Search Results (226)

Clinical manifestations of salmonellosis in humans typically include acute gastroenteritis, abdominal pain, diarrhea, nausea, and fever. Diarrhea and anorexia may persist for several days. In some cases, the organisms may invade the intestinal mucosa and cause septicemia, even in the absence of significant gastrointestinal symptoms. Most clinical signs are attributed to hematogenous dissemination of the pathogen. As with other microbial infections, disease severity is influenced by the serotype of the organism, bacterial load, and host susceptibility. Serotyping analysis of Salmonella spp. using the White–Kauffmann–Le Minor scheme remains the gold standard for strain typing. However, this method is expensive, time-consuming, and requires significant expertise and visual interpretation by trained personnel, which is why it is typically restricted to regional or national reference laboratories. In this study, we evaluated a spectroscopic technique coupled with chemometrics and multivariate machine learning algorithms for its ability to discriminate the main Salmonella spp. serogroups in a clinical routine setting. We analyzed 95 isolates of Salmonella that were randomly selected, including four strains of S. Typhi. The I-dOne Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) system (Alifax S.r.l., Polverara, Italy) also shows promising potential for distinguishing Salmonella Typhi within the D serogroup. The I-dOne system enables simultaneous identification of both species and subspecies using the same workflow and instrumentation, thus streamlining the diagnostic process. Full article

A new Schiff base, (E)-2-(((1,10-phenanthrolin-5-yl)imino)methyl)-4,6-di-tert-butylphenol (Fen-IHB), was designed to incorporate an intramolecular hydrogen bond (IHB) between the phenolic OH and the azomethine nitrogen with the goal of modulating its physicochemical and biological properties. Fen-IHB was synthesized by condensation of 5-amino-1,10-phenanthroline with 3,5-di-tert-butyl-2-hydroxybenzaldehyde and exhaustively characterized by HR-ESI-MS, FTIR, 1D/2D NMR (¹H, ¹³C, DEPT-45, HH-COSY, CH-COSY, D₂O exchange), and UV–Vis spectroscopy. Cyclic voltammetry in anhydrous CH₃CN revealed a single irreversible cathodic peak at −1.43 V (vs. Ag/Ag⁺), which is consistent with the intramolecular reductive coupling of the azomethine moiety. Density functional theory (DFT) calculations, including MEP mapping, Fukui functions, dual descriptor analysis, and Fukui potentials with dual descriptor potential, identified the exocyclic azomethine carbon as the principal nucleophilic site and the phenolic ring (hydroxyl oxygen and adjacent carbons) as the main electrophilic region. Noncovalent interaction (NCI) analysis further confirmed the strength and geometry of the intramolecular hydrogen bond (IHB). In vitro antimicrobial assays indicated that Fen-IHB was inactive against Gram-negative facultative anaerobes (Salmonella enterica serovar Typhimurium and Typhi, Escherichia coli) and strictly anaerobic Gram-positive species (Clostridioides difficile, Roseburia inulinivorans, Blautia coccoides), as any growth inhibition was indistinguishable from the DMSO control. Conversely, Fen-IHB displayed measurable activity against Gram-positive aerobes and aerotolerant anaerobes, including Bacillus subtilis, Streptococcus pyogenes, Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus haemolyticus. Overall, these comprehensive characterization results confirm the distinctive chemical and electronic properties of Fen-IHB, underlining the crucial role of the intramolecular hydrogen bond and electronic descriptors in defining its reactivity profile and selective biological activity. Full article

This study aimed to optimize the total phenolic content (TPC) and antioxidant activity (AA) of acerola (Malpighia emarginata) by-product extracts obtained by probe-type ultrasound-assisted extraction and assess the composition and antibacterial activity of the extract obtained under optimized conditions. A Box–Behnken experimental design was applied to evaluate the effects of ultrasonic power (350 to 650 W), ethanol concentration (20% to 80% v v⁻¹), and extraction time (20 to 60 min) on TPC and AA. The optimal extraction conditions were 650 W, 50% (v v⁻¹) ethanol, and 20 min, which yielded the highest values of TPC (3.36 g gallic acid equivalent 100 g⁻¹) and AA through the DPPH radical scavenging method (4.97 mM Trolox equivalents 100 g⁻¹) and a ferric reducing antioxidant power assay (11.35 mM Trolox equivalents 100 g⁻¹). Organic acids, phenolic acids, flavonoids, and alkaloids were identified in the optimized extract, including malic acid, protocatechuic acid, resorcylic acid, and rutin. The optimized extract (2.89–11.32 mg mL⁻¹) inhibited the growth of Listeria monocytogenes, Shigella sonnei, Salmonella enterica subsp. enterica Typhi, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Acerola by-products represent a promising source of extracts with the potential to replace synthetic additives, contributing to the circular economy of agroindustries. Full article

The integration of nanotechnology and green synthesis strategies provides innovative solutions in biomedicine. This study focuses on the biofabrication of silver nanoparticles (AgNPs) using Corynespora smithii, an endophytic fungus isolated from Bergenia ciliata. The eco-friendly synthesis process employed fungal extracts as reducing and stabilizing agents thereby minimizing the need for hazardous chemicals. The AgNPs demonstrated strong potent biological activities, showcasing significant antioxidant, antibacterial, and anticancer properties. The antibacterial efficacy was demonstrated against various Gram-positive and Gram-negative bacteria, while cytotoxicity on the A549 lung cancer cell line revealed an IC₅₀ value of 10.46 µg/mL. A molecular docking analysis revealed interactions between the major bioactive compound, dimethylsulfoxonium formylmethylide, and the pathogenic proteins, Staphylococcus aureus and Salmonella typhi, displaying moderate binding affinities. Furthermore, the ADME analysis of dimethylsulfoxonium formylmethylide indicated favourable pharmacokinetic properties, including high gastrointestinal absorption, minimal lipophilicity, and low potential for drug–drug interactions, making it a promising candidate for oral drug formulations. These findings further support the compound’s suitability for biomedical applications. This research emphasizes the potential of C. smithii as a sustainable source for synthesizing bioactive nanoparticles, paving the way for their application in developing novel therapeutic agents. This study highlights the significance of harnessing endophytic fungi from medicinal plants for sustainable nanotechnology advancements. Full article

Wastewater-based epidemiology (WBE) has historically proven to be a powerful surveillance tool, particularly during the SARS-CoV-2 pandemic. Effective WBE depends on the sensitive detection of pathogens in wastewater. However, determining the process limit of detection (PLOD) of WBE through a comprehensive evaluation that accounts for pathogen concentration, nucleic acid extraction, and molecular analysis has rarely been documented. We prepared dilution series with known concentrations of S. Typhi, V. cholerae, rotavirus, and SARS-CoV-2 in surface water and wastewater. Pathogen concentration was performed using Nanotrap particles with the KingFisher™ Apex robotic platform, followed by nucleic acid extraction. Quantitative real-time PCR (qPCR) and digital PCR (dPCR) were used to detect the extracted nucleic acids of the pathogens. The PLODs and recovery efficiencies for each of the four pathogens in surface water and wastewater were determined. Overall, the observed PLODs for S. Typhi, V. cholerae, and rotavirus in surface water and wastewater were approximately 3 log₁₀ loads (2.1–2.8 × 10³/10 mL) using either qPCR or dPCR as the detection method. For SARS-CoV-2, the PLOD in surface water was 2.9 × 10⁴/10 mL with both RT-qPCR and dPCR, one log₁₀ higher than the PLODs of the other three pathogens. In wastewater, the PLOD for SARS-CoV-2 was 2.9 × 10⁴/10 mL using RT-qPCR and 2.9 × 10³/10 mL using dPCR. The mean recovery rates of S. Typhi, V. cholerae, rotavirus, and SARS-CoV-2 for dPCR in both surface water and wastewater were below 10.4%, except for S. Typhi and V. cholerae in wastewater, which showed significantly higher recoveries, from 26.5% at 4.6 × 10⁵/10 mL for S. Typhi to 58.8% at 4.8 × 10⁵/10 mL for V. cholerae. Our study demonstrated that combining qPCR or dPCR analysis with automated Nanotrap particle concentration and nucleic acid extraction using the KingFisher™ platform enables the sensitive detection of S. Typhi, V. cholerae, rotavirus, and SARS-CoV-2 in surface water and wastewater. Full article

Background: Salmonella infections impose a substantial global health burden, with an estimated 95.1 million cases occurring annually. Pregnant women exhibit a heightened vulnerability due to pregnancy-specific immune adaptations and dietary habits that increase their risk of Salmonella exposure, facilitating possible damage to the placental barrier. Despite this significant burden, Salmonella-associated placental pathology remains poorly understood, particularly its impact on foetal development through microstructural alterations. Aim: This study utilised stereology to assess histomorphological and functional alterations in term placentae of Salmonella Typhi-exposed placentae, compared to unexposed controls. Methods: A hospital-based case-control study was conducted in Ghana. Of 237 screened women, 62 placentae were selected for analysis, comprising 31 Salmonella-exposed cases (IgG/IgM-positive in placental and cord blood) and 31 gestational age-matched controls (IgG/IgM-negative). Placental tissues were processed for histology and stereology. Neonatal birthweights were also compared. Results: Stereological assessment revealed significantly higher mean volume densities of syncytial knots in the study group (0.4755 ± 0.04) compared to the controls (0.3342 ± 0.04, p = 0.0219). Syncytial denudation was increased in the study group (0.8113 ± 0.09) relative to the controls (0.1975 ± 0.08, p < 0.0001). Foetal capillary volume density was also significantly elevated in the study group (5.1010 ± 0.32) compared to the controls (3.562 ± 0.47, p < 0.0001). In contrast, intervillous space volume was significantly reduced in the study group (9.5810 ± 0.05) compared to the controls (11.593 ± 0.26, p = 0.0053). Neonates of exposed mothers showed a non-significant reduction in birthweight. Conclusion: Salmonella Typhi exposure in pregnancy induces subtle, yet significant alterations in placental architecture, compromising villous integrity and vascular organisation. Although birthweight may appear unaffected, the observed changes point to reduced placental efficiency and merit further research into their developmental consequences and long-term effects on babies. Full article

Background: The genus Enterococcus includes a diverse group of bacteria that are commonly found in the gastrointestinal tracts of humans and animals, as well as in various environmental habitats. Methods: In this study, Enterococcus lactis RB10, isolated from goat feces, was subjected to comprehensive genomic and functional analysis to assess its safety and potential as a probiotic strain. Results: The genome of E. lactis RB10, with a size of 2,713,772 bp and a GC content of 38.3%, was assembled using Oxford Nanopore Technologies (ONT). Genome annotation revealed 3375 coding sequences (CDSs) and highlighted key metabolic pathways involved in carbohydrate, protein, and amino acid metabolism. The strain was susceptible to important antibiotics, including ampicillin, chloramphenicol, tetracycline, and vancomycin, but exhibited resistance to aminoglycosides, a common trait in Enterococcus species with non-hemolytic activity. Genomic analysis further identified two intrinsic antimicrobial resistance genes (ARGs). The strain also demonstrated antimicrobial activity against Bacillus cereus DMST 11098 and Salmonella Typhi DMST 22842, indicating pathogen-specific effects. Key genes for adhesion, biofilm formation, and stress tolerance were also identified, suggesting that RB10 could potentially colonize the gut and compete with pathogens. Moreover, the presence of bacteriocin and secondary metabolite biosynthetic gene clusters suggests its potential for further evaluation as a biocontrol agent and gut health promoter. Conclusions: However, it is important to note that E. lactis RB10 was isolated from goat feces, a source that may harbor both commensal and opportunistic bacteria, and therefore additional safety assessments are necessary. While further validation is needed, E. lactis RB10 exhibits promising probiotic properties with low pathogenic risk, supporting its potential use in food and health applications. Full article

We have used a rapid, portable assay (Bacterisk) to determine the bacterial water quality along several inland waters in SW England. Water samples were compared by a conventional membrane filter and culture methods for faecal indicator bacteria (FIB; E. coli and enterococci) and endotoxin measurement by Bacterisk. The Bacterisk data, measured in near-real-time, correlate well with both E. coli and enterococci, but also allow the presence of potential pathogens of a non-faecal origin to be detected. The sensitivity was calculated to be 92.96% with a specificity of 46.3% for E. coli with an expanded uncertainty of 22.07% and an Endotoxin Risk detection limit of 25 units. The presence of Bacterisk detectable non-faecal pathogenic bacteria in the water samples was successfully confirmed by Illumina MiSeq sequencing followed by target species-specific qPCR. Sequencing showed the presence of pathogens including Pseudomonas aeruginosa, Salmonella typhi, Acinetobacter baumannii, Shigella spp., and Legionella spp. as well as antimicrobial resistance genes. Furthermore, the portable Bacterisk assay was able to acquire data on the water quality from different locations and at different time points, providing a comprehensive surveillance tool that challenges the time to results by conventional methods (minutes instead of days), yielding compatible results. Full article

Lacticaseibacillus species have shown potential in managing hyperglycemia, hypercholesterolemia, and oxidative stress, depending on the strain and species. This study aimed to isolate a novel Lacticaseibacillus rhamnosus strain from healthy newborns and assess its hypoglycemic and antioxidative activity, along with other probiotic properties. A non-hemolytic L. rhamnosus LBUX2302 was isolated, and it exhibited survival rates of 2.7%, 22%, and 27.5% at pH 2, 3, and 5 for 120 min. It metabolized various carbon sources and showed resistance to gentamicin, dicloxacillin, and penicillin; coaggregated with Salmonella typhi ATCC14028, Staphylococcus aureus STCC6538, and Escherichia coli O157:H7. L. rhamnosus LBUX2302 showed hydrophobicity, autoaggregation, and adhesion to HaCat, HeLa, MCF-7, SK-LU-1, and SW620 cell lines. It also exhibited extracellular activity of bile salt hydrolase. Enzymatic inhibition assays revealed 66% and 24% inhibitions of α-amylase and α-glucosidase, respectively. Its cell-free supernatant inhibited DPPH (89%), hydroxyl (81%), and superoxide anion radicals (61%). Also, antioxidant activity was observed in whole cells and cell fragments. Finally, the presence of ferulic acid activity was detected. The results highlight L. rhamnosus LBUX2302 as a promising probiotic with hypoglycemic and antioxidant effects, warranting further in vivo evaluation for its possible inclusion in functional food and health formulations. Full article

Herein, we present in-depth investigations of the biological activities of a CaO/NiO nanocomposite synthesized via a sustainable eco-friendly approach, utilizing Citrus limonium fruit extract as a natural stabilizing and facilitating agent. The efficacy of the nanocomposite is compared with those of individual CaO and NiO nanoparticles. X-ray diffraction analysis confirms the cubic phase of CaO as well as NiO within a unified matrix, demonstrating a refined crystallite size of 48 nm, which is smaller than that of the individual nanoparticles. FTIR study substantiates the occurrence of strong Ca-O-Ni-O bonds, along with CO₃²⁻, C–H, and CH₂ bonds. The CaO, NiO, and CaO/NiO samples exhibit bandgap values of 1.70, 3.46, and 3.44 eV, respectively. Surface morphology analysis reveals that CaO/NiO holds a well-defined heterostructure with porous morphology. An XPS study confirms that Ca and Ni elements exist in the 2+ oxidation state in the CaO/NiO. The nanocomposite exhibits superior antibacterial activity, with inhibition zones of 24.3 mm against Bacillus subtilis and 20.6 mm against Salmonella typhi, and MIC values of 23.4 and 46.8 µg/mL, respectively. It also demonstrates strong antioxidant potential, with IC₅₀ values of 96.8 ± 0.4 µg/mL (DPPH) and 91.8 ± 0.1 µg/mL (superoxide anion). Furthermore, it shows the lowest IC₅₀ for α-amylase (98.6 ± 0.7 µg/mL) and strong α-glucosidase inhibition (81.96 ± 0.5 µg/mL). Consequently, this insightful study reveals how biogenic synthesis helps develop high-performance multifunctional CaO/NiO nanocomposites for biomedical applications. Full article

Salmonella enterica serovar Typhi (S. Typhi) produces outer membrane vesicles (OMVs) that remain comparatively underexplored as potential biotechnological tools. Here, we investigated how hypervesiculating S. Typhi mutants (ΔtolR and ΔdegS) can be engineered to load and deliver the fluorescent reporter protein mCherry, targeting human epithelial cells and the murine immune system. Deletions in tolR and degS led to distinct OMV phenotypes characterized by higher vesicle production and altered cargo composition, underscoring the impact of disrupted membrane integrity and envelope stress on OMV biogenesis. By fusing mCherry with the S. Typhi OmpA signal peptide (SP_ompA), we achieved robust and functionally intact intravesicular packaging in all strains. Flow cytometry and confocal microscopy revealed that the ΔtolR mutant exhibited particularly high cargo loading in the OMV fraction and pronounced mCherry delivery to epithelial cells, highlighting the potential of hypervesiculation to enhance OMV-based protein transport. However, immunization studies in mice showed that wild-type OMVs, despite carrying less mCherry than their hypervesiculating counterparts, induced the strongest anti-mCherry IgG responses. These findings indicate that, at least under these conditions, antigen loading alone is not sufficient to fully determine immunogenicity. Instead, the intrinsic composition or adjuvant-like properties of OMVs play a pivotal role in driving robust immune activation. Our results establish S. Typhi OMVs, especially when genetically modified with a Sec-dependent targeting signal (SP_ompA), as versatile platforms for heterologous protein delivery. Although hypervesiculation facilitates increased protein encapsulation and delivery to epithelial cells, native OMVs appear to better preserve and/or present antigens for effective immunogenic responses in vivo. These insights set the stage for further optimization of S. Typhi OMVs in vaccine development and protein therapeutics, where balancing cargo loading with immunostimulatory features may be key to achieving maximal efficacy. Full article

Enteric fever is caused by Salmonella enterica serovar Typhi (S. Typhi) and Salmonella enterica serovar Paratyphi (S. Paratyphi) A, B, and C. Globally, an estimated 11 to 21 million cases of typhoid and paratyphoid fever occur annually, with approximately 130,000–160,000 deaths, most of which are reported in South/Southeast Asia and sub-Saharan Africa. The antibiotic susceptibility of S. Typhi strains varies between countries within broad limits, from 3% to 97% for ampicillin, 9% to 95% for ciprofloxacin, 4% to 94% for chloramphenicol (India vs. Pakistan), and 0% to 99% for ceftriaxone (India vs. Iraq). With S. Typhi increasingly exhibiting resistance to antibiotics, vaccination becomes an essential preventive measure. Currently, three vaccines are licensed for typhoid fever: the typhoid conjugate vaccine (TCV), live-attenuated oral vaccine Ty21a (Ty21a), and Vi capsular polysaccharide vaccine (Vi-CPS). While no specific vaccine exists for paratyphoid fever, the genetic and antigenic similarities between S. Paratyphi and S. Typhi offer potential for the development of such a vaccine. Early studies show promising results, demonstrating both safety and immunogenicity in preclinical trials. Whole genome sequencing (WGS) provides a powerful tool for assigning genotypes, identifying plasmids, comparing genetic elements, and investigating molecular factors that contribute to antibiotic resistance and virulence. Full article

Background: From 2018 to 2021, travel-related extensively drug-resistant (XDR) Salmonella Typhi was identified in Ontario, Canada. Opportunities remain to characterize typhoidal Salmonella antimicrobial susceptibility trends (including multi-drug resistance phenotypes; MDR) within a large health authority in British Columbia, Canada. Methods: This retrospective study included patients with Salmonella Typhi or Paratyphi A, B or C bacteremia identified at Fraser Health regional microbiology laboratory from 2018 to 2024. The primary outcome was the proportion of cases with MDR and XDR typhoidal Salmonella. Secondary outcomes included annual antimicrobial susceptibility for ampicillin, ceftriaxone, ciprofloxacin, trimethoprim-sulfamethoxazole, ertapenem, meropenem and azithromycin. Clinical outcomes included hospitalization length, and 30-day mortality, clinical cure and infection relapse. Results: Among 271 patients, most were previously healthy and recently travelled. There were extended spectrum beta-lactamase (1.1%) and MDR (1.5%) typhoidal Salmonella, with no XDR cases observed. In 2024, ciprofloxacin resistance was 96% while susceptibility rates were high for other studied antimicrobials. Within 30 days, no deaths were reported; however, six patients (3%) had infection relapse. Conclusions: Currently, in British Columbia, MDR typhoidal Salmonella remains rare. Empiric ciprofloxacin should be avoided due to persistently high resistance rates. With ongoing travel patterns, it is beneficial for institutions to continue typhoidal Salmonella antimicrobial susceptibility surveillance, and travelers should seek pre-travel health assessments. Full article

Background/Objectives: Typhoid fever caused by Salmonella enterica serovar Typhi remains an important public health problem in Ghana. Understanding the epidemiology and antimicrobial resistance patterns of S. Typhi is crucial to guide the treatment and control of typhoid fever. This systematic review and meta-analysis aimed to estimate the prevalence of typhoid fever in Ghana and describe the antibiotic susceptibility profiles. Methods: Literature searches were conducted using the PubMed repository and three databases: Scopus, Web of Science, and ScienceDirect. Observational studies reporting typhoid fever prevalence among Ghanaian participants diagnosed by culture or Widal test and published between 1 January 2004 and 16 August 2024 were eligible. Quality was assessed using standardized JBI critical appraisal checklists. Random-effects meta-analysis with a 95% confidence interval was performed to estimate pooled prevalence and conduct subgroup analyses. Results: A total of 22 studies involving 228,107 participants were included in the systematic review. The pooled prevalence of typhoid fever was 4.14% (95% CI: 2.78–5.75). Blood culture detected more cases (3.68%) than stool culture (1.16%). Multidrug resistance was documented in 20–66% of isolates, and ciprofloxacin had the lowest prevalence of resistance (0–17%). Conclusions: This review highlights the substantial typhoid fever burden and evolving antimicrobial resistance in Ghana. Continuous surveillance of the disease is warranted to optimize empiric treatment and control strategies, given the resistance to first-line drugs. Enhanced prevention through water, sanitation, and vaccination programs is imperative. Full article

This study evaluates the chemical composition, fatty acid profiles, and bioactive properties of ethanolic (SPE), methanolic (SPM), and acetonic (SPA) extracts of Arthrospira platensis. The chemical analysis revealed a high protein content (72.08%), moderate lipid levels (6.49%), and a diverse fatty acid profile, dominated by polyunsaturated fatty acids. Antibacterial testing showed that SPE exhibited the strongest activity against Gram-negative bacteria, including Escherichia coli (ATCC 25922), Enterobacter cloacae (ATCC 49141), Proteus mirabilis (ATCC 25933), Salmonella typhi (ATCC 6539), Salmonella typhimurium (ATCC 14028), Salmonella enteritidis (ATCC 13076), Salmonella gallinarum (ATCC 9184), and Pseudomonas aeruginosa (ATCC 27853). The anticoccidial activity was also significant, with SPE reducing Eimeria sp. oocyst counts in poultry intestines and ceca. Antioxidant activity was highest in SPM, which also had the highest phenolic content. LC-MS/MS profiling of the methanolic extract revealed various bioactive compounds, including phenolic acids, flavonoids, carotenoids, chlorophylls, and phycobiliproteins. These results suggest that A. platensis has great potential as a nutraceutical supplement in poultry farming, offering a sustainable alternative to synthetic additives. Full article