Formulating antibiotic policy: Analysis of India's ban on colistin use in food producing animals

Antibiotics remain key tools for maintaining human health, and in many settings, food production. However, emergence of antibiotic resistance has become a global challenge, one that has resulted in multi-national calls for policy to improve antibiotic use. One such call has been to restrict the use of antibiotics deemed critically important for human health, such as colistin, during the production of food producing animals. Between 2016 and 2019 numerous countries, including India, implemented policies to heavily restricted the use of colistin in livestock. While this represents a key shift in the antibiotic policy landscape, other classes of critically important antibiotics continue to be used during food production. This paper provides a policy analysis of India's 2019 colistin ban to provide insight into how this came to be and to identify factors which could shape the development of future legislation. The analysis revealed that while antibiotic reform in food production had been in the background of India's policy agenda for some time, it took key-focusing events to shift the policy climate into a period of action. These focusing events included reporting of mobile colistin resistance genes in bacteria isolated from pigs in China and colistin resistant bacteria isolated from food samples in India. Consistent narratives had been built around colistin's role as a last resort antibiotic which, together with relatively low proportion of colistin resistance in bacteria isolated from human patients, framed legislation as a worthwhile endeavour for policy makers. In addition, India acted as a global player in antibiotic stewardship and followed the precedent set by several other countries in restricting colistin use during food production. As most colistin for animal use was imported into India from China, and viable alternative animal treatments existed, there was limited industry opposition that could block legislation. We suggest evaluation of these five critical factors (focusing events, consistent narratives, worthwhile endeavour, precedent for change, and industry opposition) should be part of the policy formulation process for legislation regarding the use of other critically important antibiotics in food production.

Unravelling AMR dynamics in the rumenofaecobiome: Insights, challenges and implications for One Health

Antimicrobial resistance (AMR) is a critical global threat to human, animal and environmental health, exacerbated by horizontal gene transfer (HGT) via mobile genetic elements. This poses significant challenges that have a negative impact on the sustainability of the One Health approach, hindering its long-term viability and effectiveness in addressing the interconnectedness of global health. Recent studies on livestock animals, specifically ruminants, indicate that culturable ruminal bacteria harbour AMR genes with the potential for HGT. However, these studies have focused predominantly on using the faecobiome as a proxy to the rumen microbiome or using easily isolated and culturable bacteria, overlooking the unculturable population. These unculturable microbial groups could have a profound influence on the rumen resistome and AMR dynamics within livestock ecosystems, potentially holding critical insights for advanced understanding of AMR in One Health. In order to address this gap, this review of current research on the burden of AMR in livestock was undertaken, and it is proposed that combined study of the rumen microbiome and faecobiome, termed the 'rumenofaecobiome', should be performed to enhance understanding of the risks of AMR in ruminant livestock. This review discusses the complexities of the rumen microbiome and the risks of AMR transmission in this microbiome in a One Health context. AMR transmission dynamics and methodologies for assessing the risks of AMR in livestock are summarized, and future considerations for researching the impact of AMR in the rumen microbiome and the implications within the One Health framework are discussed.

Pathogens and drug resistance or virulence genes from animals and surrounding environment in Shenzhen, 2023 using targeted next-generation sequencing

Identifying the pathogen spectrum of animals and surrounding environment is essential for the prevention and control of zoonotic diseases. From February 1 to June 30, 2023, we randomly collected respiratory and intestinal samples from animals and swab samples from surrounding environment in 33 units in Shenzhen, and carried out pathogen/gene screening using pathogen targeted next-generation sequencing technology. A total of 2000 samples were collected and mixed to obtain 415 samples for detection. The detection rate of respiratory pathogens (76.9 %, χ2 = 15.892, P < 0.001), drug resistance genes (59.0 %, χ2 = 52.888, P < 0.001), the co-detection proportion of intestinal pathogens (87.0 %, χ2 = 9.605, P = 0.002) in livestock and poultry, and drug resistance genes in surrounding environment (30.5 %, χ2 = 14.932, P < 0.001) were higher than dogs and cats, and wild animals. Escherichia coli (37.3 %, 30.5 %) and β-lactamase-resistance NDM genes (31.3 %, 27.1 %) were the main respiratory pathogens in livestock and poultry, and surrounding environment. The detection rate of Pasteurella multocide was 25.0 % in dogs and cats. The detection rates of intestinal pathogens Campylobacter coli and Clostridium perfringens in livestock and pourtry were 23.9 % and 17.9 %, and Clostridium perfringens in dogs and cats and wild animal was 18.2 % and 15.7 %. The total detection rate of intestinal pathogens of wild animals in wildlife parks (44.0 %) and indoor pet parks (38.9 %) was higher than that in animal nature reserves (χ2 = 15.686, P = 0.001). The respiratory/intestinal pathogens in animals and surrounding environment was common in Shenzhen. The drug resistance genes in livestock and poultry, and intestinal pathogens of wild animals in indoor pet parks needed more attention.

Prevalence and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli over time in Thailand under a One Health approach: A systematic review and meta-analysis

Campylobacter spp. are major food-borne zoonotic pathogens impacting food safety worldwide. Thailand is one of the countries facing with a significant burden of Campylobacter infections and is recognized as a hotspot of AMR. Our study applied a systematic review and meta-analysis, using a One Health perspective, to investigate the prevalence and AMR of Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) over time in Thailand, from 1985 to 2023. Based on the PRISMA guidelines, a literature search using PubMed, ScienceDirect, and Google Scholar to identify the articles reporting prevalence, sequence types (STs), antimicrobial susceptibility, and resistance genes of Campylobacter spp. in humans, animals, food, and environmental samples was performed. Eighty-one articles were retrieved for systematic review, with 33 reporting Campylobacter spp. prevalence and 20 containing AMR data collected for meta-analysis. The highest prevalence of C. jejuni was found in chickens (43.6 %) and chicken products (31.4 %), followed by ducks (16.7 %), the general human population with diarrhea (15.9 %), children with diarrhea (10.7 %). C. coli was also prevalent in chickens (12.6 %) and chicken products (10.4 %). C. jejuni prevalence decreased by 14.8 % among children with diarrhea (p = 0.006), but increased by 16.7 % in chicken products (p = 0.007). Sixty-two STs were identified, with ST 574, ST 1075, ST 51 being the most prevalent STs recorded. Five STs, including ST 50, ST 51, ST 354, ST 464, and ST 574, were reported in both humans and chickens. The AMR levels were highest against quinolones, ranging 75.4 %-94.8 % in human-related categories and 71.6 %-88.7 % in chicken-related categories. Notably, ciprofloxacin-resistant and nalidixic acid-resistant C. jejuni strains collected from chickens increased by 11.9 % (p = 0.004) and 16.1 % (p = 0.027), respectively. Thirteen resistance genes/mutations were reported, with the phenotypic resistance linked to gyrA mutations and tet(O) genes. The high prevalence and increasing trend of AMR in C. jejuni and C. coli underscore the critical need for One Health surveillance to address the rising AMR challenge posed by these pathogens in Thailand.

Random antimicrobial peptide mixtures as non-antibiotic antimicrobial agents for cultured meat industry

Antibiotics, commonly used in cell culture studies to prevent microbial contamination, cannot be employed in Cultured meat (CM) due to potential residues in the final food products. Hence, there is an urgent need to develop novel and safe non-antibiotic antimicrobial agents. Here, we investigated the potential of random antimicrobial peptide mixtures (RPMs) as non-antibiotic antimicrobial agents. RPMs are synthetic peptide cocktails that have previously shown strong and broad antimicrobial activity; however, their use in cell culture media and their effect on mammalian cells have not yet been explored. Here we show that RPMs had no significant impact on mesenchymal stem cells (MSCs) at concentrations that effectively inhibit bacterial growth. RPMs displayed strong bactericidal activity against Gram-positive bacteria, achieving a 6-log reduction of L. monocytogenes in cell culture medium without any cytotoxicity. Additionally, RPMs showed a low occurrence of resistance development with no significant resistance developed in compared with a combination of penicillin and streptomycin. Moreover, LK20 mixture was rapidly digested and a rapid digestion in a simulated digestion model. Our results indicate that RPMs have great potential to serve as safe and effective non antibiotic antimicrobial agents in cultured meat industry.

Remediation of antibiotic pollution in the global environment by iron-based materials activating advanced oxidation processes: A systematic review

Antibiotic pollution and its associated resistance genes have emerged as a global environmental and health concern, with widespread detection in various environmental media such as water, soil, atmosphere, and sediment, as well as in organisms. Hence, it is imperative to develop effective remediation technologies for the targeted treatment of antibiotic pollution to mitigate its environmental and health risks. This paper reviews the status of antibiotic pollution in major countries, territories, and regions worldwide. Addressing the risks cause by antibiotics and their resistance genes and achieving efficient remediation of antibiotic pollutants. Additionally, the study explores the issue of antibiotic use and resistance in detail from a global perspective. It provides a critical scientific foundation for controlling global antibiotic resistance through multi-dimensional integrated analysis. In 2021, 4.71 million deaths globally were attributed to antibiotic resistance, with countries such as India and China being the most affected. It also examined the predominant types and sources of antibiotic pollutants, as well as key remediation technologies for addressing antibiotic contamination. Antibiotics such as amoxicillin and ciprofloxacin are commonly found in surface waters at concentrations ranging from 1 to 120 μg L-1. Furthermore, this paper highlighted the distinctive advantages of advanced oxidation processes (AOPs) in addressing antibiotic pollution, demonstrating removal efficiencies exceeding 90 % under optimal conditions. Our review underscored the pivotal role of iron-based materials and porous biochar in AOPs, showing promising results in various environmental settings. Future research should prioritize the development of multifunctional iron-based composites with improved catalytic stability, environmental compatibility, and recyclability. Moreover, expanding the field-scale application of these materials, particularly in low-resource or high-risk regions, will be essential to translate laboratory successes into global impact. This analysis is designed to inform and guide future initiatives to control and eliminate antibiotic contamination.

Network pharmacology and experimental validation of Compound Kushen Powder for the treatment of diarrhea in vivo

To explore the mechanism of sophora flavescens, cortex fraxini, and pomegranate peel complex powder (Compound Kushen Powder) in the treatment of animal diarrhea, a network pharmacology approach leveraging databases like TCMSP and SwissTarget was applied in this study. Molecular docking was executed between the primary constituents and pivotal targets, enabling an additional refinement of main targets and key medications. Subsequently, a rat diarrhea model induced by folium sennae leaves was established for in vivo validation. The rats were divided into four groups: negative control group, positive control group, positive drug treatment group, and Compound Kushen Powder treatment group. Key protein targets, such as Caspase-3, IL-1β, IL-10, MMP9, STAT3, TNF, TP53, and VEGFA, essential for mitigating diarrhea in response to the composite medication were found through network pharmacology. Additionally, the results of molecular docking analysis unveiled fundamental constituents of Compound Kushen Powder, namely beta-sitosterol, ursolic acid, formononetin, and matrine, which demonstrated significant binding affinities with those identified key protein targets. The results of mRNA and protein expression analyses of rat colonic tissue validated the in vivo alterations of core genes identified through network screening. Except for IL-10 and STAT3, the expression of all targets exhibited noteworthy reductions when compared to the positive control group (P < 0.05). These results demonstrated that Compound Kushen Powder can inhibit inflammation and regulate cell apoptosis by modulating signaling pathways such as IL-17, TNF-α, MAPK, and NF-κB. Collectively, this study sheds light on the traditional application of complex powder for the prevention and treatment of diarrhea.

A global atlas and drivers of antimicrobial resistance in Salmonella during 1900-2023

Although previous studies using phenotypic or/and genomic approaches monitoring have revealed the spatiotemporal distribution of antimicrobial resistance (AMR) in Salmonella in local areas, their geographical patterns and driving factors remain largely unknown at a global scale. Here, we performed an analysis of publicly available data of 208,233 Salmonella genomes in 148 countries/regions between 1900 and 2023 and explored driving indicators of AMR. Overall, we found that the geographic distribution of AMR varied depending on the location, source, and serovar. The proportion of AMR levels increased across six continents, especially in serovars Agona, Dublin, I 1,4,[5],12:i:-, Muenchen, Senftenberg, Mbandaka mainly from chickens, food, wild animals, and the environment, while decreased in Schwarzengrund and Saintpaul mainly from cattle, pigs, and turkeys. We also found that S. Typhimurium exhibiting macro, red, dry, and rough was detected as early as 1992 in the USA, earlier than in China. Moreover, we identified that antibiotic consumption, agriculture, climate, urban, health, and socioeconomic factors contribute to the development of AMR in Salmonella. We present a globally high-resolution genetic atlas of Salmonella and also identify some factors driving the rise of AMR, which can provide valuable information for understanding the transmission dynamics and evolutionary trajectories of Salmonella.

Enhancing Holstein steers growth performance: oregano essential oil's impact on rumen development, functionality and microorganism

BACKGROUND

Dietary supplementation with oregano essential oil (OEO), a natural plant extracts, is an effective and acceptable method to improve growth, beef quantity and quality, but the undergoing mechanism in rumen has not yet been reported in Holstein steers. This study investigated the effects of oregano essential oil (OEO) on growth performance, fermentation parameters, digestive enzymes activity, rumen development and microbiota in Holstein steers. Eighteen steers were randomly divided into two groups (n = 9) and fed either a basal diet (CCK) or the same diet supplemented with 20 g/(d·head) OEO (CEO) for 270 days.

RESULTS

OEO increased the rumen contents of volatile fatty acids (VFA, acetate (P = 0.011), propionate (P = 0.008), butyrate (P = 0.018)) and digestive enzymes activity (cellulase (P = 0.018), protease and β-glucosidase (P < 0.001)), and improved rumen development (papillae width (P = 0.008) and micropapillary density (P = 0.001)), which reasons contribute to increase body weight (BW, P = 0.022), average daily gain (ADG, P = 0.021), carcass weight (P = 0.001), dressing percentage (P < 0.001), and net meat production (P = 0.001) of steers. Meanwhile, metagenomic and metabolomic analysis revealed OEO significantly reduced abundance of rumen microorganisms, especially methanogenic archaea and viruses while beneficial bacteria (Bifidobacterium) and virulence factors were not affected. KEGG analysis revealed that OEO significantly reduces the host risk of disease, improves the digestive system, and reduces the energy basic metabolism level. A correlation analysis indicated fourteen kinds key microbiome and six downregulated metabolites interfere with each other and together influence the growth performance of steers.

CONCLUSION

These results suggest that feed with 20 g/(d·head) OEO in steers diets could improve growth performance, and reduces virus abundance and disease risk. And the findings provide fundamental insights into OEO, as an alternative source of natural bioactive compounds, how effect on rumen development, composition and function of microorganisms.

Exposure and health risks of livestock air resistomes

Most of the global antibiotic consumption is by the livestock industry, making livestock farms a hotspot of antibiotic resistance genes (ARGs). Farm air poses direct ARG exposure to workers, but the health risks of air resistomes remain unclear. We evaluated the human exposure and health risks of air resistomes in pig and chicken farms and compared air resistomes in Chinese farms to those in European farms given their long-term restrictions on use of antibiotics in livestock. We found that livestock air was highly enriched in ARGs, with each cell harboring seven times more ARGs than urban air. The daily ARG inhalation of farm workers was equivalent to several years of ARG inhalation by urban residents. ARGs encoding resistance to last-resort antibiotics such as mcr-1 and tetX were detected in farm air, and tetX variants were prevalent in both Chinese and European farms. ARGs in livestock air were highly associated with mobile genetic elements, and conjugation experiments confirmed their cross-phyla transferability. The projected resistome risk of farm air was significantly higher than well-recognized ARG hotspots like air from hospitals, sewage treatment plants, and from animal manures. The diversity, abundance, and risk score of air resistomes in Chinese farms were significantly higher than those in European farms, suggesting that long-term restriction of antibiotic use mitigates antibiotic resistance in the livestock environment. Our results underscore the high exposure of farm workers to ARGs via farm air and highlight its role in ARG dissemination, supporting the importance of antibiotic stewardship practices in combating antibiotic resistance.

Short-term exposure to ciprofloxacin and microplastic leads to intrahepatic cholestasis, while long-term exposure decreases energy metabolism and increases the risk of obesity

Microplastics (MPs) and antibiotics are pervasive pollutants that may pose a risk to human health. Studies have shown that both MPs and antibiotics adversely affect lipid metabolism and increase the risk of obesity. However, it remains unclear whether combined exposure to these pollutants intensify the cumulative detrimental effect on obesity and metabolism. This study demonstrated the impact of exposure to polystyrene MPs (PS, 25 nm) and ciprofloxacin (CIP), both individually and combined, for 30 d and 90 d on the hepatic metabolism of male C57BL/6J mice. The results showed that mice exposed to PS and CIP for either 30 d or 90 d exhibited lipid metabolism disorders such as increased body weight, enlarged adipocytes, triglyceride accumulation in the liver, and higher HDL-C. Differentially expressed hepatic proteins were identified via proteomic analysis. The findings indicated that exposure for 30 d caused abnormal bile acid (BA) secretion in the liver and inhibited the BA secretion pathway, which resulted in intrahepatic cholestasis. Furthermore, exposure for 90 d resolved cholestasis and reduced the overall number of differentially expressed proteins. Intestinal pathology revealed more severe damage after exposure for 30 d, while 90 d exposure decreased the adverse effect. Combined CIP and PS exposure caused damage to the organism. However, the adaptive capacity of the organism during prolonged exposure mitigated the damage caused by both, but did not imply the complete eradication of adverse effects. This study found that 90 d exposure to PS and CIP resulted in weight gain, possibly due to changes in the gut flora and suppressed energy metabolism. These results indicated that simultaneous exposure to CIP and PS exacerbated the adverse impact on the liver, causing short-term intrahepatic cholestasis. Prolonged exposure reduced the energy metabolism in the body, exhibiting varied toxicity outcomes and mechanisms at different exposure durations. This study offers novel insights into the effect of MPs and antibiotic CIP exposure on metabolic abnormalities and provides a scientific basis for assessing these risks. It also emphasizes that the adverse effect resulting from 30 d (short-term) toxic exposure may not persist and that long-term chronic toxicity needs warrants.

Antimicrobial Resistance Situation and Control Measures in Hong Kong: From a One Health Perspective

Multidrug-resistant organisms pose a critical public health challenge globally, particularly in densely populated Hong Kong with a rapidly aging population, where over 90% of food is imported. This review examines the targeted surveillance and control efforts implemented under the One Health framework to combat antimicrobial resistance (AMR). Between 2010 and 2023, surveillance revealed a prevalence of extended-spectrum-beta-lactamase-producing Escherichia coli (ESBL-E.coli) in tested pigs (51.5%) and chickens (86.3%). Alarmingly, carbapenemase-producing E. coli was increasingly detected in pigs (<5 to 19.2% from 2017 to 2023). For other food items, ESBL-producing Enterobacterales were found in sashimi (11.5%), sushi (4.8%) ready-to-eat (RTE) vegetables (26.9%), RTE cut fruits (5.6%), braised dishes (19.8%), and roast meat (2.4%). Mean antimicrobial consumption in food animals was 113.4mg/kg target animal biomass for pigs from 2019 to 2022. Antimicrobial consumption in hospitals and community, expressed as defined daily doses per 1,000 inhabitants per day, declined from 20.4 to 13.8 during the COVID-19 pandemic, and gradually rebounded to 17.1 in 2023. In residential care homes for the elderly (RCHE), MRSA prevalence rapidly escalated from 2.8 to 48.7% between 2005 and 2021, triggering a pilot MRSA decolonization program in 257 RCHEs, which led to a significant reduction in community-onset MRSA infections (from 3.526 to 2.632 per 1,000-resident-days,p<0.005) and MRSA bacteremia (from 0.322 to 0.197 per 1,000-resident-days,p=0.025). These findings highlight the challenges in the control of ESBL and carbapenemase-producing E. coli in animals, compliance with food hygiene measures, and infection control in overcrowded and understaffed RCHE or hospitals in perpetuating MRSA infections in healthcare settings.

Antimicrobial Resistance and Genomic Insights into Enterococcus faecalis Isolates from Broilers and Their Handlers in Punjab, India

Enterococcus faecalis, a common constituent of human and animal gut microbiota, has emerged as a significant pathogen due to its antimicrobial resistance (AMR) capabilities. This study investigates AMR profiles, virulence factors, and genetic diversity of E. faecalis isolates from broiler farms in Ludhiana, Punjab, India, to explore transmission dynamics between poultry and handlers. A total of 240 samples were collected from 20 farms, comprising 200 broiler droppings, 34 hand swabs from poultry handlers, and 6 human stool samples. Selective media and standard microbiological techniques were employed to isolate and identify E. faecalis. Whole genome sequencing (WGS) was performed on representative isolates to uncover antimicrobial resistance genes (ARGs) and virulence factors. E. faecalis was isolated from 47% of broiler droppings and 26.47% of handler hand swabs, whereas no isolates were recovered from stool samples. High resistance was observed for erythromycin (96.11%), tetracycline (78.64%), ciprofloxacin (76.69%), streptomycin (76.69%), and linezolid (65.04%), with 83.49% of isolates exhibiting multidrug resistance (MDR). Vancomycin resistance genes (vanC1-34.95% and vanC2/C3-9.70%) were also detected. WGS analysis of four isolates identified ARGs such as dfrE, efrA, vanT gene in vanG cluster, vanY gene in vanB cluster, ermB, tet45, tetM, tetA, aac(6')-Ie-aph(2″)-Ia, ant(4')-Ib, aph(3')-Ia, sul1, sul3, mphA, qnrS1, and catA8, as well as virulence factors associated with biofilm formation, adherence, capsule formation, and protease production. Sequence typing identified was ST-1866, ST-7317, and ST-403, with ST-7317 common between broiler droppings and handler swab isolates, indicating potential transmission. While these findings highlight poultry environments as reservoirs for MDR E. faecalis, the directionality of transmission (zoonotic vs. reverse zoonotic) remains unclear. This underscores the need for expanded surveillance and molecular studies to better understand transmission dynamics and mitigate risks to farm workers and public health.

Environmental fate of antibiotic resistance genes in livestock farming

As emerging environmental pollutants, antibiotic resistance genes (ARGs) are prevalent in livestock farms and their surrounding environments. Although existing studies have focused on ARGs in specific environmental media, comprehensive research on ARGs within farming environments and their adjacent areas remains scarce. This review explores the sources, pollution status, and transmission pathways of ARGs from farms to the surrounding environment. Drawing on the "One Health" concept, it also discusses the potential risks of ARGs transmission from animals to human pathogens and the resulting impact on human health. Our findings suggest that the emergence of ARGs in livestock farming environments primarily results from intrinsic resistance and genetic mutations, while their spread is largely driven by horizontal gene transfer. The distribution of ARGs varies according to the type of resistance genes, seasonal changes, and the medium in which they are present. ARGs are disseminated into the surrounding environment via pathways such as manure application, wastewater discharge, and aerosol diffusion. They may be absorbed by humans, accumulating in the intestinal microbiota and subsequently affecting human health. The spread of ARGs is influenced by the interplay of microbial communities, antibiotics, heavy metals, emerging pollutants, and environmental factors. Additionally, we have outlined three control strategies: reducing the emergence of ARGs at the source, controlling their spread, and minimizing human exposure. This article provides a theoretical framework and scientific guidance for understanding the cross-media migration of microbial resistance in livestock farming environments.

Quantifying national burdens of foodborne disease-Four imperatives for global impact

Estimates of national burdens of the foodborne disease (FBD) inform country-level food safety policies, ranking infectious and non-infectious FBD hazards in terms of health and socioeconomic impact to mitigate FBD burdens. Using relevant publications on FBD burdens from scientific literature, this review contends that four major imperatives (health, economic, planetary boundaries, governance) argue for a sustainable programme to quantify national FBD burdens. FBD disproportionately affects children under five years of age, and low- and middle-income countries. The economic costs are significant and include medical care, child development, lost productivity and international trade losses. Climatic changes and environmental contamination cause socio-ecological disruptions, increasing risk factors for FBD. Good governance promotes food safety initiatives, addressing in part under-diagnosis and underreporting. Strengthening national policies on FBD surveillance and burden estimation can promote food safety policies and address the global and national imperatives for FBD control. Evidence-based educational and regulatory interventions for FBD can promote improvements in the health and socioeconomic circumstances of the most vulnerable.

Antibiotics in the global river system arising from human consumption

The presence of antibiotics in surface waters poses risks to aquatic ecosystems and human health due to their toxicity and influence on antimicrobial resistance. After human consumption and partial metabolism, antibiotic residues are excreted and undergo complex accumulation and decay processes along their pathway from wastewater to natural river systems. Here, we use a global contaminant fate model to estimate that of the annual human consumption of the 40 most used antibiotics (29,200 tonnes), 8,500 tonnes (29%) are released into the river system and 3,300 tonnes (11%) reach the world's oceans or inland sinks. Even when only domestic sources are considered (i.e. not including veterinary or industrial sources), we estimate that 6 million km of rivers worldwide are subject to total antibiotic concentrations in excess of thresholds that are protective of ecosystems and resistance promotion during low streamflow conditions, with the dominant contributors being amoxicillin, ceftriaxone, and cefixime. Therefore, it is of concern that human consumption alone represents a significant risk for rivers across all continents, with the largest extents found in Southeast Asia. Global antibiotic consumption has grown rapidly over the last 15 years and continues to increase, particularly in low- and middle-income countries, requiring new strategies to safeguard water quality and protect human and ecosystem health.

Distribution of Antimicrobial Resistance and Biofilm Production Genes in the Genomic Sequences of S. aureus: A Global In Silico Analysis

Background:Staphylococcus aureus constitutes a significant public health threat due to its exceptional adaptability, antimicrobial resistance (AMR), and capacity to form biofilms, all of which facilitate its persistence in clinical and environmental settings. Methods: This study undertook an extensive in silico analysis of 44,069 S. aureus genomic sequences acquired from the NCBI database to assess the global distribution of biofilm-associated and resistance-associated genes. The genomes were categorized into human clinical and environmental groups, with clinical samples representing a predominant 96%. Results: The analysis revealed notable regional discrepancies in sequencing efforts, with Europe and North America contributing 76% of the genomes. Key findings include the high prevalence of the ica locus, which is associated with biofilm formation, and its robust correlation with other genes, such as sasG, which was exclusively linked to SCCmec type IIa. The AMR gene analysis revealed substantial genetic diversity within environmental samples, with genes like vga(E) and erm being identified as particularly prominent. The clonal complex analysis revealed ST8 (USA300) and ST5 as the predominant types in human clinical isolates, while ST398 and ST59 were most frequently observed in environmental isolates. SCCmec type IV was globally prevalent, with subtype Iva being strongly associated with ST8 in North America and subtype IVh with ST239 in Europe. Conclusions: These findings underscore the dynamic evolution of S. aureus via mobile genetic elements and highlight the necessity for standardized metadata in public genomic databases to improve surveillance efforts. Furthermore, they reinforce the critical need for a One Health approach in monitoring S. aureus evolution, particularly concerning the co-dissemination of biofilm and resistance genes across various ecological niches.

The future of antibiotic use in livestock

Governments worldwide have pledged to reduce antimicrobial use in the agri-food system. This study projects global livestock antibiotic use quantities through 2040 under various scenarios. This work indicates that under a business-as-usual scenario, global antibiotic use could reach ~143,481 tons by 2040, representing a 29.5% increase from the 2019 baseline of ~110,777 tons. However, alternative scenarios suggest that these projections could vary by +14.2% to -56.8%, depending on changes in livestock biomass and antibiotic use intensity. A key contribution of this research is the development of the Livestock Biomass Conversion method, a novel indicator offering improved accuracy in estimating livestock biomass. The findings have important policy implications, highlighting that meaningful reductions in antibiotic use quantity can only be achieved through coordinated efforts targeting both antibiotic use intensity and livestock biomass.

Feeding systems influence the rumen resistome in yaks by changing the microbiome

The rumen microbiome serves as a reservoir of antibiotic-resistance genes (ARGs) with significant implications for public health. This study aimed to investigate the effects of different feeding systems on the rumen resistome in yaks. Yaks that grazed naturally on pasture were used as controls, while the experimental yaks were housed in a high-density pen environment and fed a specially designed diet to optimally meet their nutritional requirements, with increased interactions with farm workers. Metagenomic analysis was performed to assess changes in the rumen microbiome and resistome. Dietary factors influencing changes in the rumen microbiome and resistome were identified. A greater variety of microbiomes associated with carbohydrate digestion was found in yaks under a house-feeding system, such as Stomatobaculum longum and Succiniclasticum ruminis. Although grazing yaks exhibited various dominant antibiotic resistance genes (ARGs) at the class level, house-fed yaks were mainly enriched with tetracycline-resistant genes. A random forest model identified specific ARG signatures for each group, such as Sent_cmlA and Sliv_cmlR (Phenicol) and vanHD (Glycopeptide) prevalent in grazing yaks, while tet44, tetW, tetW/N/W, and tet40 were abundant in house-fed yaks. ARG interactions varied by feeding system, with signature ARGs in each group showing distinct correlations. Nevertheless, strong correlations among ARGs existed regardless of the treatments, such as the positive correlation between tetW and tetW/N/W in both groups. The rumen microbiome was strongly associated with the resistome, especially regarding abundant microbiomes and ARGs. Proteobacteria carrying ARGs were observed in grazing yaks, while Firmicutes served as hosts for ARGs in yaks under a housed feeding system. The specific bacteria contributing to the distinct ARGs in each group were identified. For instance, members of Firmicutes (Clostridium tepidiprofundi) carried their ARG signatures, such as tet44. These findings emphasized that diet, along with environmental factors and farmworker interactions, contributed to changes in the rumen resistome of yaks. This study is the first to discuss how multiple factors within a feeding regime influence the gut resistome, highlighting the drawbacks of intensive feedings with respect to the gut resistome.

Rationally designed highly amphipathic antimicrobial peptides demonstrating superior bacterial selectivity relative to the corresponding α-helix peptide

De novo design of antimicrobial peptides is a pivotal strategy for developing new antibacterial agents, leveraging its rapid and efficient nature. (XXYY)n, where X represents cationic residues, Y denotes hydrophobic residues, and n varies from 2 to 4, is a classical α-helix template. Based on which, numerous antimicrobial peptides have been synthesized. Herein, we hypothesize that the amphipathy of this type of α-helix template can be further enhanced based on the principles of α-helical protein folding, characterized by a rotation occurring every 3.6 amino acid residues, and propose the highly amphipathic template XXYYXXYXXYYX (where X represents cationic residues and Y denotes hydrophobic residues). Accordingly, the amino acid composition and arrangement of the α-helix peptide (RRWF)3 are adjusted, yielding the highly amphipathic counterpart H-R (RRWFRRWRRWFR). The structure-activity relationship of which is further explored through the substitution of residues at positions 8 and 12. Notably, the highly amphipathic peptides exhibit enhanced antimicrobial activity and reduced hemolytic toxicity compared to (RRWF)3, resulting in superior bacterial selectivity. The most highly amphipathic peptide, H-R, demonstrates potent activity against biofilms and multidrug-resistant bacteria, low propensity for resistance, and high safety and effectiveness in vivo. The antibacterial mechanisms of H-R are also preliminarily investigated in this study. As noted, H-R represents a promising antimicrobial candidate for addressing infections associated with drug-resistant bacteria.

A Surface-Enhanced Raman Spectroscopy Platform Integrating Dual Signal Enhancement and Machine Learning for Rapid Detection of Veterinary Drug Residues in Meat Products

The detection and quantification of veterinary drug residues in meat remain a significant challenge due to the complex background interference inherent to the meat matrix, which compromises the stability and accuracy of spectroscopic analysis. This study introduces an advanced label-free surface-enhanced Raman spectroscopy (SERS) platform for the precise identification and quantification of veterinary drugs. By employing a dual enhancement strategy involving sodium borohydride activation and calcium ion-deuterium oxide guidance, this platform achieves the efficient capture and signal amplification of drug molecules on highly active nanoparticles. High-quality SERS spectra were obtained for carprofen, doxycycline hydrochloride, chloramphenicol, and penicillin G sodium salt, enabling accurate classification and interference suppression. In addition, the application of machine learning algorithms, including PCA-LDA, heatmap, and decision tree modeling, allows for accurate differentiation of mixed drug samples. Quantitative analyses in meat samples were achieved through Raman intensity ratios and multivariate curve resolution-alternate least-squares (MCR-ALS) analysis, with results showing high consistency with high-performance liquid chromatography (HPLC) measurements. These findings highlight the potential of this SERS-based platform for accurate and rapid detection of multicomponent veterinary drug residues in complex food matrices.

A Bacteria-Targeting Supramolecular Nanophotosensitizer for Combating Multidrug Resistant Bacteria

The increasing prevalence of multidrug-resistant bacteria is a significant global health threat. In contrast to conventional antibiotic treatments, photodynamic therapy (PDT) offers a promising alternative by reducing the bacterial adaptability to antibiotics and bactericides. However, traditional photosensitizers encounter poor antimicrobial efficacy due to poor hydrophilicity of photosensitizers, short lifespan, narrow diffusion radius of reactive oxygen species (ROS), and the risk of exacerbating inflammation. In this study, we report a bacterial-targeting supramolecular nanophotosensitizer for combating multidrug resistant bacteria. The nanophotosensitizer, formed through host-guest interactions and self-assembly of tetra-cyclodextrin-modified silver porphyrin (AgTPP-CD4), adamantyl-modified phenylboronic acid (Ad-PBA), and curcumin (Cur), can effectively target and kill methicillin-resistant Staphylococcus aureus (MRSA). Moreover, it reduces inflammation and promotes wound healing in MRSA-infected wounds without inducing drug resistance. The combination of supramolecular chemistry and targeted PDT offers a promising strategy for combating multidrug-resistant bacterial infections.

Escherichia coli in Brazilian Poultry Fecal Samples: Co-Carriage of Fosfomycin and ESBL Resistance

Background/Objectives: Fosfomycin, a critically important antibiotic, is widely used to treat urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Escherichia coli, particularly those producing extended-spectrum β-lactamases (ESBLs). However, its increasing use in livestock has raised concerns about resistance development and global dissemination. This study investigated fosfomycin resistance in E. coli isolates from 400 fecal samples collected at Brazilian broiler farms. Methods: The samples were tested for their minimum inhibitory concentration (MIC), screened with PCR for specific resistance genes, and selected isolated were whole genome sequenced. Results: Phenotypic resistance to fosfomycin was detected in 19% (75/400) of the isolates, while the fosA3 gene, encoding enzymatic resistance, was identified in 4% (16/400) via PCR screening. Long-read sequencing of seven fosA3-positive isolates revealed the presence of fosA3 on IncFII and IncX plasmids, often co-located with blaCTX-M-55 within a conserved IS26-flanked transposon. Comparative genomic analysis of 133,541 global E. coli genomes from EnteroBase showed that 35% harbored similar transposon structures, with 2% carrying fosA3. These fosA3-positive isolates were significantly associated with South America and exhibited high co-carriage of ESBL genes, particularly in environmental and poultry-associated isolates. Phylogenetic analysis demonstrated no clustering by host or geographic origin, highlighting the global dissemination of these resistance determinants. Conclusions: Our findings emphasize the role of poultry production in the spread of fosfomycin and ESBL resistance, driven by transmissible plasmids and co-selection with third-generation cephalosporins. Improved antimicrobial stewardship, surveillance programs, and alternative management strategies are urgently needed to mitigate the dissemination of resistance and preserve fosfomycin's efficacy in human medicine.

The prevalence, distribution, and diversity of Salmonella isolated from pork slaughtering processors and retail outlets in the Shandong Province of China

Salmonella is a foodborne pathogen of global significance and is highly prevalent in pork. This study investigated the prevalence, contamination distribution, virulence genes and antibiotic resistance of Salmonella in 3 pork processors in the Shandong Province of China. Samples were collected from 13 different sampling sources across the slaughter procedures (600 samples) as well as at retail outlets supplied by these processors (45 samples). The prevalence was 18.9 % among all the samples, with the highest prevalence observed in feces (40.0 %), lairage pens (38.0 %), and hides (34.0 %). A total of 6 serotypes were identified, with S. Rissen (46.3 %) and S. typhimurium (32.0 %) found to be the most prevalent serotypes. 86.8 % of Salmonella isolates were multi-drug resistant, with the majority of strains resistant to erythromycin, sulfisoxazole, and ampicillin. The multilocus sequence typing analysis revealed 6 STs were obtained from 45 isolates, with the dominant type ST469 accounting for 40.0 % of the total, which suggested a high possibility of cross-contamination between the plant processing chain and retail outlets. This work reveals the prevalence and correlation of Salmonella isolates between pork slaughter and retail outlets and acts as a case-study for stakeholders wishing to improve pork supply chain hygiene, control cross-contamination between the various slaughtering processes, and obtain continuous updates on Salmonella surveillance.

Observed Prevalence and Characterization of Fluoroquinolone-Resistant and Multidrug-Resistant Bacteria in Loggerhead Sea Turtles (Caretta caretta) from the Adriatic Sea

Background/Objectives: Antimicrobial resistance (AMR) is a major global health concern with profound implications for human, animal, and environmental health. Marine ecosystems are emerging as reservoirs of resistant bacteria due to contamination from anthropogenic activities. This study aimed to investigate fluoroquinolone-resistant and multidrug-resistant bacteria in loggerhead sea turtles (Caretta caretta). Methods: Cloacal swabs were collected from 28 loggerhead sea turtles at a rescue center in southern Italy. Swabs were cultured in nutrient media supplemented with enrofloxacin. Bacterial isolates underwent identification by MALDI-TOF, antimicrobial susceptibility testing, and assessment for multidrug resistance. Conjugation experiments evaluated the transferability of enrofloxacin resistance. Results: Thirty-six enrofloxacin-resistant bacterial strains were isolated from 22 turtles. The identified species included Vagococcus fluvialis (13 strains), Citrobacter freundii (5), Escherichia coli (6), and Pseudomonas mendocina (4). Thirty-five isolates exhibited multidrug resistance, with resistance to critically important antibiotics such as imipenem observed in C. freundii and Enterobacter faecium. Conjugation experiments showed no transfer of resistance genes. Conclusions: The study highlights the prevalence of fluoroquinolone-resistant and multidrug-resistant bacteria in C. caretta, implicating marine environments as reservoirs of AMR. The findings underscore the need for stricter regulation of antimicrobial use and monitoring of resistance dissemination in marine ecosystems. These results contribute to understanding AMR dynamics within the One Health framework, emphasizing the interconnectedness of environmental, animal, and human health.

Understanding the bovine mastitis co-infections: Coexistence with Enterobacter alters S. aureus antibiotic susceptibility and virulence phenotype

The World Health Organization recently reported an alarming evolution and spread of antibiotic resistance, a global risk factor recognized as a One Health challenge. In veterinary, the general lack of clear treatment guidelines often leads to antibiotic misuse. Bovine mastitis is responsible for major economic losses and the main cause of antibiotic administration in the dairy industry, favoring the emergence of multi-resistant phenotypes. The complexity of inter-microbial and host-pathogen interactions in the mammary gland, demonstrated by culture-independent techniques, not only complicates the prediction of antibiotic treatment outcomes but also underscores the urgent need for further research in this field. This work evaluated the interactions between S. aureus L33 and Enterobacter sp. L34 obtained from an intramammary co-infection. The behavior of the dual-species culture resembled that of the Enterobacter monoculture in all the evaluated contexts. Most of the selected S. aureus virulence factors and the antibiotic susceptibility were altered by coexisting with Enterobacter. Under the protection of Enterobacter, S. aureus was able to survive upon exposure to concentrations of cloxacillin and other antibiotics that would be bactericidal for the monoculture. This could have serious implications for bacterial clearance of mastitis originating from the underestimated co-infections. These findings highlight the importance of broadening our knowledge of how microbial interactions in intramammary infections could contribute to antibiotic treatments failures. Moreover, they open new perspectives for the design of bovine mastitis therapies that consider the ecological context in order to optimize the antibiotic usage, improve the success rates and reduce antibiotic resistance.

Emergence of two novel tmexCD-toprJ subtypes mediating tigecycline resistance in the megaplasmids from Pseudomonas putida

The widespread antimicrobial resistance (AMR) problem poses a serious health threat, leaving few drug choices, including tigecycline, to treat multidrug resistance pathogens. However, a plasmid-borne tigecycline resistance gene cluster, tmexCD1-toprJ1, emerged and conferred tigecycline resistance. In this study, we identified two novel subtypes, tmexCD2.3-toprJ2.3 and tmexCD2.4-toprJ1b, obtained from three chicken-origin Pseudomonas putida isolates. Two types of megaplasmids were found as the vital vehicle of these tmexCD-toprJ variants. Phylogenetic and genomic analysis indicated the two variants were mainly distributed in Pseudomonas and acted as an evolved intermediated state precursor of tmexCD2-toprJ2. Further gene cloning assay revealed both the expression of tmexCD2.3-toprJ2.3 and tmexCD2.4-toprJ1b could confer multiple antimicrobial resistance, mediating 8- to 16-fold increase of tigecycline MIC. Importantly, two key nucleotide differences in promoter region influence the promoter activity between PtmexC2.3 and PtmexC2.4, while the downregulation effect of TNfxB on the transcriptional expression level of tmexCD2.3-toprJ2.3 and tmexCD2.4-toprJ1b were observed. The emergency of two novel tmexCD-toprJ variants necessitates preventive measures to curb their spread and highlights concerns about more emerging tmexCD-toprJ variants.

Dirt floors and domestic animals are associated with soilborne exposure to antimicrobial resistant E. coli in rural Bangladeshi households

Soil can harbor enteropathogens and antimicrobial-resistant organisms in settings with domestic animals. We enrolled 49 households with young children (28 soil floors, 21 concrete floors) in Bangladesh and recorded animal ownership/management. Staff swabbed the floor of children's sleeping area with a sterile sponge and collected floor dust and a child hand rinse. We used IDEXX QuantiTray/2000 with and without cefotaxime supplementation to enumerate cefotaxime-resistant and generic E. coli . There was 8.0 g/m 2 of dust on soil floors vs. 0.2 g/m 2 on concrete floors (p-value=0.005). We detected E. coli on 100% of soil vs. 86% of concrete floors and cefotaxime-resistant E. coli on 89% of soil vs. 43% of concrete floors (p-values<0.05). Cefotaxime-resistant E. coli prevalence on floors was 36% in compounds without animals, 79% in compounds with animals and 100% if animals stayed indoors overnight or the floor had animal feces; associations were strongest for chickens. In multivariable models, generic and cefotaxime-resistant E. coli counts were 1.5-2 log higher on soil vs. concrete floors, and counts on floors and child hands were 0.17-0.24 log higher for every 10 additional chickens owned (p-values<0.05). Efforts to mitigate infections and antimicrobial resistance in low-income countries should test flooring improvements and hygienic animal management.

Synopsis

In rural Bangladeshi households, generic and cefotaxime-resistant E. coli were more common on soil floors than concrete floors and among households with higher cohabitation intensity with domestic animals, especially chickens.

Antimicrobial Susceptibility Profile and Extended-Spectrum Beta-Lactamase Phenotype of E. coli Isolated From Poultry

Bacterial resistance to antibiotics is increasing globally, with the food-animal sector (FAS) playing a key role. Knowledge of the antimicrobial resistance (AMR) of microbes from the FAS is important in the development of country-specific methods to minimize the AMR burden. In Ghana, there is limited data on the susceptibility of FAS bacteria to frequently used antimicrobials. We evaluated the susceptibility of 58 Escherichia coli isolates obtained from chickens to nine antibiotics and further assessed their potential to produce extended-spectrum beta-lactamase (ESBL). The Kirby-Bauer disc diffusion and combined disc methods were used following the Clinical and Laboratory Standards Institute guidelines. Nearly all isolates showed high resistance (> 50%) to all the antibiotics except gentamicin, to which more than two-thirds (n = 48, 83%) were susceptible. Resistance to streptomycin, tetracycline, and ampicillin was observed to be 93%, 97%, and 100%, respectively. All isolates were multidrug resistant. Over one-third of the isolates (n = 22, 37.9%) were resistant to seven classes of antibiotics, and a substantial proportion (n = 12, 20.7%) exhibited resistance to all eight antimicrobial classes. None of the isolates was detected as an ESBL producer. Most farms (86%) did not have a footbath, and the majority (71%) changed the bedding material after 4 weeks. Free-range chickens were kept on 80% of the farms. The high resistance to frequently used antibiotics suggests long-term use of these antimicrobials, which may be attributed to poor biosecurity practices that may be exposing the birds to frequent infections. There is a need to educate farmers on the prudent use of antibiotics and adherence to good biosecurity practices.

The impact of health and technology shifts on antibiotic use among the elderly in Thailand

The utilization of antibiotics among the geriatric population in Thailand has been markedly influenced by the COVID-19 pandemic. This investigation sought to analyze the correlation between antibiotic utilization and determinants such as pharmacy density, healthcare workforce, household internet accessibility, and income during the period of 2021-2023. A spatial examination employing panel regression was performed on data derived from Thailand's National Statistical Office Health and Welfare Survey 2023, encompassing all 77 provinces. The research scrutinized antibiotic usage trends among individuals aged 60 and above, associating them with diverse socioeconomic and healthcare access metrics. Notable spatial and temporal variations in antibiotic utilization were detected. The physician ratio demonstrated a negative association with antibiotic usage (Coefficient=- 0. 613, P = 0.035), while household internet accessibility showed a positive relationship (Coefficient = 0.003, P = 0.001). Household income exhibited a slight negative effect (Coefficient=- 0.0002, P = 0.024). No statistically significant associations were found between antibiotic usage and pharmacy density or nurse ratio. The study clarifies complex interrelations between healthcare accessibility, socioeconomic determinants, and antibiotic usage among the elderly in post-COVID-19 Thailand. These results indicate the necessity for targeted interventions to foster judicious antibiotic utilization, including enhancements in healthcare accessibility, the development of dependable digital health infrastructures, and the execution of income-sensitive health education initiatives.

Impact of different continuous fertilizations on the antibiotic resistome associated with a subtropical triple-cropping system over one decade

The prevalence of antibiotic resistance genes (ARGs) in agricultural soils has garnered significant attention. However, the long-term impacts of various nitroge (N)-substitution fertilization regimes on the distribution of soil ARGs and their dominant drivers in a subtropical triple-cropping system remain largely unexplored. This study employed a metagenomic approach to analyze soil ARGs, microbial communities, mobile genetic elements (MGEs), and viruses from a maize-maize-cabbage rotation field experiment with five different fertilization regimes. Soil samples were collected in 2012 and 2021. A total of 615 unique ARG subtypes were identified, with multidrug, bacitracin, and rifamycin resistance genes being the most abundant. Notably, ARG types. the continuous application of fresh chicken manure (CM) over 10 years significantly increased both the count of unique ARG subtypes and the total ARG abundance compared to other fertilization regimes, such as inorganic fertilizer and composted chicken manure. Specifically, the abundance of genes associated with antibiotic target replacement (e.g., sul1 and sul2) in the CM-treated soil rose by 8.83-fold from 2021 to 2012. Our random forest analysis revealed that the abundance of three MGEs (QacEdelta, plasmids, and IstB), two viral families (Myoviridae and Podoviridae), two bacterial phyla (Chloroflexi and Planctomycetes), and two environmental factors (pH and soil organic matter (SOM)) significantly influenced the distribution of ARGs. Furthermore, variance decomposition analysis underscored the critical roles of the three MGEs and the two viral families in the dissemination of ARGs, suggesting that horizontal gene transfer (HGT) may play a key role in ARG spread. These findings enhance our understanding of how different fertilization practices influence ARG dissemination in subtropical triple-cropping agroecosystems over the long term and provide valuable insights for optimizing fertilization management strategies.

Epidemic trend of Salmonella from swines and broilers in China from 2014 to 2023 and genetic evolution analysis of ESBLs-producing strains

Introduction

In recent years, the epidemic trend and antimicrobial resistance of Salmonella from swines and broilers, especially the extended-spectrum β-lactamase (ESBLs)-producing Salmonella, pose a serious threat to human and animal health.

Methods

In this study, we employed serotype identification, drug sensitivity testing, detection of ESBL-producing strains, and whole genome sequencing to analyze the epidemiological trends and drug resistance of Salmonella isolates from swines and broilers, as well as the genetic evolutionary relationships of ESBL-producing strains in China from 2014 to 2023.

Results

The results showed that the most prevalent serotypes of Salmonella from swines and broilers in China in recent 10 years were S. Typhimurium (133/381, 34.91%) and S. Enteritidis (156/416, 37.50%), respectively. Overall, 80.58% strains from swines and 70.67% strains from broilers were multidrug resistant. The multidrug resistance rate (MDR) showed a downward trend. The types of drugs exhibiting an increasing trend in resistance rates among Salmonella from broilers (7) were significantly greater than those from swines (2). The detection rates of ESBLs-producing Salmonella from swines and broilers were 9.45 and 29.58%, respectively, with the former showing a downward trend and the latter showing an upward trend. The drug resistance phenotype of Salmonella produced in ESBLs from swines and broilers is consistent with the results of the resistance genes carried. Whole genome sequencing analysis revealed that 36 swine-derived ESBL-producing Salmonella strains contained 6 ST-types and 13 cgST-types, among which ST34 and ST17 were dominant ST-types; a total of 35 resistance genes across 11 classes, blaCTX-M-14, blaTEM-1B, and blaCTX-M-65 were the predominant subtypes of β-lactam resistance genes. 126 broiler-derived ESBL-producing Salmonella strains included 19 ST-types and 37 cgST-types, with ST17 and ST198 as the dominant ST-types; a total of 52 resistance genes belonging to 12 classes, blaCTX-M-55, blaCTX-M-65, blaTEM-1B, and blaOXA-1 identified as the major subtypes of β-lactam resistance genes.

Discussion

This suggests that we should thoroughly implement management policies aimed at reducing the use of veterinary antimicrobials. Additionally, we should enhance research on traceability technology and the abatement of resistance genes, thereby providing support for the effective prevention and control of the spread of Salmonella and its drug resistance.

High temperatures promote antibiotic resistance genes conjugative transfer under residual chlorine: Mechanisms and risks

The impact of residual chlorine on the dissemination of antibiotic resistance during the distribution and storage of water has become a critical concern. However, the influence of rising temperatures attributed to global warming on this process remains ambiguous, warranting further investigation. This study investigated the effects of different temperatures (17, 27, 37, and 42°C) on the conjugative transfer of antibiotic resistance genes (ARGs) under residual chlorine (0, 0.1, 0.3, and 0.5 mg/L). The results indicated that high temperatures significantly increased the conjugative transfer frequency of ARGs in intra-species under residual chlorine. Compared to 17°C, the transfer frequencies at 27°C, 37°C, and 42°C increased by 1.07-2.43, 1.20-4.80, and 1.24-2.82 times, respectively. The promoting effect of high temperatures was mainly due to the generation of reactive oxygen species, the triggered SOS response, and the formation of pilus channels. Transcriptomic analysis demonstrated that higher temperature stimulates the electron transport chain, thereby enhancing ATP production and facilitating the processes of conjugative, as confirmed by inhibitor validation. Additionally, rising temperatures similarly promoted the frequency of conjugative transfer in inter-species and communities under residual chlorine. These further highlighted the risk of antibiotic resistance spread in extreme and prolonged high-temperature events. The increased risk of antibiotic resistance in the process of drinking water transmission under the background of climate warming is emphasized.

Selection of resistant coliform bacteria in the intestine of pigs following flock versus individual treatment with neomycin against post-weaning diarrhoae or amoxicillin against umbilical infection

The aim of this study was to investigate the effect of avoiding flock treatment on resistance levels in the intestine of pigs. To investigate this, studies, each in two pig herds, quantified resistant coliforms by culture method in pigs treated as flock or as individual animal treatments orally with neomycin against post-weaning diarrhea (PWD) or intramuscularly with amoxicillin to prevent umbilical infection. Individual oral treatment against PWD did not lead to a lower number or proportion of resistant coliforms compared to flock treated pigs in any of the two herds under study, despite reduction of treatment incidences to 32% and 35% of pigs. After intramuscular treatment against umbilical infection, fewer resistant bacteria were seen in individually treated piglets in a herd with low treatment incidence (33%), while no reduction of resistant coliform bacteria compared to flock treatment was observed in the other herd with higher treatment incidence (86%). Thus, individual animal treatment reduced the amount of antimicrobial used, but concurrent reduction in resistant coliform bacteria was not always observed.

A slime-inspired phycocyanin/κ-carrageenan-based hydrogel bandage with ultra-stretchability, self-healing, antioxidative, and antibacterial activity for wound healing

Hydrogels have attracted extensive attention as wound dressing owing to their excellent multifunctionality, flexibility, and biocompatibility. Due to the frequent movement and stretching of skin as well as complex surface of wound, traditional wound dressings have difficulty to adapt to motion and irregular wounds. Furthermore, excessive reactive oxygen species (ROS) and bacterial infection can induce delayed wound healing. To this end, we developed a set of versatile phycocyanin-based dual network hydrogels (PPC hydrogels) with polyvinyl alcohol (PVA) and κ-carrageenan (CRG) as substrate via forming of borate ester bonds, hydrogen bonds, and electrostatic interaction. The PPC hydrogels not only possessed adaptivity, ultra-stretchability (7036.12 %), efficient self-healing and injectability, but also possessed antioxidative and antibacterial capacities conferred by C-phycocyanin (PC) and rhein. Moreover, the hydrogels also exhibited excellent hemostatic ability and high biocompatibility. More remarkably, the PPC-I hydrogel could accelerate wound healing by effect of anti-inflammation (downregulating TNF-α and IL-6) and promoting collagen deposition and angiogenesis (upregulating CD31), which may be utilized as hydrogel bandages and applied to motion and irregular wounds, thereby promising the application prospect of the hydrogels as wound dressing.

Effects of UVC doses on the removal of antimicrobial resistance elements from secondary treated sewage

Wastewater treatment plants (WWTPs) currently face major challenges toward the removal of microcontaminants and/or microbial matrices and consequently play an important role in the potential dissemination of biological resistance in freshwater. The ultraviolet (UV) system is a tertiary treatment strategy increasingly applied worldwide, although many studies have shown that disinfected effluent can still contain antibiotic-resistant bacteria and resistance genes. Therefore, to better understand the effects of UV radiation doses on the removal of all resistance elements (antibiotics, antibiotic-resistant bacteria, and antibiotic resistance genes), the present study was designed using a pilot-scale photoreactor. The UV doses could be varied to investigate whether there is an optimal UV dose capable of removing all resistance elements and also if the UV dose frequently applied in full-scale systems is able to reduce the resistance elements. The effect of different UV doses (A, 0-10 mJ/cm2; B, 10-15 mJ/cm2; and C, > 15 mJ/cm2) in a pilot-scale photoreactor on the removal of antibiotics, antibiotic-resistant bacteria, and genes from the effluent of a UASB reactor followed by a biological trickling filter system (UASB-TF) fed with real sanitary sewage was investigated. Samples of influent and effluent from the UVC photoreactor were collected, and the concentration levels of norfloxacin (NOR), ciprofloxacin (CIP), and levofloxacin (LEV) were assessed. The qnrB, sul1, ermB, integron-integrase (intI1), and 16S rRNA genes, total heterotrophic bacteria (THB), and bacterial resistance to azithromycin and sulfamethoxazole were also investigated. Results indicated that LEV and intI1 were found in the highest median concentrations in the photoreactor influent. Although most antibiotics (NOR and CIP) and ARGs (intI1, 16S rRNA, and qnrB) were apparently better removed with the highest UV dose (> 15 mJ/cm2) applied, except for LEV, sul1, and ermB genes, the Kruskal-Wallis test reported no significant difference between low and high doses. ARB removal (from 80 to 100%) was observed at all UV doses. Principal component analysis (PCA) suggested a clear pattern of pollutant groups, i.e., antibiotics, ARG, and ARB, which exhibited low (median of 8-16%), medium (37-96%), and high (> 97%) removal percentages, respectively. These results demonstrated that UVC photoreactors can be an alternative to complement biological treatment in sewage treatment plants at the dose normally applied in full-scale WWTPs (> 15 mJ/cm2). However, there was no optimal single dose capable of removing all the resistance elements investigated.

Insights into the ecological and climate crisis: Emerging infections threatening human health

The Anthropocene era is marked by unprecedented human-induced alterations to the environment, resulting in a climate emergency and widespread ecological deterioration. A staggering number of up to one million species of plants and animals are in danger of becoming extinct, which includes over 10 % of insect species and 40 % of plant species. Unrestrained release of greenhouse gases, widespread deforestation, intense agricultural practices, excessive fishing, and alterations in land use have exceeded the ecological boundaries that were once responsible for humanity's wellbeing. As per the Intergovernmental Panel on Climate Change (IPCC), existing policies are expected to result in a minimum rise in global temperature of +2 °C, with more recent assessments indicating a potential increase of up to +2.9 °C. The effects of climate change and ecological degradation on the formation of diseases are complex and have multiple aspects. Deforestation diminishes biodiversity and compels wildlife to come into greater proximity with humans, hence promoting the transmission of zoonotic diseases. Climate change intensifies these impacts by modifying the habitats of disease carrying organisms, resulting in the expansion of vector-borne diseases such as malaria, dengue, and Zika virus into previously unaffected areas. Furthermore, climate change amplifies the occurrence and severity of extreme weather phenomena, which undermines water, sanitation, and hygiene (WASH) practices. This creates an environment conducive to the transmission of waterborne diseases such as cholera in densely populated resettlement camps. Climate-induced disasters contribute to the complexity of epidemiological landscapes, exacerbating antimicrobial resistance and posing a threat to modern medical advancements. This narrative review investigates the complex connections between the ecological-climatic crises and emerging illnesses, offering an overview on how environmental changes contribute to outbreaks that pose a substantial threat to public health.

Knowledge and Perceptions of Antimicrobial Stewardship Concepts Among Final Year Veterinary Students in South Africa

Antimicrobial resistance (AMR) has become a major global public health crisis due to inappropriate use in humans, animals, and crops. Studies to assess the knowledge and perceptions of antimicrobial stewardship (AMS) practices among medical and health care professionals have been conducted, yet this is the first among veterinary students in South Africa. A descriptive study surveyed 147 final year veterinary students at the Faculty of Veterinary Science, University of Pretoria. Of these, 102 completed the questionnaire (69% response rate). Most stated they knew what AMS was, while a minority heard of it for the first time. A small number understood poor hand washing could contribute to AMR. Almost a quarter of students stated their AMS knowledge was poor, and most noted a need for more training. The Bachelor of Veterinary Sciences curriculum should include more material on AMS and AMR to bridge training gaps.

Houseflies (Musca domestica) as vectors of multidrug-resistant, ESBL-producing Escherichia coli in broiler poultry farms of North India: implications for antibiotic resistance transmission

The transmission of antibiotic resistance (AR) from farm animals to healthy human communities, beyond the food chain, is often facilitated by biological vectors, notably houseflies (Musca domestica). This study aimed to evaluate the role of M. domestica collected from commercial broiler chicken farms as a carrier of multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. E. coli were isolated separately from the housefly's external surface (ES) and internal homogenate (IH) to determine the primary AR transmission route within houseflies. Remarkably, 68.6% houseflies harboured E. coli. Isolated E. coli were evaluated for susceptibility to clinically relevant antibiotics and screened for the presence of 22 plasmid-borne AR genes (ARGs) using PCR. Results revealed significant resistance to key antibiotics, with > 70% of isolates resistant to ampicillin and > 50% resistant to tetracycline and nalidixic acid in both ES- and IH-derived E. coli. Notably, a significant prevalence of resistance was observed to third-generation cephalosporins. Additionally, > 80% of E. coli isolates were MDR. A statistically significant difference (unpaired t-test, p < 0.05) was observed in the presence of ESBL-producing E. coli between the houseflies' ES (28.14%) and IH (38.14%). ARGs such as, ampC, tetA, qnrS, strA, strB, and sul3 were frequently detected in both ES- and IH-derived E. coli isolates. Among the ESBL-producing genes, blaCTX-M was the most abundant. Pearson's correlation analysis predicted the ARGs responsible for phenotypic resistance to specific antibiotics. Farm-derived flies harboured a significantly higher number of MDR E. coli (unpaired t-test, p < 0.05) than the ones isolated from flies housing a distant non-farm environment. Conclusively, this study illustrates the role of houseflies as vectors for AR transmission from AR hotspots to human communities.

Genomic and metabolic characterization of Trueperella pyogenes isolated from domestic and wild animals

Trueperella pyogenes is an important bacterial pathogen implicated in infections such as mastitis, metritis, pneumonia, and liver abscesses in both domestic and wild animals, as well as endocarditis and prosthetic joint infections in humans. Understanding the genomic and metabolic features that enable T. pyogenes to colonize different anatomical sites within a host and its inter-kingdom transmission and survival is important for the effective control of this pathogen. We employed whole-genome sequencing, phenotype microarrays, and antimicrobial susceptibility testing to identify genomic, metabolic and phenotypic features, and antimicrobial resistance (AMR) genes in T. pyogenes recovered from different livestock, companion, and wildlife animals. For comparative genomic analysis, 83 T. pyogenes genomes, including 60 isolated in the current study and 23 publicly available genomes were evaluated. These genomes represented T. pyogenes strains originating from 16 different body sites of 11 different animal hosts (e.g., cattle, swine, ovine, deer, bison, horse, chamois, and cat). Additionally, 49 T. pyogenes isolates (cattle, sheep, deer, swine, and cats) were evaluated for phenotypic AMR using disk diffusion, and for metabolic profiling using the Biology GENIII MicroPlates. The T. pyogenes strains were found not to be host- or body site-specific. The presence of conserved virulence genes (plo and fimA), as well as genotypic and phenotypic AMR may contribute to the ability of T. pyogenes to cause infections in livestock, wildlife, and pets. Most of the tested isolates metabolized diverse carbon sources and chemical compounds, suggesting that this metabolic versatility may enhance the survival, competitiveness, and pathogenic potential of T. pyogenes.IMPORTANCETrueperella pyogenes is an important animal pathogen with zoonotic potential, posing a significant health concern to both animals and humans due to its ability to cause infections across different animal host species and tissues. Current understanding of this pathogen's adaptability and survival mechanisms is limited. Here, we evaluated the genomic, virulence, metabolic, and antimicrobial resistance (AMR) characteristics of T. pyogenes recovered from 16 different body sites of 11 different animal hosts (livestock, companion, and wild animals). We identified multiple AMR and virulence genes that may enable T. pyogenes for sustained infection and transmission. Additionally, T. pyogenes strains displayed metabolic versatility which could also contribute to its ability to thrive in diverse environments. Understanding the genomic and metabolic, and AMR characteristics that enable T. pyogenes to colonize different anatomical sites within a host and its transmission between different animal species is important for the effective control of this pathogen.

LC-AMP-I1, a novel venom-derived antimicrobial peptide from the wolf spider Lycosa coelestis

Antibiotic resistance has become a critical concern in recent years, and antimicrobial peptides may function as innovative antibacterial agents to address this issue. In this work, we identified a novel antimicrobial peptide, LC-AMP-I1, derived from the venom of Lycosa coelestis, demonstrating substantial antibacterial properties and minimal hemolytic activity. LC-AMP-I1 was subjected to additional assessment for antibacterial efficacy, anti-biofilm properties, drug resistance, stability, and cytotoxicity in vitro. It exhibited comparable antibacterial efficacy to melittin against six common clinical multidrug-resistant bacteria, effectively inhibiting biofilm formation and disrupting established biofilms. Additionally, LC-AMP-I1 demonstrated minimal bacterial resistance, excellent stability, negligible mammalian cell toxicity, low hemolytic activity, and appropriate selectivity for both normal and tumor cells. When combined with traditional antibiotics, LC-AMP-I1 exhibited additive or synergistic therapeutic effects. In a neutropenic mouse thigh infection model, LC-AMP-I1 exhibited a therapeutic effect in inhibiting bacterial proliferation in vivo. The mechanistic investigation indicated that LC-AMP-I1 could influence bacterial cell membrane permeability at low concentrations and directly disrupt structure-function at high concentrations. The results of this work indicate that LC-AMP-I1 may function as a viable alternative to traditional antibiotics in addressing multidrug-resistant bacteria.

Prevalence and antimicrobial resistant Campylobacter spp. in broiler chicken carcasses and hygiene practises in informal urban markets in a low-income setting

Campylobacteriosis is one of the most commonly reported foodborne diseases and is of particular importance in low-income countries. More data is needed to better understand the epidemiology of Campylobacter spp. in food sold at informal markets, where most people in low-income countries buy their food. This study aimed to determine the prevalence and antimicrobial resistance (AMR) of Campylobacter spp. among broiler chicken carcasses sold at informal urban markets in Uganda and to gain more knowledge about hygienic handling practices and awareness of foodborne bacterial diseases among the market vendors. In total, 120 broiler chicken carcasses from 30 different markets were analysed using ISO 10272 and confirmed by PCR. AMR analyses were performed using the disc diffusion test. Epidemiological data on food safety practices and awareness was collected from the vendors using a questionnaire. Campylobacter spp. was isolated from 66% (79/120) of the carcasses; 32% were C. jejuni, 14% were C. coli and 54% comprised of a mixture of both species. All C. jejuni isolates showed resistance to tetracycline, 88% to ciprofloxacin and 28% to erythromycin. Of the C. coli isolates, 82% showed resistance to tetracycline, 73% to erythromycin and the quinolones ciprofloxacin and nalidixic acid. More than half of the vendors had heard about food-borne illnesses, but none knew about Campylobacter spp., and the knowledge regarding hygienic practices was low. These data calls for urgent interventions to improve food safety, protect the public from foodborne illness, and prevent the spreading of AMR.

Morphometric characteristics of organs of female chickens (Pazo de Vilane) supplemented with Curcuma longa

The breeding and exploitation of chickens at the backyard or commercial family level is an activity of great economic relevance for families in Ecuador. In addition to providing protein of high biological value for food security, it revalues local food resources that could provide productive benefits. With this objective, a study has been conducted in order to explore the effect of C. longa flour on the final weight as well as morphometric characteristics of the organs of female chickens. Therefore, a total of 200 birds were randomly distributed into four homogeneous groups, being Control, basal diet only, followed by T1, basal diet + 1 g/d, T2, basal diet + 2 g/d and T3, basal diet + 3 g/d of C. longa. The data analyzed under a general linear model yielded that including C. longa between 1 or 2 g/d did not differ in the final weight compared to the control (2763 ± 28 g, on average; P < 0.32). In the morphometry of the upper organs, T1 indicated a shorter length of the esophagus (3.7 ± 0.5 mm; P < 0.002) and gizzard (4.9 ± 0.3 mm), but with a larger heart than the other treatments (P < 0.02). In addition, differences were evident in the liver, gallbladder and cecum (P = 0.01 to 0.001) that were more marked when C. longa was administered between 1 or 2 g/d. In conclusion, supplementation of female chickens with C. longa proved to be a potential option to have greater final weights with important findings in the morphometric characteristics that could improve different aspects of their development, productivity and well-being. Therefore, more studies at the level of immunology and histology are recommended to support the benefits of C. longa.

Photodynamic and photothermal bacteria targeting nanosystems for synergistically combating bacteria and biofilms

The escalating hazards posed by bacterial infections underscore the imperative for pioneering advancements in next-generation antibacterial modalities and treatments. Present therapeutic methodologies are frequently impeded by the constraints of insufficient biofilm infiltration and the absence of precision in pathogen-specific targeting. In this current study, we have used chlorin e6 (Ce6), zeolitic imidazolate framework-8 (ZIF-8), polydopamine (PDA), and UBI peptide to formulate an innovative nanosystem meticulously engineered to confront bacterial infections and effectually dismantle biofilm architectures through the concerted mechanism of photodynamic therapy (PDT)/photothermal therapy (PTT) therapies, including in-depth research, especially for oral bacteria and oral biofilm. Ce6@ZIF-8-PDA/UBI nanosystem, with effective adhesion and bacteria-targeting, affords a nuanced bacterial targeting strategy and augments penetration depth into oral biofilm matrices. The Ce6@ZIF-8-PDA/UBI nanosystem potentiated bacterial binding and aggregation. Upon exposure to red-light (RL) irradiation, Ce6@ZIF-8-PDA/UBI showed excellent antibacterial effect on S. aureus, E. coli, F. nucleatum, and P. gingivalis and exceptional light-driven antibiofilm activity to P. gingivalis biofilm, which was a result of the efficient bacterial localization mediated by PDA/UBI, as well as the PDT/PTT facilitated by Ce6/PDA interactions. Collectively, these versatile nanoplatforms augur a promising and strategic avenue for controlling infection and biofilm, thereby holding significant potential for future integration into clinical paradigms. The original application of the developed nanosystem in oral biofilms also provides a new strategy for effective oral infection treatment.

Nowcasting Vector Mosquito Abundance and Determining Its Association With Malaria Epidemics in South Korea

Since a resurgence occurred in 1993, malaria has remained an endemic disease in the Republic of Korea (ROK). A major challenge is the inaccessibility of current vector mosquito abundance data due to a 2-week reporting delay, which limits timely implementation of control measures. We aimed to nowcast mosquito abundance and assess its utility by evaluating the predictive value of mosquito abundance for malaria epidemic peaks. We used machine learning models to nowcast mosquito abundance, employing gradient boosting models (GBMs), extreme gradient boosting (XGB), and an ensemble model combining both. Various meteorological factors served as predictors. The models were trained with data from mosquito collection sites between 2009 and 2021 and tested with data from 2022. To evaluate the utility of nowcasting, we calculated the effective reproduction number (R t), which can indicate malaria epidemic peaks. Generalized linear models (GLMs) were then used to assess the impact of vector mosquito abundance on R t. The ensemble models demonstrated the best performance in nowcasting mosquito abundance, with a root mean square error (RMSE) of 0.90 and R-squared value (R 2) value of 0.85. The GBM model showed an RMSE of 0.91 and R 2 of 0.84, while the XGB model had an RMSE of 0.92 and R 2 of 0.85. Additionally, the R 2 of the GLMs predicting R t using mosquito abundance 2 weeks in advance was >0.72 for all provinces. The mosquito abundance coefficients were also significant. We constructed reliable models to nowcast mosquito abundance. These outcomes could potentially be incorporated into a malaria early warning system. Our study provides evidence to support the development of malaria management strategies in regions where malaria remains a public health challenge.

A self-supplied hydrogen peroxide and nitric oxide-generating nanoplatform enhances the efficacy of chemodynamic therapy for biofilm eradication

Bacterial biofilms present a profound challenge to global public health, often resulting in persistent and recurrent infections that resist treatment. Chemodynamic therapy (CDT), leveraging the conversion of hydrogen peroxide (H2O2) to highly reactive hydroxyl radicals (•OH), has shown potential as an antibacterial approach. Nonetheless, CDT struggles to eliminate biofilms due to limited endogenous H2O2 and the protective extracellular polymeric substances (EPS) within biofilms. This study introduces a multifunctional nanoplatform designed to self-supply H2O2 and generate nitric oxide (NO) to overcome these hurdles. The nanoplatform comprises calcium peroxide (CaO2) for sustained H2O2 production, a copper-based metal-organic framework (HKUST-1) encapsulating CaO2, and l-arginine (l-Arg) as a natural NO donor. When exposed to the acidic microenvironment within biofilms, the HKUST-1 layer decomposes, releasing Cu2+ ions and l-Arg, and exposing the CaO2 core to initiate a cascade of reactions producing reactive species such as H2O2, •OH, and superoxide anions (•O2-). Subsequently, H2O2 catalyzes l-Arg to produce NO, which disperses the biofilm and reacts with •O2- to form peroxynitrite, synergistically eradicating bacteria with •OH. In vitro assays demonstrated the nanoplatform's remarkable antibiofilm efficacy against both Gram-positive Methicillin-resistant Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, significantly reducing bacterial viability and EPS content. In vivo mouse model experiments validated the nanoplatform's effectiveness in eliminating biofilms and promoting infected wound healing without adverse effects. This study represents a breakthrough in overcoming traditional CDT limitations by integrating self-supplied H2O2 with NO's biofilm-disrupting capabilities, offering a promising therapeutic strategy for biofilm-associated infection.

Antibiotic Residues in Animal Products from Some African Countries and Their Possible Impact on Human Health

This review investigates the levels of antibiotic residues in animal products, types of antibiotics, and their possible impact on human health in Africa. The literature search involved the use of a systematic survey using data that were published from Africa from 2015 to 2024. The search terms used the Boolean operators with keywords such as antibiotics, antibiotic residues, antibiotics in animal products in Africa, and impact on human health. Only research conducted in Africa was used in the present study. The findings showed that the most prevalent groups of antibiotic residues were aminoglycoside, macrolides, β-lactams, fluoroquinolones, tetracyclines sulfonamides, and phenicols. Tetracycline showed the most prevalent antibiotic residue with 43% mostly from East Africa, followed by sulfonamides at 19%, and β-lactams at 16%; most of the antibiotic residue levels were higher than the World Health Organization permissible limit. Noncompliance with withdrawal periods and maximum residue limits for antibiotics used in food-producing animals may lead to negative outcomes such as allergic reactions, teratogenicity, carcinogenicity, microbiome alterations, and, most notably, antibiotic resistance. As a result, there is a need for constant monitoring of antibiotic residues in animal products in addition to the consideration of alternatives to antibiotics in order to avoid their health implications.

Antimicrobial resistance in wild game mammals: a glimpse into the contamination of wild habitats in a systematic review and meta-analysis

BACKGROUND

Wild game meat has over the years gained popularity across the globe as it is considered a food source with high protein content, low fat content, and a balanced composition of fatty acids and minerals, which are requirements for a healthy diet. Despite this popularity, there is a concern over its safety as many species of wildlife are reservoirs of zoonotic diseases including those of bacterial origin, more so antibiotic-resistant bacteria.

METHODS

This study aimed to describe the prevalence of antibiotic-resistant bacteria in mammalian wild game, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

The overall pooled prevalence of antibiotic resistance was established at 59.8% while the prevalence of multidrug resistance (MDR) was 17.2%. Resistance was reported in 32 wild game species and the meta-analysis revealed the highest prevalence of antibiotic resistance in Yersinia spp. (95.5%; CI: 76.8 - 100%) followed by Enterococcus spp. (71%; CI: 44.1 - 92%), Salmonella spp. (69.9%; CI: 44.3 - 90.0%), Staphylococcus spp. (69.3%; CI: 40.3 - 92.3%), and Escherichia coli (39.5%; CI: 23.9 - 56.4%). Most notably, resistance to highest priority, critically important antimicrobials, was recorded in all genera of bacteria studied. Additionally, a significantly higher prevalence of antibiotic resistance was observed in studies conducted in remote settings than those in the vicinity of anthropogenic activities, pointing to extensive contamination of wild habitats.

CONCLUSION

This review shows the presence of antibiotic resistance and the carriage of antimicrobial resistance (AMR) genes by bacteria isolated from mammalian wild game species. This is a cause for concern if critical steps to prevent transmission to humans from meat and meat products are not applied in the wild game meat production chain. The extensive occurrence of antibiotic resistance in the wild calls for expansion and adaptation of future AMR surveillance plans to include areas with various anthropogenic pressures including in sylvatic habitats.