Farm Animal Veterinarians' Knowledge and Attitudes toward Antimicrobial Resistance and Antimicrobial Use in the Republic of Serbia

Unveiling the landscape of resistance against high priority critically important antimicrobials in food-producing animals across Africa: A scoping review

The rapid population growth in Africa is associated with an increasing demand for livestock products which in turn can lead to antimicrobial use. Antimicrobial usage in animals contributes to the emergence and selection of resistant bacteria which constitutes a serious public health threat. This study aims to review and summarize the available information on highest priority critically important antimicrobials (HPCIAs) resistance in livestock production in Africa. This work will help to inform future policies for controlling antimicrobial resistance (AMR) in the food production chain. A scoping review was conducted according to the Cochrane handbook and following PRISMA 2020 guidelines for reporting. Primary research studies published after 1999 and reporting resistance of Escherichia coli, Enterococcus spp, Staphylococcus aureus, Salmonella spp, and Campylobacter spp to HPCIAs in poultry, cattle, pigs, goats, and sheep in Africa were searched in four databases. A total of 312 articles were included in the review. The majority of the studies (40.7) were conducted in North African countries. More than 49.0% of included studies involved poultry and 26.2% cattle. Cephalosporins and quinolones were the most studied antimicrobial classes. Of the bacteria investigated in the current review, E. coli (41.7%) and Salmonella spp (24.9%) represented the most commonly studied. High levels of resistance against erythromycin in E. coli were found in poultry (MR 96.1%, IQR 83.3-100.0%), cattle (MR 85.7%, IQR 69.2-100.0%), and pigs (MR 94.0%, IQR 86.2-94.0%). In sheep, a high level of resistance was observed in E. coli against nalidixic acid (MR 87.5%, IQR 81.3-93.8%). In goats, the low level of sensibility was noted in S. aureus against streptomycin (MR 86.8%, IQR 19.4-99.0%). The study provides valuable information on HPCIAs resistance in livestock production in Africa and highlights the need for further research and policies to address the public health risk of AMR. This will likely require an investment in diagnostic infrastructure across the continent. Awareness on the harmful impact of AMR in African countries is a requirement to produce more effective and sustainable measures to curb AMR.

Assessment of antibiotic use patterns in bovine mastitis treatment in the dairy sector in Serbia

The dairy sector is essential for the world's food systems, playing a vital role in agricultural production. Yet, mastitis, an inflammation of the mammary gland, affects a considerable portion of the dairy cow population annually, leading to reduced productivity and sustainability. Insight into therapeutic protocols is essential for a better understanding of the situation on farms with the aim of developing new or harmonizing existing protocols in the mastitis treatment. This study conducted on dairy farm in Serbia aimed to explore the most commonly used antibiotics during bovine mastitis treatment and their association with daily milk yield. Data from 100 lactating cows, including therapeutic protocols, lactation numbers, mastitis episodes, milk yield, and antibiotic usage, were obtained from a computerized database and statistically analysed. The results demonstrated a high prevalence of narrow-spectrum antibiotics usage, with the majority of cows treated with combination therapy. The route of antibiotic application did not significantly impact daily milk yield, while treatment duration had no discernible effect. Nonetheless, specific antibiotics were associated with milk yield variations, suggesting the need for careful antibiotic selection and management in mastitis therapy. These findings emphasize the importance of prudent antibiotic use to safeguard animal health and long-term milk production sustainability.

Genomic Insights into Methicillin-Resistant Staphylococci and Mammaliicocci from Bulk Tank Milk of Dairy Farms in Serbia

The potential risk to human and animal health provides a rationale for research on methicillin-resistant staphylococci (MRS) and mammaliicocci (MRM) in dairy herds. Here, we aimed to estimate their occurrence in the bulk tank milk (BTM) samples collected in 2019-2021 from 283 bovine dairy farms in the Belgrade district. We used whole-genome sequencing to characterize the obtained isolates and assess their genetic relatedness. A total of 70 MRS/MRM were recovered, most frequently Staphylococcus haemolyticus and Mammaliicoccus sciuri. Five clusters of 2-4 genetically related isolates were identified and epidemiological data indicated transmission through, e.g., farm visits by personnel or milk collection trucks. Most MRSA isolates belonged to the typical livestock-associated lineage ST398-t034. One MRSA isolate (ST152-t355) harbored the PVL-encoding genes. Since MRS/MRM isolates obtained in this study frequently harbored genes conferring multidrug resistance (MDR), this argues for their role as reservoirs for the spread of antimicrobial resistance genes. The pipeline milking system and total bacterial count >100,000 CFU/mL were significantly associated with higher occurrences of MRS/MRM. Our study confirms that BTM can be a zoonotic source of MRS, including MDR strains. This highlights the urgent need for good agricultural practices and the continuous monitoring of MRS/MRM in dairy farms.

Alternatives to Antimicrobial Treatment in Bovine Mastitis Therapy: A Review

Despite preventive and therapeutic measures, mastitis continues to be the most prevalent health problem in dairy herds. Considering the risks associated with antibiotic therapy, such as compromised effectiveness due to the emergence of resistant bacteria, food safety issues, and environmental impact, an increasing number of scientific studies have referred to the new therapeutic procedures that could serve as alternatives to conventional therapy. Therefore, the aim of this review was to provide insight into the currently available literature data in the investigation of non-antibiotic alternative approaches. In general, a vast number of in vitro and in vivo available data offer the comprehension of novel, effective, and safe agents with the potential to reduce the current use of antibiotics and increase animal productivity and environmental protection. Constant progress in this field could overcome treatment difficulties associated with bovine mastitis and considerable global pressure being applied on reducing antimicrobial therapy in animals.

Chemical Composition, Antimicrobial Activity, and Withdrawal Period of Essential Oil-Based Pharmaceutical Formulation in Bovine Mastitis Treatment

Due to the emergence of antibiotic-resistant bacteria, the risk it represents to public health, and the possible consequences for animal health and welfare, there is an increasing focus on reducing antimicrobial usage (AMU) in animal husbandry. Therefore, a great interest in developing alternatives to AMU in livestock production is present worldwide. Recently, essential oils (EOs) have gained great attention as promising possibilities for the replacement of antibiotics. The current study aimed to test the potential of using a novel EO-based pharmaceutical formulation (Phyto-Bomat) in bovine mastitis treatment. The antibacterial activity was performed using the microdilution technique. Lactating dairy cows were treated with 15 mL of Phyto-Bomat in the inflamed quarter for 5 consecutive days in order to analyze blood and milk samples for thymol and carvacrol residues using gas chromatography and mass spectrometry (GC-MS). Antimicrobial activity expressed as the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) indicates that this formulation has the highest activity against Gram-positive strains. The dominant compounds in Phyto-Bomat were thymol and carvacrol, at 12.58 ± 1.23 mg/mL and 23.11 ± 2.31 mg/mL, respectively. The quantification of these two compounds in evaluated biological samples showed that 24 h after administration the concentration of thymol and carvacrol in milk samples was at the same level as before application. On the other hand, thymol and carvacrol were detectable in plasma samples even after 24 h post-treatment, with values ranging from 0.15-0.38 and 0.21-0.66 µg/mL, respectively. The tested formulation showed encouraging results of antibacterial activity against bovine mastitis pathogens, as well as the withdrawal period of dominant compounds, which implies that further testing regarding the bacteriological and clinical cure rates in clinical settings is needed.

Antimicrobial use and resistance in food-producing animals-How can we protect the efficacy of antibiotics for reproductive diseases?

The ongoing emergence of antibiotic resistance jeopardizes efficacy of antibiotics in curing animals from bacterial infections that threaten their health, welfare and productivity. This review gives an overview of antimicrobial use data in food-producing animals, a discussion on how antimicrobials are used for some infections in the reproductive system in cattle, the horse and pig in Europe where there are differences in treatment practices including options to refine the use of antibiotics, and finally, a presentation of the antibiotic resistance for some bacteria collected from the reproductive system. It is shown that there are differences in applied treatment regimens for, as well as prevention of, several reproductive diseases in Europe. Some of the treatments are not evidence-based, which should be considered by clinicians and other stakeholders. It is concluded that a more refined and restrictive use of antibiotics could be achieved by adhering to evidence-based guidelines by national and international expertise including the scientific literature when available. This may call for a re-think among the animal health stakeholders regarding the use of antibiotics and may demand new skill-sets in the animal health sphere.

Environmental Bovine Mastitis Pathogens: Prevalence, Antimicrobial Susceptibility, and Sensitivity to Thymus vulgaris L., Thymus serpyllum L., and Origanum vulgare L. Essential Oils

Mastitis is considered to be one of the most important diseases of dairy cows in terms of health, production, and economy. Being the most common cause of antibiotic consumption in dairy cows, treatment of this disease is one of the biggest challenges in the veterinary profession as an increasing number of pathogens develop resistance to antibiotics used in the treatment. Therefore, new alternative approaches for limiting the use of antibiotics in livestock are required. For this reason, our study aimed to investigate prevalence of environmental mastitis associated bacterial strains, as well as the sensitivity of isolated strains to different antibiotics. Additionally, the therapeutic potential of three essential oils (EOs) was tested against bovine Serratia spp. and Proteus spp. mastitis pathogens, based on their chemical composition, as well as antibacterial potential. The study was carried out on 81 milk samples collected from dairy cows with mastitis. In order to determine prevalence of S. marcescens and P. mirabilis, microbiological isolation and identification were performed. Antimicrobial susceptibility testing was performed by disk diffusion method and the microdilution method was used to determine the antibacterial activity of selected EOs. In the oregano EO, a total of 23 compounds were detected, with carvacrol as a dominant component (78.94%). A total of 26 components were present in the EO of common thyme, where thymol was the most abundant compound (46.37%). Thymol also dominated (55.11%) the wild thyme EO. All tested EOs displayed antibacterial activity against all strains to different extents, while wild and common thyme EOs were the most effective. It could be concluded that the tested EOs represent promising therapeutic candidates for effective non-antibiotic treatment of mastitis.

Veterinary Practitioners' Standpoints and Comprehension towards Antimicrobial Use-Are There Opportunities for Antimicrobial Stewardship Improvement?

The main subject of the research is the assessment of the knowledge, attitudes and behaviors of veterinarians regarding the use of antibiotics (AMU) and antimicrobial resistance (AMR) through a questionnaire conducted among veterinarians in the northern region of Serbia. A total of 62 respondents completed the questionnaire, which represents a response rate of 44.3%. Male veterinarians are less likely to be in the group of veterinarians with insufficient knowledge (p < 0.05). Veterinarians engaged in mixed practice (small and large animals) (p < 0.001) and veterinarians who have over 100 patients per month (p < 0.005) are also less likely to be in the group with insufficient knowledge of antimicrobial resistance. The proportion of those with insufficient knowledge is growing among veterinarians whose source is the Internet (p < 0.01), while the proportion of those with insufficient knowledge about antimicrobial resistance is declining among veterinarians whose source of information is continuous education (p < 0.05). The majority of the respondents (n = 59, 95.2%) completely agreed that AMR is a very big issue in the global health sector right now. Unfortunately, there are crucial gaps in the knowledge and attitudes of the surveyed participants. They do not appear to be aware of the importance of AMU in veterinary medicine and its influence on overall AMR, or the crucial part that non-prescribed antibiotics have in all of it. Positively, many veterinarians use good practice AMU guidelines in their everyday practice and in line with the global trend of AMU reduction, respondents have also decreased their AMU compared to the previous year.

Fijian Veterinarian and Para-Veterinarians' Behavior, Attitude and Knowledge Toward Antimicrobial Use and Antimicrobial Resistance: A Qualitative Study

Antimicrobial resistance (AMR) is a global health issue affecting humans and livestock. Reduction in antimicrobial use (AMU) and appropriate use of antimicrobials in livestock production systems have been encouraged. Lack of access to qualified veterinarians, policies regulating AMU and knowledge of AMU and AMR have been identified as drivers of inappropriate AMU behavior in developing countries. Hence, para-veterinarians take a lead role in providing veterinary services to livestock farmers in developing countries. Our previous work found Fijian farmers lack knowledge and understanding of AMU and AMR. However, the attitude, knowledge, and behavior of Fijian veterinary professionals toward AMU and AMR is currently unknown. Therefore, this qualitative study used face-to-face, semi-structured interviews to explore and understand Fijian veterinarian and para-veterinarians' attitude, knowledge, and behavior toward AMU and AMR. A sample of at least ten participants was targeted and recruited from the Central and Western divisions of Viti Levu, Fiji. The Theory of Planned Behavior (TPB) informed the development of the semi-structured interview guide. The interviews were audio-recorded and analyzed using reflexive thematic analysis and deductively using the TPB framework. Our analysis generated three key themes: 1) Antimicrobials prescribed and used based on availability and cost rather than clinical need, 2) Para-veterinarians awareness and knowledge of AMR influence treatment decisions, and 3) Limited resources impede effective consultation and veterinary service delivery. This study demonstrated para-veterinarians (not veterinarians) lacked knowledge and understanding of AMU and AMR. The availability and cost of antimicrobials rather than clinical justification drove antimicrobial prescribing amongst the para-veterinarians. Veterinarians did not visit farms to provide veterinary services; therefore, para-veterinarians provided the veterinary services to the livestock farmers. Lack of human resources, antimicrobials, and physical resources incapacitated veterinary service delivery, where services to farmers' were delayed or not provided at all. Terms of reference for veterinary service delivery and para-veterinarian training framework targeting prescribing, dispensing, use of antimicrobials and risks associated with inappropriate AMU are recommended as part of antimicrobial stewardship (AMS) programmes. Allocation of physical and human resources to Fijian veterinary services should be considered part of AMS programmes to improve veterinary service delivery to livestock farmers and optimize the AMU at the country level.