Residues of veterinary drugs in eggs and their distribution between yolk and white

Long-term effects of iopamidol as a contrast medium for computed tomography in Cloudy Catsharks Scyliorhinus torazame

OBJECTIVE

The use of computed tomography (CT) in aquarium animals, including elasmobranchs, has increased dramatically. To take advantage of CT, contrast medium is used to enhance internal organs and provide contrast since elasmobranchs lack visceral fat. In this study, the contrast effects of iopamidol were examined for up to 260 days after intravenous administration to establish the time course of the CT values for the target organs in eight mature Cloudy Catsharks Scyliorhinus torazame.

METHODS

A micro-CT system was used to measure the CT values of the designated region of interest in the target organs (ventricular cavity, kidneys, liver, gallbladder, ovarian follicles, uterine horn cavity) over time and the eggs laid, following administration of iopamidol (700 mg of iodine/kg).

RESULT

The CT values of the ventricular cavity and kidneys peaked at 30 min and showed low values after day 22. The CT values for the liver increased over time and peaked at day 200, whereas values for the gallbladder and ovarian follicles peaked on day 6, with the gallbladder showing a low value and the ovarian follicles still showing a high value on day 260. Computed tomography images with identifiable enhancement within bilateral uterine horns were followed from days 1 to 35. The mean and maximum CT values of yolk and jelly in eggs laid after day 30 were significantly higher than the values for eggs laid up to day 29; embryonic development was confirmed in 88.7% of the eggs.

CONCLUSION

There was no mortality or morbidity of the sharks during the experiment, indicating that the administration of iopamidol at 700 mg of iodine/kg did not result in any adverse effects for 260 days. This is the first study to describe the long-term contrast effects of iopamidol, thus contributing new information about the application of contrast studies in Cloudy Catsharks.

Distribution and Elimination of Deltamethrin Toxicity in Laying Hens

Deltamethrin, an important pyrethroid insecticide, is frequently detected in human samples. This study aims to assess the potential effects of deltamethrin on human health and investigate the patterns of residue enrichment and elimination in 112 healthy laying hens. These hens were administered 20 mg·kg-1 deltamethrin based on their body weight. Gas chromatography-mass spectrometry (GC-MS) was used to investigate the residue enrichment pattern and elimination pattern of deltamethrin in the hens. The results indicated a significant increase in the concentration of deltamethrin in chicken manure during the treatment period. By the 14th day of administration, the concentration of deltamethrin in the stool reached 13,510.9 ± 172.24 μg·kg-1, with a fecal excretion rate of 67.56%. The pulmonary deltamethrin concentration was the second highest at 3844.98 ± 297.14 μg·kg-1. These findings suggest that chicken feces contain substantial amounts of deltamethrin after 14 days of continuous administration, and that it can easily transfer to the lungs. After 21 days of drug withdrawal, the residual concentration of deltamethrin in the fat of laying hens was 904.25 ± 295.32 μg·kg-1, with a half-life of 17 days and a slow elimination rate. In contrast, the lungs showed relatively low elimination half-lives of 0.2083 days, indicating faster elimination of deltamethrin in this tissue. These results highlight differences in the rate of deltamethrin elimination in different tissues during drug withdrawal. The fat of laying hens exhibited the highest residue of deltamethrin and the slowest elimination rate, while the lungs showed the fastest elimination rate. Moreover, deltamethrin was found to accumulate in the edible tissues of eggs and laying hens, suggesting that humans may be exposed to deltamethrin through food.

Veterinary pharmaceuticals and declining Cape Griffon Vulture (Gyps coprotheres) numbers: A potential threat to developing embryos

Cape Vultures (Gyps coprotheres) are a vulnerable Old-World Vulture species in southern Africa. Of the numerous threats to their survival, malicious and accidental poisonings remain a major concern. Despite the dangers of poisonings little is however known about the more insidious effects of toxins on egg survival, despite the species known to have a long generational length. For this study, an extensive literature review focusing on veterinary pharmaceuticals was undertaken. Literature for vultures was scarce, with most studies focusing on the domestic chicken. Using information for domestic chickens, the risk was characterised from likely vulture exposure to production animal carcasses with residues of said drugs. From this various antibiotics, medetomidine and albendazole were identified with embryotoxic or teratogenic effects. We suggest that these drugs be tested to elucidate their dose-response relationship and/or mitigation measures to minimise vulture exposure.

Screening for antimicrobial residues in poultry eggs in Bangladesh using Charm II radio-receptor assay technique following validation

The aim of the study was to screen for the presence of antimicrobial residues in poultry eggs from Bangladesh using the Charm II radio-receptor assay in the absence of expensive confirmatory instrumentation. This was based on cut-off values as set in the validation guidelines according to Commission Decision 2002/657/EC and Commission Implementing Regulation (EU) 2021/808. Fortified eggs spiked with fixed concentrations of doxycycline, erythromycin A, sulphamethazine, and benzylpenicillin were used to determine the cut-off values and detection capabilities (CCβ). Other validation parameters included were applicability, ruggedness, and robustness. A total of 201 egg mix samples from native organic chicken, duck, and commercial farm-raised laying hens (both brown and white eggs) were tested and after analysis 13%, 10%, and 4.5% of the egg mix samples showed positive signals for sulphonamides, macrolides/lincosamides, and tetracyclines, respectively. Presence of multiple drug residues were also suspected in 11 out of 201 egg mix samples.

Sea turtle egg yolk and albumen as biomonitoring matrices for maternal burdens of organic pollutants

To establish the use of eggs as biomonitoring tools for maternal body burdens, we investigated the mother-to-egg ratio of 56 PCB, 12 OCP and 34 PBDE unique compounds from maternal plasma into replicate egg yolk and albumen samples in the loggerhead turtle (Caretta caretta) as a case study of a threatened migratory marine species. We applied robust Regression on Order Statistics to fully account for the information in both censored and uncensored data. Our results added new insights into the use of yolk as a suitable biomonitoring matrix; the difference between yolk and albumen which were previously analysed as a homogeneous mixture; and the value of accounting for censored data. Overall, compound-specific mother-to-egg ratios need to be considered when translating yolk levels back to maternal pollution burdens, and when assessing the risk to the subsequent generations of turtle embryos.

Screening and quantification of antibiotic residues in poultry products and feed in selected areas of Bangladesh

Background and Aim

Antibiotic residues in livestock farming have been identified as a potential cause of antimicrobial resistance in humans and animals. This study aimed to determine whether antibiotic residues were present in the chicken meat, eggs, feces, and feed collected from all four districts in the Mymensingh division of Bangladesh.

Materials and Methods

To detect antibiotic residues in the collected samples, qualitative thin-layer chromatography (TLC) and quantitative high-performance liquid chromatography (HPLC) were used. A total of 230 samples were analyzed for antibiotic residues of commonly used 11 antibiotics. Out of these, 40 meat and 40 feces samples were collected from broilers and layers, 30 egg samples from ducks and layers, and 120 feed samples from broilers and layers from the study area. Thin-layer chromatography was used to screen the presence of antibiotic residues; TLC-positive samples were then subjected to further HPLC analysis to determine the residue concentrations.

Results

Thin-layer chromatography analysis revealed that 23.5% of the tested samples contained residues from six different antibiotic classes (tetracyclines, quinolones, beta-lactams, sulfonamides, aminoglycosides, and macrolides). Thin-layer chromatography analysis showed that 35% and 25% of the meat samples were positive for residues from the broiler and layer, respectively. About 15% and 30% of layer and duck egg samples had positive residues, respectively. Out of 120 feed samples analyzed, about 15.8% had various antibiotic residues. In addition, feces samples from broilers and layers had 50% and 35% antibiotic residues, respectively. A total of 2.5% meat and 3.3% egg samples had antibiotic residues above the maximum residue limit (MRL). Based on the findings of this study, the highest percentage of oxytetracycline, followed by doxycycline and ciprofloxacin, were detected in feed samples, and oxytetracycline was detected in meat and egg samples.

Conclusion

This study clearly showed the misuse of antibiotics in the poultry sector in Bangladesh. Although antibiotic residues below the MRL level are suitable for human consumption, they may result in antimicrobial drug resistance to pathogens.

Ionophore coccidiostats - disposition kinetics in laying hens and residues transfer to eggs

Poultry production is linked with the use of veterinary medicinal products to manage diseases. Ionophore coccidiostats have been permitted for use as feed additives within the European Union (EU) for the prevention of coccidiosis in various species of poultry with except of laying hens. The presence of chemical residues in eggs is a matter of major concern for consumers' health. Despite such prohibition of use in laying hens, they were identified as the most common non-target poultry species being frequently exposed to these class of coccidiostats. Many factors can influence the presence of residues in eggs. Carryover of these class of coccidiostat feed additives in the feed of laying hens has been identified as the main reason of their occurrence in commercial poultry eggs. The physicochemical properties of individual compounds, the physiology of the laying hen, and the biology of egg formation are believed to govern the residue transfer rate and its distribution between the egg white and yolk compartments. This paper reviews the causes of occurrence of residues of ionophore coccidiostats in eggs within the EU with special emphasis on their disposition kinetics in laying hens, and residue transfer into eggs. Additional effort was made to highlight future modeling perspectives on the potential application of pharmacokinetic modeling in predicting drug residue transfer and its concentration in eggs.

Quantification of antibiotic residues in raw and layers hen eggs by rp-hplc

Antibiotics (Oxytetracycline & Enrofloxacin) residual levels in raw and layered samples are to be quantified using RP-HPLC. The antibiotic (oxytetracycline and enrofloxacin) residual levels in raw and layers hen egg samples were evaluated qualitatively by high performance liquid chromatography in this investigation, which used one hundred randomly selected samples (HPLC). C18 (Hypersil ODS-BPS, 250 4.6mm; 5) was used for the separation at a flow rate of 1 ml/min in a mobile phase of 0.1 percent formic acid: acetonitrile (50:50, v/v). At a detection wavelength of 350 nm, the residues were measured. Found oxytetracycline residues, which indicate widespread usage of antibiotics on farms and a lack of application of required withdrawal durations, were detected in samples. Because of this, the antibiotic residues found in broiler hen eggs have been reduced. Restrictive methods and stricter restrictions should be implemented to prevent the presence of abuse residues prior to marketing, according to these findings.

Veterinary antibiotics in swine and cattle wastewaters of China and the United States: Features and differences

Veterinary antibiotics (VAs) have been widely used in livestock for disease prevention, treatment, and growth promotion. This study compared top 20 VAs in Chinese and US swine and cattle wastewater with published literatures. The sulfonamides (SAs) were found to be predominant, accounting for 62% of the top 20 VAs in Chinese swine wastewater, while tetracyclines (TCs) contributed to about 68.7% of the 18 VAs in US swine wastewater. The average concentration of the 20 major VAs in Chinese swine wastewater was estimated to be 1145 μg/L against 253.6 μg/L in the United States. On the other hand, the five major VAs in Chinese cattle wastewater were identified to be oxytetracycline, nafcillin, apramycin, lincomycin, and amikacin, while monensin was found to be dominant in US cattle wastewater. The average concentration of the top 20 VAs in Chinese and US cattle wastewaters were found to be 54.6 and 46.2 μg/L, respectively. These analyses suggested that VAs were probably over-used in Chinese swine industry, eventually causing the development and spreading of antibiotic resistant-bacteria and genes, which should be paid with attention. PRACTITIONER POINTS: Major veterinary antibiotics (VAs) in swine and cattle wastewater were identified. Top 20 VAs in swine and cattle wastewater of China and the United States were compared. VAs concentration in Chinese swine wastewater was 4.52 times that in the United States. VAs concentration in Chinese cattle wastewater was 1.18 times that of the United States.

Depletion of clomiphene residues in eggs and muscle after oral administration to laying hens

The selective oestrogen receptor modulator (SERM) clomiphene is therapeutically used to induce ovulation. While prohibited as a doping agent in sports, it is frequently detected in sports drug testing urine samples. Few reports exist on clomiphene's (illicit) use in the farming industry to increase the egg production rate of laying hens, which creates a risk that eggs as well as edible tissue of these hens contain residues of clomiphene. To investigate the potential transfer of clomiphene into eggs and muscle tissue, laying hens were orally administered with clomiphene citrate at 10 mg/day for 28 days. To determine clomiphene residues in eggs, chicken breast and chicken thigh, the target analyte was extracted from homogenised material with acetonitrile and subjected to ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The test method reached a limit of quantification (LOQ) of 1 µg/kg and was characterised concerning specificity, precision, trueness and linearity. Analyses were performed on whole egg, egg white and yolk separately, and chicken muscle from breast and thigh. Clomiphene was detectable in eggs two days after the beginning of the drug administration period. The drug concentrations increased to 10-20 µg per egg within one week, and after withdrawal of clomiphene, residues decreased after 4 days, but traces of clomiphene were still detectable until the end of the study (14 days after the last administration). In the chicken's muscle tissue, clomiphene levels up to 150 µg/kg (thigh) and 36 µg/kg (breast) were found. Six days after the last dose, tissue clomiphene concentrations fell below the LOQ. Overall, these results underline the concerns that clomiphene may be transferred into animal-derived food and future research will therefore need to focus on assessing and minimising the risk of unintentional adverse analytical findings in doping controls.

Transfer of enrofloxacin, ciprofloxacin, and lincomycin into eggshells and residue depletion in egg components after multiple oral administration to laying hens

Regardless of whether antimicrobial drugs are administered to laying hens legally or illegally, residues of these drugs may be present in the eggs. Even if the eggs are not intended for human consumption, byproducts/biowaste, such as eggshells, may contain residues of the drugs used, which may pose a risk to human health and the environment. In the presented research, 2 different groups of laying hens received enrofloxacin (10 mg/kg body weight) and lincomycin (20 mg/kg body weight) once daily for 5 d. Eggs were collected daily and the concentration of enrofloxacin, its metabolite ciprofloxacin, and lincomycin residue in the eggshells, whole eggs, egg yolks, and egg whites were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry. This study demonstrates the transfer of enrofloxacin, ciprofloxacin, and lincomycin into the eggshells and provides evidence for the distribution into the eggshells after administration of these drugs to laying hens. The enrofloxacin residues were detected in the eggshell for 10 d after cessation of treatment, ciprofloxacin and lincomycin were rapidly eliminated and 2 d after finish drugs administration they were no longer detected in the eggshell.

Risk of residues of toltrazuril sulfone in eggs after oral administration - Could setting maximum residue limit be helpful?

A depletion study of toltrazuril and its metabolites was performed using 20 hens medicated via drinking water for two days in a dosage of 7 mg kg^-1 per kg body weight. Afterward, eggs were collected for 42 days. Residues were analyzed in whole eggs and yolk and whites. Toltrazuril sulfone was found to be the most predominant in all matrices, the highest concentration was found in the yolk - 5567 µg kg^-1, followed by whole eggs samples - 4767 µg kg^-1 and egg whites - 532 µg kg^-1. On last day toltrazuril sulfone were still detected - 22.5 µg kg^-1. 70 days is required to concentration of toltrazuril sulfone reach zero. Administrating toltrazuril before the laying phase can pose a risk of residues of toltrazuril sulfone in eggs. Setting Maximum Residue Limit could reduce the risk of non-complaint samples and ensure the safety of consumers, but still requires 44 days of the withdrawal period.

Oral and topical extra-label administration of fipronil to laying hens: Assessment of the egg residue patterns

This experimental work reproduces the fipronil extra-label administration performed by producers in laying hens. The scientific goal was to characterize the residual concentrations in eggs from treated hens and suggest the withdrawal periods that should be respected to avoid risk for consumers. Thirty-four laying hens were allocated into two groups: Group A was treated with fipronil in feed, two single doses of 1 mg kg^-1  day^-1 ; Group B was administered a single dose of 1 mg kg^-1 by the topical route. Fipronil egg residues were quantified by HPLC-MS/MS. Fipronil and its sulphone metabolite (fipronil-SO₂ ) were measured in egg after both treatments. The highest egg residual profile was always for fipronil-SO₂ . Mean maximum egg concentrations (C_max ) of 228.5 ± 79.8 ng/g (fipronil) and 1,849 ± 867 ng/g (fipronil-SO₂ ) were found after fipronil administration in feed. The lowest residual levels were quantified after the topical treatment with C_max of 27.1 ± 4.9 and 163 ± 26 ng/g for fipronil and fipronil-SO₂ . Mean fipronil marker residues and established MRLs allowed calculating the withdrawal periods, the shortest being 74 days after topical administration. Such a long withdrawal period is difficult to meet in egg production systems. Thus, the extra-label use of fipronil in laying hens should not be recommended under any circumstances.

Multi-Class Procedure for Analysis of 50 Antibacterial Compounds in Eggshells Using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

In this work, for the first time, Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry (UHPLC–MS/MS) method was developed for qualitative and quantitative analysis of veterinary antibiotics (cephalosporins, diaminopyrimidines, fluoro(quinolones), lincosamides, macrolides, penicillins, pleuromutilins, sulfonamides, tetracyclines, and sulfones) in hen eggshells. The sample preparation method is based on a liquid–liquid extraction with a mixture of metaphosphoric acid, ascorbic acid, EDTA disodium salt dihydrate, and acetonitrile. The chromatographic separation was performed on Luna^® Omega Polar C18 10 column in gradient elution mode and quantitated in an 8 min run. Validation such as linearity, selectivity, precision, recovery, matrix effect, limit of quantification (LOQ), and limit of detection (LOD) was found to be within the acceptance criteria of the validation guidelines of the Commission Decision 2002/657/EC and EUR 28099 EN. Average recoveries ranged from 81–120%. The calculated LOQ values ranged from 1 to 10 µg/kg, the LOD values ranged from 0.3 to 4.0 µg/kg, depending on analyte. The developed method has been successfully applied to the determination of antibacterial compounds in hen eggshell samples obtained from different sources. The results revealed that enrofloxacin, lincomycin, doxycycline, and oxytetracycline were detected in hen eggshell samples.

Deposition, depletion, and potential bioaccumulation of bisphenol F in eggs of laying hens after consumption of contaminated feed

Increasing concerns over bisphenol A (BPA) as an endocrine disrupting chemical (EDC) and its adverse effects on both humans and animals have led to the substitution by structural analogs, such as bisphenol F (BPF), in many application areas. Information regarding to the carry-over of this emerging chemical in farm animals is essential for legislation and risk assessment purposes. In this study, a large-scale number of animal experiments were designed to investigate the transfer of BPF from feed to eggs. One control and three experimental groups of laying hens (72 hens per group) were fed with basal diets and BPF-contaminated feed at concentration levels of 0.1, 0.5 and 2.5 mg kg^-1, respectively, for two weeks. The hens were then fed with BPF-free diets for a further four weeks. Eggs were collected daily, and separated into egg yolk and white for BPF analysis. The effects of different levels of BPF exposure on laying performance followed a non-monotonic dose-response curve, since low level BPF (0.1 mg kg^-1) exposure did increase the laying rate, mean egg weight and daily feed intake, while high level BPF (2.5 mg kg^-1) exposure showed a decreasing trend. BPF residues were detected in both egg yolks and whole eggs after two days of administration, and plateau phase was achieved within 9-18 days. There are clear linear dose-response relationships between the plateau BPF concentrations in feed and eggs. The residue of BPF was found mainly in egg yolks with conjugated form and depleted slowly (still detected 21 days after feeding the BPF-free diet of the high level group). Mean carry-over rate of 0.59% BPF from feed to eggs was obtained. Compared with the carry-over rates of PCBs and dioxins, BPF showed a relatively minor trend of bioaccumulation in eggs. To the best of our knowledge, this is the first report on the deposition, depletion, and bioaccumulation study of bisphenols in farm animals. The quantity of data can therefore be helpful in the frame of risk assessment, especially for a comprehensive estimation of consumer exposure to the residues of bisphenols.

Depletion of florfenicol and florfenicol amine in eggs of laying hens and growing pullets after oral administration

In this study, we carried out two experiments to evaluate depletion of florfenicol (FF) and its metabolite florfenicol amine (FFA) in eggs from growing pullets and laying hens. Eggs were collected, and the egg white and yolk were separated. FF and FFA were analysed by liquid chromatography-tandem mass spectrometry. In the first experiment, 30 laying hens were given FF capsules at 50 mg/kg·bw^-1 daily for 5 d. FF + FFA was detectable in egg white (1,190 µg/kg) on day 1 of treatment and increased slowly thereafter. After treatment, the residues decreased rapidly and were not detected by day 11. In yolk, residues were detected at a lower concentration on day 1 and increased dramatically to 3308 µg/kg at the end of treatment. The residues remained steady over the next 4 days post-treatment, followed by a rapid drop. Residues were not detectable on day 15 post-treatment. In the second experiment, four groups (B1 through B4) of growing pullets were treated in the same manner for 25, 20, 15, and 10 days before egg primiparity. FF and FFA were not detectable in the eggs of group B1; however, they were detectable in egg whites and yolks of groups B2, B3, and B4. The highest total concentrations of FF and FFA detected in egg white and yolk of group B4 were 3,190 µg/kg and 3,214 µg/kg, respectively. Thereafter, concentrations decreased until no more residues were detected in egg whites or yolks on days 17 and 21 post-treatment, respectively. Therefore, drug treatment should be stopped at least 21 d before primiparity of growing pullets to guarantee food safety.

Determination of Chloramphenicol in Honey and Milk by HPLC Coupled with Aptamer-Functionalized Fe3 O4 /Graphene Oxide Magnetic Solid-Phase Extraction

An aptamer-functionalized Fe₃ O₄ /graphene oxide was synthesized by chemical co-precipitation method and then employed in the magnetic solid-phase extraction for selective enrichment of chloramphenicol before HPLC. The aptamer was covalently bonded to the Fe₃ O₄ /graphene oxide complex by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. Parameters affecting extraction efficiency including solution pH, extraction time and temperature, types and volume of elution solvent, and elution time were investigated in detail. Under the optimal conditions, good linearity was obtained between the peak area and analyte concentration in the range of 7.0 to 1.0 × 10³  µg/L with the correlation coefficient of 0.9994. The limit of detection and quantitation were 0.24 µg/L and 0.79 µg/L, respectively. The developed method was employed to the analysis of chloramphenicol in honey and milk samples. The recoveries ranged from 80.5% to 105.0% with relative standard deviations less than 8.9%. PRACTICAL APPLICATION: An aptamer-functionalized Fe₃ O₄ /graphene oxide was synthesized and employed in magnetic solid phase extraction for the enrichment of chloramphenicol before HPLC. The presented assay was employed for the determination of chloramphenicol in honey and milk with satisfactory results.

Pesticides (Hexachlorocyclohexane, Aldrin, and Malathion) Residues in Home-Grown Eggs: Prevalence, Distribution, and Effect of Storage and Heat Treatments

The abuse of pesticides in home gardens may lead to contamination of home-grown eggs. This study aimed to determine the prevalence of hexachlorocyclohexane (HCH), aldrin, and malathion pesticides residues in egg white and egg yolk of home-grown eggs in Jordan; and the effect of refrigerated storage and heat treatment (boiling and frying) on residues level. High-performance liquid chromatography was used to detect pesticide residues in egg samples (n = 200) obtained from households that raise laying hens in Jordan. About 96% of the tested eggs showed pesticide residues. None of the tested egg samples showed residual level above maximum residue limit (MRL 0.02 mg/kg) for HCH, whereas 33% and 44% of samples were above MRL for aldrin and malathion, respectively. All studied pesticide residues were detected from both egg yolk and egg white. The concentrations of malathion and aldrin (0.075 and 0.067 mg/kg) in egg yolk were higher than those (0.049 and 0.058 mg/kg) in egg white samples. Pesticide residue levels were quite stable during refrigeration storage whereas heat treatment (boiling at 100 °C and frying at 160 °C) significantly reduced contamination levels to values below MRL. The high level of pesticide residues in home-grown egg in Jordan may reflect the improper use of pesticides in home gardens and thus exposing the environment to unwanted pollution and the risk they may pose on human health. PRACTICAL APPLICATION: Home-grown eggs could be exposed to pesticides more than commercial eggs as free-range hens interact directly with the environment and ingest soil or materials on/in the soil that might be contaminated with pesticides used in home gardens or farms. Exploring pesticides residues in home-grown eggs and effect of refrigerated storage and heat treatment (boiling and frying) on residue levels would be useful to consumers and health authorities.

Reducing Veterinary Drug Residues in Animal Products: A Review

A survey we conducted suggests that the ingestion of veterinary drug residues in edible animal parts constitutes a potential health hazard for its consumers, including, specifically, the possibility of developing multidrug resistance, carcinogenicity, and disruption of intestinal normal microflora. The survey results indicated that antibiotics, parasitic drugs, anticoccidial, or nonsteroidal anti-inflammatory drugs (NSAIDs) are broadly used, and this use in livestock is associated with the appearance of residues in various animal products such as milk, meat, and eggs. We observed that different cooking procedures, heating temperatures, storage times, fermentation, and pH have the potential to decrease drug residues in animal products. Several studies have reported the use of thermal treatments and sterilization to decrease the quantity of antibiotics such as tetracycline, oxytetracycline, macrolides, and sulfonamides, in animal products. Fermentation treatments also decreased levels of penicillin and pesticides such as dimethoate, malathion, Dichlorodiphenyldichloroethylene, and lindane. pH, known to influence decreases in cloxacillin and oxacillin levels, reportedly enhanced the dissolution of antimicrobial drug residues. Pressure cooking also reduced aldrin, dieldrin, and endosulfan in animal products. Therefore, this review provides updated information on the control of drug residues in animal products, which is of significance to veterinarians, livestock producers, and consumer health.

Evaluation of Tilmicosin Contamination in Eggs Following Its Administration to Laying Hens and Subsequent Assessment of Dietary Risks to Chinese Consumers

In the present study, we analyzed the tilmicosin residues in eggs as well as the dietary risks posed by the residual drug to Chinese consumers. Tilmicosin was administrated to laying hens via drinking water in doses of 100 mg/L and 300 mg/L (dose 1 and dose 2) for 5 days. Its residues distribution within egg matrices were detected using a QuEChERS method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results indicated that the tilmicosin residue was the highest in the whole eggs and yolks on day 2 after medication and in the whites on day 5 of drug administration for dose 1 and dose 2 with the residues (µg/kg) being the following: 73.4 and 444.3 in the whole eggs; 152.0 and 1141.1 in the yolks; and 48.8 and 277.6 in the whites, respectively. During withdrawal phase, the tilmicosin levels declined to less than the limit of detection (LOD) after 29 days and 49 days for the whole eggs, after 24 days and 44 days for the yolks, and after 19 days and 49 days for the whites for doses 1 and 2, respectively. An assessment of the dietary risk for Chinese consumers revealed that the hazard quotients (HQ) values for tilmicosin consumption were less than 1 for dose 1 and greater than 1 for dose 2, with children (2 to 7 years) and adult males (over 65 years) being the high-risk groups. These results suggest that the possible risk associated with tilmicosin contamination in eggs should not be ignored since the accidental or occasional misuse of tilmicosin in the case of egg-laying hens may occur from time to time, particularly on small farms. PRACTICAL APPLICATION: The modified QuEChERS method was used to analyze the tilmicosin residues in egg matrices and a subsequent dietary exposure assessment for Chinese consumers was performed, which can serve as a reference for the food safety risk posed by antibiotic misuse in egg layers.

Spiramycin adsorption behavior on activated bentonite, activated carbon and natural phosphate in aqueous solution

Efficacy of activated bentonite, activated carbon, and natural phosphate under experimental conditions was tested as low-cost adsorbents for spiramycin antibiotic removal from aqueous solution. Equilibrium kinetic and isotherm adsorption process are well described by pseudo-second order and Langmuir isotherm models for activated bentonite and activated carbon, while natural phosphate follows pseudo-first order and Freundlich models, respectively. Obtained results revealed that activated bentonite has the highest adsorption capacity (260.3 mg/g) as compared to activated carbon (80.3 mg/g) and natural phosphate (1.7 mg/g). The adsorption capacity decreases for all adsorbents in the presence of NaCl. The adsorption processes are facilitated in the alkaline pH range for activated bentonite and activated carbon, whereas, for natural phosphate, the acidic pH range is favorable. They are involving ion exchange and hydrogen bond mechanisms as well as Van der Waals forces and also π interactions for activated carbon. Thermodynamic calculation shows that spiramycin adsorption is endothermic and spontaneous on all adsorbents. The activated bentonite reusability is more efficient by more than 95% in two-step desorption using NaOH and HCl eluents compared to activated carbon. Thus, activated bentonite is a promising adsorbent for spiramycin removal from aqueous solution.

Distribution and elimination of levamisole in eggs and tissues after oral administration to laying hens, determined by LC-MS/MS

Levamisole was administered to laying hens, and concentrations in eggs and tissues (thigh muscle, breast muscle, liver and kidney) were determined by a newly developed liquid chromatography tandem mass spectrometry method, which allowed trace level quantification of levamisole. The adopted analytical method showed good sensitivity, repeatability and percentage of recovery from spiked matrices. Maximum concentrations of levamisole were found on the first day after the administration (531.1 μg/kg in liver, 164.3 μg/kg in egg yolk, 130.7 μg/kg in kidney, 78.0 μg/kg in breast muscle, 70.7 μg/kg in thigh muscle and 64.0 μg/kg in egg white), after which there is a decline. The compound was rapidly eliminated from eggs, with a half-life of 1.3 days. Elimination appeared to be slower in thigh muscle (3.5 days), breast muscle (3.4 days) and liver (3.3 days). According to this experiment, the levamisole withdrawal periods calculated for eggs, liver, kidney, breast muscle and thigh muscle in laying hens were 14.1, 6.1, >4.0, 14.5 and 13.0 days, respectively. The longest time for levamisole residues to be completely released from tissues was seen in liver samples (37.4 days), followed by thigh muscle, breast muscle and kidney. Elimination from eggs was fastest (16.4 days for levamisole residues to drop below the method quantification limit).

Estimation of the Withdrawal Time of Levamisole in Eggs after Oral Administration to Laying Hens

This study was conducted to evaluate withdrawal time of levamisole in eggs after oral administration in laying hens at different doses. Sampling of eggs was conducted for 37 days after the end of treatment, and levamisole concentrations were measured by liquid chromatography-tandem mass spectrometry validated according to the Commission Decision 2002/657/EC. Estimated validation parameters were as follows: decision limit, 0.54 μg/kg; detection capability, 0.56 μg/kg; limit of detection, 0.04 μg/kg; limit of quantification, 0.15 μg/kg; accuracy (recovery), between 92.9 and 102.3%; precision (relative standard deviation), ≤4.62%; and within-laboratory precision (relative standard deviation), ≤5.19%. Levamisole residue levels were significantly higher in egg yolks than in egg whites. The highest levels of levamisole were detected on day 2 posttreatment in groups receiving 50 mg/kg of body weight (556.2 μg/kg in egg yolks and 166.5 μg/kg in egg whites). Significant elimination occurred within 5 days after the cessation of treatment in all groups, with an elimination half-life of 1.3 days. Levamisole was still detectable on day 30 after the end of treatment in egg whites (0.06 μg/kg) and on day 37 in egg yolks (0.06 μg/kg). The longest withdrawal time for levamisole in eggs (14.9 days) was determined in a group treated with 25 mg of levamisole per kg of body weight for two consecutive days. According to the results, oral treatment of laying hens with levamisole may result in noncompliant egg samples even 14 days after treatment.

Determination of tylosin excretion from sheep to assess tylosin spread to agricultural fields by manure application

Antibiotics administered to livestock are partly excreted with urine and feces. As livestock excrement is used as manure on agricultural fields, soil may be contaminated by excreted antibiotics, potentially resulting in the development of antibiotic-resistant bacteria. Therefore, it is necessary to determine the amount of antibiotic administered to livestock that could spread to agricultural fields through manure application. This study reveals the excretion ratio of tylosin from sheep. After developing an analysis procedure for tylosin in urine and feces from sheep, a tylosin excretion study was performed with two sheep. Tylosin was excreted in urine and feces for four days, after which its concentrations dropped below the limits of quantification (urine: 0.5μg/kg, feces: 2.4μg/kg). The total excretion ratio was 11% on average. The results of our study can provide useful knowledge for treating excrement in order to prevent the spread of antibiotics to agricultural fields through manure application.

Detection and Quantitation of Lomefloxacin and Pefloxacin Residues in the Organ Tissues and Eggs of Laying Hens

Lomefloxacin (LOM) and pefloxacin (PEF) are synthetic antibiotics that have been used in the treatment of infectious diseases in both human and animals. In the People's Republic of China, the use of LOM and PEF in livestock has been prohibited because of the concern that the residues of these drugs may pose a risk to public health. Despite this prohibition, these drugs are still being used in the poultry industry illegally, and so far there has been no systematic study of the persistence of LOM and PEF residues in chickens. In this study, laying hens were treated with a daily dose (10 mg/kg of body weight) of LOM or PEF for five consecutive days, and the drug residues in various tissues and eggs were determined over a 15-day period after the last drug administration. The highest LOM and PEF residual concentrations were found in the tissues 4 h after the last drug administration, and concentrations gradually decreased over time. Plasma had the lowest and liver had the highest residual concentrations throughout the 15-day study period. At the end of the 15 days, 3.64 ± 0.74 μg/kg LOM and 1.78 ± 0.28 μg/kg PEF were detected in the liver, with slightly lower residual concentrations in the kidney. No LOM or PEF residue was detected in the ovarian follicle, plasma, and muscle at the end of the 15 days. In eggs, the depletion rate of LOM was slower than that of PEF. LOM and PEF residues were detected in whole eggs for up to 10 and 8 days, respectively, after drug administration ceased. These findings suggest that the liver and, to a lesser extent, the kidney may be the sites where LOM or PEF residues would persist. This information can be a reliable reference for governmental agencies with respect to the screening of LOM and PEF residues in food products derived from laying hens.

Validation of an UHPLC-MS/MS Method for Screening of Antimicrobial Residues in Eggs and Their Application to Analyses of Eggs from Laying Hens Subjected to Pharmacological Treatment

A multiresidue method by UHPLC/MS-MS was optimized and validated for the screening and semiquantitative detection of antimicrobials residues from tetracyclines, aminoglycosides, quinolones, lincosamides, β-lactams, sulfonamides, and macrolides families in eggs. A qualitative approach was used to ensure adequate sensitivity to detect residues at the level of interest, defined as maximum residue limit (MRL), or less. The applicability of the methods was assessed by analyzing egg samples from hens that had been subjected to pharmacological treatment with neomycin, enrofloxacin, lincomycin, oxytetracycline, and doxycycline during five days and after discontinuation of medication (10 days). The method was adequate for screening all studied analytes in eggs, since the performance parameters ensured a false-compliant rate below or equal to 5%, except for flumequine. In the analyses of eggs from laying hens subjected to pharmacological treatment, all antimicrobial residues were detected throughout the experimental period, even after discontinuation of medication, except for neomycin, demonstrating the applicability of the method for analyses of antimicrobial residues in eggs.

A Simple and Fast Extraction Method for the Determination of Multiclass Antibiotics in Eggs Using LC-MS/MS

The purpose of this study was to develop and validate a simple, fast, and specific extraction method for the analysis of 64 antibiotics from nine classes (including sulfonamides, quinolones, tetracyclines, macrolides, lincosamide, nitrofurans, β-lactams, nitromidazoles, and cloramphenicols) in chicken eggs. Briefly, egg samples were simply extracted with a mixture of acetonitrile-water (90:10, v/v) and 0.1 mol·L^-1 Na₂EDTA solution assisted with ultrasonic. The extract was centrifuged, condensed, and directly analyzed on a liquid chromatography coupled to tandem mass spectrometry. Compared with conventional cleanup methods (passing through solid phase extract cartridges), the established method demonstrated comparable efficiencies in eliminating matrix effects and higher or equivalent recoveries for most of the target compounds. Typical validation parameters including specificity, linearity, matrix effect, limits of detection (LODs) and quantification (LOQs), the decision limit, detection capability, trueness, and precision were evaluated. The recoveries of target compounds ranged from 70.8% to 116.1% at three spiking levels (5, 20, and 50 μg·kg^-1), with relative standard deviations less than 14%. LODs and LOQs were in the ranges of 0.005-2.00 μg·kg^-1 and 0.015-6.00 μg·kg^-1 for all of the antibiotics, respectively. A total of five antibiotics were successfully detected in 22 commercial eggs from local markets. This work suggests that the method is suitable for the analysis of multiclass antibiotics in eggs.

Detection of antibiotics in chicken eggs obtained from supermarkets in Ho Chi Minh City, Vietnam

The residual levels of antibiotics in Vietnamese eggs were monitored from 2014 to 2015. A total of 111 egg packages, distributed by 11 different companies, were collected from supermarkets in Ho Chi Minh City and the levels of 28 antibiotics were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method. Sixteen samples tested positive for antibiotics; a total of eight compounds (enrofloxacin, ciprofloxacin, norfloxacin, sulfadimethoxine, sulfamethazine, sulfamonomethoxine, tilmicosin and trimethoprim) were detected. Enrofloxacin was detected in eight samples, with two samples exhibiting concentrations exceeding 1,000 µg kg^-1. Tilmicosin was detected in three samples at a range of 49-568 µg kg^-1. We observed that two of the 11 companies frequently sold antibiotic-contaminated eggs (detection rates of 56 and 60%), suggesting that a number of companies do not regulate the use of antibiotics in egg-laying hens. Our findings indicate that livestock farmers require instruction regarding antibiotic use and that continual antibiotic monitoring is essential in Vietnam.

Egg residue considerations during the treatment of backyard poultry

The purpose of this digest was to provide US veterinarians guidance on the responsible treatment of backyard poultry flocks. The treatment of backyard poultry can be a daunting task for veterinarians because only limited resources are available; however, it is likely to become an increasingly common task owing to the increasing popularity of backyard poultry throughout the United States, especially in urban and suburban areas. Although backyard poultry flock owners may consider their birds pets, the FDA considers them food-producing animals, and veterinarians should follow all regulations that pertain to food-producing animals when administering or prescribing drugs to those birds. The lack of FDA-approved drugs for use in laying hens frequently necessitates the use of drugs in an extralabel manner in backyard poultry. Unfortunately, information regarding the depletion of drug residues in eggs from hens treated with various drugs in an extralabel manner is sparse or lacking, and veterinarians need to be cognizant of this issue, especially when the eggs from treated hens are intended for human consumption.

Abusive use of antibiotics in poultry farming in Cameroon and the public health implications

The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

Distribution of Animal Drugs between Skim Milk and Milk Fat Fractions in Spiked Whole Milk: Understanding the Potential Impact on Commercial Milk Products

Seven animal drugs [penicillin G (PENG), sulfadimethoxine (SDMX), oxytetracycline (OTET), erythromycin (ERY), ketoprofen (KETO), thiabendazole (THIA), and ivermectin (IVR)] were used to evaluate the drug distribution between milk fat and skim milk fractions of cow milk. More than 90% of the radioactivity was distributed into the skim milk fraction for ERY, KETO, OTET, PENG, and SDMX, approximately 80% for THIA, and 13% for IVR. The distribution of drug between milk fat and skim milk fractions was significantly correlated to the drug's lipophilicity (partition coefficient, log P, or distribution coefficient, log D, which includes ionization). Data were fit with linear mixed effects models; the best fit was obtained within this data set with log D versus observed drug distribution ratios. These candidate empirical models serve for assisting to predict the distribution and concentration of these drugs in a variety of milk and milk products.

Florfenicol induces early embryonic death in eggs collected from treated hens

Background

Florfenicol, a commonly used veterinary antibiotic, was reported to have caused a severe drop in egg hatchability following its off-label use on a broiler breeder farm in South Africa. According to the pharmacovigilance report, hatchability dropped by 80 % for up to a week following a five day course at 10 mg/kg (both males and females treated metaphylactically) to manage an Escherichia coli infection. While mammalian toxicity studies indicate the potential for early embryonic death in utero or testicular damage, no literature is available on the avian toxicity of florfenicol. For this study we investigated the effects of florfenicol at various doses from 10 to 90 mg/kg on the egg hatchability in a breeder flock we kept and established under controlled conditions, with the same cockerels and hens being exposed in a phased manner.

Results

Following five days of oral exposure, no toxic signs were evident in any of the cockerels or hens treated at doses up to 90 mg/kg. Treatment of only the cockerels had no effect on egg hatchability, while treatment of only the hens at doses of 60 and 90 mg/kg resulted in decreased hatchability of 0 % in comparison to 70 % of the control as early 24 h after treatment. In all cases, decreased hatchability was associated with embryonic death at 5 days of development. The toxic effects of florfenicol were completely reversible with comparable hatchability being present by day 4 post-treatment withdrawal. Toxicity correlated with total egg florfenicol concentrations with an LC₅₀ of 1.07 μg/g.

Conclusion

Florfenicol appears to be toxic to the developing chick embryo at around day 5 of incubation, in the absence of related toxicity in the hen or cockerel.

Occurrence and distribution of antibiotics in urban soil in Beijing and Shanghai, China

The recycling of reclaimed wastewater for irrigation and road cleaning is an important strategy to minimize water scarcity in megacities. However, little is known regarding the potential accumulation of antibiotics contained in reclaimed wastewater in urban soil. We investigated the occurrence and distribution of eight quinolones (QNs), nine sulfonamides (SAs), and five macrolides (MLs) antibiotics in urban surface soil in Beijing and Shanghai, China. QNs, especially norfloxacin (NOR), ofloxacin (OFL), and ciprofloxacin (CIP) were the predominant antibiotics in urban surface soil, and NOR revealed the highest average concentration of 94.6 μg kg(-1). The antibiotic concentrations in urban soil in our study were higher than those detected in agricultural soils after long-term wastewater irrigation and manure fertilization. The concentrations of antibiotics in Shanghai urban soil showed a significant negative correlation with soil pH and a positive correlation with total organic carbon (TOC), reflecting the effect of speciation and soil organic matter content on sorption and retention. In addition, antibiotic concentrations in the urban soil were positively correlated with heavy metal contents, likely due to their coexistence in reclaimed wastewater and the promoting effect of metals on the sorption of antibiotics. In several soil samples, NOR, OFL, CIP, enrofloxacin (ENR), and fleroxacin (FLE) showed higher concentrations than the trigger value of 100 μg kg(-1) in soil, indicating a potential risk for the environment.

Deposition and depletion of decoquinate in eggs after administration of cross-contaminated feed

Decoquinate, a chemical coccidiostat used as a feed additive, can occur in eggs due to cross-contamination of feedstuffs for laying hens. An experiment was designed to assess the transfer of decoquinate to hen eggs and its distribution between egg yolk and egg white. Hens were given the feed containing decoquinate at a cross-contamination level (0.34 mg kg(-1)) and collected eggs were analysed using an LC-MS/MS method. The plateau level was reached on the eighth day of the experiment and averaged 8.91 µg kg(-1), which is far below the maximum level established at 20 µg kg(-1) for whole eggs. Decoquinate was deposited mostly in egg yolks (26.2 µg kg(-1)) and did not deplete completely during 14 days of administration of decoquinate-free feed. The results confirmed that administration of cross-contaminated feed is associated with very low risk of non-compliant residue levels of decoquinate in eggs.

Residue depletion of ampicillin in eggs

A residue depletion study of ampicillin (AMP) was performed after oral dosing (60.0 mg/kg and 120.0 mg/kg body weight once a day for 5 days) to laying hens, through the use of reversed-phase high-performance liquid chromatography with fluorescence detection (RP-HPLC-FLD) to achieve detection of ampicillin residue in eggs. Limit of detection was 0.5 ng/g, and limit of quantitation was 1.2 ng/g for ampicillin. Extraction recoveries of ampicillin from samples fortified at 5.0-125.0 ng/g levels ranged from 77.5% to 84.6% in albumen, 77.9% to 87.5% in yolk, and 77.9% to 88.6% in whole egg, with coefficients of variation ≤ 9.3%. The maximum concentrations of ampicillin in albumen, yolk, and whole egg were detected at 1, 2, and 1 day after the last administration of ampicillin, respectively. Ampicillin was not detectable in albumen at day 9 of withdrawal time, at day 10 and 11 in yolk, and day 9 and 11 in whole egg at each of those 2 dose levels. The theoretical withdrawal time of AMP in whole egg was 6.730 and 7.296 days for 60 and 120 mg/kg oral dosage, respectively. This method also proved to be suitable as a rapid and reliable method for the determination of ampicillin in other poultry eggs.

A survey of chlortetracycline concentration in feed and its residue in chicken egg in commercial layer farms

The worldwide increase in the use of antibiotics as an integral part of poultry and livestock production industry has recently received increasing attention as a contributory factor in the international emergence of antibiotic-resistant bacteria in human beings. To gauge the presence of the aforementioned scenario in the Indian context, a preliminary survey was conducted to assess the use of chlortetracycline (CTC) in 12 commercial layer farms and to quantify and confirm its residue in the egg. Samples of feed and eggs were collected at day 0 (prior to CTC addition), 3rd, 5th and 7th day during treatment and on the 9th and 14th day (2nd and 7th day after withdrawal of CTC) from each of the 12 commercial poultry farms studied. Concentration of CTC in feed was significantly (P less than 0.01) high on the 3rd, 5th and 7th day. On the 9th day and 14th day CTC concentration in feed was significantly (P less than 0.01) lower compared to the earlier 3 days studied. A highly significant difference (P less than 0.01) of the antibiotic residue in egg was observed in all the 5 days with high residual levels of CTC in egg. CTC in feed and its residue in egg were detected even on the 9th and 14th day respectively.

Occurrence, seasonal variation and removal efficiency of antibiotics and their metabolites in wastewater treatment plants, Jiulongjiang River Basin, South China

Wastewater treatment plants (WWTPs) are regarded as one of the most important sources of antibiotics in the environment. The occurrence, seasonal variation and removal efficiency of 21 antibiotics and 10 metabolites, including five sulfonamides and three of their metabolites, six quinolones, two macrolides, two β-Lactams and five tetracyclines and seven of their metabolites, were investigated in five WWTPs in different seasons in the Jiulongjiang River Region, South China. 16 antibiotics and 6 metabolites in summer and 14 antibiotics and 6 metabolites in winter were found, respectively. The most frequently detected antibiotics were sulfamethazine, sulfamethoxazole, n-acetyl sulfamethazine, n-acetyl sulfamethoxazole, ofloxacin, cephalexin monohydrate and cephradine; of these, the concentration of cephradine was the highest in most of the influent and effluent samples. The highest level of total antibiotics was found in Longyan City WWTPs, where there are more population and swine farms. Seasonal variation of the antibiotics in wastewater samples was also studied. The concentrations of antibiotics in winter were higher than those in summer. The antibiotics could not be removed completely by the WWTPs, and the mean removal efficiency ranged from -71.6 to 56.3%. Of all the antibiotics, the tetracyclines were removed comparatively more efficiently, probably due to their adsorption to sludge. The low removal efficiency of antibiotics in WWTPs could be one of the important reasons for the presence of antibiotics in the environment in Jiulongjiang Region.

Fluoroquinolone antibiotics: an emerging class of environmental micropollutants

The aim of this review paper is to provide a comprehensive overview of different chemical and environmental aspects concerning fluoroquinolone antibiotics as emerging contaminants. A literature survey has been performed based on 204 papers from 1998 to mid-2013, resulting in a dataset consisting out of 4100 data points related to physical-chemical properties, environmental occurrence, removal efficiencies, and ecotoxicological data. In a first part, an overview is given on relevant physical-chemical parameters to better understand the behavior of fluoroquinolones during wastewater treatment and in the environment. Secondly, the route of these antibiotics after their application in both human and veterinary surroundings is discussed. Thirdly, the occurrence of fluoroquinolone residues is discussed for different environmental matrices. The final part of this review provides a tentative risk assessment of fluoroquinolone compounds and their transformation products in surface waters by means of hazard quotients. Overall, this review shows that fluoroquinolone antibiotics have a wide spread use and that their behavior during wastewater treatment is complex with an incomplete removal. As a result, it is observed that these biorecalcitrant compounds are present in different environmental matrices at potentially hazardous concentrations for the aquatic environment. The latter calls for actions on both the consumption as well as the wastewater treatment aspect to diminish the discharge of these biological active compounds.