28], the Jacobson catalyst [29] and the inhibition and biotransformation under different redox conditions [30].…”

Section: Introductionmentioning

confidence: 99%

Prediction of Transformation Products of Monensin by Electrochemistry Compared to Microsomal Assay and Hydrolysis

et al. 2019

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The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation.

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“…Previous studies and on-farm experiences have shown a decrease in methane production upon the first introduction of monensin or monensin-laden manure to anaerobic digesters ( 9 – 12 ). These studies indicated that monensin indirectly inhibits methanogenesis by depleting the precursor acetate.…”

Section: Introductionmentioning

confidence: 99%

Redundancy in Anaerobic Digestion Microbiomes during Disturbances by the Antibiotic Monensin

Spirito

Daly

Werner

et al. 2018

Appl Environ Microbiol

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The antibiotic monensin is fed to dairy cows to increase milk production efficiency. A fraction of this monensin is excreted into the cow manure. Previous studies have found that cow manure containing monensin can negatively impact the performance of anaerobic digesters, especially upon first introduction. Few studies have examined whether the anaerobic digester microbiome can adapt to monensin during the operating time. Here, we conducted a long-term time series study of four lab-scale anaerobic digesters fed with cow manure. We examined changes in both the microbiome composition and function of the anaerobic digesters when subjected to the dairy antibiotic monensin. In our digesters, monensin was not rapidly degraded under anaerobic conditions. The two anaerobic digesters that were subjected to manure from monensin feed-dosed cows exhibited relatively small changes in microbiome composition and function due to relatively low monensin concentrations. At higher concentrations of monensin, which we dosed directly to control manure (from dairy cows without monensin), we observed major changes in the microbiome composition and function of two anaerobic digesters. A rapid introduction of monensin to one of these anaerobic digesters led to the impairment of methane production. Conversely, more gradual additions of the same concentrations of monensin to the other anaerobic digester led to the adaptation of the anaerobic digester microbiomes to the relatively high monensin concentrations. A member of the candidate OP11 (Microgenomates) phylum arose in this anaerobic digester and appeared to be redundant with certain Bacteroidetes phylum members, which previously were dominating.IMPORTANCE Monensin is a common antibiotic given to dairy cows in the United States and is partly excreted with dairy manure. An improved understanding of how monensin affects the anaerobic digester microbiome composition and function is important to prevent process failure for farm-based anaerobic digesters. This time series study demonstrates how anaerobic digester microbiomes are inert to low monensin concentrations and can adapt to relatively high monensin concentrations by redundancy in an already existing population. Therefore, our work provides further insight into the importance of microbiome redundancy in maintaining the stability of anaerobic digesters.

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Inhibition and Biotransformation Potential of Veterinary Ionophore Antibiotics under Different Redox Conditions

Cited by 11 publications

References 38 publications

Effects of solid-liquid separation and storage on monensin attenuation in dairy waste management systems

Effects of solid-liquid separation and storage on monensin attenuation in dairy waste management systems

Prediction of Transformation Products of Monensin by Electrochemistry Compared to Microsomal Assay and Hydrolysis

Redundancy in Anaerobic Digestion Microbiomes during Disturbances by the Antibiotic Monensin

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