Shigella Dysenteriae Research Articles

A newly developed oral infection mouse model of shigellosis for immunogenicity and protective efficacy studies of a candidate vaccine.

Shigella infection poses a significant public health challenge in the developing world. However, lack of a widely available mouse model that replicates human shigellosis creates a major bottleneck to better understanding of disease pathogenesis and development of newer drugs and vaccines. BALB/c mice pre-treated with streptomycin and iron (FeCl3) plus desferrioxamine intraperitoneally followed by oral infection with virulent Shigella flexneri 2a resulted in diarrhea, loss of body weight, bacterial colonization and progressive colitis characterized by disruption of epithelial lining, loss of crypt architecture with goblet cell depletion, increased polymorphonuclear infiltration into the mucosa, submucosal swelling (edema), and raised proinflammatory cytokines and chemokines in the large intestine. To evaluate the usefulness of the model for vaccine efficacy studies, mice were immunized intranasally with a recombinant protein vaccine containing Shigella invasion protein invasion plasmid antigen B (IpaB). Vaccinated mice conferred protection against Shigella, indicating that the model is suitable for testing of vaccine candidates. To protect both Shigella and Salmonella, a chimeric recombinant vaccine (rIpaB-T2544) was developed by fusing IpaB with Salmonella outer membrane protein T2544. Vaccinated mice developed antigen-specific serum IgG and IgA antibodies and a balanced Th1/Th2 response and were protected against oral challenge with Shigella (S. flexneri 2a, Shigella dysenteriae, and Shigella sonnei) using our present mouse model and Salmonella (Salmonella Typhi and Paratyphi) using an iron overload mouse model. We describe here the development of an oral Shigella infection model in wild-type mouse. This model was successfully used to demonstrate the immunogenicity and protective efficacy of a candidate protein subunit vaccine against Shigella.

Synergistic efficacy of phage Henu10 with antibiotics against Shigella dysenteriae with insight into phage resistance and fitness trade-offs

IntroductionThe irrational use of antibiotics has facilitated the emergence of multidrug- resistant Shigella spp., undermining the effectiveness of the currently available antibiotics. Consequently, there is an urgent need to explore new approaches, with phage therapy emerging as a promising alternative.MethodsIn this study, we isolated a phage targeting Shigella dysenteriae from sewage samples using DLA methold, designated Henu10. The morphology, biological characteristics, genomic composition, and phylogenetic relationships of Henu10 were thoroughly characterized. To investigate the trade-off relationship between phage resistance and bacterial fitness, phage Henu10-resistant strains R6 and R11 were identified using continuous passage and bidirectional validation methods.ResultsPhage-resistant strains R6 and R11 exhibited impaired adsorption, increased sensitivity to temperature and pH stress, heightened susceptibility to certain antibiotics (such as ciprofloxacin and kanamycin), reduced biofilm-forming capacity, and diminished colonization ability in vivo compared to the wild-type strain.DiscussionThese results indicate that phage Henu10 may effectively control the pathogenic bacteria associated with S. dysenteriae, representing a promising new therapeutic option for treating S. dysenteriae infections.

Gb3 trisaccharide-bearing exosomes as a novel neutralizer for Shiga toxin type 1

Shiga toxin types 1 (Stx1) and 2 (Stx2), produced by Shiga toxin-producing Escherichia coli (STEC) and Shigella dysenteriae, are key virulence factors responsible for severe foodborne diseases, such as hemorrhagic colitis and hemolytic uremic syndrome (HUS). The receptors for Stxs are Gb3 and P1 glycotope, which contain the Galα1→4Galβ epitope and are synthesized by human α1,4-galactosyltransferase (A4galt). Stx-related infections pose a global public health challenge, owing to the limited therapeutic options due to the restricted use of antibiotics. Therefore, there is an urgent need to develop novel therapeutic strategies. This study proposes an innovative strategy utilizing exosomes derived from CHO-Lec2 cells, which were modified with Functional-Spacer-Lipid (FSL) conjugates bearing the Gb3 carbohydrate epitope (exo-Gb3-FSL). Flow cytometry analysis confirmed the presence of Galα1→4Galβ disaccharides on exo-Gb3-FSL constructs, enabling them to bind Stx1. Moreover, using CHO-Lec2 cells verified the ability of exo-Gb3-FSL agents to bind Stx1 and protect these cells from Stx1-mediated cytotoxicity. For Stx1-treated CHO-Lec2 cells, increased cell survival was observed when using 25 μM exo-Gb3-FSL constructs, compared to control cells. These findings highlight the potential of exosome-based anti-Stx1 agents as promising alternatives to conventional therapies. This innovative strategy may provide novel directions for studies on Stx1 neutralization, offering a valuable strategy for the treatment of Stx-related diseases.

Shigella sonnei: epidemiology, evolution, pathogenesis, resistance and host interactions.

Shigella sonnei is a major cause of diarrhoea globally and is increasing in prevalence relative to other Shigella because of multiple demographic and environmental influences. This single-serotype species has traditionally received less attention in comparison to Shigella flexneri and Shigella dysenteriae, which were more common in low-income countries and more tractable in the laboratory. In recent years, we have learned that Shigella are highly complex and highly susceptible to environmental change, as exemplified by epidemiological trends and increasing relevance of S. sonnei. Ultimately, methods, tools and data generated from decades of detailed research into S. flexneri have been used to gain new insights into the epidemiology, microbiology and pathogenesis of S. sonnei. In parallel, widespread adoption of genomic surveillance has yielded insights into antimicrobial resistance, evolution and organism transmission. In this Review, we provide an overview of current knowledge of S. sonnei, highlighting recent insights into this globally disseminated antimicrobial-resistant pathogen and assessing how novel data may impact future vaccine development and implementation.

Shiga Toxins Produced by Enterohaemorrhagic Escherichia coli Induce Inflammation in Toxin-Sensitive Cells through the p38 MAPK/MK2/Tristetraprolin Signaling Pathway.

Shiga toxins (Stxs), produced by Shigella dysenteriae serotype 1 and certain Escherichia coli pathotypes, cause hemorrhagic colitis, which can progress to hemolytic uremic syndrome (HUS) and central nervous system (CNS) pathology. The underlying mechanisms of toxin-induced inflammation remain unclear. The p38 mitogen-activated protein kinase (MAPK) and its downstream target, MAPKAPK2 (MK2), play key roles in various cellular responses. We identified Tristetraprolin (TTP) as a novel substrate of MK2 in Stx-intoxicated cells. Western blot analysis showed that Stxs induce phosphorylation of MK2 (Thr334) and TTP in globotriaosylceramide (Gb3)-positive cells, including DTHP-1 macrophage-like cells and HK-2 renal epithelial cells, but not in Gb3-negative T84 colon carcinoma cells. After treatment with wild-type Stx, the activity of phosphorylated MK2 and TTP persists for up to 8 h, while Stx2amut, which lacks N-glycosidase activity, causes transient MK2/TTP phosphorylation. This suggests that Stxs selectively mediate MK2 and TTP activation in a Gb3- dependent manner. Knockdown of TTP in Stx2a-treated D-THP-1 cells upregulates proinflammatory cytokines such as TNF-α, IL-1β, IL-6, IL-8, MCP-1, and MIP-1α. The MK2 inhibitor PF-3644022 significantly reduces TTP phosphorylation and blocks the production of IL-6, IL-8, MCP-1, and MIP1α in Stx2a-stimulated HK-2 cells. In conclusion, the MK2-TTP signaling pathway regulates the inflammatory response induced by Stxs in toxin-sensitive cells.

Facile fabrication and characterization of carboxymethyl cellulose hydrogel loaded with TiO2NPs as a promising disinfectant for eliminating the dissemination of waterborne pathogens through wastewater decontamination

The purpose of this work was to develop and characterize an intriguing hydrogel called TiO₂NPs@CMC hydrogel, which is composed of carboxymethyl cellulose (CMC) loaded with titanium oxide nanoparticles (TiO₂NPs) for effective waterborne pathogen disinfection in wastewater. The TiO₂NPs were synthesized through hydrolysis and peptization. Then, incorporated into CMC matrix, and subsequently cross-linked with calcium chloride (CaCl₂). In this study, TiO2NPs was prepared and affirmed the particle distribution with a small size using TEM. The TiO₂NPs@CMC hydrogel exhibited significant antimicrobial and antibiofilm properties against various pathogens, such as Salmonella typhi, E. coli O157, Shigella dysenteriae, Enterococcus faecalis, Bacillus cereus, and Candida albicans, with highest inhibition zone diameters 29 mm for S. typhi. The inhibitory effect demonstrated that the hydrogel significantly decreased bacterial populations at 100 μg/mL concentrations. The hydrogel demonstrated a 2.7-log reduction in microbial counts in sewage within 120 min, achieving complete inactivation of pathogens at a concentration of 2xMIC within 180 min. The biofilm inhibition rate reached 87.6 % against B. cereus. Toxicity assessments demonstrated significant biocompatibility, with no adverse effects noted in environmental applications. The findings indicate that TiO₂NPs@CMC hydrogel is a viable option for sustainable wastewater treatment, providing an efficient, safe, and environmentally friendly method for removing waterborne pathogens and preventing biofilm formation.

Antibacterial Potential of Ethanol Extract from White Pidada (Sonneratia alba) Leaves Against Gastrointestinal Pathogens

The antibacterial properties of the ethanol extract of White Pidada leaves (Sonneratia alba), a mangrove plant rich in bioactive compounds such as phenols, flavonoids, steroids, saponins, triterpenoids, tannins, and alkaloids, were evaluated in this study. The research focused on determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against gastrointestinal infection-causing bacteria, including Salmonella typhii, Shigella dysenteriae, Escherichia coli, and Vibrio cholerae. The MIC results showed effective inhibition at concentrations as low as 0.025% for Shigella dysenteriae, 0.05% for Salmonella typhii and Vibrio cholerae, and 0.5% for Escherichia coli. The MBC analysis indicated bactericidal activity at higher concentrations, with significant effects observed at 1% for Salmonella typhii, 0.05% for Shigella dysenteriae and Vibrio cholerae, and 0.1% for Escherichia coli. Agar diffusion tests confirmed that increasing extract concentrations correlated positively with the inhibition zone diameter, highlighting the potential of White Pidada leaves as a natural antibacterial agent.

Antibacterial Activity of Endophytic Fungi Isolated from Parang Romang (Boehmeria virgata (G.Forst) Guill) Leaves Against Gastrointestinal Pathogens

Parang romang (Boehmeria virgata (G.Forst) Guill) is a plant traditionally used for treating various digestive tract infections. However, obtaining bioactive compounds directly from the plant requires significant biomass. Therefore, endophytic fungi, sourced from specific plant parts, are explored for their ability to produce similar bioactive compounds. The research examined the potential antibacterial activity of endophytic fungi isolated from parang romang leaves against common gastrointestinal pathogens. The methods used in was, characterization of endophytic fungal isolates, and antagonistic activity was evaluated using the agar diffusion method. The results showed that the endophytic fungal strains, namely isolates IFBV 6, IFBV 7, and IFBV 10 could inhibit the bacteria Escherichia coli, Salmonella typhi, Shigella dysenteriae, and Vibrio cholera. With an average zone of inhibition for each strains isolate against Esherichia coli respectively 11.53 mm, 10.49 mm, and 14.85 mm; Salmonella typhi 14.47 mm, 8.66 mm, and 15.51 mm; Shigella dysenteriae 22.28 mm, 13.76 mm, and 15.33 mm; and Vibrio cholera 16.91mm, 11.94mm, 15.16mm. In conclusion, isolated endophytic fungal strains hold promise as potential as antibacterialn agents.

Antibacterial Properties in Fermentate Extracts of Endophytic Fungus Derived from Marine Algae Caulerpa lentillifera Against Gastrointestinal Pathogenic Bacteria

Endophytic fungi, residing symbiotically within living plant tissues, are a promising source of novel bioactive compounds. These fungi are known to produce secondary metabolites with a wide range of biological activities, including antibacterial properties. This study explored the antibacterial potential of fermented extracts from endophytic fungi isolated from the marine alga Caulerpa lentillifera, a food source consumed by coastal communities and traditionally used for medicinal purposes. Thin-layer chromatography (TLC) bioautography was employed to identify extracts with activity against common gastrointestinal pathogenic bacteria, such as Escherichia coli, Shigella dysenteriae, and Salmonella typhi. Two endophytic fungal isolates displayed promising antibacterial activity against these pathogens. TLC analysis tentatively identified the presence of flavonoids and alkaloids, potentially responsible for the observed effects. This research sheds light on the pharmacological potential of endophytic fungi and their applications in combating bacterial infections.

Antibacterial Activity in Ethanol Extract of Kersen Flowers (Muntingia calabura L.) Against Bacteria Causing Gastrointestinal Tract Infections Using the Agar Diffusion Method

The increasing prevalence of antibiotic resistance necessitates the exploration of alternative treatments such as medicinal plants. This study evaluates the antibacterial potential of Kersen flowers (Muntingia calabura L.) against pathogens causing gastrointestinal infections. Aimed at determining the antibacterial effectiveness of ethanol extracts from Kersen flowers, the research tests the activity against Escherichia coli, Salmonella typhi, Vibrio cholerae, and Shigella dysenteriae. Employing the agar diffusion method, various concentrations of the extract (0.05% to 10%) were analyzed. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were also assessed to identify the lowest effective concentrations. The ethanol extract demonstrated significant antibacterial activity; notably, the largest inhibition zone measured 30.74 mm at a concentration of 10%. Effective MICs were as low as 0.1% for all tested bacteria, while MBCs ranged from 0.1% to 0.4%. These results suggest that ethanol extracts of Kersen flowers exhibit potent antibacterial properties against major gastrointestinal pathogens, supporting further exploration of these extracts as a natural antibacterial treatment and offering a potential alternative to conventional antibiotics.

Fabrication of NiO nanoparticles modified with carboxymethyl cellulose and D-carvone for enhanced antimicrobial, antioxidant and anti-cancer activities

Colon cancer is a deadly disease while pathogens such as Klebsiella pneumoniae (K. pneumoniae), Shigella dysenteriae (S. dysenteriae), Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) are serious threat to the human health due to their persistent nature and resistant to conventional drugs. This study aims to develop NiO nanoparticles via single one pot chemical approach and to modifying them with natural molecules carboxymethyl cellulose and D-carvone to enhance antioxidant, anticancer and antibacterial activity. The NiO and NiO-CMC-Dcar exhibit fcc structure confirmed by XRD. The band gap values were found be 4.15 eV for NiO and 4.23 eV for NiO-CMC-Dcar nanocomposite. DLS study confirmed that the mean particles diameter of NiO and NiO-CMC-Dcar were 154.1 nm and 130.3 nm respectively. The TEM and SEM analysis confirmed that both NiO and NiO-CMC-Dcar samples were roughly spherical. PL emission spectra of NiO-CMC- Dcar nanoparticles at 426 nm and 506 nm indicate the electronic structural modification due to incorporation of CMC and Dcar molecules in to NiO materials. The green emission observed at 506 nm is due to oxygen vacancy that can be correlated to production of more reactive oxygen species (ROS) to kill microorganism. The experimental results show that the NiO-CMC- Dcar nanoparticles exhibit enhanced antimicrobial, anticancer and antioxidant activity when compared to NiO alone.

Dr. Kiyoshi Shiga (1871-1957): Outstanding Bacteriologist Who Discovered Dysentery Bacillus and Contributed Immensely to Public Health in Japan.

Kiyoshi Shiga (1871-1957) was a renowned Japanese bacteriologist best known for discovering the dysentery bacillus. Born in Sendai during the Meiji Restoration, Shiga graduated from Tokyo Imperial University's School (later University of Tokyo) of Medicine and began microbiological research under Shibasaburo Kitasato. In 1897, during a dysentery (sekiri) epidemic, he isolated and identified the causative organism (later named Shigella dysenteriae) using Koch's postulates, laying the foundation for enteric disease research. Shiga later worked with Paul Ehrlich in Germany, pioneering chemotherapy research for trypanosomiasis. Upon returning to Japan, he continued studying infectious diseases such as tuberculosis and beriberi, significantly contributing to public health improvements. As a professor at Keio University School of Medicine, Shiga advanced medical education in Japan and abroad. In his later years, he returned to his hometown near Sendai, living in harmony with nature. His gentle demeanor and scientific achievements earned him deep respect and affection from the local community. Shiga's funeral was marked by a long line of mourners, a testament to the impact he had on those around him. His life embodied the balance between scientific inquiry and humanitarian spirit, profoundly influencing the development of bacteriology and public health globally.

The Current Prevalence of the Food-Borne Shigella Spp in Local Stored Cheese in Al-Diwaniyah City, Iraq: The Virulence ipaH and uidA Genes as Targets for a Molecular Study

The current study was carried out to evaluate the current prevalence of the food-borne pathogen; Shigella spp., in local stored cheese in Al-Diwaniyah City, Iraq, by using the virulence ipaH and uidA genes as targets for molecular tools. The study included the bacterial cultivation of 450 local cheese samples (collected during June to September, 2022) utilizing conventional methodology. The recovered Shigella spp. isolates were subjected to a real-time PCR (RT-PCR) that focused on the genes mentioned above. The results of the cultivation revealed the presence of 110 (24.4%) Shigella spp. isolates in the examined cheese samples. The RT-PCR showed that the virulence genes were identified in 84 (76.4%) and 98 (89.1%), respectively, in the bacterial isolates, which indicated the existence of Shigella dysenteriae. The current findings indicate the presence of Shigella spp. in local cheese, which needs urgent control to eliminate the source of infection or contamination.

Eco-friendly synthesis of curcumin-loaded ZnO nanoparticles encapsulated in Pluronic F-127: Implications for bacterial and breast cancer therapies

The development of a nanomaterials production process that is both economical and environmentally friendly is a result of the growing importance placed on people’s health. The Zinc oxide (ZnO)-Pluronic F127 (PF127)-Curcumin (CUR) nanoparticles (NPs) were synthesized through a green method using Senna auriculata flower extracts. These NPs were characterized using a variety of techniques, such as ultraviolet–visible spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), photoluminescence (PL), and dynamic light scattering (DLS). From the XRD studies, synthesized ZnO-PF127-CUR NPs exhibit a wurtzite hexagonal crystal structure. The antimicrobial activity of ZnO-PF127-CUR NPs and Amoxicillin was tested against Staphylococcus aureus, Klebsiella pneumoniae, Shigella dysenteriae, Staphylococcus pneumoniae, Bacillus subtilis, proteus vulgaris, and candida albicans, respectively. The anticancer activity of ZnO-PF127-CUR NPs was tested against human breast cancer cell line (MDA-MB-237), and ZnO-PF127-CUR exhibits potential anticancer activity. These results support using ZnO-PF127-CUR NPs in healthcare manufacturing environments to improve human health.

Bioactivity of biogenic silver/silver chloride nanoparticles from Maranta arundinacea rhizome extract: Antibacterial and antioxidant properties with anticancer potential against Ehrlich ascites carcinoma and human breast cancer cell lines

IntroductionThis study explores the synthesis and characterization of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Maranta arundinacea rhizome extract and evaluates their bioactivities, including antibacterial, antioxidant, and anticancer potentials. MethodsThe synthesis of Ag/AgCl-NPs was initially confirmed by a color change and a sharp peak at 463 nm in UV–visible spectroscopy. Further characterization was conducted using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). Antibacterial properties were checked against four pathogenic bacteria (Shigella boydii, Escherichia coli, Shigella dysenteriae, and Staphylococcus aureus), and antioxidant activities were assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) assay. In addition, the anticancer potential was evaluated in vitro using MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) colorimetric assay and in vivo using the mouse models. Finally, toxicity was determined by employing the brine shrimp nauplii lethality assay. ResultsAg/AgCl-NPs most effectively inhibited the growth of Staphylococcus aureus, showing maximum zone of inhibition and 7 μg/mL of minimum inhibitory concentration (MIC), and prevented the biofilm formation by Escherichia coli at 40 μg/mL. They displayed antioxidant activities against DPPH and ABTS with IC50 values of 90.65 and 24.34 μg/mL, respectively. In vitro, they inhibited 61.96 % EAC and 49.63 % MCF-7 cells growth at 32 and 128 μg/mL, respectively. Subsequently, inhibition rates of EAC cells growth in mice were measured as 38.30 %, 57.38 %, and 31.81 % after employing 2.5, 5, and 10 mg/kg/day of Ag/AgCl-NPs, respectively. Moreover, Ag/AgCl-NPs treated mice were found to carry more apoptotic EAC cells with distorted morphology. Treated mice showed decreased tumor weight, increased mean survival time, and a lifespan increase of up to 30 %, with improved hematological parameters. Later, Ag/AgCl-NPs exhibited moderate toxicity with an LC50 value of 208.41 μg/mL in brine shrimp nauplii lethality assay. ConclusionThe promising antibacterial, antioxidant, and anticancer activities along with mild toxicity suggest the potential biomedical uses of Maranta arundinacea rhizome extract-mediated Ag/AgCl-NPs.

Fortification of cotton fabrics with dithiocarbamate-metal complexes to prepare durable antimicrobial fabrics

In this study, a simple and practical method is reported to fortify cotton fabrics with dithiocarbamate (DTC-Ct), dithiocarbamate-Cu (Cu-Ct) and dithiocarbamate-Ni (Ni-Ct) complexes via impregnation process to prepare durable antimicrobial fabrics. FTIR analysis indicates the presence of characteristic peaks corresponding to cellulose functional groups in the fortified fabrics. SEM micrographs illustrate the transition from a closed-packed, smooth surface in untreated cotton to a rough texture enveloped with metal complexes in fortified fabrics. EDX images confirm successful impregnation, with prominent peaks due to C and O in the untreated cotton, while additional signals of S, Cu, and Ni were observed in the fortified samples. TEM images revealed irregular, spherical nanoparticles within fortified cotton, compared with the rough surface of untreated fabrics. The average size of the treated cotton fabric fell within the range of 2.20–7.32, 3.83–28.50, and 2.70–7.32 nm for DTC-Ct, Cu-Ct and Ni-Ct, respectively. Untreated cotton fabric exhibits no inherent antibacterial properties, whereas fortified cotton fabrics demonstrate enhanced antibacterial efficacy against strains including Salmonella typhi, Enterobacter aerogenes, Shigella dysenteriae, and Klebsiella pneumonia, with Ni-Ct-fortified cotton proving most effective. Furthermore, the durability of additive adhesion to cotton fabrics was evaluated through washing tests, revealing robust adherence even after multiple cycles, with sustained antimicrobial inhibition observed for up to five wash cycles.

Multidrug-Resistant Proteus mirabilis and Other Gram-Negative Species Isolated from Native Egyptian Chicken Carcasses.

Poultry carcasses may be reservoirs for the zoonotic transmission of antimicrobial-resistant bacteria to humans and pose a major public health hazard. During the isolation of Salmonella from poultry and other foods, many of the presumptive typical Salmonella colonies on xylose lysine deoxycholate (XLD) agar were found to lack the invA gene, which is the specific target gene for Salmonella spp. Therefore, the current study aimed to estimate the prevalence and antimicrobial resistance profiles of extensively drug-resistant invA-negative non-Salmonella isolates recovered from native Egyptian chicken carcasses as presumptive Salmonella colonies on XLD agar. The non-Salmonella isolates were detected in 84% (126/150) of the examined native Egyptian chicken carcasses and classified into five genera, with prevalence rates of 64% (96/150), 14% (21/150), 6.7% (10/150), 3.3% (5/150), and 1.3% (2/150) for Proteus, Citrobacter, Shigella, Pseudomonas, and Edwardsiella, respectively. One hundred and ninety-five invA-negative, non-verified presumptive Salmonella isolates were recovered and classified at the species level into Proteus mirabilis (132/195; 67.7%), Proteus vulgaris (11/195; 5.6%), Citrobacter freundii (26/195; 13.3%), Shigella flexneri (8/195; 4.1%), Shigella sonnei (6/195; 3.1%), Shigella dysenteriae (3/195; 1.5%), Pseudomonas fluorescens (6/195; 3.1%), and Edwardsiella tarda (3/195; 1.5%). All (195/195; 100%) of these isolates showed resistance against cefaclor and fosfomycin. Additionally, these isolates showed high resistance rates of 98%, 92.8%, 89.7%, 89.2%, 89.2%, 86.7%, 80%, 78.5%, 74.4%, and 73.9% against cephalothin, azithromycin, vancomycin, nalidixic acid, tetracycline, sulfamethoxazole/trimethoprim, cefepime, gentamicin, cefotaxime, and ciprofloxacin, respectively. Interestingly, all (195/195; 100%) of the identified isolates were resistant to at least five antibiotics and exhibited an average MAR (multiple antibiotic resistance) index of 0.783. Furthermore, 73.9% of the examined isolates were classified as extensively drug-resistant, with an MAR index equal to 0.830. The high prevalence of extensively drug-resistant foodborne Proteus, Citrobacter, Shigella, Pseudomonas, and Edwardsiella isolated from native chicken carcasses poses a great hazard to public health and necessitates more monitoring and concern about the overuse and misuse of antibiotics in humans and animals. This study also recommends the strict implementation of GHP (good hygienic practices) and GMP (good manufacturing practices) in the chicken meat supply chain to protect consumer health.

Green synthesis of copper oxide nanoparticles using Ficus racemosa leaf extract and investigation of its antibacterial properties

ABSTRACT The present work reports a one-pot green synthesis of copper oxide nanoparticles (CuO NPs) using Ficus racemosa leaf extract via a green chemistry approach without using any harsh chemical reagents. The crystalline and single-phase CuO NPs were analysed via XRD. DLS revealed the average particle size distribution, and zeta potential was used for the evaluation of surface charge. Optical properties were determined at 530 nm through UV–Vis spectroscopy with a broad peak in the range from 500 to 590 nm. Different functional groups in the leaf extract containing flavonoids and polyphenols as reducing agents responsible for the synthesis of CuO NPs were verified through FTIR. The FESEM images revealed the average particle size in the range from 30 to 300 nm with a spherical morphology, and EDS was used for the quantitative elemental analysis. The strong bacterial inhibition tendency of CuO NPs against 12 bacterial strains including Bacillus cereus, Campylobacter jejuni, Bacillus subtilis, Clostridium perfringens, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Shigella dysenteriae, Listeria monocytogenes, Helicobacter pylori, and Salmonella typhi was observed with MIC values between 60 and 1000 µg/mL. The findings suggest that the synthesis of CuO NPs via green chemistry can serve as a potential substitute for traditional multi-step chemical synthetic routes.

Enhancement of antimicrobial properties and cytocompatibility through silver and magnesium doping strategies on copper oxide nanocomposites

In the present study, silver (Ag), magnesium (Mg), and the various molar ratios of Ag:Mg-doped copper oxide nanocomposites (CuO NCs) were synthesized by the co-precipitation method. The CuO NC samples calcined at 500 °C were further analyzed for their morphological, structural, functional, and optical properties. Adding single and dual doping increased the pristine CuO band gap from 1.28 to 1.50 eV. The Ag and Mg metal peaks were revealed in the Fourier transform infrared (FTIR) analysis, while an elevated Mg band was observed in all Mg-doped samples in the Raman results. All CuO NCs showed a monoclinic crystalline structure, flake, and rod-like morphologies. Microbes of Bacillus subtilis, Shigella dysenteriae, and Candida albicans were tested against different concentrations of CuO NCs. Better results for all tested microbes were observed with the 2 mg concentration. The high cytotoxicity effect was observed in the pristine and Cu:Ag (94:6) sample, and other CuO NCs, which demonstrated over 80 % viability in RAW 246.7 cells at a concentration of 0.5 µg/ml. Remarkably, over 94 % cell viability at 0.5 µg/ml was achieved with the Cu:Ag:Mg (94:3:3) NCs ratio, owing to the synergistic effect of the ion-releasing ability of Cu2+, Ag2+, and Mg2+ ions. It possesses a distinctive high aspect ratio shape, is ion-releasing, and has excellent cytocompatibility. The suitability of the Cu:Ag:Mg (94:3:3) NCs ratio for addressing microbial challenges in healthcare is suggested by their distinct characteristics, indicating the promising potential for future biomedical applications.

Novel α-N-heterocyclic thiosemicarbazone complexes: synthesis, characterization, and antimicrobial of properties investigation.

In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via organic elemental analysis, nuclear magnetic resonance spectroscopy, infrared spectra, thermogravimetric analysis, ultraviolet-visible spectroscopy, molar conductance and magnetic susceptibility measurements. The in vitro antimicrobial activity of these complexes was examined against ten disease-causing pathogens: Gram-positive bacteria (Micrococcus luteus ATCC9341, Staphylococcus epidermidis ATCC12228, Bacillus cereus RSKK863) and Gram-negative bacteria (Pseudomonas aeroginosa ATCC27853, Klebsiella pneumonia ATCC27853, Enterobacter aerogenes ATCC51342, Salmonella typhi H NCTC9018394, Shigella dysenteria NCTC2966, Proteus vulgaris RSKK96026) and yeast (Candida albicans Y-1200-NIH). The results revealed that the α-N-heterocyclic thiosemicarbazone compounds showed potent activity. It was observed that all thiosemicarbazone complexes were more susceptible to Gram-negative strains based on the presence of an electron-withdrawing substituent (-Br/-Cl/-F). It was determined that thiosemicarbazone Cu2+complexes showed stronger antifungal effects.