Anthony Ayodeji Adegoke

* Background Fresh produce is a vital vehicle for the transmission of foodborne pathogens, yet data from low- and middle-income countries on contamination levels and associated health risks remain scarce. Methods This study provided an analysis of Listeria species contamination in 208 fruit and vegetable samples from major geopolitical regions in Nigeria. Conventional microbiological techniques and molecular methods were used for the analysis. Results We reported a high prevalence (38.5%) and substantial bacterial loads (up to 8.33×10 2 CFU/25g) among the organically grown crops, with produce from Northern states exhibiting the highest contamination. Genetic characterisation revealed significant diversity, including genetically distinct and others closely related to global clones, confirming a resilient environmental presence. Importantly, antibiotic susceptibility testing high rates of resistance to vancomycin (83.1%) and oxacillin (88.1%), with hierarchical clustering identifying distinct multidrug-resistant clusters. The presence of resistance genes ( vanA, vanB, tetL, tetM ) and the virulence gene hly was confirmed. A quantitative microbial risk assessment (QMRA), incorporating this empirical data, estimated the annual probability of illness, highlighting high-risk produce-region combinations. Conclusions These findings demonstrate that fresh produce in Nigeria is a significant reservoir of pathogenic, antimicrobial-resistant L. monocytogenes , posing a potential serious public health threat, particularly when considered at the population level. This study highlights the urgent need for targeted interventions, including enhanced agricultural water safety and strengthened surveillance of antimicrobial resistance, to mitigate risks and support evidence-based food safety policies in Nigeria and similar regions.

* Background Fresh produce is a vital vehicle for the transmission of foodborne pathogens, yet data from low- and middle-income countries on contamination levels and associated health risks remain scarce. Methods This study provided an analysis of Listeria species contamination in 208 fruit and vegetable samples from major geopolitical regions in Nigeria. Conventional microbiological techniques and molecular methods were used for the analysis. Results We reported a high prevalence (38.5%) and substantial bacterial loads (up to 8.33×10 2 CFU/25g) among the organically grown crops, with produce from Northern states exhibiting the highest contamination. Genetic characterisation revealed significant diversity, including novel strains and others closely related to global clones, confirming a resilient environmental presence. Importantly, antibiotic susceptibility testing uncovered alarming resistance rates to vancomycin (83.1%) and oxacillin (88.1%), with hierarchical clustering identifying distinct multidrug-resistant clusters. The presence of resistance genes ( vanA, vanB, tetL, tetM ) and the virulence gene hly was confirmed. A quantitative microbial risk assessment (QMRA), incorporating this empirical data, estimated the annual probability of illness, highlighting high-risk produce-region combinations. Conclusions These findings demonstrate that fresh produce in Nigeria is a significant reservoir of pathogenic, antimicrobial-resistant L. monocytogenes , posing a serious public health threat. This study highlights the urgent need for targeted interventions, including enhanced agricultural water safety and strengthened surveillance of antimicrobial resistance, to mitigate risks and support evidence-based food safety policies in Nigeria and similar regions.

Spices such as Xylopia aethiopica, Piper nigrum, and Tetrapleura tetraptera are traditionally employed in postpartum healthcare in Southern Nigeria due to their perceived therapeutic properties. However, scientific validation of their antioxidant and antimicrobial activities, particularly against multidrug-resistant (MDR) pathogens, remains limited. Aqueous and methanol extracts of the three spices were evaluated for their phytochemical constituents, total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity (DPPH, FRAP, and metal chelating assays), and antimicrobial activity against MDR bacterial isolates using agar well diffusion, MIC, and MBC assays. Methanol extracts generally exhibited higher TPC and TFC values, with X. aethiopica showing the highest flavonoid content (81.0 mg QE/g) and T. tetraptera the highest phenolic content (29.1 mg GAE/g). Antioxidant assays revealed superior activity in methanol extracts, particularly P. nigrum (FRAP IC₅₀: 36.09 µg/mL). Antimicrobial tests showed that methanol extracts had greater inhibitory and bactericidal effects than aqueous counterparts, with P. nigrum methanol extract demonstrating the lowest MIC (25 mg/mL) and the highest activity index (AI up to 0.95) against Bacillus sp. and Pseudomonas aeruginosa. The methanol extracts, especially from Piper nigrum, exhibited potent antioxidant and antimicrobial activities, supporting their traditional use in postpartum therapy and suggesting potential for pharmaceutical applications. This study provides empirical evidence linking the phytochemical richness of these spices to their bioactivities, emphasising the need for further compound isolation, characterisation, and clinical evaluation in the fight against antimicrobial resistance.

The increasing prevalence of antibiotic-resistant bacteria has necessitated the search for novel antimicrobial agents from microbial sources. This study investigated the antibacterial potential of Klebsiella pneumoniae isolates, characterized through morphological, biochemical, and molecular approaches. The isolates were confirmed via 16S rDNA sequencing, aligning with established phylogenetic analyses and supporting their taxonomic classification. The antibacterial activity of the identified K. pneumoniae strain EKA-02 against Bacillus subtilis and Enterococcus sp. was assessed, revealing significant inhibition zones, with diameters reaching up to 38 mm. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined, with an MIC of 3.125 mg/ml and an MBC of 6.25 mg/ml, demonstrating the bactericidal efficacy of the microbial extract. Thin-layer chromatography (TLC) profiling indicated the presence of multiple bioactive compounds, and gas chromatography-mass spectrometry (GC-MS) analysis identified octadecane, heptadecane, tetradecanoic acid, and 7β-acetoxyvouacapane as predominant antimicrobial constituents. The findings highlight the potential of K. pneumoniae EKA-02 as a source of novel antimicrobial agents, particularly against Gram-positive bacteria. The presence of fatty acids, terpenes, and halogenated compounds suggests a multifaceted mode of action. The study reinforces the rich dynamics of untapped microbial resources in the Nigerian environment which could be focused in order to address the global antibiotic resistance crisis.

Virulence attributes and putative antibiotic resistance genes from enterococcal isolates from wastewater treatment facilities for sustainable reuse and the areas where they discharge treated water were assessed using phenotypic and molecular methods. This analysis was performed on 269 Enterococci, of which 202 were vancomycin-resistant Enterococcus (VRE). VRE strains show markedly higher resistance across multiple antibiotics, especially glycopeptides and beta-lactams, compared to the more susceptible profile observed in vancomycin-susceptible Enterococcus (VSE) strains. vanC was found in every instance of E. gallinarum among VRE and enterococci susceptible to vancomycin (VSE) isolates but not in VR E. faecium/faecalis. Among VRE, 127 (62.9%) possessed at least one of the tetK, tetL, tetM, or tetO, while 22 (17.3%) had two of these genes. The multidrug efflux pump gene emeA was detected in 27 out of 202 (13.4%) VRE isolates and 8 out of 67 (11.9%) VSE isolates. Exactly 69 (78.4%) possessed at least one of the virulence determinants tested, with 10 (11.4%) and seven (8%) positive for haemolysis and gelatinase activity respectively. The gelatinase gene, gelE, was detected in 16 (18.1%) isolates, while more isolates (n = 23; 26.1%) were positive for gelatinase activity. Cytolytic (cyl) genes (1.1%), Angiotensin-converting-enzyme genes (ace) (13.6%), endocarditis-specific antigen A genes (efaA) (25%), hyaluronidase (hyl) genes (9.1%), enterococcal surface protein (esp) genes (4.5%), among others, were detected. Gelatinase activity and the amplified virulence genes were further validated by sequencing the gel-positive amplicons, which were almost identical (98.97%), and the gelE gene of Enterococcus sp. strain SQ07C was deposited under the GenBank accession number PQ381122. Overall, our results showed that the enterococcal isolates were considered as potential pathogens of notable threat to human health via exposure through reuse, and there is a need for more stringent treatment protocols.

This study explored the occurrence of Listeria monocytogenes in fresh produce across Nigeria and selected developing countries, applying a holistic health perspective through a structured review and quantitative synthesis of available research published between 2006 and 2022. Following PRISMA standards, a pre-specified protocol for the review was designed and documented in PROSPERO (ID = CRD42024521833). A comprehensive search of PubMed, Scopus, and Google Scholar databases yielded 12 eligible studies. Data were extracted using standardized protocols, and pooled prevalence was calculated using a random-effects model. The overall prevalence was 8.4% (95% CI: 6.3-10.8%), with higher contamination in West Africa (10.5%) compared to Southeast Asia (5.2%). Leafy vegetables exhibited the highest contamination (12.1%). Molecular detection via PCR had higher detecting sensitivity (11.6%) compared to traditional culture methods (7.3%). The analysis revealed significant heterogeneity among the included studies (I2 = 97.79%, p < 0.0001), indicating considerable variability in the reported prevalence of Listeria spp. Environmental factors, such as temperature and poor agricultural practices, contributed to contamination. These findings underscore the need for robust hygiene controls and monitoring to mitigate L. monocytogenes risks in fresh produce.

Hepatitis E virus (HEV) is a pathogen that can be transmitted to humans through contaminated meat consumption, posing potential public health risks. This investigation aimed to assess the prevalence of HEV in meat and fecal samples from four animal species using anti-Hepatitis E Virus antibody [5F3] (ab233244) and Nested Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) techniques. Almost all samples (n = 44) exhibited significant HEV seroprevalence, with Swine Genotype 3/4 HEV detected in both pig meat and fecal samples. The use of Nested RT-PCR targeting the 3331N/3332N region identified this genotype in 6 pig samples, indicating a prevalence of 66.7%. No HEV was found using a universal nested RT-PCR assay on the primer region 3158/3159N, suggesting the presence of non-typical or novel HEV strains. This emphasizes the need for genotype-specific primers for thorough surveillance. These findings highlight the circulation of the specific genotype in the animal population, underscoring its potential as a source of HEV infections in humans. The positive immunological results in all 3 HEV-positive samples affirm the accuracy of the ELISA technique, crucial for viral diagnostics and surveillance. This study contributes valuable data on HEV prevalence in meat and fecal samples from diverse animal species, providing insights into the zoonotic risks associated with HEV through meat consumption or precooking exposure.

Editorial: Emerging pathogens and contaminants in water matrices: human health risks, exposure pathways and epidemiological outcomes

Bacterial species responsible for food infections and intoxication are sometimes carried through the food production and processing. Very few published literatures exist on integrons among antibiotic-resistant staphylococcal strains from foods of animal origin in Gauteng Province, South Africa, hence this study. A total of 720 samples (360 meat and 360 dairies) from a community abattoir of a research farm in South Africa, using conventional bacteriological and molecular methods. Nine (9) bacterial strains, including Bacillus subtilis AYO-123, Acinetobacter baumannii AYO-241, Staphylococcus lentus AYO-352, among others were identified and submitted to GenBank. More bacterial strains were recovered from raw meat (90.5%) than dairy products (9.5%). Resistance was shown (0–100%) to Imipenem, Meropenem, Norfloxacin, Clindamycin, and 22 other antibiotics, without any carbapenem-resistant Acinetobacter baumannii and methicillin/vancomycin-resistant Staphylococcus species (MRSS/VRSS). Virulence genes for fibronectin-binding protein A (FnbA) were predominant (56.24%) followed by the circulating nucleic acids (cna) gene (43.75%). Others were staphylococcal enterotoxin A (sea, 41%), staphylococcal enterotoxin B (seb, 23.5%). Co-presence of sea and seb genes occurred in 11.76% of the isolates, but no coa genes was amplified. Antibiotic resistance genes (ARGs), tetK (70.58%), linA (29.4%), and ermA (11.76%) were detected, but none of the mecA and vat genes was amplified. Class 2 integron (50%) was more predominantly detected than integron 1 (25%), but no Class 3 integron was detected. Bacteria with both the detected virulence and antibiotic resistance genes are of potential risks to human health.