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Animal waste is a potential pollution hazard as it can harbour contaminants, such as antimicrobial residues, mycotoxins, and pesticides, becoming a risk to the public, animal, and environmental health. To assess this risk, 15 experimental broiler chickens orally received contaminants to evaluate excretion levels. An analytical method was previously developed to detect 18 substances in poultry droppings using high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). Contaminants including tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, chlortetracycline, 4-epi-chlortetracycline, tylosin, erythromycin, enrofloxacin, ciprofloxacin, flumequine, florfenicol, sulfachloropyridazine, sulfadiazine, 2,4-dichlorophenoxyacetic acid, zearalenone, alpha- and beta-zearalenol, were extracted with EDTA-McIlvain and acetonitrile. This method showed a p-value < 0.05, RSD < 25%, and R2 > 0.95 in the calibration curves linearity for all analytes. The limit of quantification, selectivity, decision limit for confirmation, matrix effect, precision, and recovery parameters were validated according to European Union document 2021/808/EC, technical report CEN/TR 16059, SANTE/11813/2017 and according to the Veterinary International Conference on Harmonization: VICH GL2 and GL49. This method confirmed the detection of most analytes 12–36 h post-administration and simultaneously detected and quantified mixed contaminants. Thereby, poultry droppings are a potential matrix for spreading contaminants in animal production before slaughter and their control will minimize environmental impacts and mitigate antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Antimicrobial residues in milk pose a significant risk to human health, prompting regulatory bodies to establish safety limits to protect consumers. While traditional screening methods have primarily targeted single analytes or classes, recent advancements in multiclass screening techniques offer more comprehensive and efficient monitoring. This review highlights these advancements and focuses on methods developed since 2010, such as microbial inhibition tests, immunoassays, biosensors and LC–MS‐based approaches. It also discusses the strengths and limitations of these techniques, as well as the challenges associated with analysing milk's complex matrix, emphasising the ongoing need for innovation in food safety practices. [ABSTRACT FROM AUTHOR]

Antimicrobials are administered in livestock for different uses leading to milk contamination and several undesirable effects. Because there is a lack of surveillance of antimicrobial residues (AMRs) in milk and dairy products in Lebanon, this study aims to determine the occurrence of AMRs in 90 Lebanese samples of milk and labneh (concentrated yoghurt). Multi-residue screening methods with suitable sample preparations were applied to detect 71 AMRs in milk and labneh, respectively, using LC-MS/MS. Of the total number of samples, 71% was contaminated with AMRs and (fluoro)quinolones and macrolides were the most detected families. Additional confirmation tests proved that 6.7% of the milk samples were non-compliant for the macrolides tilmicosin, tulathromycin and spiramycin. Moreover, some labneh prepared from contaminated milk samples was analysed to determine the fate of AMRs during the manufacturing process. The results showed that some AMRs could be concentrated, eliminated or degraded, based on their physicochemical characteristics. [ABSTRACT FROM AUTHOR]

The excessive and uncontrolled application of antibiotics in the fish farming industry, coupled with a lack of health monitoring and medication practices, is a driving force behind the escalating development of antimicrobial resistance. The present study assessed and compared qualitative field diffusion (QFD) and disk diffusion (DD) assays for the detection of antimicrobial residues (ARs) in diverse freshwater aquaculture fish. A total of 380 freshwater aquaculture fish (160 fresh and 180 frozen) samples were systematically collected between January and June 2021 from various retail stores located in Erbil Governorate, Iraq. Based on QFDA results, overall, ARs were detected (52; 15.3%) at a relatively lower frequency with comparatively higher frequency (21; 31.1%) in fresh than (31; 17.2%) frozen fish samples. On the other hand, DDA also revealed a comparable (45; 13.2%) prevalence rate of ARs. However, a low detection was observed more in fresh (17; 10.6%) than frozen (28; 15.6%) fish samples. Moreover, no statistically significant disparity (χ2 = 0.069; p = 0.79) between two assays and types of fish was recorded. In conclusion, the results of the present study showed that detecting a considerable frequency of ARs in these fish samples raises concerns about potential threats to public health. This underscores the necessity for understanding antibiotic application in aquaculture and its potential connection to antibiotic resistance in bacterial pathogens. Such comprehension is pivotal for formulating and implementing effective control and farm management strategies to address this pressing issue. [ABSTRACT FROM AUTHOR]

Oxytetracycline (OTC), enrofloxacin (EFX), and sulfachloropyridazine (SCP) are critically important antimicrobials (AMs) in both human and veterinary medicine, where they are widely used in farm animals. Lettuce has become a matrix of choice for studying the presence of residues of these AMs in plants, as the concentrations of residues detected in lettuce can range from ng to mg. While several analytical methodologies have been developed for the purpose of detecting AMs in lettuce, these currently do not detect both the parent compound and its active metabolites or epimers, such as in the case of ciprofloxacin (CFX) and 4-epi-oxitetracycline (4-epi-OTC), which also pose a risk to public health and the environment due to their AM activity. In light of this situation, this work proposes an analytical method that was developed specifically to allow for the detection of OTC, 4-epi-OTC, EFX, CFX, and SCP in a lettuce matrix. This method uses acetonitrile, methanol, 0.5% formic acid, and McIlvaine-EDTA buffer as extraction solvents, and dispersive solid-phase extraction (dSPE) for the clean-up. The analytes were detected using a liquid chromatography technique coupled to mass spectrometry (HPLC-MS/MS). Parameters such as the specificity, linearity, recovery, precision, limit of detection, and limit (LOD) of quantification (LOQ) were calculated according to the recommendations established in the European Union decision 2021/808/EC and VICH GL2: Validation of analytical procedures. The LOQ for the analytes OTC, 4-epi-OTC, CFX, and SCP was 1 μg·kg−1, whereas for EFX, it was 5 μg·kg−1 dry weight. All calibration curves showed a coefficient of determination (R2) of >0.99. The recovery levels ranged from 93.0 to 110.5% and the precision met the acceptance criteria, with a coefficient of variation of ≤14.02%. Therefore, this methodology allows for the precise and reliable detection and quantification of these analytes. The analysis of commercial samples confirmed the suitability of this method. [ABSTRACT FROM AUTHOR]

Background: Organic egg is among the most common organic foods offered for sale in Egyptian markets in recent years, and consumers buy them at a higher price because they believe organic eggs are safer and have superior nutritional value than conventional eggs. Aim: The present work aimed to monitor antimicrobial residues in brown table eggs, whether conventional or organic type, in Aswan governorate markets and assessed their physical and chemical quality and their public health hazards. Methods: Brown table egg samples (n=400 total) were randomly selected in the present study, whereas they represented two equal groups (n=200 each) including conventional eggs and organic eggs. Eggs were collected from different retail stores in Aswan governorate, Egypt. Egg samples were subjected to thorough physical and chemical quality evaluation as well as assessment of antimicrobial residues. Results: The results reported organic eggs were cleaner and had a better odor, less blood and meat spots, but smaller with more shell cracks than conventional eggs. Chemical analysis of some nutrient contents in the egg yolk revealed significantly higher nutritive values of organic eggs than that of conventional ones as the organic eggs contain significantly higher levels of vitamin A and vitamin D/D3 and significantly lower values of cholesterol, calcium, magnesium and zinc than those in conventional eggs. Disc diffusion assay has been used for monitoring antimicrobial residues in egg samples. The results have shown that all examined organic eggs were free from antimicrobial residues, while 12% and 8% of conventional egg yolk and white were positive for antimicrobial residues, respectively. Conclusion: The study concludes the higher nutritive value of organic eggs compared with the conventional type because of their significantly higher contents of vitamins A and D and their significantly lower contents of cholesterol. Moreover, organic eggs were free from antimicrobial residues which maximize their public health benefits. [Open Vet J 2023; 13(5.000): 523-531]

Background: Organic egg is among the most common organic foods offered for sale in Egyptian markets in recent years, and consumers buy them at a higher price because they believe organic eggs are safer and have superior nutritional value than conventional eggs. Aim: The present work aimed to monitor antimicrobial residues in brown table eggs, whether conventional or organic type, in Aswan governorate markets and assessed their physical and chemical quality and their public health hazards. Methods: Brown table egg samples (n = 400 total) were randomly selected in the present study, in which they represented two equal groups (n = 200 each) including conventional eggs and organic eggs. Eggs were collected from different retail stores in the Aswan governorate, Egypt. Egg samples were subjected to thorough physical and chemical quality evaluation as well as an assessment of antimicrobial residues. Results: The results reported that organic eggs were cleaner and had a better odor, less blood, and meat spots, but smaller with more shell cracks than conventional eggs. Chemical analysis of some nutrient contents in the egg yolk revealed significantly higher nutritive values of organic eggs than that of conventional ones as the organic eggs contain significantly higher levels of vitamin A and vitamin D/D3 and significantly lower values of cholesterol, calcium, magnesium, and zinc than those in conventional eggs. Disc diffusion assay has been used for monitoring antimicrobial residues in egg samples. The results have shown that all examined organic eggs were free from antimicrobial residues, while 12% and 8% of conventional egg yolk and white were positive for antimicrobial residues, respectively. Conclusion: The study concludes the higher nutritive value of organic eggs compared with the conventional type because of their significantly higher contents of vitamins A and D and their significantly lower contents of cholesterol. Moreover, organic eggs were free from antimicrobial residues which maximizes their public health benefits.. [ABSTRACT FROM AUTHOR]

India at present is one of the leading countries in antimicrobial drug production and use, leading to increasing antimicrobial resistance (AMR) and public health problems. Attention has mainly been focused on the human and food animals' contribution to AMR neglecting the potential contribution of the perceptibly degraded aquatic environment in India. The paper reviews the available published literature in India on the prevalence of antimicrobial residues and their dissemination pathways in wastewater of pharmaceutical industries, sewage treatment plants, hospitals, riverine, community pond water, and groundwater. The prevalence of antimicrobial residue concentration, pathogenic and non-pathogenic bacteria antimicrobial resistant bacteria (ARB), their drug resistance levels, and their specific antimicrobial resistant genes (ARGs) occurring in various water matrices of India have been comprehensively depicted from existing literature. The concentration of some widely used antimicrobials recorded from the sewage treatment plants and hospital wastewater and rivers in India has been compared with other countries. The ecotoxicological risk posed by these antimicrobials in the various water matrices in India indicated high hazard quotient (HQ) values for pharmaceutical effluents, hospital effluents, and river water. The degraded aquatic environment exhibited the selection of a wide array of co-existent resistant genes for antibiotics and metals. The review revealed improper use of antibiotics and inadequate wastewater treatment as major drivers of AMR contaminating water bodies in India and suggestion for containing the challenges posed by AMR in India has been proposed. [ABSTRACT FROM AUTHOR]

The excessive and uncontrolled application of antibiotics in the fish farming industry, coupled with a lack of health monitoring and medication practices, is a driving force behind the escalating development of antimicrobial resistance. The present study assessed and compared qualitative field diffusion (QFD) and disk diffusion (DD) assays for the detection of antimicrobial residues (ARs) in diverse freshwater aquaculture fish. A total of 380 freshwater aquaculture fish (160 fresh and 180 frozen) samples were systematically collected between January and June 2021 from various retail stores located in Erbil Governorate, Iraq. Based on QFDA results, overall, ARs were detected (52; 15.3%) at a relatively lower frequency with comparatively higher frequency (21; 31.1%) in fresh than (31; 17.2%) frozen fish samples. On the other hand, DDA also revealed a comparable (45; 13.2%) prevalence rate of ARs. However, a low detection was observed more in fresh (17; 10.6%) than frozen (28; 15.6%) fish samples. Moreover, no statistically significant disparity (χ2 = 0.069; p = 0.79) between two assays and types of fish was recorded. In conclusion, the results of the present study showed that detecting a considerable frequency of ARs in these fish samples raises concerns about potential threats to public health. This underscores the necessity for understanding antibiotic application in aquaculture and its potential connection to antibiotic resistance in bacterial pathogens. Such comprehension is pivotal for formulating and implementing effective control and farm management strategies to address this pressing issue.

Oxytetracycline (OTC), enrofloxacin (EFX), and sulfachloropyridazine (SCP) are critically important antimicrobials (AMs) in both human and veterinary medicine, where they are widely used in farm animals. Lettuce has become a matrix of choice for studying the presence of residues of these AMs in plants, as the concentrations of residues detected in lettuce can range from ng to mg. While several analytical methodologies have been developed for the purpose of detecting AMs in lettuce, these currently do not detect both the parent compound and its active metabolites or epimers, such as in the case of ciprofloxacin (CFX) and 4-epi-oxitetracycline (4-epi-OTC), which also pose a risk to public health and the environment due to their AM activity. In light of this situation, this work proposes an analytical method that was developed specifically to allow for the detection of OTC, 4-epi-OTC, EFX, CFX, and SCP in a lettuce matrix. This method uses acetonitrile, methanol, 0.5% formic acid, and McIlvaine-EDTA buffer as extraction solvents, and dispersive solid-phase extraction (dSPE) for the clean-up. The analytes were detected using a liquid chromatography technique coupled to mass spectrometry (HPLC-MS/MS). Parameters such as the specificity, linearity, recovery, precision, limit of detection, and limit (LOD) of quantification (LOQ) were calculated according to the recommendations established in the European Union decision 2021/808/EC and VICH GL2: Validation of analytical procedures. The LOQ for the analytes OTC, 4-epi-OTC, CFX, and SCP was 1 μg·kg−1, whereas for EFX, it was 5 μg·kg−1 dry weight. All calibration curves showed a coefficient of determination (R2) of >0.99. The recovery levels ranged from 93.0 to 110.5% and the precision met the acceptance criteria, with a coefficient of variation of ≤14.02%. Therefore, this methodology allows for the precise and reliable detection and quantification of these analytes. The analysis of commercial samples confirmed the suitability of this method.

This study was carried out to validate the liquid scintillation counter method (Charm II) for the detection of tetracyclines, beta-lactams, and sulfonamides (Sulfa drugs) in a range of Aquaculture Products. This method of validation followed primary validation performed in Belgium and was therefore transferred to Nigeria but further validation was required, and this was performed according to the European Commission Decision 2002/657/EC. Method performance was based on the detection capability (CCβ), specificity (cross-reactivity), robustness, repeatability, and reproducibility for the detection of antimicrobial residues. Seafood and aquaculture samples used for the validation process included tilapia (Oreochromis niloctus), catfish (Siluriformes), African threadfin (Galeoides decadactylus), common carp (Cyprinus carpio), and shrimps (penaeidae). These were spiked with varying concentrations of tetracyclines, beta-lactams, and sulfonamides standards to determine the validation parameters. Results of the validation showed tetracyclines had detection capabilities of 50 µg/kg, while beta-lactams and sulphonamides had detection capabilities of 25 µg/kg. The relative standard deviation for both repeatability and reproducibility studies ranged between 1.36% and 10.50%. Results of this study are suitable and comparable to the initial validation reports from the primary validation of Charm II tests for the detection of antimicrobial residues in a range of aquaculture fish conducted in Belgium. The results also prove the specificity, ruggedness, and reliability of the radio receptor assay tests for detection of the various antimicrobials in aquaculture products. This could be used in seafood/aquaculture products monitoring in Nigeria.

Livestock intensification has facilitated antimicrobial use (AMU) with consequent antimicrobial resistance (AMR) development. We assessed AMU in beef farms, pathways for residues and resistance dissemination to humans, risk status, residues identification, and drivers for antimicrobial residues and resistance emergence in beef cattle production systems. A cross-sectional survey was conducted in randomly selected beef farms of Northern Nigeria, between 2018 and 2019. Traffic Light model and Disc Diffusion Test were used to assess risk status and determined residues, respectively. Data was analyzed using descriptive statistics and logistic regression models at 95% confidence level. About 92% (n = 608) farmers participated. The majority of farmers managing intensive (78.9%) and semi-intensive (76.6%) farms did not follow antimicrobial dosage instructions. Also, 72.4% and 83.9% of the farmers on intensive and semi-intensive systems, respectively, did not observed withdrawal periods after AMU. Furthermore, 71.5% farmers in intensive and 53.2% in semi-intensive farms used antimicrobials as growth promoters. Antimicrobials frequently used include tetracyclines, sulfonamides and penicillin. Antimicrobial residues and resistance dissemination pathways from beef herds were: consumption of contaminated meat with residues (p = 0.007); contacts with contaminated cattle and fomites (p < 0.001); and contaminated manure and aerosols in farm environment (p = 0.003). Significant drivers of residues and resistance emergence were antimicrobial misuse and overuse (OR = 2.72; 95% CI:1.93–3.83), non-enforcement of laws (OR = 2.98; 95% CI:2.11–4.21), poor education and expertise (OR = 1.52; 95% CI:1.09–2.12), and husbandry management system (OR = 10.24; 95% CI:6.75–15.54). The majority of intensive (63.6%) and semi-intensive (57.63%) farm systems belonged to Class 3 (Red risk) status. Antimicrobial residues were detected in 48.4% intensively and 34.4% semi-intensively managed farms. The study revealed poor practices of AMU in beef cattle production. Many factors were found to influenced antimicrobial residues and resistance occurrence and dissemination. A 'One Health' approach mitigation with adequate sanitation, hygiene, and good biosecurity measures will assure food safety, public and environmental health. [ABSTRACT FROM AUTHOR]

Antimicrobial drugs are used as chemotherapeutic agents for treatment, prophylactic medication, growth promoters, and the improvement of feed efficiency. Indiscriminate use of these drugs may leave residues in milk, which could pose a potential threat to human health and have undesirable effects on consumers, including allergic or toxic reactions, carcinogenic effects, bacterial resistance, and imbalance of the gut microfloraTo guarantee the safety of food products as well as public health, monitoring the levels of antimicrobial residues is necessary. The sample preparation, extraction of different physicochemical residues of milk, preconcentration of the extract, and elimination of any matrix interferences that may affect the overall performance of the analytical methods. SPE extraction with an Oasis HLB column is one of the most commonly used techniques for sample preparation and provides an effective and repeatable method for the selective concentration of target analytes in complex matrices. Different variations of this method, including acetonitrile, methanol, and acetonitrile: methanol (50:50), 20% trichloroacetic acid, and McIlvaine buffer, were optimized. According to the obtained results, the prescribed criteria for the analytical yield are met only by the extraction method using 20% trichloroacetic acid and Na2EDTA-Mcllvaine buffer. Chromatographic separation of analytes was achieved on a Kinetex®C18 column and provided satisfactory resolution within the shortest run time. The ESI positive ionization was promoted, and the detection of the compounds was improved with the acidic mobile phase. After optimization of chromatographic conditions, MS/MS conditions, and extraction procedures, the LCMS/MS method was validated according to the criteria of Commission Decision 2002/657/EC. [ABSTRACT FROM AUTHOR]

This study described the presence of twenty antimicrobial substances in farmed shrimp from southeast China and performed a probabilistic health risk assessment. Quinolones (QNs), tetracyclines (TCs), nitrofuran metabolites (NMs), chloramphenicols (CAPs), malachite green (MG), and leucomalachite green (LMG) were targeted for analysis in different shrimp species. The detection frequencies were 49.07 % for QNs, 33.39 % for NMs, 3.59 % for TCs, and 1.49 % for CAPs. It revealed high detectable levels of enrofloxacin, ciprofloxacin, and semicarbazide in shrimp samples. Detection frequencies varied among different shrimp species. Seasonal variations in residue concentrations were observed with higher levels detected in the summer months. The health risk assessment, conducted using Monte Carlo simulation, indicated that the estimated daily intake (EDI) of these substances was below the acceptable daily intake (ADI). It suggests there are minimal health risks to local consumers. However, the surveillance of antimicrobial substance residues in shrimp should be continuously conducted considering other potential hazards, such as antibiotic resistance and allergic reactions. • Antimicrobial substances were tested in shrimp with a large sample size (n=485). • Detection frequency was 49.07 % for quinolones, and 33.39 % for nitrofuran metabolites. • High levels of enrofloxacin, ciprofloxacin, and semicarbazide were found. • The detection frequencies of analytes were influenced by sampling months. • Enrofloxacin was the primary contributor to the targeted hazard quotients. [ABSTRACT FROM AUTHOR]

• Florfenicol metabolites synthesized with standard lab techniques. • High linearity (>0.99) and ±10 % accuracy confirmed in fish analysis. • Consistent detection of florfenicol metabolites in treated fish fillets. • Developed synthesis and SPE-UHPLC-MS/MS methods aids fish drug metabolism studies. This study concerns the synthesis of the florfenicol (FF) metabolites florfenicol amine (FFA), florfenicol alcohol (FFOH), and monochloroflorfenicol (FFCl), for their subsequent use as reference standards in On-line solid-phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (SPE-UHPLC-MS/MS) analysis. The metabolites were characterized using 1H and 13C NMR, as well as HRMS, and their purities were confirmed by quantitative NMR to ensure analytical reliability. Validation of the developed analytical method showed that it presented acceptable performance, with linearity >0.99 for all the target analytes, accuracies within ±10 % of nominal concentrations, and intra- and inter-day precisions within 15 %. Application of this method to fillets from fish that had been treated with florfenicol (dose of 10 mg/kg bw daily) demonstrated its effectiveness in consistently detecting FF and its metabolites throughout the treatment. The results emphasized the utility of the method for enhancing pharmacokinetic and residue depletion research. The ability to precisely monitor the drug and its metabolites in treated fish provides important insights into florfenicol metabolism, laying the groundwork for further comprehensive profiling studies of metabolites in fish tissue. [ABSTRACT FROM AUTHOR]

Abstract Background Due to high disease burden and poor animal health services in Uganda, administration of antimicrobials particularly oxytetracycline (OTC) is often done by farm owners and workers without any prescription. This results in misuse of OTC with consequent high chances of antibiotic residues and antimicrobial resistance hence posing public health threat. The degree of public health threat from OTC use is not well established due to limited published data on antibiotic residues and usage in livestock production in Uganda. This study comparatively determined OTC residue levels in 318 samples of bovine muscles, liver and kidney tissues from Kiruhura, Mbarara and Ntungamo districts of South Western Uganda during dry and wet seasons. Results The results revealed that the overall OTC residues positivity levels was 74.84% while the district wise rates were 56.88%, 84% and 84.52% for Kiruhura, Mbarara and Ntungamo, respectively. The mean OTC residue levels in bovine muscles, liver and kidney tissues were above the recommended maximum residue limits of 200, 600 and 1200 µg/kg, respectively as established by FAO/WHO. Of the collected samples, 72.41% (236/318) had OTC residues in concentrations above the recommended maximum residue limits. Wilcoxon signed rank test results showed that change in the seasons did not cause any significant changes in the liver OTC residue levels for all the districts, though this was significant for muscles from Kiruhura and Mbarara districts. Unacceptably high OTC levels were found in the muscles, liver and some kidney samples: Kiruhura muscles and liver samples had mean OTC concentrations of 1094 ± 378 µg/kg and 967 ± 198 µg/kg; Mbarara muscles, liver and kidney samples had mean OTC mean concentrations of 668 ± 163 µg/kg, 3778 ± 1140 µg/kg and 12,576 ± 1630 µg/kg, respectively while Ntungamo samples had mean OTC concentrations of 586 ± 123 µg/kg and 5194 ± 1463 µg/kg in muscle and liver tissues. Conclusions The results of this study indicated that there are unacceptably high OTC residue levels in bovine tissues consumed in South Western Uganda. This poses a public and veterinary health threat to consumers of these bovine tissues.

Background: The widespread use of antimicrobials in agriculture, coupled with bioactive chemicals like pesticides and growth-promoting agents, has accelerated the global crisis of antimicrobial resistance (AMR). Agroecosystems provides a platform in the evolution and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which pose significant threats to both environmental and public health., Aim of Review: This review explores the ecological consequences of antimicrobial residues and bioactive chemicals in agroecosystems, with a focus on their role in shaping AMR. It delves into the mechanisms by which these substances enter agricultural environments, their interactions with soil microbiomes, and the subsequent impacts on microbial community structure., Key Scientific Concepts of Review: Evidence indicates that the accumulation of antimicrobials promotes resistance gene transfer among microorganisms, potentially compromising ecosystem health and agricultural productivity. By synthesizing current research, we identify critical gaps in knowledge and propose strategies for mitigating the ecological risks associated with antimicrobial residues. Moreover, this review highlights the urgent need for integrated management approaches to preserve ecosystem health and combat the spread of AMR in agricultural settings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Production and hosting by Elsevier B.V.)

The presence and fate of antimicrobial residues in the environment is a subject of growing concern. Previous researchers have demonstrated the persistence of residues in soil and water. Additionally, antimicrobial resistance is a growing concern, particularly to public health, animal health and economic development. In this study, a low cost, commercial blood glucose meter was explored as the basis for detecting antimicrobial residues in conjunction with a microorganism sensitive to this residue. A microbial bioassay was developed based on the metabolic response of Geobacillus stearothermophilus, a sensitive bacteria used in the determination of antimicrobial residues in food products, by measuring changes in glucose as a result of metabolic activity. After optimizing experimental conditions, this sensing strategy was tested using bacterial cultures in the presence of colistin, a last-resort antibiotic used for human and animal health. Growth of G. stearothermophilus was measurable as a change in glucose concentration after 2–4 h incubation at 60 °C, when LB media was supplemented with 100 mg/dL of glucose. The lowest measured colistin concentration that resulted in inhibition of growth was 1 mg/L colistin and an increase in lag phase resulted at 100 µg/L colistin. To increase the sensitivity of the assay, we then added a sub-inhibitory concentration of chloramphenicol to the media and found that growth inhibition could be achieve at a lower colistin concentration of 8 µg /L. These results provide a promising basis for a future low-cost sensor to identify antimicrobial residues from environmental samples in the field.

In Tanzania, the increased demand for animal-derived foods, particularly eggs, meat, and milk, has resulted in the intensification of farming systems with the use of antimicrobials, particularly sulphonamides and tetracyclines. According to the FAO/WHO Codex Alimentarius commission, concentrations of antimicrobial residues in food exceeding the acceptable daily intake (ADI) and maximum residual limit (MRL) pose a health risk to consumers. This cross-sectional study determined the concentrations of sulphonamide and tetracycline residues in the liver tissues of commercial broiler chicken sold in Dar es Salaam, Tanzania, to find out whether the amounts of residues were within the legally permitted and acceptable limits in food. We conveniently sampled eighty-four liver tissue samples from broiler chicken sold in two out of six large markets in Dar es Salaam. The amounts of tetracycline and sulphonamide residues were determined using an ELISA kit (Shenzhen Lvshiyuan Biotechnology Company, Shenzhen, China). The results showed that all 100% (n = 84) samples contained tetracycline residues and 21.4% (n = 18) samples contained sulphonamide residues, while 21.4% (n = 18) contained both sulphonamide and tetracycline residues. The concentrations of sulphonamide residues were within the maximum residual limit (MRL). However, 90.5% (n = 76) of the samples had tetracycline levels that exceeded the acceptable daily intake (ADI) range 0–3 µg/kg and 13.1% (n = 11) of the samples had tetracycline levels that exceeded the maximum residue limit of 300 µg/kg. The observed presence of antibiotic residues in the poultry tissues poses a health risk to consumers, and may lead to antimicrobial resistance micro-organisms, which may spread to humans and animals via the environment. Vigorous surveillance and observation of the withdrawal periods should be advocated to ensure that the food from animals is safe with regard to the residues of veterinary medicines. [ABSTRACT FROM AUTHOR]

A total of 300 quail eggs were collected randomly from different markets in Cairo and Giza Governorates. Five eggs were represented as one egg sample. Shell and content of each egg were examined for their microbiological contents, sensory evaluation and study of Escherichia coli O157 survival in artificially contaminated eggs. Moreover, qualitative detection of antimicrobial residues by seven plates microbiologically bioassay and confirmed by validated high‐performance liquid chromatography (HPLC) methods for positively reacted antimicrobials in raw and boiled samples. There was a significant difference (P < 0·05) between the grading score of eggs after the boiling at 2‐, 4‐, 5‐ and 7‐min. Based on the survival results, the refrigeration storage and boiling for 5 min of quail eggs was confirmed that such eggs are without E. coli O157. After the boil, the concentrations of oxytetracycline (OTC) and 4‐Epi‐OTC residues were significantly reduced, and there was no effect on the concentration of sulphadimidine (SDD), amoxicillin (AMO) and Diketo residues. Samples that exceeded the maximum residual limits (MRLs) were 17·0%, 12·0%, 10·0%, 16·0% and 14·0% for SDD, OTC, 4‐Epi‐OTC, AMO and Diketo, respectively. After boiling, no significant change was noted for SDD, AMO and Diketo, but all OTC and 4‐Epi‐OTC were completely below MRLs. Therefore, SDD and AMO with their metabolite (Diketo) are heat‐stable antimicrobial residues with multiple human health hazards. [ABSTRACT FROM AUTHOR]

A 500 composite egg samples (2500 eggs-each sample represented by 5 eggs) collected from layer farms and local markets from all over Jordan were studied for presence of antimicrobials using Premi®Test screening test. Positive samples indicated by inhibition of microbial growth represented 12.8% out of total screened egg samples. Positive samples were examined quantitatively using HPLC technique to detect the presence of enrofloxacin and ciprofloxacin. Ciprofloxacin and enrofloxacin residues were detected in 1% and 0.8% of the total samples, respectively, where both drugs were recovered from white but not yolk. The effect of boiling on either drugs concentration in fortified white or yolk was demonstrated by gradual increases in the mean reduction percentages within treatment time with an average of 87% reduction after 15 minutes of boiling for both drugs and egg compartments and 5 minutes of frying at 160°C. The average concentration reduction percentages by the end of four weeks of refrigeration of fortified yolk and white were around 45 and 50% for enrofloxacin and ciprofloxacin respectively. The significance and mechanism of drug deposition and reduction during processing is being highlighted.

Mastitis is one of the major diseases of dairy cows that affects milk quality and quantity and increases the potential risk for the presence of antimicrobial residues (AR) in milk, which could lead to the development of antimicrobial resistance (AMR) among human pathogens. Even if the presence of AR in milk and milk products is low in many countries, the threat is not negligible and cannot be ignored. These problems may be investigated by applying a One Health approach, and this prevalence study aimed to estimate the risks for human health related to milk production applied to dairy herds in Lombardy. Three hundred thirty-one bulk tank milk samples were randomly collected and analyzed by CombiFoss 7 and MilkoScan 7 (milk quality, bacteria, and somatic cell count), an HPLC system coupled to a Q-Exactive Orbitrap (AR), and qPCR (contagious pathogens). The data were analyzed by a generalized linear model. The results showed a relatively high prevalence of contagious pathogens (S. aureus 28.1%; Str. agalactiae 7.3%; M. bovis 3%), which primarily affect milk nutritional components decreasing mainly milk fat content (range 1%–2.5%), but did not show them to be associated to an increase of the risk of antimicrobial residues. These latter ones were recovered only in 7/331 samples at concentrations far below official MLRs. The results support currently active surveillance programs' efficacy in reducing AR risks, which may be further improved by prioritizing them based on geographical area characteristics. [ABSTRACT FROM AUTHOR]

Considering that plasmid conjugation is a major driver for the dissemination of antimicrobial resistance in bacteria, this study aimed to investigate the effects of residual concentrations of antimicrobial growth promoters (AGPs) in poultry litter on the frequencies of IncFII‐FIB plasmid conjugation among Escherichia coli organisms. A 2 × 5 factorial trial was performed in vitro, using two types of litter materials (sugarcane bagasse and wood shavings) and five treatments of litter: non‐treated (CON), herbal alkaloid sanguinarine (SANG), AGPs monensin (MON), lincomycin (LCM) and virginiamycin (VIR). E. coli H2332 and E. coli J62 were used as donor and recipient strains, respectively. The presence of residues of monensin, lincomycin and virginiamycin increased the frequency of plasmid conjugation among E. coli in both types of litter materials. On the contrary, sanguinarine significantly reduced the frequency of conjugation among E. coli in sugarcane bagasse litter. The conjugation frequencies were significantly higher in wood shavings compared with sugarcane bagasse only in the presence of AGPs. Considering that the presence of AGPs in the litter can increase the conjugation of IncFII‐FIB plasmids carrying antimicrobial resistance genes, the real impact of this phenomenon on the dissemination of antimicrobial resistant bacteria in the poultry production chain must be investigated. [ABSTRACT FROM AUTHOR]

Background: Due to high disease burden and poor animal health services in Uganda, administration of antimicrobials particularly oxytetracycline (OTC) is often done by farm owners and workers without any prescription. This results in misuse of OTC with consequent high chances of antibiotic residues and antimicrobial resistance hence posing public health threat. The degree of public health threat from OTC use is not well established due to limited published data on antibiotic residues and usage in livestock production in Uganda. This study comparatively determined OTC residue levels in 318 samples of bovine muscles, liver and kidney tissues from Kiruhura, Mbarara and Ntungamo districts of South Western Uganda during dry and wet seasons. Results: The results revealed that the overall OTC residues positivity levels was 74.84% while the district wise rates were 56.88%, 84% and 84.52% for Kiruhura, Mbarara and Ntungamo, respectively. The mean OTC residue levels in bovine muscles, liver and kidney tissues were above the recommended maximum residue limits of 200, 600 and 1200 µg/kg, respectively as established by FAO/WHO. Of the collected samples, 72.41% (236/318) had OTC residues in concentrations above the recommended maximum residue limits. Wilcoxon signed rank test results showed that change in the seasons did not cause any significant changes in the liver OTC residue levels for all the districts, though this was significant for muscles from Kiruhura and Mbarara districts. Unacceptably high OTC levels were found in the muscles, liver and some kidney samples: Kiruhura muscles and liver samples had mean OTC concentrations of 1094 ± 378 µg/kg and 967 ± 198 µg/kg; Mbarara muscles, liver and kidney samples had mean OTC mean concentrations of 668 ± 163 µg/kg, 3778 ± 1140 µg/kg and 12,576 ± 1630 µg/kg, respectively while Ntungamo samples had mean OTC concentrations of 586 ± 123 µg/kg and 5194 ± 1463 µg/kg in muscle and liver tissues. Conclusions: The results of this study indicated that there are unacceptably high OTC residue levels in bovine tissues consumed in South Western Uganda. This poses a public and veterinary health threat to consumers of these bovine tissues. [ABSTRACT FROM AUTHOR]

The existence of antimicrobial residues in food of animal origin is a safety concern worldwide. This study investigated the occurrence of such residues in table eggs collected from Erbil city (Iraq) markets according to shell color, location, and season. Results showed that the total proportion was 15.2%. The differences were not significant for the shell color (White color 13.7%; Brown color 16.8%), location (Urban 16.4%; Rural 13.8%), and months (July 12.1%, August 13.5%, September 18.8%, October 15.7%, December 16.9%, and November 14.1%). Such level of residue contamination requires a response from in-charge Iraqi health authorities to regulate antibiotics usage and ensure food safety.

Abstract The study carried out a primary validation of Charm II tests for the detection of antimicrobial residues in aquaculture fish. The validation was performed according to European Commission Decision 2002/657/EC and the parameters determined included: detection capability, repeatability, reproducibility, specificity and robustness for the detection of antimicrobial residues in fish. Fish materials from different species including cat fish, trout, salmon, sea bass, tilapia, lingue and pangasius, were spiked with varying concentrations of selected antimicrobials including sulfonamides, β-lactams, macrolides, tetracyclines and aminoglycosides to determine the detection capabilities and other validation parameters of the Charm II tests. Results of the validation showed that the detection capabilities for the tetracyclines ranged from 25 to 100 µg/kg, while the sulfonamides and aminoglycosides were detected at 25 µg/kg for all species under study. The detection capabilities for the beta-lactams ranged from 25 to 300 µg/kg; and was 100 µg/kg for the tested macrolides. Results of the study showed that there was no significant difference between counts for samples read immediately after addition of the scintillation liquid and those read 14 h after addition of the scintillation liquid, provided that there was good vortexing before analysis. There was also no significant difference between counts for the same samples analyzed in different runs under repeatability and reproducibility conditions at the same spiking concentrations for the different fish species analyzed. The relative standard deviation for both repeatability and reproducibility ranged from 1.2 to 15.1%. The Charm II tests were found to be 100% group specific, as none of the antimicrobials kits, gave false positive results when testing non-target antimicrobial drugs. Results of this study demonstrate the suitability of the Charm II technique as a rapid screening tool for detection of antimicrobial residues in a variety of fish species at maximum residue limits (MRL) established in the EU guidelines, with the exception of tilmicosin which was detected at 2 MRL. The results also prove the robustness, specificity, reliability and precision of the Charm II assay in the detection of various antimicrobial residuals in fish and its applicability for the rapid evaluation of the quality of aquaculture fish for safety and trade purposes.

The feeding of waste milk containing antibiotic residues (WMA) to calves has been associated with the shedding of antibiotic-resistant bacteria by calves. However, little is known regarding farmers' intrinsic factors affecting this practice, and on which it would be relevant to intervene in order to change this practice. The objectives of this study were (1) to describe the farmers' intrinsic factors, such as perceived benefits, risks, and social norms related to the feeding of WMA to calves, antibiotic resistance, and antibiotic use, and (2) to evaluate how the feeding of WMA to calves is related to farmers' personal values and perceptions related to WMA feeding and antibiotic resistance. Answers to an online survey were collected from 233 Swiss dairy producers (38.3% response rate). The proportion of respondents who fed WMA to calves was 48.3%. In a hierarchical logistic regression model, only perception factors extracted by factor analysis were associated with the feeding of WMA to calves, namely (in decreasing order of magnitude): farm-level benefits of WMA feeding, the interaction of farm-level benefits with support from governmental authorities, and causes and threats of antibiotic resistance. The results suggest that, in order to reduce the feeding of WMA to calves, communications to dairy producers should focus on changing the perceived benefits of this practice in comparison to those of alternative WMA disposal methods carrying a lower risk of antibiotic resistance. The involvement of veterinarians and governmental authorities in these communications and in supporting producers may increase the successful adoption of alternative WMA disposal methods.

Antimicrobial resistance caused by the overuse of antimicrobials by farmers is an essential health issue. Currently, signing contracts between farmers and cooperatives has become crucial for small farmers to integrate into the modern agricultural industry chain. Unlike vertical government governance, which aims to intervene in the overuse of antimicrobials by farmers through many mandatory or incentive measures, contract governance refers to the social governance model that clarifies rights and obligations between farmers and cooperatives to ensure the adequate performance of contracts, which is especially beneficial to regulate farmers' safe production behavior such as the standard use of antimicrobials. However, there is a research gap concerning the effectiveness of contract governance in inhibiting farmers' overuse of animal antimicrobials. This study applies propensity score matching and mediation analysis method to assess how contract governance affects the overuse of antimicrobials by hog farmers. The paper uses data from 498 hog farmers of China's Hebei, Henan, and Hubei provinces to explore the impact and underlying mechanisms of contract governance on antimicrobial overuse in agriculture. The results showed that contract governance was found to inhibit the overuse of antimicrobials, with the amount paid for antimicrobials reduced by 118 yuan/household. We found evidence that this effect is exerted through three mechanisms: cooperative supervision ( CS ), technical guidance ( TG ), and product premium perception ( PP ). The CS , TG , and PP mediation effects accounted for 19.94%, 27.90%, and 26.93% of the total impact, respectively. Therefore, policy implications of these results include strengthening the standard of contract signing procedures and the integrity of executing contracts, increasing the market premium for products that meet the antimicrobial residue standards, and enhancing farmers' knowledge and contracting ability., Competing Interests: The authors declare that they have no competing interests., (© 2024 The Authors. Published by Elsevier B.V.)

The antibiotic residues in the food chain are a growing public health concern due to their involvement in the development of antimicrobial resistance, mutagenicity, carcinogenicity, hypersensitivity, bone marrow suppression, and disruption of gut microbiota. The indiscriminate use of antibiotics for the treatment of diseases and improved animal production results in the deposition of these residues in milk, eggs, and meat although their use is not highlighted for the foods consumed by human beings. Moreover, the antibiotics consumed in the clinical settings and animal production are excreted into the environment at a large scale which may adversely disturb the terrestrial and aquatic ecosystems. The matter can become more momentous soon because the production of food animals at an industrial scale will significantly increase the use of antimicrobials. The problem caused by these antibiotic residues in the food chain is two-fold; the direct toxicity to humans and the possibility of the emergence of resistant bacterial strains ultimately leading to the failure of antibiotic therapy. Present article critically analyses the factors contributing to the presence of antibiotic residues in the food chain and their implications and perilous impact on consumers and proposes the possible ways to reduce the antimicrobial residues in the food. [ABSTRACT FROM AUTHOR]

In Tanzania, the increased demand for animal-derived foods, particularly eggs, meat, and milk, has resulted in the intensification of farming systems with the use of antimicrobials, particularly sulphonamides and tetracyclines. According to the FAO/WHO Codex Alimentarius commission, concentrations of antimicrobial residues in food exceeding the acceptable daily intake (ADI) and maximum residual limit (MRL) pose a health risk to consumers. This cross-sectional study determined the concentrations of sulphonamide and tetracycline residues in the liver tissues of commercial broiler chicken sold in Dar es Salaam, Tanzania, to find out whether the amounts of residues were within the legally permitted and acceptable limits in food. We conveniently sampled eighty-four liver tissue samples from broiler chicken sold in two out of six large markets in Dar es Salaam. The amounts of tetracycline and sulphonamide residues were determined using an ELISA kit (Shenzhen Lvshiyuan Biotechnology Company, Shenzhen, China). The results showed that all 100% (n = 84) samples contained tetracycline residues and 21.4% (n = 18) samples contained sulphonamide residues, while 21.4% (n = 18) contained both sulphonamide and tetracycline residues. The concentrations of sulphonamide residues were within the maximum residual limit (MRL). However, 90.5% (n = 76) of the samples had tetracycline levels that exceeded the acceptable daily intake (ADI) range 0–3 µg/kg and 13.1% (n = 11) of the samples had tetracycline levels that exceeded the maximum residue limit of 300 µg/kg. The observed presence of antibiotic residues in the poultry tissues poses a health risk to consumers, and may lead to antimicrobial resistance micro-organisms, which may spread to humans and animals via the environment. Vigorous surveillance and observation of the withdrawal periods should be advocated to ensure that the food from animals is safe with regard to the residues of veterinary medicines.

Mastitis is one of the major diseases of dairy cows that affects milk quality and quantity and increases the potential risk for the presence of antimicrobial residues (AR) in milk, which could lead to the development of antimicrobial resistance (AMR) among human pathogens. Even if the presence of AR in milk and milk products is low in many countries, the threat is not negligible and cannot be ignored. These problems may be investigated by applying a One Health approach, and this prevalence study aimed to estimate the risks for human health related to milk production applied to dairy herds in Lombardy. Three hundred thirty-one bulk tank milk samples were randomly collected and analyzed by CombiFoss 7 and MilkoScan 7 (milk quality, bacteria, and somatic cell count), an HPLC system coupled to a Q-Exactive Orbitrap (AR), and qPCR (contagious pathogens). The data were analyzed by a generalized linear model. The results showed a relatively high prevalence of contagious pathogens (S. aureus 28.1%; Str. agalactiae 7.3%; M. bovis 3%), which primarily affect milk nutritional components decreasing mainly milk fat content (range 1%–2.5%), but did not show them to be associated to an increase of the risk of antimicrobial residues. These latter ones were recovered only in 7/331 samples at concentrations far below official MLRs. The results support currently active surveillance programs’ efficacy in reducing AR risks, which may be further improved by prioritizing them based on geographical area characteristics.

A 500 composite egg samples (2500 eggs-each sample represented by 5 eggs) collected from layer farms and local markets from all over Jordan were studied for presence of antimicrobials using Premi®Test screening test. Positive samples indicated by inhibition of microbial growth represented 12.8% out of total screened egg samples. Positive samples were examined quantitatively using HPLC technique to detect the presence of enrofloxacin and ciprofloxacin. Ciprofloxacin and enrofloxacin residues were detected in 1% and 0.8% of the total samples, respectively, where both drugs were recovered from white but not yolk. The effect of boiling on either drugs concentration in fortified white or yolk was demonstrated by gradual increases in the mean reduction percentages within treatment time with an average of 87% reduction after 15 minutes of boiling for both drugs and egg compartments and 5 minutes of frying at 160°C. The average concentration reduction percentages by the end of four weeks of refrigeration of fortified yolk and white were around 45 and 50% for enrofloxacin and ciprofloxacin respectively. The significance and mechanism of drug deposition and reduction during processing is being highlighted. [ABSTRACT FROM AUTHOR]

Antimicrobial residues in pork products are a hazard to public health. They contribute to antimicrobial resistance (AMR) as the exposure of bacteria to trace amounts of these residues can hasten its incidence and emergence. In the Philippines, the quality of meat products is regulated by the National Meat Inspection Service (NMIS) through antimicrobial sensitivity testing (AST) via disc diffusion. Analytical methods such as the use of high-performance liquid chromatography (HPLC) may also be used in monitoring antibiotic residues in meat samples. This experimental study aims to develop a screening method for tetracycline residues in pork (Sus scrofa domesticus) muscle and liver from public wet markets; and to determine the feasibility of this method based on specified critical parameters such as LOD, LOQ, and linearity. Twenty (20) pork muscle and 14 pork liver samples were collected from stalls in three public wet markets and were subjected to AST through the NMIS and HPLC analysis. The HPLC analysis utilized an isocratic elution with a mobile phase of 85:15 0.1% formic acid in acetonitrile: 0.1% formic acid in water and a flow rate of 1.0 mL/min. The detection of tetracycline was observed at peaks with a retention time of 3.95 ± 0.15 min. The determined retention time was used to identify tetracycline in the pork samples. AST results showed no presence of tetracycline in all samples. HPLC results, however, revealed that two out of 20 pork muscle samples and eight out of 14 pork liver samples contained tetracycline. The results have demonstrated that instrumental methods of analysis such as HPLC are necessary to confirm the absence or presence of the residues and to quantify the concentration to compare it to the established MRL. Further validation studies are recommended to ensure the accuracy and specificity of the optimized method. [ABSTRACT FROM AUTHOR]

The study carried out a primary validation of Charm II tests for the detection of antimicrobial residues in aquaculture fish. The validation was performed according to European Commission Decision 2002/657/EC and the parameters determined included: detection capability, repeatability, reproducibility, specificity and robustness for the detection of antimicrobial residues in fish. Fish materials from different species including cat fish, trout, salmon, sea bass, tilapia, lingue and pangasius, were spiked with varying concentrations of selected antimicrobials including sulfonamides, β-lactams, macrolides, tetracyclines and aminoglycosides to determine the detection capabilities and other validation parameters of the Charm II tests. Results of the validation showed that the detection capabilities for the tetracyclines ranged from 25 to 100 µg/kg, while the sulfonamides and aminoglycosides were detected at 25 µg/kg for all species under study. The detection capabilities for the beta-lactams ranged from 25 to 300 µg/kg; and was 100 µg/kg for the tested macrolides. Results of the study showed that there was no significant difference between counts for samples read immediately after addition of the scintillation liquid and those read 14 h after addition of the scintillation liquid, provided that there was good vortexing before analysis. There was also no significant difference between counts for the same samples analyzed in different runs under repeatability and reproducibility conditions at the same spiking concentrations for the different fish species analyzed. The relative standard deviation for both repeatability and reproducibility ranged from 1.2 to 15.1%. The Charm II tests were found to be 100% group specific, as none of the antimicrobials kits, gave false positive results when testing non-target antimicrobial drugs. Results of this study demonstrate the suitability of the Charm II technique as a rapid screening tool for detection of antimicrobial residues in a variety of fish species at maximum residue limits (MRL) established in the EU guidelines, with the exception of tilmicosin which was detected at 2 MRL. The results also prove the robustness, specificity, reliability and precision of the Charm II assay in the detection of various antimicrobial residuals in fish and its applicability for the rapid evaluation of the quality of aquaculture fish for safety and trade purposes. [ABSTRACT FROM AUTHOR]

Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains.

Antimicrobial drug residues in food are strictly controlled and monitored by national laws in most territories. Tetracyclines are a major broad-spectrum antibiotic class, active against a wide range of Gram-positive and Gram-negative bacteria, and they are the leading choice for the treatment of many conditions in veterinary medicine in recent years. In dairy farms, milk from cows being treated with antibiotic drugs, such as tetracyclines, is considered unfit for human consumption. Contamination of the farm bulk tank with milk containing these residues presents a threat to confidence of supply and results in financial losses to farmers and dairy. Real-time monitoring of milk production for antimicrobial residues could reduce this risk and help to minimise the release of residues into the environment where they can cause reservoirs of antimicrobial resistance. In this article, we review the existing literature for the detection of tetracyclines in cow’s milk. Firstly, the complex nature of the milk matrix is described, and the test strategies in commercial use are outlined. Following this, emerging biosensors in the low-cost biosensors field are contrasted against each other, focusing upon electrochemical biosensors. Existing commercial tests that identify antimicrobial residues within milk are largely limited to beta-lactam detection, or non-specific detection of microbial inhibition, with tests specific to tetracycline residues less prevalent. Herein, we review a number of emerging electrochemical biosensor detection strategies for tetracyclines, which have the potential to close this gap and address the industry challenges associated with existing tests.

The extensive use of antibiotics leads to antibiotic residues in frequently consumed foods. Generally, the main use of antibiotics in animals is to treat and prevent diseases and growth promotion. However, the residues and their breakdown products have several side effects on the human body and, in a broader sense, on the environment. In relation to the human body, the frequency of mutations is increased, the bone marrow is damaged (chloramphenicol), and the reproductive organs of humans are affected. Carcinogenic effects have been found with antibiotics such as sulfamethazine, oxytetracycline, and furazolidone. We summarized data from 73 scientific studies reporting antimicrobial residues in animal products that were freely available for sale. The studies were published in English starting from 1999 till 2021 and identified through the Pubmed search engine. The aims were to find out which antibiotics, legal or illegal, could be found in animal foods worldwide. Which are stable to get into the food chain and exceed the maximum residue limits (MRL) regarding the EU guidelines as a comparison. Reducing antimicrobial residues in food from animal origin and, in addition to this, fighting the tremendous growth and spread of antimicrobial resistance will undoubtedly be one of the most difficult food safety challenges in the coming years.

A cross-sectional observation and an intervention study were conducted in Chittagong, Bangladesh in 2015 to assess the status of antimicrobial residues in chicken and fish. The samples were tested for selected antimicrobials (amoxicillin, ciprofloxacin, oxytetracycline and enrofloxacin) using thin-layer chromatography (TLC). The TLC-based overall prevalence of residues was 87.9% in chicken (N = 182) and 56.9% in fish (N = 153). The prevalences in chicken in June (N = 91) and in October (N = 91), respectively, were 91.2% and 83.5% (amoxicillin), 1.1% and 1.1% (enrofloxacin), 1.1% and 0% (ciprofloxacin), and 0% and 6.6% (oxytetracycline). In fish, the prevalence in September (N = 74) and in October (N = 79) was 52.7% and 44.3% (amoxicillin) and 1.4% and 27.8% (oxytetracycline), respectively. The mean concentration of amoxicillin residue was evaluated by ultra-high-performance liquid chromatography to be 508.4 mg/kg (chicken) and 515.4 mg/kg (fish). The random effect model identified market (Chawkbazar vs. Boalkhali: OR 5.7; Steelmill bazar vs. Boalkhali: OR 5.6) as significant factors for amoxicillin residue in chicken. Amoxicillin concentration was significantly reduced in chicken of Kazirhat (β= − 1.3) and Chawkbazar (β= − 1.1) and increased in October (β= 0.77) based on a generalized linear model (GLM). Climbing perch fish had significantly more risk of having amoxicillin residue than that of Bombay duck (OR = 0.05). All samples were treated by washing, boiling and cooking with spices, and then, TLC-based screening of amoxicillin residues was done. A subset of each treated group was evaluated by UHPLC. Treatment reduced amoxicillin residue levels significantly. [ABSTRACT FROM AUTHOR]

• The model estimated that at least 15.67% of the total amount of these ten orally administered antimicrobials are present in manure which is readily applied onto soil. • Based on sales of antimicrobials, it was estimated that this percentage corresponds to over 21, 000 kg of antimicrobial residues in pig manure in Belgium. • If export and processing are considered, the aforementioned percentage is reduced to at least 8.23%. • Besides usage amounts, the pharmacokinetic behavior of different antimicrobials is a decisive factor in the occurrence of antimicrobial residues ending up in the environment. Veterinary antimicrobials can spread via manure onto agricultural fields, representing an emission of these products or their active metabolites into the environment. This causes concerns regarding the role of antimicrobial residues in the development, selection and spread of resistance. Aiming to approach this issue quantitatively, first a literature review was performed on the bioavailability and extent of in vivo biotransformation of twelve antimicrobials commonly used in pigs orally, and on the level of their persistence in manure. This information was then used in a model estimating the level of each of these administered antimicrobials that is present in manure at the end of common storage durations in pits and, thus, readily applied onto soil. From the studied antimicrobials, the highest level of residues in stored manure was estimated for doxycycline (55% of the initial amount of doxycycline administered orally to pigs after six months of manure storage), as a combining result of its high use in pigs, low bioavailability and high stability in manure. Other antimicrobials (e.g. amoxicillin) are readily degraded and therefore pose less threat. The results of this study highlight the importance of rational antimicrobial use and of further research on pharmacokinetics of antimicrobials and their degraded products in different environmental compartments, to efficiently control the spread of residues and/or resistance genes from manure to these matrices. [ABSTRACT FROM AUTHOR]

The detection of antimicrobial residues in food products of animal origin is of utmost importance. Indeed antimicrobial residues could be present in animal derived food products because of animal treatments for curative purposes or from illegal use. The usual screening methods to detect antimicrobial residues in food are microbiological, immunological or physico-chemical methods. The development of biosensors to propose sensitive, cheap and quick alternatives to classical methods is constantly increasing. Aptasensors are one of the major trends proposed in the literature, in parallel with the development of immunosensors based on antibodies. The characteristics of electrochemical sensors (i.e., low cost, miniaturization, and portable instrumentation) make them very good candidates to develop screening methods for antimicrobial residues in food products. This review will focus on the recent advances in the development of electrochemical aptasensors for the detection of antimicrobial residues in food products. The contribution of nanomaterials to improve the performance characteristics of electrochemical aptasensors (e.g., Sensitivity, easiness, stability) in the last ten years, as well as signal amplification techniques will be highlighted.

The presence of antimicrobial residues in food-producing animals can lead to harmful effects on the consumer (e.g., allergies, antimicrobial resistance, toxicological effects) and cause issues in food transformation (i.e., cheese, yogurts production). Therefore, to control antimicrobial residues in food products of animal origin, screening methods are of utmost importance. Microbiological and immunological methods (e.g., ELISA, dipsticks) are conventional screening methods. Biosensors are an innovative solution for the development of more performant screening methods. Among the different kinds of biosensing elements (e.g., antibodies, aptamers, molecularly imprinted polymers (MIP), enzymes), aptamers for targeting antimicrobial residues are in continuous development since 2000. Therefore, this review has highlighted recent advances in the development of aptasensors, which present multiple advantages over immunosensors. Most of the aptasensors described in the literature for the detection of antimicrobial residues in animal-derived food products are either optical or electrochemical sensors. In this review, I have focused on optical aptasensors and showed how nanotechnologies (nanomaterials, micro/nanofluidics, and signal amplification techniques) largely contribute to the improvement of their performance (sensitivity, specificity, miniaturization, portability). Finally, I have explored different techniques to develop multiplex screening methods. Multiplex screening methods are necessary for the wide spectrum detection of antimicrobials authorized for animal treatment (i.e., having maximum residue limits).

Antimicrobial residues might persist in products and by-products destined for human or animal consumption. Studies exploring the depletion behavior of florfenicol residues in broiler chicken claws are scarce, even though claws can enter the food chain directly or indirectly. Hence, this study intended to assess the concentrations of florfenicol (FF) and florfenicol amine (FFA)--its active metabolite--in chicken claws from birds that were treated with a therapeutic dose of florfenicol. Furthermore, concentrations of these analytes in this matrix were compared with their concentrations in edible tissues at each sampling point. A group of 70 broiler chickens were raised under controlled conditions and used to assess residue depletion. Sampling points were on days 5, 10, 20, 25, 30, 35, and 40 after ceasing treatment, thus extending beyond the withdrawal period established for muscle tissue (30 days). Analytes were extracted using HPLC-grade water and acetone, and dichloromethane was used for the clean-up stage. Liquid chromatography coupled to mass spectroscopy detection (LC-MS/MS) was used to detect and quantify the analytes. The analytical methodology developed in this study was validated in-house and based on the recommendations described in the Commission Decision 2002/657/EC from the European Union. Analyte concentrations were calculated by linear regression analysis of calibration curves that were fortified using an internal standard of chloramphenicol-d5 (CAF-d5). The depletion time of FF and FFA was set at 74 days in claws, based on a 95% confidence level and using the limit of detection (LOD) as the cut-off point. Our findings show that FF and FFA can be found in chicken claws at higher concentrations than in muscle and liver samples at each sampling point. [ABSTRACT FROM AUTHOR]

Antibiotics are generally used worldwide against bacterial diseases in the treatment of food-producing animals. Since the residues of active agents or their metabolites can appear in these foods, the European Union, for instance, has set maximum residue limit concentrations for authorised veterinary drugs in foodstuffs. However, as yet, regulatory limits have not been established for honey and thus far, only recommendations exist. The aim of this study is to present a multiscreening method for residues in honey for the determination of 36 antimicrobial residues associated with several antibiotics of the B1 group (sulfonamides, trimethoprim, aminoglycosides, tetracyclines, quinolones and lincomycin) as well as the antibiotic griseofulvin. During the screening analysis, samples are hydrolysed in an acidified medium, purified on polymeric solid-phase extraction cartridges and subsequently analysed by reversed phase ion pair liquid chromatography tandem mass spectrometry. The liquid chromatographic separation was optimised by computer simulation with DryLab software. The positive identification of target compounds in suspicious samples was confirmed using earlier developed antibiotic class specific methods of which the aminoglycoside method is herein described in detail. The developed approaches were then applied to samples in the national monitoring program after their successful validation. Moreover, the screening and confirmatory methods were applied to proficiency test samples resulting in satisfactory identification and quantification. However, the analysis of real samples revealed that co-eluting target compounds can have considerable influence on the accuracy of this semi-quantitative multiscreening method. [ABSTRACT FROM AUTHOR]

Excessive antimicrobial usage and deficiencies in hygiene in meat production systems may result in undesirable human health hazards, such as the presence of antimicrobial drug residues and non-typhoidal Salmonella (NTS), including antimicrobial resistant (AMR) NTS. Recently, Vietnam has witnessed the emergence of integrated intensive animal production systems, coexisting with more traditional, locally-sourced wet markets. To date no systematic studies have been carried out to compare health hazards in beef, pork and chicken in different production systems. We aimed to: (1) estimate the prevalence of antimicrobial residues in beef, pork and chicken meat; (2) investigate the prevalence and levels of NTS contamination; and (3) investigate serovar distribution and AMR against critically important antimicrobials by animal species and type of retail (wet market vs. supermarket) in Vietnam. Fresh pork, beef and chicken meat samples ( N = 357) sourced from wet markets and supermarkets in Ho Chi Minh City (HCMC), Hanoi and Dong Thap were screened for antimicrobial residues by PremiTest, and were further investigated by Charm II. Samples from HCMC ( N = 113) were cultured using ISO 6579:2002/Amd 1:2007. NTS bacteria were quantified using a minimum probable number (MPN) technique. NTS isolates were assigned to serovar by Multilocus Sequence Typing (MLST), and were investigated for their phenotypic susceptibility against 32 antimicrobials. A total of 26 (7.3%) samples tested positive by PremiTest (9.5% beef, 4.1% pork and 8.4% chicken meat). Sulfonamides, tetracyclines and macrolides were detected by Charm in 3.1%, 2.8% and 2.0% samples, respectively. Overall, meat samples from wet markets had a higher prevalence of residues than those from supermarkets (9.6% vs. 2.6%) ( p = 0.016). NTS were isolated from 68.4% samples from HCMC. Chicken samples from wet markets had by far the highest NTS counts (median 3.2 log MPN/g). NTS isolates displayed high levels of resistance against quinolones (52.2%) and β -lactams (49.6%), but low levels against 3rd generation cephalosporins (4.4%) and aminoglycosides (0.8%). The highest adjusted prevalence of multidrug resistance (MDR) corresponded to isolates from chicken meat and pork (OR 8.3 and 1.8, respectively) (baseline = beef). S . Kentucky was the most common serovar identified (11 from chicken, 1 from beef) and 91.7% isolates was MDR. 11/12 isolates corresponded to ST198, a worldwide-disseminated multi-resistant NTS clone. We recommend stepping up policy measures to promote responsible antimicrobial use in animal production, as well as awareness about withdrawal periods to limit the hazard of residues in animal products, and improving slaughtering/hygiene procedures to limit cross-contamination with NTS, particularly in poultry wet markets. [ABSTRACT FROM AUTHOR]