Antibacterial and Anti-Quorum Sensing Properties of Silver Nanoparticles Phytosynthesized Using .

The rise in antibiotic resistance (AR) poses an imminent threat to human health. Nanotechnology, together with mechanisms such as quorum sensing (QS), which relies on communication between bacterial cells, may decrease the selective pressure for AR. Thus, this study aimed to investigate the effectiveness of silver nanoparticles (AgNPs) synthesized at room temperature (Rt) and 80 °C using leaf, stem-bark, and fruit extracts as antibacterial and anti-QS agents.

Multiple Vaccines and Strategies for Pandemic Preparedness of Avian Influenza Virus.

Avian influenza viruses (AIV) are a continuous cause of concern due to their pandemic potential and devasting effects on poultry, birds, and human health. The low pathogenic avian influenza virus has the potential to evolve into a highly pathogenic avian influenza virus, resulting in its rapid spread and significant outbreaks in poultry. Over the years, a wide array of traditional and novel strategies has been implemented to prevent the transmission of AIV in poultry.

Evaluation of dendritic cell-targeting T7 phages as a vehicle to deliver avian influenza virus H5 DNA vaccine in SPF chickens.

Introduction: There is a growing demand for effective technologies for the delivery of antigen to antigen-presenting cells (APCs) and their immune-activation for the success of DNA vaccines. Therefore, dendritic cell (DC)-targeting T7 phages were used as a vehicle to deliver DNA vaccine.

Methods: In this study, a eukaryotic expression plasmid pEGFP-C1-HA2-AS containing the HA2 gene derived from the avian H5N1 virus and an anchor sequence (AS) gene required for the T7 phage packaging process was developed.

Genotyping and biofilm formation of Mycoplasma hyopneumoniae and their association with virulence.

Mycoplasma hyopneumoniae, the causative agent of swine respiratory disease, demonstrates differences in virulence. However, factors associated with this variation remain unknown. We herein evaluated the association between differences in virulence and genotypes as well as phenotype (i.

Construction of a T7 phage display nanobody library for bio-panning and identification of chicken dendritic cell-specific binding nanobodies.

Dendritic cells (DCs) are the antigen-presenting cells that initiate and direct adaptive immune responses, and thus are critically important in vaccine design. Although DC-targeting vaccines have attracted attention, relevant studies on chicken are rare. A high diversity T7 phage display nanobody library was constructed for bio-panning of intact chicken bone marrow DCs to find DC-specific binding nanobodies.

Biological Characterization and Evolution of Bacteriophage T7-△holin During the Serial Passage Process.

Bacteriophage T7 gene coding for the only known holin is one of the components of its lysis system, but the holin activity in T7 is more complex than a single gene, and evidence points to the existence of additional T7 genes with holin activity. In this study, a T7 phage with a gene deletion (T7-△holin) was rescued and its biological characteristics and effect on cell lysis were determined. Furthermore, the genomic evolution of mutant phage T7-△holin during serial passage was assessed by whole-genome sequencing analysis.

High prevalence of multidrug resistant ESBL- and plasmid mediated AmpC-producing clinical isolates of Escherichia coli at Maputo Central Hospital, Mozambique.

Background: Epidemiological data of cephalosporin-resistant Enterobacterales in Sub-Saharan Africa is still restricted, and in particular in Mozambique. The aim of this study was to detect and characterize extended-spectrum β-lactamase (ESBL) - and plasmid-mediated AmpC (pAmpC)-producing clinical strains of Escherichia coli at Maputo Central Hospital (MCH), a 1000-bed reference hospital in Maputo, Mozambique.

Methods: A total of 230 clinical isolates of E.

Molecular Epidemiology of Antibiotic-Resistant from Farm-To-Fork in Intensive Poultry Production in KwaZulu-Natal, South Africa.

The increased use of antibiotics in food animals has resulted in the selection of drug-resistant bacteria across the farm-to-fork continuum. This study aimed to investigate the molecular epidemiology of antibiotic-resistant from intensively produced poultry in the uMgungundlovu District, KwaZulu-Natal, South Africa. Samples were collected weekly between August and September 2017 from hatching to final retail products.

Biochar-Mediated Control of Phytophthora Blight of Pepper Is Closely Related to the Improvement of the Rhizosphere Fungal Community.

Biochar is a new eco-material with the potential to control soilborne diseases. This study explored the relationship between the rhizosphere fungal community and the suppression of Phytophthora blight of pepper in the context of time after biochar application. A pot experiment was conducted and rhizosphere soils were sampled to determine the biochar-induced soil chemical properties, fungal community composition, and abundance of biocontrol fungi.

β-lactam and fluoroquinolone resistance in Enterobacteriaceae from imported and locally-produced chicken in Mozambique.

Introduction: Plasmid-mediated resistance to β-lactam and fluoroquinolone antibiotics was investigated in Enterobacteriaceae isolated from retailed frozen chickens from Brazil, South Africa and Mozambique.

Methodology: Carcass swabs and the liquid thaw of 33 chickens from each of the three countries constituted the total sample size of 198. Isolates were identified by biochemical tests, antibiotic susceptibility was ascertained by the disc diffusion assay and β-lactamases were detected using the double-disk synergy test.

Sesquiterpene lactones from and their quorum sensing inhibitory activity.

The leaves of , with the synonym are widely used as purgative agents for gastrointestinal problems, and other members of Vernonieae have been used in African traditional medicine for decades. A new sesquiterpene lactone of the keto-hirsutinolide type, 13-acetoxy-1(4),5(6)-diepoxy-8-(senecioyloxy)-3-oxo-1,7(11)-germacradiene-12,6-olide , was isolated from the hexane extract of its leaves, in addition to the known 13-acetoxy-1,4-epoxy-8-(senecioyloxy)-3-oxo-1,5,7(11)-germacratriene-12,6-olide . Three common flavonoids (apigenin , luteolin and velutin ) were also isolated.

Draft Genome Sequence of Providencia rettgeri APW139_S1, an NDM-18-Producing Clinical Strain Originating from Hospital Effluent in South Africa.

is an opportunistic pathogen implicated in various clinical infections. Here, we report the genome sequence of a strain isolated from hospital effluent in South Africa, which harbors the New Delhi metallo-β-lactamase (NDM) variant 18 gene ( ). The 4,835,047-bp genome encodes a resistome and virulome that are of cardinal importance to infections.

Emergence and Spread of Extended Spectrum β-Lactamase Producing Enterobacteriaceae (ESBL-PE) in Pigs and Exposed Workers: A Multicentre Comparative Study between Cameroon and South Africa.

Extended spectrum β-lactamase-producing (ESBL-PE) represent a significant public health concern globally and are recognized by the World Health Organization as pathogens of critical priority. However, the prevalence of ESBL-PE in food animals and humans across the farm-to-plate continuum is yet to be elucidated in Sub-Saharan countries including Cameroon and South Africa. This work sought to determine the risk factors, carriage, antimicrobial resistance profiles and genetic relatedness of extended spectrum β-lactamase producing (ESBL-PE) amid pigs and abattoir workers in Cameroon and South Africa.

biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments.

is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units.

Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system.

Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays.

Prevalence and characterization of plasmid-mediated quinolone resistance genes in Aeromonas spp. isolated from South African freshwater fish.

An increasing incidence of multidrug-resistant Aeromonas spp., which are both fish and emerging opportunistic human pathogens, has been observed worldwide. Quinolone-resistant Aeromonas spp.

Quorum sensing inhibitory potential and molecular docking studies of sesquiterpene lactones from Vernonia blumeoides.

The increasing incidence of multidrug-resistant Gram-negative bacterial pathogens has focused research on the suppression of bacterial virulence via quorum sensing inhibition strategies, rather than the conventional antimicrobial approach. The anti-virulence potential of eudesmanolide sesquiterpene lactones previously isolated from Vernonia blumeoides was assessed by inhibition of quorum sensing and in silico molecular docking. Inhibition of quorum sensing-controlled violacein production in Chromobacterium violaceum was quantified using violacein inhibition assays.

Anti-quorum sensing potential of crude Kigelia africana fruit extracts.

The increasing incidence of multidrug-resistant pathogens has stimulated the search for novel anti-virulence compounds. Although many phytochemicals show promising antimicrobial activity, their power lies in their anti-virulence properties. Thus the quorum sensing (QS) inhibitory activity of four crude Kigelia africana fruit extracts was assessed qualitatively and quantitatively using the Chromobacterium violaceum and Agrobacterium tumefaciens biosensor systems.

Biofilm formation and adherence characteristics of an Elizabethkingia meningoseptica isolate from Oreochromis mossambicus.

Background: Elizabethkingia spp. are opportunistic pathogens often found associated with intravascular device-related bacteraemias and ventilator-associated pneumonia. Their ability to exist as biofilm structures has been alluded to but not extensively investigated.

Characterization of integrons and tetracycline resistance determinants in Aeromonas spp. isolated from South African aquaculture systems.

An increasing incidence of multidrug resistance amongst Aeromonas spp. isolates, which are both fish pathogens and emerging opportunistic human pathogens, has been observed worldwide. This can be attributed to the horizontal transfer of mobile genetic elements, viz.

Analysis of the mechanisms of fluoroquinolone resistance in urinary tract pathogens.

Objectives: To characterize the mechanisms of fluoroquinolone resistance in urinary tract pathogens exhibiting a multiple antibiotic resistance phenotype as well as a high-level resistance to fluoroquinolones.

Methods: Nineteen Escherichia coli urinary tract infection pathogens exhibiting high-level resistance to fluoroquinolones were characterized in this study. Alterations in outer membrane proteins (OMPs) and lipopolysaccharide (LPS) were analysed by PAGE.