Perspectives in Veterinary Pharmacology and Toxicology

Veterinary Students' Knowledge and Awareness of Antimicrobial Stewardship before and after Clinical Rotations

Given the global threat of antimicrobial resistance, it is imperative that veterinary graduates are effective antimicrobial stewards. Veterinary students learn the principles of antimicrobial stewardship explicitly, through pre-clinical coursework, and implicitly, through the cases they each encounter on clinical rotations. We aimed to understand the influence of pre-clinical versus clinical learning on veterinary students' knowledge and awareness of antimicrobial concepts to guide efforts to improve instruction in these areas. To assess knowledge acquisition and to explore student perceptions of antimicrobial stewardship, a standardized online survey was administered to Cornell University veterinary students at two timepoints: in August 2020 before clinical rotations (N = 26 complete responses and N = 24 partial responses) and again in May 2021 after their clinical rotations (N = 17 complete responses and N = 6 partial responses). Overall and section-specific confidence and knowledge scores were calculated, using pairwise deletion for incomplete responses. Students generally had low confidence in antimicrobial topics and correctly answered only half of knowledge questions correctly; they performed the best on antimicrobial resistance knowledge questions. There were no significant differences in knowledge or confidence after clinical rotations. On average, students had only read one antimicrobial stewardship guideline. Students reported that human health care providers contributed more to antimicrobial resistance than veterinarians. In conclusion, graduating veterinary students at our institution have significant knowledge gaps in critical principles that are essential to become antimicrobial stewards. Explicit instruction in antimicrobial stewardship is necessary in the pre-clinical and clinical coursework, and the practical use of antimicrobial stewardship guidelines should be emphasized.

Availability of Antibiotics for Veterinary Use on the Internet: A Cross-Sectional Study

The misuse or overuse of antibiotics can favor the emergence of antimicrobial resistance, with a direct impact on human and animal health as well as on ecosystems. In this work, we have analyzed the web pages in which antibiotics for veterinary use can be purchased online. By using a specifically developed software, we carried out a detailed search to know if each individual antibiotic and the families included in the OIE list of antimicrobial agents of veterinary importance (in English and in Spanish) were sold, reviewing the offers according to the administration route and the species for which the antibiotics were intended. The greatest offer of antibiotics was for those compounds considered critically important by OIE. In the search in English, penicillins were available on 55.8% of the sites, tetracyclines on 55.0%, and fluoroquinolones on 52.7%. In Spanish, the families with the greatest presence were fluoroquinolones (67.9% of the sites), tetracyclines (67.9% of the sites), and penicillins (65.4% of the sites). Regarding individual antibiotics, the most offered in both searches were amoxicillin (49.6% of the sites in English and 57.7% in Spanish) and doxycycline (46.5% of the sites in English and 53.8% in Spanish). Most offers were for oral and parenteral administration and intended for cats and dogs and for bovines.

Assessing knowledge, attitude, and practices of veterinarians towards antimicrobial use and stewardship as drivers of inappropriate use in Abuja, Nigeria

INTRODUCTION

Antimicrobial resistance (AMR) has recently gained worldwide recognition, as the emergence of multi-drug resistant organisms has led to increased mortality and economic burden. This study aimed to assess knowledge, attitudes, and practices of veterinarians towards rational antimicrobial prescribing and identify factors influencing use.

METHODS

We interviewed veterinary doctors in Abuja, Nigeria using a 50-point questionnaire distributed via WhatsApp mobile application. The questionnaire inquired about their experiences, knowledge, attitudes, and practices towards AMR and stewardship. We analyzed the data by calculating frequencies and proportions.

RESULTS

Of 220 registered veterinarians, 144 (65.5%) participated in the survey. Most (52.8%) were within the age group 30 - 39 years; males (72.2%), with a Master's degree (42.4%) and worked in public service (44.4%). Three-quarters (75.7%) had good knowledge of antimicrobials; 47.2% had received training on stewardship while 88.9% reported that they believed that overuse of antimicrobials was the major contributory factor towards AMR. Antimicrobial stewardship regulations are important in veterinary practice. Veterinarians were aware of the occurrence of resistant pathogens and agreed that restricting antimicrobial use in animal health care was necessary to reduce AMR.

CONCLUSION

Most respondents referred to the veterinary formulary (VF) when in doubt of the appropriate antimicrobial agent to administer. We recommend that the VF be updated following the WHO list of critically-important-antimicrobials (CIA) and veterinarians educated not to use these CIAs in the treatment of food animals.

In vitro glucuronidation of 7-hydroxycoumarin derivatives in intestine and liver microsomes of Beagle dogs

Beagle dog is a standard animal model for evaluating nonclinical pharmacokinetics of new drug candidates. Glucuronidation in intestine and liver is an important first-pass drug metabolic pathway, especially for phenolic compounds. This study evaluated the glucuronidation characteristics of several 7-hydroxycoumarin derivatives in beagle dog's intestine and liver in vitro. To this end, glucuronidation rates of 7-hydroxycoumarin (compound 1), 7-hydroxy-4-trifluoromethylcoumarin (2), 6-methoxy-7-hydroxycoumarin (3), 7-hydroxy-3-(4-tolyl)coumarin (4), 3-(4-fluorophenyl)coumarin (5), 7-hydroxy-3-(4-hydroxyphenyl)coumarin (6), 7-hydroxy-3-(4-methoxyphenyl)coumarin (7), and 7-hydroxy-3-(1H-1,2,4-tirazole)coumarin (8) were determined in dog's intestine and liver microsomes, as well as recombinant dog UGT1A enzymes. The glucuronidation rates of 1, 2 and 3 were 3-10 times higher in liver than in small intestine microsomes, whereas glucuronidation rates of 5, 6, 7 and 8 were similar in microsomes from both tissues. In the colon, glucuronidation of 1 and 2 was 3-5 times faster than in small intestine. dUGT1A11 glucuronidated efficiently all the substrates and was more efficient catalyst for 8 than any other dUGT1A. Other active enzymes were dUGT1A2 that glucuronidated efficiently 2, 3, 4, 5, 6 and 7, while dUGT1A10 glucuronidated efficiently 1, 2, 3, 4, 5 and 7. Kinetic analyses revealed that the compounds' K_m values varied between 1.1 (dUGT1A10 and 2) and 250 µM (dUGT1A7 and 4). The results further strengthen the concept that dog intestine has high capacity for glucuronidation, and that different dUGT1As mediate glucuronidation with distinct substrates selectivity in dog and human.

Evaluation of the hepatocyte-derived cell line BFH12 as an in vitro model for bovine biotransformation

The knowledge of drug metabolising enzymes (DMEs) in cattle is rather limited. The capability of the bovine foetal hepatocyte-derived cell line BFH12 to serve as model for biotransformation was evaluated. Gene expression analysis of DMEs was performed by reverse transcription PCR (RT-PCR). The presence of efflux transporters was visualised by immunocytochemistry, and functional induction of cytochrome P450 (CYP) 1A was assessed by the ethoxyresorufin-O-deethylase (EROD) assay. The production of bile acids was measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). RT-PCR revealed the expression of cytochromes 1A1, 1A2, 3A4 and phase II enzymes UGT1A1, UGT1A6 and GSTM1. Immunofluorescence demonstrated efflux transporters ABCG2 and ABCC1. The EROD assay revealed a dose-dependent CYP1A induction after treatment with benzo[a]pyrene (BP). LC-MS/MS analysis of cell culture supernatants showed the production of bile acids including taurocholic acid, tauro-chenodeoxycholic acid, taurodeoxycholic acid and taurolithocholic acid. The results strongly suggest the applicability of the cell line BFH12 for subsequent experiments in the emerging field of bovine biotransformation.

Authorization and Toxicity of Veterinary Drugs and Plant Protection Products: Residues of the Active Ingredients in Food and Feed and Toxicity Problems Related to Adjuvants

Chemical substances applied in animal husbandry or veterinary medicine and in crop protection represent substantial environmental loads, and their residues occur in food and feed products. Product approval is governed differently in these two sectors in the European Union (EU), and the occurrence of veterinary drug (VD) and pesticide residues indicated by contamination notification cases in the Rapid Alert System for Food and Feed of the EU also show characteristic differences. While the initial high numbers of VD residues reported in 2002 were successfully suppressed to less than 100 cases annually by 2006 and on, the number of notification cases for pesticide residues showed a gradual increase from a low (approximately 50 cases annually) initial level until 2005 to more than 250 cases annually after 2009, with a halt occurring only in 2016. Main notifiers of VD residues include Germany, Belgium, the UK, and Italy (63, 59, 42, and 31 notifications announced, respectively), and main consigning countries of non-compliances are Vietnam, India, China, and Brazil (88, 50, 34, and 23 notifications, respectively). Thus, countries of South and Southeast Asia are considered a vulnerable point with regard to VD residues entering the EU market. Unintended side effects of VDs and plant protection products may be caused not only by the active ingredients but also by various additives in these preparations. Adjuvants (e.g., surfactants) and other co-formulants used in therapeutic agents and feed additives, as well as in pesticide formulations have long been considered as inactive ingredients in the aspects of the required main biological effect of the pharmaceutical or pesticide, and in turn, legal regulations of the approval and marketing of these additives specified significantly less stringent risk assessment requirements, than those specified for the active ingredients. However, numerous studies have shown additive, synergistic, or antagonistic side effects between the active ingredients and their additives in formulated products; moreover, toxicity has been evidenced for various additives. Therefore, toxicological evaluation of surfactants and other additives is essential for proper environmental risk assessment of formulations used in agriculture including animal husbandry and plant protection.