The emergence of antimicrobial resistance (AMR) is a global health problem without geographic boundaries. This increases the risk of complications and, thus, makes it harder to treat infections, which can result in higher healthcare costs and a greater number of deaths. Antimicrobials are often used to treat infections from pathogens in food-producing animals, making them a potential source of AMR. Overuse and misuse of these drugs in animal agriculture can lead to the development of AMR bacteria, which can then be transmitted to humans through contaminated food or direct contact. It is therefore essential to take multifaceted, comprehensive, and integrated measures, following the One Health approach. To address this issue, many countries have implemented regulations to limit antimicrobial use. To our knowledge, there are previous studies based on AMR in food-producing animals; however, this paper adds novelty related to the AMR pathogens in livestock, as we include the recent publications of this field worldwide. In this work, we aim to describe the most critical and high-risk AMR pathogens among food-producing animals, as a worldwide health problem. We also focus on the dissemination of AMR genes in livestock, as well as its consequences in animals and humans, and future strategies to tackle this threat.

Vegetables are an essential component of a balanced diet. The consumption of ready-to-eat foods may lead to the risk of infections and illnesses due to microbial contamination. To mitigate the potential of microbial contamination risks, it is critical to promote safe handling practices among consumers. In this study, our research evaluated the efficacy of different vegetable washing methods, specifically with lettuce, tomato, and cucumber, to establish optimal practices for reducing microbial contamination. This study consisted of two phases. Initially, a survey was distributed to 150 volunteers using snowball sampling to assess everyday vegetable handling and washing methods. The survey’s results identified four predominant methods: washing with a 5% vinegar solution for 3 min followed by tap water rinse (37.3% of participants), rinsing with tap water for 1 min (29.3%), washing with a 5% salt solution (vegetable soap) for 3 min followed by a tap water rinse (16.6%), and a 3 min tap water rinse (14%). A minor segment (3.33%) reported not washing their vegetables at all. The survey’s findings guided the second phase, which tested the aforementioned washing protocols’ effectiveness in reducing Escherichia coli (E. coli) levels on spiked contaminated salad vegetables. The tested vegetables were sterilized using UV light, inoculated with 0.5 McFarland E. coli, and then washed using the four identified methods. After that, E. coli enumeration after washing was performed using 3M™ Petrifilm and the comparison was analyzed via one-way ANOVA. During this study, it was revealed that the cucumbers had the highest E. coli contamination levels in comparison to the lettuce and tomato after washing. Interestingly, by comparing the three washing methods, it was found that washing the vegetables with vinegar proved to be the most effective solution for reducing microbial presence on both lettuce and cucumbers. Notably, the natural smoothness of tomato skin led to no significant differences in contamination levels across washing methods. In summary, vinegar washing effectively reduces microbial contamination from salad vegetables, highlighting the need for informed consumer practices to prevent foodborne outbreaks. This study emphasizes the importance of monitoring contamination sources and using safe washing techniques.

Valley surface water is considered a focal public health concern owing to the presence of multi-drug-resistant bacteria. The distribution of antimicrobial resistance (AMR) bacteria in the surface water is affected by the presence of multiple factors, including antibiotics coming from wastewater discharge or other contaminant sources such as pharmaceuticals, biocides, and heavy metals. Furthermore, there is evidence suggesting that high levels of antibiotic resistance genes (ARGs) can be transferred within bacterial communities under the influence of heavy metal stress. Hence, the primary aim of this study is to investigate the presence of heavy metals and bacterial ARGs in upstream as well as downstream locations of Wadi Hanifah Valley in Riyadh, Saudi Arabia. Sample collection was conducted at eighteen surface water sites within the valley in total. The selection of ARGs was associated with the most common antibiotics, including β-lactam, tetracycline, erythromycin, gentamicin, sulphonamide, chloramphenicol, vancomycin, trimethoprim, and colistin antibiotics, which were detected qualitatively using polymerase chain reaction (PCR) technology. The tested antibiotic resistance genes (ARGs) included (bla_NDM-1 (for the antibiotic class Beta-lactamases), mecA (methicillin-resistant Staphylococcus aureus), tet(M) and tet(B) (for the antibiotic class Tetracycline), ampC (for the antibiotic class Beta-lactamases), vanA (for the antibiotic class vancomycin), mcr-1 (for the antibiotic class colistin), erm(B) (for the antibiotic class erythromycin), aac6′-Ie-aph2-Ia (for the antibiotic class Gentamicin), sulII (for the antibiotic class sulphonamide), catII (for the antibiotic class Chlorophincol), and dfrA1 (for the antibiotic class trimethoprim). Moreover, an assessment of the levels of heavy metals such as lithium (Li), beryllium (Be), chromium (Cr), cobalt (Co), arsenic (As), cadmium (Cd), tin (Sn), mercury (Hg), and lead (Pb) was conducted by using inductively coupled plasma mass spectrometry (ICPMS). According to our findings, the concentrations of sulphonamide, erythromycin, and chloramphenicol ARGs (erm(B), sulII, and catII) were observed to be the most elevated. Conversely, two ARGs, namely mecA and mcr-1, were not detected in the samples. Moreover, our data illustrated a significant rise in ARGs in the bacteria of water samples from the upstream sites as compared with the water samples from the downstream sites of Wadi Hanifah Valley. The mean concentration of Li, Be, Cr, Co, As, Cd, Sn, Hg, and Pb in the water samples was estimated to be 37.25 µg/L, 0.02 µg/L, 0.56 µg/L,0.32 µg/L, 0.93 µg/L, 0.01 µg/L, 200.4 µg/L, 0.027 µg/L, and 0.26 µg/L, respectively, for the selected 18 sites. Furthermore, it was revealed that the concentrations of the screened heavy metals in the water samples collected from various sites did not surpass the maximum limits set by the World Health Organization (WHO). In conclusion, this study offers a concise overview of the presence of heavy metals and ARGs in water samples obtained from the Wadi Hanifah Valley in Riyadh, KSA. Such findings will contribute to the ongoing monitoring and future risk assessment of ARGs spread in surface water.

Introduction: Salmonella enterica remains one of the leading causes of foodborne illness globally, with poultry and eggs recognized as major transmission vehicles. In Saudi Arabia, data integrating genomic epidemiology with conventional microbiological surveillance in eggs remain limited. This study aimed to provide the first comprehensive genomic characterization of Salmonella isolated from chicken eggs in the Kingdom, assessing prevalence, serovar distribution, virulence determinants, and antimicrobial resistance (AMR) profiles to better inform food safety risk assessment within a One Health framework. Methods: A total of 260 chicken eggs were collected and analyzed using conventional microbiological culture methods for Salmonella detection. Confirmed isolates underwent whole-genome sequencing (WGS) to determine serovar identity, virulence-associated genes, and antimicrobial resistance determinants. Comparative genomic analyses were conducted to evaluate differences between isolates recovered from eggshell surfaces and egg contents, with particular focus on multidrug resistance (MDR) genes, plasmid-mediated β -lactamases, and fluoroquinolone resistance determinants. Results: Salmonella was detected in 9% of the analyzed samples. Contamination was more frequently identified on eggshells than within egg contents, suggesting a substantial contribution of environmental exposure during handling and distribution. Twelve distinct serovars were identified, with Salmonella Enteritidis and Salmonella typhimurium predominating.Eggshell isolates demonstrated broader serovar diversity but carried fewer antimicrobial resistance determinants. In contrast, isolates recovered from egg contents were associated with clinically significant serovars and exhibited a higher prevalence of antimicrobial resistance genes. Whole-genome analysis revealed multidrug resistance profiles, including plasmid-mediated β -lactamase genes and fluoroquinolone resistance determinants, indicating the potential for dissemination of resistant strains through the food chain. Discussion: The findings demonstrate dual contamination pathways in eggs: external contamination linked to environmental handling factors and internal contamination associated with serovars of greater clinical relevance and elevated AMR gene burden. The detection of multidrug resistance determinants highlights the risk of horizontal transmission of resistance elements across foodborne bacteria.These results underscore the importance of integrating genomic surveillance into national food safety systems to strengthen risk assessment, guide targeted control measures, and support antimicrobial resistance monitoring. Within the Saudi context, implementing WGS-based surveillance aligns with One Health principles and enhances preparedness against emerging foodborne AMR threats.

Salmonella presents serious risks to human health, causing about 150,000 deaths per year through the consumption of contaminated food, especially chicken eggs. Consequently, risk of salmonellosis from chicken eggs is of significant interest to the Saudi Food and Drug Authority (SFDA). Models that predict the risk of salmonellosis from chicken eggs are valuable tools for protecting public health. After a review of existing models, the SFDA selected the Poultry Food Assess Risk Model (PFARM) for the purpose of evaluating its ability to assess the risk and severity of salmonellosis for a small cohort of chicken egg consumers in Riyadh, Saudi Arabia, as a proof-of-concept and pilot study. The PFARM was selected because it uses novel methods to consider more risk factors for salmonellosis than other models, such as growth potential and zoonotic potential of Salmonella, buffering capacity of the meal, and consumer behavior, health, and immunity. The SFDA examined chicken eggs from retail stores in Riyadh for Salmonella contamination and surveyed 125 consumers to obtain data for simulating how they store, prepare, and consume eggs at home, and their resistance to salmonellosis. The prevalence of Salmonella in chicken eggs at retail was 7% (7/100). The isolated Salmonella serotypes were Cerro (n = 4), Enteritidis, Stanley, and Winston. Salmonella’s mean number (growth units) per contaminated egg was 1.58 log₁₀ (range: 0 to 3.08 log₁₀). The mean category for consumer survey results ranged from 1.1 (very low risk) for meal preparation time to 3.7 (high risk) for home storage time with 34.4% of consumers having low resistance to salmonellosis. Per 100,000 egg meals, the PFARM predicted 88 infections, two illnesses, and no hospitalizations or deaths. The consumers who became ill were exposed to Salmonella Enteritidis, had moderate resistance to salmonellosis but high-risk behaviors for egg storage (temperature abuse), meal preparation (poor hygiene), and consumption (undercooked eggs). These results showed that the studied chicken eggs posed a low risk and severity of salmonellosis for the surveyed consumer cohort in Riyadh, Saudi Arabia, and that the PFARM was fit-for-purpose. The next step is to improve the PFARM and apply it more broadly in Saudi Arabia to better define the problem and its control.

Background/Objectives: The emergence of colistin resistance mediated by the mcr-1 gene in Salmonella enterica poses a significant public health concern. In 2022, mcr-1 was identified for the first time in Salmonella isolates recovered from chicken meat in Saudi Arabia, prompting the need for further genomic investigation. Methods: Four Salmonella enterica isolates—two serovar Minnesota and two serovar Infantis—underwent antimicrobial susceptibility testing (AST), whole-genome sequencing (WGS), and bioinformatics analyses including antimicrobial resistance genes (ARGs), virulence factors, plasmid replicons, and mcr-1 locations. Results: All isolates exhibited resistance to colistin, polymyxin B, and multiple first-line antibiotics. All four isolates were classified as multidrug-resistant (MDR). The mcr-1 gene was plasmid-borne in all isolates, located on IncI1_1_Alpha plasmids in S. Minnesota and IncFIB(K)_1_Kpn3 plasmids in S. Infantis. Additional antimicrobial resistance genes (ARGs) were detected, including bla_CTX-M-65, qnrB5, ermB, and aminoglycoside-modifying enzymes, alongside multiple efflux pump genes. Virulence gene profiles showed minor differences between serovars, including the presence of the cdtB toxin gene in S. Infantis isolates. Phylogenetic analysis indicated that the isolates clustered within a distinct clade, suggesting a potential common local source or clonal expansion. Conclusions: This study provides the first detailed genomic insight into mcr-1-positive Salmonella isolates from food in Saudi Arabia. The co-existence of resistance and virulence determinants, together with mobile plasmids carrying the mcr-1 gene, emphasizes the risk of dissemination through the food chain. These findings highlight the urgent need for integrated genomic surveillance and strengthened antimicrobial stewardship within a One Health framework.