A new extraction procedure to abate the burden of non-extractable antibiotic residues in manure

Antibiotic residues in the cirata reservoir, Indonesia and their effect on ecology and the selection for antibiotic-resistant bacteria

Antibiotic residues, their mixture toxicity, and the potential selection for antibiotic-resistant bacteria could pose a problem for water use and the ecosystem of reservoirs. This study aims to provide a comprehensive understanding of the occurrence, concentration, distribution, and ecological risks associated with various antibiotics in the Cirata reservoir, Indonesia. In our water and sediment samples, we detected 24 out of the 65 antibiotic residues analyzed, revealing a diverse range of antibiotic classes present. Notably, sulphonamides, diaminopyrimidine, and lincosamides were frequently found in the water, while the sediment predominantly contained tetracyclines and fluoroquinolones. Most antibiotic classes reached their highest concentrations in the water during the dry season. However, fluoroquinolones and tetracyclines showed their highest concentrations in the water during the wet season. Ecotoxicological risk assessments indicated that the impact of most antibiotic residues on aquatic organisms was negligible, except for fluoroquinolones. Looking at the impact on cyanobacteria, however, varying risks were indicated, ranging from medium to critical, with antibiotics like sulfamethoxazole, ciprofloxacin, norfloxacin, and lincomycin posing substantial threats. Among these, ciprofloxacin emerged as the antibiotic with the strongest risk. Furthermore, fluoroquinolones may have the potential to contribute to the selection of antibiotic-resistant bacteria. The presence of mixtures of antibiotic residues during the wet season significantly impacted species loss, with Potentially Affected Fraction of Species (msPAF) values exceeding 0.75 in almost 90% of locations. However, the impact of mixtures of antibiotic residues in sediment remained consistently low across all locations and seasons. Based on their occurrences and associated risks, 12 priority antibiotic residues were identified for monitoring in the reservoir and its tributaries. Moreover, the study suggests that river inflow serves as the most significant source of antibiotic residues in the reservoir. Further investigations into the relative share attribution of antibiotic sources in the reservoir is recommended to help identify effective interventions.

Safety and transfer of veterinary drugs from substrate to black soldier fly larvae

There is an increasing interest in edible insects in Europe for feed and food purposes. Quantitative information on the transfer of chemical hazards from substrates to larvae is needed to evaluate food and feed safety aspects. This evaluation is especially needed when organic substrates or residual streams such as manure will be applied as substrate, contributing to a circular food system. This study investigated the transfer of veterinary drugs from spiked substrate to black soldier fly larvae (Hermetia illucens). Veterinary drugs that are commonly administered to chicken, fattening pigs, and cattle and regularly detected in manure were included: three different antibiotics (enrofloxacin, oxytetracycline, sulfamethoxazole), three coccidiostats (narasin, salinomycin, toltrazuril) and one antiparasitic drug (eprinomectin). The chemicals were spiked to insect substrate to reach final concentrations of 0.5 and 5 mg/kg for the antibiotics and the antiparasitic drug, and 5 and 50 mg/kg for the coccidiostats. Black soldier fly larvae were reared for 1 week on the spiked substrates, and the transfer of the veterinary drugs to the larvae and frass was quantified using liquid chromatography coupled with tandem mass spectrometry. Only oxytetracycline and eprinomectin reduced the average weight and/or survival of the black soldier fly larvae. The transfer of the veterinary drugs to the larvae was on average 19.2% for oxytetracycline, 12% for enrofloxacin, 9.5% for narasin, 8.1% for eprinomectin, 3.9% for salinomycin, 4.2% for toltrazuril, and 0.2% for sulfamethoxazole, relative to concentrations in the substrate. Mass-balance calculations revealed that the larvae seem to metabolise veterinary drugs, and indeed, metabolites of enrofloxacin, sulfamethoxazole, and toltrazuril were detected in the larvae and frass. In conclusion, insect-rearing substrates should be evaluated for the presence of veterinary drug residues to ensure feed (and food) safety, as well as because of possible effects on insect growth.

Residues of veterinary antibiotics in solid natural and organic fertilizers-method development and sample analysis

Livestock excrement is used around the world as natural fertilizers or, after processing, as organic fertilizers for crops and grasslands. But due to the presence of veterinary antibiotics in them, they may pose a threat not only to the natural environment, mainly to soil microorganisms, but also to human and animal health. This article describes a method for detecting 21 antibacterial substances in solid natural and organic fertilizers. Antibiotics from fertilizers were extracted with a mixture of acetonitrile and McIlvain-Na2EDTA buffer, twice. The extracts were purified by solid phase extraction technique on Strata-X cartridges and analyzed with the use UHPLC-MS/MS technique. The method was validated in accordance with EU Commission Implementing Regulation 2021/808; the obtained recovery ranged from 93.6 to 116.6% (depending on the analytes), and the linearity ranged from 50 to 1000 µg/kg. The developed method was used to analyze 73 samples of solid natural and organic fertilizers. Our research has shown that over 38% of natural fertilizers were contaminated with antibiotics, mainly doxycycline in concentrations reaching several dozen milligrams per kilogram of fertilizers. In the case of processed organic fertilizers, the presence of antibiotics was found in over 37% of the analyzed samples. The research results showed that the developed and validated analytical method may be useful for assessing the presence and content of antibacterial substances in solid natural and organic fertilizers.

Impact of Soil Fertilization with Pig Slurry on Antibiotic Residues and Resistance Genes: A Longitudinal Study

The impact of soil fertilization with animal manure on the spread and persistence of antibiotic resistance in the environment is far from being fully understood. To add knowledge about persistence and correlations between antibiotic residues and antibiotic resistance genes (ARGs) in fertilized soil, a longitudinal soil mesocosm study was conducted. Soil samples were collected from the mesocosms immediately before spreading and then afterward at fifteen time points during a 320-day observation period. Eight ARGs (ermB, sul1, tetA, tetG, tetM, cfr, fexA, and optrA) and the class 1 integron-integrase gene, intI1, were determined in both pig slurry and soil, as well as residues of 36 antibiotics. Soil chemical and biochemical parameters were also measured. Twelve antibiotics were detected in the slurry in the range of 3 µg kg-1-3605 µg kg-1, with doxycycline, lincomycin, and tiamulin being the most abundant, whereas ermB, sul1, and tetM were the predominant ARGs. Before spreading, neither antibiotic residues nor ARGs were detectable in the soil; afterwards, their concentrations mirrored those in the slurry, with a gradual decline over the duration of the experiment. After about three months, the effect of the amendment was almost over, and no further evolution was observed.

The Identification and Quantification of 21 Antibacterial Substances by LC-MS/MS in Natural and Organic Liquid Fertilizer Samples

Antibiotics in animal production are widely used around the world for therapeutic and preventive purposes, and in some countries, they still serve as antibiotic growth stimulants. Regardless of the purpose of using antibiotics in livestock, they may be present in animal tissues and organs as well as in body fluids and excretions (feces and urine). Farm animal excrement in unprocessed form (natural fertilizers) or processed form (organic fertilizers) is applied to agricultural fields because it improves soil fertility. Antibiotics present in fertilizers may therefore contaminate the soil, surface, groundwater, and plants, which may pose a threat to the environment, animals, and humans. Therefore, it is important to develop analytical methods that will allow for the control of the presence of antibacterial substances in natural and organic fertilizers. Therefore, in this study, an LC-MS/MS method was developed and validated for the determination of 21 antibacterial substances in natural and organic liquid fertilizers. The developed method was used to analyze 62 samples of natural and organic liquid fertilizers, showing that over 24% of the tested samples were contaminated with antibiotics, mainly from the group of tetracyclines and fluoroquinolones. Studies of post-fermentation sludge from biogas plants have shown that the processes of anaerobic methane fermentation, pH, and temperature changes taking place in bioreactors do not lead to the complete degradation of antibiotics present in the material used for biogas production. For this reason, monitoring studies of natural and organic fertilizers should be undertaken to limit the introduction of antibiotics into the natural environment.

Assessment of the combined inputs of antimicrobials from top soil improvers and irrigation waters on green leafy vegetable fields

Sustainable food systems involve the recycling of biowaste and water. This study characterizes thirty-one top soil improvers of anthropogenic, animal, and green waste origin, along with eleven irrigation waters from rivers, channels, and civil wastewater treatment plants (cWWTPs) for the presence of antimicrobials. Liquid chromatography coupled with hybrid High-Resolution Mass Spectrometry (LC-HRMS/MS) was employed to identify forty-eight drugs belonging to the classes of sulfonamides (11), tetracyclines (7), fluoroquinolones (10), macrolides (12), amphenicols (3), pleuromutilins (2), diaminopyrimidines (1), rifamycins (1) and licosamides (1). Sludge from cWWTPs, animal manure, slurry, and poultry litter exhibited the highest loads for sulfonamides, tetracyclines, fluoroquinolones and macrolides (80, 470, 885, and 4,487 ng g-1 wet weight, respectively) with nor- and ciprofloxacin serving as markers for anthropogenic sources. In compost and digestate, antimicrobials were found to be almost always below the limits of quantification. Reused water from cWWTPs for irrigation in open-field lettuce production were contaminated in the range of 12-221 ng L-1 with sulfonamides, tetracyclines, and fluoroquinolones, compared to very few detected in channels and surface waters. The Antimicrobials Hazard Index (HI), based on the Predicted No Effect Concentration for Antimicrobial Resistance (PNECAMR), was significantly >100 in contaminated topsoil improvers from urban and animal sources. Accounting for worst-case inputs from topsoil improvers and irrigation water, as well as dilution factors in amended soil, fluoroquinolones only exhibited an HI around 1 in open fields for lettuce production. The origin of topsoil improvers plays a pivotal role in ensuring safe and sustainable leafy vegetable production, thereby mitigating the risk of Antimicrobial Resistance (AMR) onset in food-borne diseases and the transfer of AMR elements to the human gut flora.

Prediction of the mobility and persistence of eight antibiotics based on soil characteristics

Antibiotics are widely used in intensive animal husbandry in the Netherlands and are subsequently emitted to soil via manure. To predict degradation and mobility in soil, generic sorption models have been derived. However, most of the coefficients used in generic models are based on a limited range of soils and have not been validated for agricultural soils in the Netherlands. To improve model predictions and assess to what extent differences among soils affect sorption and degradation, an experimental study has been performed. Using a recently developed experimental approach, both the degradation (DT50) and mobility (Kd) of eight selected commonly used antibiotics were determined in 29 typical Dutch agricultural soils. Median DT50 values range from 5.3 days for Sulfadiazine to 120 days for Trimethoprim but are affected by soil type. The ratio of the lowest and highest DT50 for a given antibiotic among soils can be as large as 151, for Tylosin. Measured values of the logKd also range from 0.19 for Sulfadiazine to more than 2 for Doxycycline, Flumequine, Trimethoprim, Tylosin and Enrofloxacine. The impact of soil on Kd is large, especially for more mobile antibiotics such as Sulfadoxine and Sulfadiazine. Both the range in DT50 and Kd can be predicted reasonably well using a Freundlich type regression model that accounts for the variation in soil type and sampling depth. Organic matter, iron oxides, pH and clay content appear to be the main constituents and explain between 29 % (Trimethoprim) and 77 % of the variation in DT50 and between 64 % (Lincomycin) and 87 % (Sulfadoxine and Sulfadiazine) of the variation of Kd. The effect of depth on DT50 and Kd is however limited. The information thus obtained in combination with local data on soil type can be used to more accurately predict the potential risk of relevant antibiotics in soil and transport to ground- and nearby surface waters.

Prevalence of veterinary antibiotics in natural and organic fertilizers from animal food production and assessment of their potential ecological risk

BACKGROUND

Veterinary antibiotics are emerging contaminants and enter into soil principally by agricultural application of organic fertilizers. This article presents the results of the research obtained for the analyzed 70 samples of fertilizers (pig and poultry manure and slurry and digestate) for various classes of antibiotics.

RESULTS

Doxycycline, oxytetracycline, tetracycline, lincomycin, tiamulin and enrofloxacin were found in tested samples. Doxycycline was found as a dominant compound, and its highest concentration was 175 mg/kg in pig manure. This investigation indicated that fertilization with manure, especially animal feces, might be the primary source of antibiotics. Additionally, a risk assessment based on a risk quotient was carried out, which showed that the determined concentrations of antibiotics in fertilizers may pose a threat to soil microorganisms.

CONCLUSIONS

Results suggested that the ecological risk effects of antibiotic contamination on soil bases and their potential adverse risk on human health needs special attention. © 2023 Society of Chemical Industry.

Validation of modified QuECHERS extraction method for quantitative enrichment of seven multiclass antibiotic residues from vegetables followed by RP-LC-UV analysis

A modified rapid, simple quick, cheap, effective, robust and safe (QuEChERS) extraction method was developed for the simultaneous extraction and purification of seven antibiotic residues in lettuce, carrot and tomato using liquid chromatography UV detector. The method was validated for linearity, sensitivity, accuracy, repeatability, and reproducibility at six concentration levels for all matrices, according to the guidelines of UNODC. A matrix-matched calibration method was used for the quantitative analysis. Linear range of 0.01-250 μg kg^-1 for target compounds with correlation coefficient (R²) 0.9978-0.9995 was obtained. The limits of detections (LODs) and quantifications (LOQs) were 0.02-2.48 μg kg^-1 were 0.06-7.52 μg kg^-1, respectively. The average recoveries of the seven antibiotics ranged from 74.5 to 105.9%, with relative standard deviation RSD (%) < 11, for all matrices and matrix effects were less than 20% for most of compounds. This comprehensive simple QuEChERS extraction method can be used for the investigation of multi-residue drugs belonging to different chemical families in vegetables.

Identification and Quantification of 29 Active Substances by HPLC-ESI-MS/MS in Lyophilized Swine Manure Samples

Veterinary drugs are frequently employed to treat and prevent diseases in food-producing animals to improve animal health and to avoid the introduction of microorganisms into the food chain. The analysis of the presence of pharmaceutical residues in animal manure could help to evaluate the legal and illegal practices during food production without harming the animals and to correctly manage manure when it is going to be applied as a fertilizer. This article describes a method for the simultaneous analysis of 29 active substances, mostly antibiotics and antiparasitic agents. Substances were extracted from lyophilized manure with a methanol:McIlvaine solution and analyzed with HPLC-ESI-MS/MS and a C18 HPLC column. The method was validated following European guidelines, the achieved trueness was between 63 and 128% (depending on the analytes), and the linearity was between 100 and 1500 µg/kg. The applicability of the method was demonstrated in 40 manure samples collected from pig farms where tetracycline was quantified in 7.5% of the samples. These results show the viability of this non-invasive method for the control of the legal and illegal administration of pharmaceuticals in food-producing animals.

Quantifying Antibiotic Distribution in Solid and Liquid Fractions of Manure Using a Two-Step, Multi-Residue Antibiotic Extraction

Antibiotic distribution and analysis within liquid and solid fractions of manure are highly variable due to each compound’s respective physiochemical properties. This study developed and evaluated a uniform method extracting 10 antibiotics from 4 antibiotic classes (tetracycline, sulfonamides, macrolides, and β-lactam) from unprocessed manure, solid−liquid separated manure, and composted solids. Through systematic manipulation of previously published liquid chromatography tandem mass spectrometry methods; this study developed an extraction protocol with optimized recovery efficiencies for varied manure substrates. The method includes a two-step, liquid-solid extraction using 10 mL of 0.1 M EDTA-McIlviane buffer followed by 10 mL of methanol. Antibiotics recoveries from unprocessed manure, separated liquids, separated solids, and heat-treated solids using the two-step extraction method had relative standard deviations < 30% for all but ceftiofur. Total antibiotic recoveries were 67−131% for tetracyclines, 56% for sulfonamide, 49−53% for macrolides, and 1.3−66% for β-lactams. This is the first study to use one protocol to assess four classes of antibiotics in liquid and solid manure fractions. This study allowed for more precise risk assessment of antibiotic transport in manure waste stream applied to fields as a liquid or solid compost.

Determination of antimicrobial agents and their transformation products in an agricultural water-soil system modified with manure

Manure fertilization is the primary source of veterinary antimicrobials in the water-soil system. The research gap is the fate of antimicrobials after their release into the environment. This study aimed to provide a detailed and multi-faceted examination of fertilized cultivated fields using two types of manure (poultry and bovine) enriched with selected antimicrobials. The research focused on assessing the mobility and stability of antimicrobials in the water-soil system. Additionally, transformation products of antimicrobials in the environment were identified. The extraction (solid-phase extraction and/or solid-liquid extraction) and LC-MS/MS analysis procedures were developed to determine 14 antimicrobials in the soil and pore water samples. Ten out of fourteen antimicrobials were detected in manure-amended soil and pore water samples. The highest concentration in the soil was 109.1 ng g^-1 (doxycycline), while in pore water, it was 186.6 ng L^-1 (ciprofloxacin). Sixteen transformation products of antimicrobials were identified in the soil and soil-related pore water. The same transformation products were detected in both soil and soil pore water extracts, with significantly higher signal intensities observed in soil extracts than in water. Transformation products were formed in oxidation, carbonylation, and ring-opening reactions.

Pretreatment Methods for the Determination of Antibiotics Residues in Food Samples and Detected by Liquid Chromatography Coupled with Mass Spectrometry Detectors: A Review

With the increasing use of antibiotics worldwide, antibiotic monitoring has become a topic of concern. After metabolizing of antibiotics in animals, the metabolites enter the environment through excreta or ingested by the human body via food chain that may exacerbate the emergence of antibiotic resistance and then threaten human's life. This article summarized several analytical methods used for the determination of antibiotics in recent 10 years. Due to the complex matrices and low concentration level of antibiotics in the food samples, a reliable analysis method is required to maximize the recovery rate. Several techniques like solid phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and QuEChERS have been frequently used in the pretreatment process for analytes extraction and concentration. After the pretreatment, ultra-high performance liquid chromatography combined with mass spectrometry has been a reliable method for quantitative analysis and is able to determine multiple antibiotics simultaneously. This review also gives an overview about analytical conditions for antibiotics residues in different food samples and their method validation parameters.

Impact of fertilization with pig or calf slurry on antibiotic residues and resistance genes in the soil

Antibiotic residues and antibiotic resistance genes can enter the environment via fertilization with calf and pig manure. In a longitudinal study, nine antibiotic resistance genes (tet(B), tet(L), tet(M), tet(O), tet(Q), tet(W), erm(B), erm(F) and sul2) and 56 antibiotic residues were investigated in 288 soil samples and 8 corresponding slurry samples from 6 pig farms and 2 veal farms using qPCR and LC-MS/MS, respectively. A significant increase in gene copy number of tet(M), erm(B), erm(F) and sul2 was observed in all the soil layers between sampling times prior to (T1) and 2-3 weeks after fertilization (T3). Tet(B), tet(Q) and tet(L) were least abundant in the soil among the genes tested. From 7 classes of antibiotics, 20 residues were detected in soil and slurry using an optimized and validated extraction method. Flumequine was detected in all soil samples in concentrations below 100 μg/kg despite being detected in only half of the corresponding slurry samples. Doxycycline, oxytetracycline, lincomycin and sulfadiazine were also frequently detected in concentrations ranging from 0.1 μg/kg to 500 μg/kg and from 2 μg/kg and 9480 μg/kg in soil and slurry, respectively. Furthermore a positive association between the presence of antibiotic residues (total antibiotic load) and antibiotic resistance genes in soil was found. One possible explanation for this is a simultaneous introduction of antibiotic residues and resistance genes upon application of animal slurry.

HPLC-FLD-Based Method for the Detection of Sulfonamides in Organic Fertilizers Collected from Poland

Antibacterial substances such as sulfonamides are widely used in veterinary medicine to treat many bacterial diseases. After their administration to animals, up to 90% of the initial dose of the antibiotic is excreted in the feces and/or urine, which can be applied to farmland as natural or organic fertilizers. In this work, an analytical method was developed with the use of HPLC-FLD for the detection and quantification of five sulfonamides (sulfaguanidine, sulfadiazine, sulfamerazine, sulamethazine and sulfamethoxazol) in poultry and pig feces, slurry and digestates. The method was validated according to EU requirements (Commission Decision 2002/657/EC and VICH GL49). Linearity, decision limit, detection capability, detection and quantification limits, recovery, precision, and selectivity were determined, and adequate results were obtained. Using the HPLC-FLD method for all analyzed matrices, recoveries were satisfactory (77.00–121.16%), with repeatability and reproducibility in the range of 4.36–17.34% to 7.94–18.55%, respectively. Decision limit (CCα) and detection capability (CCβ) were 33.87–67.63 and 53.36–92.00 µg/kg, respectively, and limit of detection (LOD) and limit of quantification (LOQ) were 13.53–23.30 and 26.02–40.38 µg/kg, respectively, depending on the analyte. The forty-four samples of natural and organic fertilizers were analyzed, and four samples showed sulfamethoxazole in the amount from range 158 to 11,070 µg/kg. The application of antibiotics including sulfonamides for farming animals is widespread and may lead to the development of antibiotic resistance and other environmental effects.

Critical review of solid phase extraction for multiresidue clean-up and pre-concentration of antibiotics from livestock and poultry manure

The release of antibiotics into the environment from agricultural industries has received tremendous attention in recent years. Nonpoint source contamination of the terrestrial environment by these compounds can result from fertilisation of agricultural soils with manure. The presence of antibiotics and their metabolites in manure may pose a threat to agro-ecosystems. This may result in the emergence of antibiotic resistance bacteria in humans through the food chain and this is a major concern globally at the moment. Therefore, monitoring of manure for antibiotic residues is of vital importance in order to assess the risks of environmental pollution to human health by these drugs. Several sample pre-treatment techniques have been developed for the extraction of antibiotic residues from complex matrices including manure over the years. Despite new developments in recent years in separation science where the common trend is miniaturisation and green approaches, solid-phase extraction is still the most widely used technique in the extraction of antibiotics from agricultural wastes such as manure. In view of this, the aim of this review was to give a critical overview of studies that have been conducted in the past 6 years on the extraction of antibiotic residues from manure employing solid-phase extraction based on Oasis HLB and Strata-X. Adsorption mechanisms of these sorbents were also briefly discussed.

A strategy to determine the fate of active chemical compounds in soil; applied to antimicrobially active substances

Data on the fate of chemical substances in the environment after e.g. manure application is mandatory input for risk assessment in perspective of a more circular biobased economy. Such fate studies include a persistence study to determine a half-life value and a mobility study. It is recognized that not only the native substance should be considered, but that also degradation products should be included that might exert a similar effect as the native substance. We report a tiered fate study strategy that starts with a persistence study. For non-persistent substances a study is performed to determine if degradation products have a similar effect as the native compound. If so, a procedure using high resolution mass spectrometry is suggested to identify the potentially active degradation products. Based on the outcomes, substances are divided into three categories: (I) persistent, (II) degradable to inactive products or (III) degradable to active products. Even though the priority is with category I and III, for all substances and possible degradation products a mobility study is proposed. The fate strategy is successfully applied to ten antimicrobially active substances originating from the tetracyclines, sulfonamides, diaminopyrimidines, fluoroquinolones, macrolides and lincosamides. The fluoroquinolones, tetracyclines and trimethoprim were relatively persistent. The sulfonamides, macrolides and lincomycin (the latter also depending on soil type) degraded relatively quickly. Tylosin A proved to degrade to antimicrobially active degradation products which were tentitatively identified as tylosin C, tylosin A acid, tylosin B acid and tylosin C acid.

Determination of five antimicrobial families in droppings of therapeutically treated broiler chicken by high-performance liquid chromatography-tandem mass spectrometry

Antimicrobials are currently used in poultry for disease treatment. However, their excretion in bird feces may contaminate the environment. Considering this, the objective of this work was to quantify antimicrobials residues concentrations in therapeutically treated broiler chicken droppings throughout the post-treatment period. For this aim a multiresidue method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was validated. Forty-eight male broiler chickens were distributed and treated with commercial formulations of 5 different antimicrobials. Results showed that oxytetracycline and 4-epi-oxytetracycline, presented the highest concentrations during all sampling period, detecting concentrations of 1471.41 µg kg⁻¹ at the last sampling point (day 22 post-treatment). Florfenicol, tylosin, enrofloxacin, and ciprofloxacin were eliminated and detected in treated chicken droppings until d 18 post-treatment. Sulfachloropyridazine decrease gradually during post-treatment period until day 30. Results demonstrate that studied antimicrobials in treated chicken droppings were eliminated for prolonged periods, therefore becoming a significant route of residues dissemination into the environment.

Evaluation of Antibiotic Dissemination into the Environment and Untreated Animals, by Analysis of Oxytetracycline in Poultry Droppings and Litter

Simple Summary

Oxytetracycline (OTC) is an antibiotic used mainly in feed and drinking water. OTC is poorly absorbed in the gastrointestinal tract of poultry; making droppings a potential route of dissemination of this antibiotic. The aim of this study was to evaluate the dissemination of oxytetracycline excreted from treated birds to the environment and other untreated animals (sentinels), through the analysis of their droppings and litter by HPLC-MS/MS following the end of treatment. In treated bird droppings, the average concentration of OTC+4-epi-OTC ranged from 347.63 to 2244.66 µg kg⁻¹. OTC+4-epi-OTC in litter reached concentrations of 22,741.68 µg kg⁻¹. Traces of OTC+4-epi-OTC were detected in the droppings and litter from sentinels. Therefore, OTC+4-epi-OTC can persist in the litter of treated animals at high concentrations and can be transferred to untreated birds that share the same environment. This exposure has the potential to increase the likelihood of selection of resistant bacteria in the environment.

Abstract

Oxytetracycline (OTC) is widely used in broiler chickens. During and after treatment a fraction of OTC is excreted in its original form and as its epimer, 4-epi-OTC in droppings. To address the transfer of OTC into the environment, we evaluated the dissemination of OTC and 4-epi-OTC from treated birds to the environment and sentinels, through the simultaneous analysis of broiler droppings and litter. Male broiler chickens were bred in controlled conditions. One group was treated by orogastric tube with 80 mg kg⁻¹ of OTC and two groups received no treatment (sentinels). OTC+4-epi-OTC were analyzed and detected by a HPLC-MS/MS post the end of treatment. The highest concentrations of OTC+4-epi-OTC were detected in the droppings of treated birds 14-days following the end of treatment (2244.66 µg kg⁻¹), and one day following the end of treatment in the litter (22,741.68 µg kg⁻¹). Traces of OTC+4-epi-OTC were detected in the sentinels’ droppings and litter (<12.2 µg kg⁻¹). OTC+4-epi-OTC can be transferred from treated birds to the environment and to other untreated birds. The presence and persistence of OTC+4-epi-OTC in litter could contribute to the selection of resistant bacteria in the environment, increasing the potential hazard to public and animal health.

Optimization of a Method for Extraction and Determination of Residues of Selected Antimicrobials in Soil and Plant Samples Using HPLC-UV-MS/MS

The residues of antimicrobials used in human and veterinary medicine are popular pollutants of anthropogenic origin. The main sources of introducing antimicrobials into the environment are sewage treatment plants and the agricultural industry. Antimicrobials in animal manure contaminate the surrounding soil as well as groundwater, and can be absorbed by plants. The presence of antimicrobials in food of plant origin may pose a threat to human health due to their high biological activity. As part of the research, a procedure was developed for the extraction and determination of ciprofloxacin, enrofloxacin, cefuroxime, nalidixic acid and metronidazole in environmental samples (soil and parsley root). An optimized solid-liquid extraction (SLE) method was used to separate antimicrobials from the solid samples and a mixture of citrate buffer (pH = 4): methanol (1:1; v/v) was used as the extraction solvent. Solid phase extraction (SPE) with OASIS^® HLB cartridges was used to purify and pre-concentrate the sample. The recovery of the developed method was in the range of 55–108%. Analytes were determined by high-performance liquid chromatography coupled with an ultraviolet (UV) detector and a tandem mass spectrometer (HPLC-UV-MS/MS). The procedure was validated and applied to the determination of selected antimicrobials in soil and parsley root samples. Five types of soil and five types of parsley roots of different origins were analyzed. The presence of nalidixic acid in the parsley root samples was found in the concentration range of 0.14–0.72 ng g⁻¹. It has been shown that antimicrobials are absorbed by the plant and can accumulate antimicrobials in its edible parts.

Detection, occurrence, and fate of emerging contaminants in agricultural environments (2020)

A review of 79 papers published in 2019 is presented. The topics ranged from detailed descriptions of analytical methods, to fate and occurrence studies, to ecological effects and sampling techniques for a wide variety of emerging contaminants likely to occur in agricultural environments. New methods and studies on veterinary pharmaceuticals, antibiotics, anthelmintics, and engineered nanomaterials in agricultural environments continue to expand our knowledge base on the occurrence and potential impacts of these compounds. This review is divided into the following sections: Introduction, Analytical Methods, Antibiotics in Agroecosystems, Pharmaceutical Fate and Occurrence, Anthelmintics and Engineered Nanomaterials. PRACTITIONER POINTS: New research describes innovative new techniques for emerging contaminant detection in agricultural settings Newer classes of contaminants include human and veterinary pharmaceuticals Research in nanomaterials show that these also occur in agricultural environments and will likely be topics of future work.

Quantification of Veterinary Antibiotics in Pig and Poultry Feces and Liquid Manure as a Non-Invasive Method to Monitor Antibiotic Usage in Livestock by Liquid Chromatography Mass-Spectrometry

Antibiotics are active substances frequently used to treat and prevent diseases in animal husbandry, especially in swine and poultry farms. The use of manure as a fertilizer may lead to the dispersion of antibiotic residue into the environment and consequently the development of antibiotic-resistant bacteria. Most pharmaceutical active ingredients are excreted after administration, in some cases up to 90% of the consumed dose can be found in the feces and/or urine as parent compound. Therefore, due to antibiotic metabolism their residues can be easily detected in manure. This article describes a method for simultaneous analysis of ciprofloxacin, chlortetracycline, doxycycline, enrofloxacin, lincomycin, oxytetracycline, tetracycline, tiamulin, trimethoprim and tylosin in feces, liquid manure and digestate. Antibiotics were extracted from the different matrices with McIlvaine-Na2EDTA buffer solution and the extract was purified by the use two techniques: d-SPE and SPE (Strata-X-CW cartridges) and final eluent was analyzed by LC-MS and LC-MS/MS. The European Commission Decision 2002/657/EC was followed to conduct the validation of the method. Recoveries obtained from spiked pig and poultry feces and liquid manures samples ranged from 63% to 93% depending on analytes. The analysis of 70 samples (feces, liquid manure and digestate) revealed that 18 samples were positive for the presence of doxycycline, oxytetracycline, tetracycline, chlortetracycline, enrofloxacin, tiamulin and lincomycin. The results obtained in the presented study demonstrated that animal feces can be used as a non-invasive method detection antibiotic usage in animal production.