This study reports the results obtained from toxicological analyses of different types of baits referred to the laboratory of the Toxicology Area (Faculty of Veterinary Medicine, Cáceres, Spain) over a 17-year period (2002–2018). These baits were suspicious materials found in the environment of the region of Extremadura (Western Spain), where such malpractices are a problem to be addressed, as wide livestock farming and hunting activities are combined with a significant wealth of wildlife (especially birds of prey). A total of 246 baits, including 32 commercial chemical products to be used in baits, were analysed. Samples from 183 cases were received and classified according to the material used for their preparation and the toxic substance found. Overall, the most common bait consisted of meat preparations (56.3% of cases) intended to eliminate predators considered ‘annoying’ for livestock and hunting practices, such as carnivores and scavengers. It should be noted that contact baits (as fenthion-impregnated perches) were also detected (7.6%). Regarding the substances detected, anticholinesterase compounds (organophosphates and carbamates) were the most commonly used substances for the preparation of baits (detected in 85.3% of positive baits). Moreover, 8% of the positive baits presented more than one toxic substance in their composition. Due to the types of toxic compounds and the methods used to prepare the baits, this study shows that the malicious use of highly toxic substances in the environment to kill wildlife is a common and current issue and poses a serious risk to different species.

Fipronil, a phenyl-pyrazole insecticide, has a wide range of uses, from agriculture to veterinary medicine. Due to its large-scale applications, the risk of environmental and occupational exposure and bioaccumulation raises concerns. Moreover, relatively little is known about the intracellular mechanisms of fipronil in trophoblasts and the endometrium involved in implantation. Here, we demonstrated that fipronil reduced the viability of porcine trophectoderm and luminal epithelial cells. Fipronil induced cell cycle arrest at the sub-G1 phase and apoptotic cell death through DNA fragmentation and inhibition of DNA replication. These reactions were accompanied by homeostatic changes, including mitochondrial depolarization and cytosolic calcium depletion. In addition, we found that exposure to fipronil compromised the migration and implantation ability of pTr and pLE cells. Moreover, alterations in PI3K-AKT and MAPK-ERK1/2 signal transduction were observed in fipronil-treated pTr and pLE cells. Finally, the antiproliferative and apoptotic effects of fipronil were also demonstrated in 3D cell culture conditions. In summary, our results suggest that fipronil impairs implantation potentials in fetal trophectoderm and maternal endometrial cells during early pregnancy.

Antibiotic proliferation in the environment and their persistent nature is an issue of global concern as they induce antibiotic resistance threatening both human health and the ecosystem. Antibiotics have therefore been categorized as emerging pollutants. Fluoroquinolone (FQs) antibiotics are an emerging class of contaminants that are used extensively in human and veterinary medicine. The recalcitrant nature of fluoroquinolones has led to their presence in wastewater, effluents and water bodies. Even at a low concentration, FQs can stimulate antibacterial resistance. The main sources of FQ contamination include waste from pharmaceutical manufacturing industries, hospitals and households that ultimately reaches the wastewater treatment plants (WWTPs). The conventional WWTPs are unable to completely remove FQs due to their chemical stability. Therefore, the development and implementation of more efficient, economical, convenient treatment and removal technologies are needed to adequately address the issue. This review provides an overview of the technologies available for the removal of fluoroquinolone antibiotics from wastewater including adsorptive removal, advanced oxidation processes, removal using non-carbon based nanomaterials, microbial degradation and enzymatic degradation. Each treatment technology is discussed on its merits and limitations and a comparative view is presented on the choice of an advanced treatment process for future studies and implementation. A discussion on the commercialization potential and eco-friendliness of each technology is also included in the review. The importance of metabolite identification and their residual toxicity determination has been emphasized. The last section of the review provides an overview of the policy interventions and regulatory frameworks that aid in retrofitting antibiotics as a central key focus contaminant and thereby defining the discharge limits for antibiotics and establishing safe manufacturing practices.

The extensive use of antibiotics in human and veterinary medicine and their subsequent release into the environment may have direct consequences for autochthonous bacterial communities, especially in freshwater ecosystems. In small streams and rivers, local inputs of wastewater treatment plants (WWTPs) may become important sources of organic matter, nutrients and emerging pollutants, such as antibiotic resistance genes (ARGs). In this study, we evaluated the effect of WWTP effluents as a source of ARGs in river biofilms. The prevalence of genes conferring resistance to main antibiotic families, such as beta-lactams (blaCTX-M), fluoroquinolones (qnrS), sulfonamides (sul I), and macrolides (ermB), was determined using quantitative PCR (qPCR) in biofilm samples collected upstream and downstream WWTPs discharge points in four low-order streams. Our results showed that the WWTP effluents strongly modified the hydrology, physico-chemistry and biological characteristics of the receiving streams and favoured the persistence and spread of antibiotic resistance in microbial benthic communities. It was also shown that the magnitude of effects depended on the relative contribution of each WWTP to the receiving system. Specifically, low concentrations of ARGs were detected at sites located upstream of the WWTPs, while a significant increase of their concentrations was observed in biofilms collected downstream of the WWTP discharge points (particularly ermB and sul I genes). These findings suggest that WWTP discharges may favour the increase and spread of antibiotic resistance among streambed biofilms. The present study also showed that the presence of ARGs in biofilms was noticeable far downstream of the WWTP discharge (up to 1 km). It is therefore reasonable to assume that biofilms may represent an ideal setting for the acquisition and spread of antibiotic resistance determinants and thus be considered suitable biological indicators of anthropogenic pollution by active pharmaceutical compounds.

Antibiotics have been widely used in human and veterinary medicine to both treat and prevent disease. Due to their high water solubility and low bioavailability, many antibiotic residues have been found in aquatic environments. Fish are an indispensable link between the environmental pollution and human health. However, the chronic effects of environmental concentrations of antibiotics in fish have not been thoroughly investigated. Sulfamethoxazole (SMX) and oxytetracycline (OTC) are frequently detected in aquatic environments. In this study, zebrafish were exposed to SMX (260 ng/L) and OTC (420 ng/L) for a six-week period. Results indicated that exposure to antibiotics did not influence weight gain of fish but increased the metabolic rate and caused higher mortality when treated fish were challenged with Aeromonas hydrophila. Furthermore, exposure to antibiotics in water resulted in a significant decrease in intestinal goblet cell numbers, alkaline phosphatase (AKP), acid phosphatase (ACP) activities, and the anti-oxidant response while there was a significant increase in expression of inflammatory factors. Antibiotic exposure also disturbed the intestinal microbiota in the OTC-exposed group. Our results indicated that environmental antibiotic concentrations can impair the gut health of zebrafish. The potential health risk of antibiotic residues in water should be evaluated in the future.

Wound healing is one of the utmost medical issues in human and veterinary medicine, which explains the urgent need for developing new agents that possess wound healing activities. The present study aimed to assess the effectiveness of green and chemical zinc oxide nanoparticles (ZnO-NPs) for wound healing. ZnO-NPs (green using Lawsonia inermis leaf extract and chemical) were synthesized and characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The gels containing the nanomaterials were prepared and inspected. Forty-five albino rats were divided into three groups, the control group was treated with normal saline 0.9%, and the other two groups were treated with gels containing green or chemical ZnO-NPs, respectively. On the 3ʳᵈ, 7ᵗʰ, 14ᵗʰ, and 21ˢᵗ days post-treatment (PT), the wounds were clinicopathologically examined. Both nanomaterials have good crystallinity and high purity, but green ZnO-NPs have a longer nanowire length and diameter than chemical ZnO-NPs. The formed gels were highly viscous with a pH of 6.5 to 7. The treated groups with ZnO-NP gels showed clinical improvement, as decreased wound surface area (WSA) percent (WSA%), increased wound contraction percent (WC%), and reduced healing time (p < 0.05) when compared with the control group. The histological scoring showed that the epithelialization score was significantly higher at the 21ˢᵗ day post-treatment in the treated groups than in the control group (p < 0.05), but the vasculature, necrosis, connective tissue formation, and collagen synthesis scores were mostly similar. The green and chemical ZnO-NP gels showed promising wound healing properties; however, the L. inermis–mediated ZnO-NPs were more effective.

Fipronil (FIP) is a highly effective insecticide that has been used in agriculture and veterinary medicine. Its neurotoxic effect to insects and to non-target organisms, after nonintentional exposure, was reported. Many studies were conducted to evaluate FIP effects on mammals. However, slight is known about its effect on the brain stem and diencephalon. The current study was designed to investigate the ability of FIP to induce oxidative stress as a molecular mechanism of FIP neurotoxicity that resulted in apoptosis and neural tissue reactivity in these regions. Ten adult male rats received 10 mg/kg of FIP technical grade by oral gavage, daily for 45 days. Brain stem and diencephalon were processed to examine oxidative stress–induced macromolecular alteration (MDA, PCC and DNA fragmentation). Also, the histopathological assessment and immunoreactivity for caspase-3 (active form), iNOS and GFAP were performed on the thalamus, hypothalamus and medulla oblongata. Our results revealed that FIP significantly raised MDA, PCC and DNA fragmentation (p ≤ 0.05). In addition, significantly increased immunoreactivity to GFAP, iNOS and caspase-3 (active form) in the FIP-treated group was noticed (p ≤ 0.05). Moreover, alterations in the histoarchitecture of the neural tissue of these regions were observed. We conclude that FIP can induce oxidative stress, leading to apoptosis and tissue reaction in brain stem and diencephalon.

Effective treatment of dairy wastewater with efficient removal of antibiotic-resistant bacteria (ARB) is a great challenge for reuse of treated wastewater. Antibiotics are widely used in human and veterinary medicine, and antibiotics misuse has led to occurrence and spread of antibiotic-resistant bacteria (ARB). Reuse of treated wastewater for irrigation is a solution to deal with water shortage in developing countries. One of the major problems of treated wastewater reuse is the possible presence of ARB. Removal of ARB from dairy wastewater using a full-scale hybrid constructed wetland (CW) at Miyagi Prefecture, Japan, was studied. It was well-defined that hybrid CW caused a complete removal of ampicillin-, gentamicin-, kanamycin-, and streptomycin-resistant bacteria resulting in an effluent free of these resistant strains. Additionally, a significant decrease in the number of vancomycin-RB was definite with a final 3.2 log unit decrease in the effluent. This study addressed the remarkable efficiency of a full-scale hybridized CW in Kawatabi, Field Science Center, Tohoku University. It decreased the output of organic matter (COD), total suspended solids (SS), and ammonia-nitrogen. The performance of CW for the removal ARB from dairy wastewater was efficient to minimize the release of these contaminants into the environment and avoid the spread of antibiotic resistance with safe discharge and reuse of treated wastewater. Finally, the current study represents the first report about the assessment of ARB removal during treatment of dairy wastewater using CW.

Cyphenothrin, one of the synthetic pyrethroids, developed as an alternative to organophosphorus and carbamate pesticides. It is used in veterinary medicine and household application against insects. Due to the contamination of the aquatic ecosystems, non-target aquatic organisms are affected. The current study aimed to evaluate the cyphenothrin effects on in vitro and in vivo models of freshwater mussels Unio delicatus Lea, 1863. While antioxidant enzyme (glutathione) was measured in both models, the total hemocyte counts were only detected in vivo models after exposure to cyphenothrin (1 and 10 μg/L) for 24-h and 48-h exposure times. A decrease in total hemocyte count occurred depending on the dose and duration (p < 0.001). In both in vitro and in vivo models of gill and digestive gland tissues, higher glutathione levels were obtained at a dose of 10 μg/L compared to the control groups in both exposure times (p < 0.001). The results of the study suggest that the antioxidant parameters could represent biomarkers to evaluate the effects of pollutants on in vitro and in vivo models of freshwater mussels.

The quality of water resources can be altered by human activities carried out in watersheds. These changes can lead to the occurrence of antibiotic-resistant bacteria and compromise public health. The aim of the present study was to evaluate the presence and concentration of total coliforms and Escherichia coli in the water at the Ecological Park Tietê in São Paulo, the antibiotics resistance of isolated E. coli, and the interaction between season, collection points, and water quality variables. Sample localities were georeferenced and identified as P1—drinking water from the distribution system (23°29′33.46″S, 46°31′16.12″O); P2—main lagoon of the park (23°29′37.59″S, 46°31′28.22″O); and P3—connection between the main lagoon and the Tietê River (23°29′14.66″S, 46°31′26.57″O). Physical–chemical and microbiological variables were measured. Data were subjected to analysis of variance. The isolated effect or the interaction between season, collection points, and variables had the means compared to each other by the Scott-Knott test. The microbiological analysis was performed by inoculating the samples in 3 M™ Petrifilm™ E. coli/Coliform Count Plates (containing agar medium with Violet Red Bile nutrients), incubated at 37 °C for 48 h and the E. coli isolated had their antibiotic resistance profile tested by the disk diffusion technique using Mueller–Hinton agar. Total coliforms and E. coli were not identified at P1. Total coliforms were identified in 64% of the samples and E. coli was identified in 36% of the samples. The microbial contamination of the surface waters of the park presents seasonal variation with higher concentrations of E. coli in the hottest and rainiest seasons (spring and summer). The isolated E. coli showed greater resistance to erythromycin (82%) and amoxicillin (55%) in P2 and to erythromycin (82%) and amoxicillin (27%) in P3, with the presence of multiresistant isolates at both points. No strain showed resistance to amikacin. The high rate of resistance of E. coli to the antibiotics frequently used in human and veterinary medicine demonstrates that the contribution of these substances in aquatic ecosystems over the years has exerted a selection pressure on microorganisms, assisting the appearance and spread of resistant bacteria, changing the environmental biota, and turning these locations in possible reservoirs of antibiotic resistance.