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.

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.

Enterobacteriaceae are a diverse family of Gram-negative, rod-shaped, facultatively anaerobic bacteria that serve as important indicators of food safety. Many species within this family, including common foodborne pathogens, are major contributors to both community- and hospital-acquired infections. The widespread use of antibiotics in agriculture has facilitated the emergence and dissemination of antimicrobial-resistant bacteria in food products, livestock, and the environment. This study investigated the prevalence and genomic characteristics of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated from food sources in Saudi Arabia. A total of 160 isolates preserved in the Saudi Food and Drug Authority (SFDA) biobank were screened for antimicrobial resistance using indicator β-lactam antibiotics according to CLSI guidelines. Phenotypic screening indicated that Escherichia coli O145, E. coli O157, Klebsiella pneumoniae, and Cronobacter sakazakii isolates were not ESBL producers. In contrast, ESBL production was detected among Salmonella spp. isolates, and 13 confirmed ESBL-producing Salmonella isolates were subsequently subjected to whole-genome sequencing (WGS). Genomic analysis identified the ESBL gene blaCTX-M-65, along with multiple antimicrobial resistance determinants, virulence-associated genes, and plasmid replicons, predominantly belonging to the IncFIB and IncX families. These findings provide important insights into the occurrence of ESBL-producing Enterobacteriaceae in food sources and highlight the value of integrating phenotypic and genomic approaches for antimicrobial resistance surveillance within food safety systems.