scholarly journals Designing P. aeruginosa synthetic phages with reduced genomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diana P. Pires ◽  
Rodrigo Monteiro ◽  
Dalila Mil-Homens ◽  
Arsénio Fialho ◽  
Timothy K. Lu ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Antibacterial Properties ◽  
Genetically Engineered ◽  
In Vivo Studies ◽  
Infection Model ◽  
Promising Therapeutic Approach ◽  
Genes Encoding ◽  
First Time

AbstractIn the era where antibiotic resistance is considered one of the major worldwide concerns, bacteriophages have emerged as a promising therapeutic approach to deal with this problem. Genetically engineered bacteriophages can enable enhanced anti-bacterial functionalities, but require cloning additional genes into the phage genomes, which might be challenging due to the DNA encapsulation capacity of a phage. To tackle this issue, we designed and assembled for the first time synthetic phages with smaller genomes by knocking out up to 48% of the genes encoding hypothetical proteins from the genome of the newly isolated Pseudomonas aeruginosa phage vB_PaeP_PE3. The antibacterial efficacy of the wild-type and the synthetic phages was assessed in vitro as well as in vivo using a Galleria mellonella infection model. Overall, both in vitro and in vivo studies revealed that the knock-outs made in phage genome do not impair the antibacterial properties of the synthetic phages, indicating that this could be a good strategy to clear space from phage genomes in order to enable the introduction of other genes of interest that can potentiate the future treatment of P. aeruginosa infections.

scholarly journals In Vitro and In Vivo Biological Activity of Berberine Chloride against Uropathogenic E. coli Strains Using Galleria mellonella as a Host Model

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5010
Author(s):  
Giulio Petronio Petronio ◽  
Marco Alfio Cutuli ◽  
Irene Magnifico ◽  
Noemi Venditti ◽  
Laura Pietrangelo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
Biological Activities ◽  
Antibacterial Properties ◽  
In Vivo Model ◽  
Infection Model ◽  
E Coli ◽  
Urinary Infections

Berberine is an alkaloid of the protoberberine type used in traditional oriental medicine. Its biological activities include documented antibacterial properties against a wide variety of microorganisms; nonetheless, its use against Escherichia coli strains isolated from urinary infections has not yet been widely investigated in vivo. The emergence of antimicrobial resistance requires new therapeutic approaches to ensure the continued effectiveness of antibiotics for the treatment and prevention of urinary infections. Moreover, uropathogenic Escherichia coli (UPEC) has developed several virulence factors and resistance to routine antibiotic therapy. To this end, several in vitro and in vivo tests were conducted to assess the activity of berberine on uropathogenic E. coli strains. Galleria mellonella as an infection model was employed to confirm the in vivo translatability of in vitro data on berberine activity and its influence on adhesion and invasion proprieties of E. coli on human bladder cells. In vitro pre-treatment with berberine was able to decrease the adhesive and invasive UPEC ability. In vivo treatment increased the larvae survival infected with UPEC strains and reduced the number of circulating pathogens in larvae hemolymph. These preliminary findings demonstrated the efficacy and reliability of G. mellonella as in vivo model for pre-clinical studies of natural substances.

scholarly journals Inactivation of Burkholderia cepacia Complex Phage KS9 gp41 Identifies the Phage Repressor and Generates Lytic Virions

2009 ◽  
Vol 84 (3) ◽  
pp. 1276-1288 ◽  
Author(s):  
Karlene H. Lynch ◽  
Kimberley D. Seed ◽  
Paul Stothard ◽  
Jonathan J. Dennis
Keyword(s):  
Burkholderia Cepacia ◽  
Bacterial Infections ◽  
Galleria Mellonella ◽  
Genetically Engineered ◽  
Molecular Techniques ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Reading Frame ◽  
Genes Encoding

ABSTRACT The Burkholderia cepacia complex (BCC) is made up of at least 17 species of Gram-negative opportunistic bacterial pathogens that cause fatal infections in patients with cystic fibrosis and chronic granulomatous disease. KS9 (vB_BcenS_KS9), one of a number of temperate phages isolated from BCC species, is a prophage of Burkholderia pyrrocinia LMG 21824. Transmission electron micrographs indicate that KS9 belongs to the family Siphoviridae and exhibits the B1 morphotype. The 39,896-bp KS9 genome, comprised of 50 predicted genes, integrates into the 3′ end of the LMG 21824 GTP cyclohydrolase II open reading frame. The KS9 genome is most similar to uncharacterized prophage elements in the genome of B. cenocepacia PC184 (vB_BcenZ_ PC184), as well as Burkholderia thailandensis phage φE125 and Burkholderia pseudomallei phage φ1026b. Using molecular techniques, we have disrupted KS9 gene 41, which exhibits similarity to genes encoding phage repressors, producing a lytic mutant named KS9c. This phage is incapable of stable lysogeny in either LMG 21824 or B. cenocepacia strain K56-2 and rescues a Galleria mellonella infection model from experimental B. cenocepacia K56-2 infections at relatively low multiplicities of infection. These results readily demonstrate that temperate phages can be genetically engineered to lytic form and that these modified phages can be used to treat bacterial infections in vivo.

scholarly journals Hexapod Assassins’ Potion: Venom Composition and Bioactivity from the Eurasian Assassin Bug Rhynocoris iracundus

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 819
Author(s):  
Nicolai Rügen ◽  
Timothy P. Jenkins ◽  
Natalie Wielsch ◽  
Heiko Vogel ◽  
Benjamin-Florian Hempel ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Galleria Mellonella ◽  
Systemic Reactions ◽  
Venom Composition ◽  
Assassin Bug ◽  
Molecular Components ◽  
First Time ◽  
Tissue Digestion

Assassin bug venoms are potent and exert diverse biological functions, making them potential biomedical goldmines. Besides feeding functions on arthropods, assassin bugs also use their venom for defense purposes causing localized and systemic reactions in vertebrates. However, assassin bug venoms remain poorly characterized. We collected the venom from the assassin bug Rhynocoris iracundus and investigated its composition and bioactivity in vitro and in vivo. It caused lysis of murine neuroblastoma, hepatoma cells, and healthy murine myoblasts. We demonstrated, for the first time, that assassin bug venom induces neurolysis and suggest that it counteracts paralysis locally via the destruction of neural networks, contributing to tissue digestion. Furthermore, the venom caused paralysis and melanization of Galleria mellonella larvae and pupae, whilst also possessing specific antibacterial activity against Escherichia coli, but not Listeria grayi and Pseudomonas aeruginosa. A combinatorial proteo-transcriptomic approach was performed to identify potential toxins responsible for the observed effects. We identified neurotoxic Ptu1, an inhibitory cystin knot (ICK) toxin homologous to ω-conotoxins from cone snails, cytolytic redulysins homologous to trialysins from hematophagous kissing bugs, and pore-forming hemolysins. Additionally, chitinases and kininogens were found and may be responsible for insecticidal and cytolytic activities. We demonstrate the multifunctionality and complexity of assassin bug venom, which renders its molecular components interesting for potential biomedical applications.

scholarly journals Antibacterial Mechanisms and Efficacy of Sarecycline in Animal Models of Infection and Inflammation

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 439
Author(s):  
Christopher G. Bunick ◽  
Jonette Keri ◽  
S. Ken Tanaka ◽  
Nika Furey ◽  
Giovanni Damiani ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Bacterial Resistance ◽  
Antibiotic Use ◽  
In Vivo Studies ◽  
Infection Model ◽  
Severe Acne ◽  
Rat Paw Edema ◽  
Infection And Inflammation

Prolonged broad-spectrum antibiotic use is more likely to induce bacterial resistance and dysbiosis of skin and gut microflora. First and second-generation tetracycline-class antibiotics have similar broad-spectrum antibacterial activity. Targeted tetracycline-class antibiotics are needed to limit antimicrobial resistance and improve patient outcomes. Sarecycline is a narrow-spectrum, third-generation tetracycline-class antibiotic Food and Drug Administration (FDA)-approved for treating moderate-to-severe acne. In vitro studies demonstrated activity against clinically relevant Gram-positive bacteria but reduced activity against Gram-negative bacteria. Recent studies have provided insight into how the structure of sarecycline, with a unique C7 moiety, interacts with bacterial ribosomes to block translation and prevent antibiotic resistance. Sarecycline reduces Staphylococcus aureus DNA and protein synthesis with limited effects on RNA, lipid, and bacterial wall synthesis. In agreement with in vitro data, sarecycline demonstrated narrower-spectrum in vivo activity in murine models of infection, exhibiting activity against S. aureus, but reduced efficacy against Escherichia coli compared to doxycycline and minocycline. In a murine neutropenic thigh wound infection model, sarecycline was as effective as doxycycline against S. aureus. The anti-inflammatory activity of sarecycline was comparable to doxycycline and minocycline in a rat paw edema model. Here, we review the antibacterial mechanisms of sarecycline and report results of in vivo studies of infection and inflammation.

scholarly journals In vivo transcriptome analysis provides insights into host-dependent expression of virulence factors by Yersinia entomophaga MH96, during infection of Galleria mellonella

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Amber R Paulson ◽  
Maureen O’Callaghan ◽  
Xue-Xian Zhang ◽  
Paul B Rainey ◽  
Mark R H Hurst
Keyword(s):  
Galleria Mellonella ◽  
Functional Enrichment ◽  
Natural Environments ◽  
Insecticidal Toxin ◽  
Heat Stable ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Cell Densities

Abstract The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.

Emergence of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae in vivo

2019 ◽  
Vol 74 (11) ◽  
pp. 3211-3216 ◽  
Author(s):  
Stephan Göttig ◽  
Denia Frank ◽  
Eleonora Mungo ◽  
Anika Nolte ◽  
Michael Hogardt ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Selection Pressure ◽  
Galleria Mellonella ◽  
Phenotypic Characterization ◽  
Infection Model ◽  
Development Of Resistance ◽  
Time Kill

Abstract Objectives The β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is active against KPC-producing Enterobacterales. Herein, we present molecular and phenotypic characterization of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae that emerged in vivo and in vitro. Methods Sequence analysis of blaKPC-3 was performed from clinical and in vitro-generated ceftazidime/avibactam-resistant K. pneumoniae isolates. Time–kill kinetics and the Galleria mellonella infection model were applied to evaluate the activity of ceftazidime/avibactam and imipenem alone and in combination. Results The ceftazidime/avibactam-resistant clinical K. pneumoniae isolate revealed the amino acid change D179Y in KPC-3. Sixteen novel mutational changes in KPC-3 among in vitro-selected ceftazidime/avibactam-resistant isolates were described. Time–kill kinetics showed the emergence of a resistant subpopulation under selection pressure with either imipenem or ceftazidime/avibactam. However, combined selection pressure with imipenem plus ceftazidime/avibactam prevented the development of resistance and resulted in bactericidal activity. Concordantly, the G. mellonella infection model revealed that monotherapy with ceftazidime/avibactam is prone to select for resistance in vivo and that combination therapy with imipenem results in significantly better survival. Conclusions Ceftazidime/avibactam is a valuable antibiotic against MDR and carbapenem-resistant Enterobacterales. Based on time–kill kinetics as well as an in vivo infection model we postulate a combination therapy of ceftazidime/avibactam and imipenem as a strategy to prevent the development of ceftazidime/avibactam resistance in KPC-producing Enterobacterales in vivo.

scholarly journals Impact of the Order of Initiation of Fluconazole and Amphotericin B in Sequential or Combination Therapy on Killing of Candida albicans In Vitro and in a Rabbit Model of Endocarditis and Pyelonephritis

2001 ◽  
Vol 45 (2) ◽  
pp. 485-494 ◽  
Author(s):  
Arnold Louie ◽  
Pamela Kaw ◽  
Partha Banerjee ◽  
Weiguo Liu ◽  
George Chen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Induced Resistance ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Infection Model ◽  
Simultaneous Exposure ◽  
The Impact

ABSTRACT In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC→AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of ≥1 μg/ml; antagonism was seen using an AMB concentration of 0.5 μg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB→AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC→AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC→AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB→FLC regimen. However, FLC→AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.

scholarly journals In vitro neuroprotective activities of two distinct probiotic consortia

2019 ◽  
Vol 10 (4) ◽  
pp. 437-447 ◽  
Author(s):  
D.R. Michael ◽  
T.S. Davies ◽  
K.E. Loxley ◽  
M.D. Allen ◽  
M.A. Good ◽  
...  
Keyword(s):  
Cell Model ◽  
Neuronal Cell ◽  
In Vivo Studies ◽  
Intact Cells ◽  
Bacterial Consortia ◽  
Differentiated Cells ◽  
Genes Encoding ◽  
Induced Apoptosis

Neurodegeneration has been linked to changes in the gut microbiota and this study compares the neuroprotective capability of two bacterial consortia, known as Lab4 and Lab4b, using the established SH-SY5Y neuronal cell model. Firstly, varying total antioxidant capacities (TAC) were identified in the intact cells from each consortia and their secreted metabolites, referred to as conditioned media (CM). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Crystal Violet (CV) assays of cell viability revealed that Lab4 CM and Lab4b CM could induce similar levels of proliferation in SH-SY5Y cells and, despite divergent TAC, possessed a comparable ability to protect undifferentiated and retinoic acid-differentiated cells from the cytotoxic actions of rotenone and undifferentiated cells from the cytotoxic actions of 1-methyl-4-phenylpyridinium iodide (MPP+). Lab4 CM and Lab4b CM also had the ability to attenuate rotenone-induced apoptosis and necrosis with Lab4b inducing the greater effect. Both consortia showed an analogous ability to attenuate intracellular reactive oxygen species accumulation in SH-SY5Y cells although the differential upregulation of genes encoding glutathione reductase and superoxide dismutase by Lab4 CM and Lab4b CM, respectively, implicates the involvement of consortia-specific antioxidative mechanisms of action. This study implicates Lab4 and Lab4b as potential neuroprotective agents and justifies their inclusion in further in vivo studies.

scholarly journals Tannic Acid with Antiviral and Antibacterial Activity as A Promising Component of Biomaterials—A Minireview

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3224 ◽  
Author(s):  
Beata Kaczmarek
Keyword(s):  
Physicochemical Properties ◽  
Tannic Acid ◽  
Phenolic Acid ◽  
Antibacterial Properties ◽  
Biological Properties ◽  
In Vivo Studies ◽  
Biomedical Sciences ◽  
Simplex Virus

As a phenolic acid, tannic acid can be classified into a polyphenolic group. It has been widely studied in the biomedical field of science because it presents unique antiviral as well as antibacterial properties. Tannic acid has been reported to present the activity against Influeneza A virus, Papilloma viruses, noroviruses, Herpes simplex virus type 1 and 2, and human immunodeficiency virus (HIV) as well as activity against both Gram-positive and Gram-negative bacteria as Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Enterococcus faecalis, Pseudomonas aeruginosa, Yersinia enterocolitica, Listeria innocua. Nowadays, compounds of natural origin constitute fundaments of material science, and the trend is called “from nature to nature”. Although biopolymers have found a broad range of applications in biomedical sciences, they do not present anti-microbial activity, and their physicochemical properties are rather poor. Biopolymers, however, may be modified with organic and inorganic additives which enhance their properties. Tannic acid, like phenolic acid, is classified into a polyphenolic group and can be isolated from natural sources, e.g., a pure compound or a component of a plant extract. Numerous studies have been carried out over the application of tannic acid as an additive to biopolymer materials due to its unique properties. On the one hand, it shows antimicrobial and antiviral activity, while on the other hand, it reveals promising biological properties, i.e., enhances the cell proliferation, tissue regeneration and wound healing processes. Tannic acid is added to different biopolymers, collagen and polysaccharides as chitosan, agarose and starch. Its activity has been proven by the determination of physicochemical properties, as well as the performance of in vitro and in vivo studies. This systematics review is a summary of current studies on tannic acid properties. It presents tannic acid as an excellent natural compound which can be used to eliminate pathogenic factors as well as a revision of current studies on tannic acid composed with biopolymers and active properties of the resulting complexes.

scholarly journals An Optimized Bacteriophage Cocktail Can Effectively Control Salmonella in vitro and in Galleria mellonella

2021 ◽  
Vol 11 ◽  
Author(s):  
Janet Y. Nale ◽  
Gurinder K. Vinner ◽  
Viviana C. Lopez ◽  
Anisha M. Thanki ◽  
Preeda Phothaworn ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Future Application ◽  
Infection Model ◽  
Prophylactic Regimen ◽  
Phage Cocktail ◽  
Resistant Strains ◽  
Future Work ◽  
Further Development

Salmonella spp. is a leading cause of gastrointestinal enteritis in humans where it is largely contracted via contaminated poultry and pork. Phages can be used to control Salmonella infection in the animals, which could break the cycle of infection before the products are accessible for consumption. Here, the potential of 21 myoviruses and a siphovirus to eliminate Salmonella in vitro and in vivo was examined with the aim of developing a biocontrol strategy to curtail the infection in poultry and swine. Together, the phages targeted the twenty-three poultry and ten swine prevalent Salmonella serotype isolates tested. Although individual phages significantly reduced bacterial growth of representative isolates within 6 h post-infection, bacterial regrowth occurred 1 h later, indicating proliferation of resistant strains. To curtail bacteriophage resistance, a novel three-phage cocktail was developed in vitro, and further investigated in an optimized Galleria mellonella larva Salmonella infection model colonized with representative swine, chicken and laboratory strains. For all the strains examined, G. mellonella larvae given phages 2 h prior to bacterial exposure (prophylactic regimen) survived and Salmonella was undetectable 24 h post-phage treatment and throughout the experimental time (72 h). Administering phages with bacteria (co-infection), or 2 h post-bacterial exposure (remedial regimen) also improved survival (73–100% and 15–88%, respectively), but was less effective than prophylaxis application. These pre-livestock data support the future application of this cocktail for further development to effectively treat Salmonella infection in poultry and pigs. Future work will focus on cocktail formulation to ensure stability and incorporation into feeds and used to treat the infection in target animals.

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