Assessment of in vivo antimicrobial activity of the carbene silver(I) acetate derivative SBC3 using Galleria mellonella larvae

The global health emergency caused by multi-drug resistant bacteria has led to the search for and development of new antimicrobial agents. Phage therapy is an abandoned antimicrobial therapy that has been resumed in recent years. In this study, we mutated a lysogenic phage from Acinetobacter baumannii into a lytic phage (Ab105-2phiΔCI) showing antimicrobial activity against A.baumannii clinical strains (such as Ab177_GEIH-2000 which showed MICs to meropenem and imipenem of 32 µg/ml and 16 µg/ml, respectively as well as belonging to GEIH-REIPI Spanish Multicenter A. baumannii Study II 2000/2010, Umbrella Genbank Bioproject PRJNA422585). We then enhanced the time kill curves (in vitro) and in Galleria mellonella survival assays (in vivo) antimicrobial activity of the new lytic phage by combining it with carbapenem antibiotics (meropenem and imipenem). We observed in vitro, an antimicrobial synergistic effect (from 4 log to 7 log CFU/ml) with meropenem plus lytic phage in all combinations analysed (0.1, 1 and 10 MOI of Ab105-2phiΔCI mutant as well as 1/4 and 1/8 MIC of meropenem). Moreover, we had a decrease in bacterial growth of 8 log CFU/ml for the combination of imipenem at 1/4 MIC plus lytic phage (Ab105-2phiΔCI mutant) and of 4 log CFU/ml for the combination of imipenem at 1/8 MIC plus lytic phage (Ab105-2phiΔCI mutant) in both MOI 1 and 10. These results were confirmed in in vivo (G. mellonella) obtaining a higher effectiveness in the combination of imipenem and Ab105-2phiΔCI mutant (P<0.05 by Log Rank-Matel Cox test). This approach could help to reduce the emergence of phage resistant bacteria and restore sensitivity to the antibiotics when used to combat multiresistant strains of Acinetobacter baumannii.

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Delivery of antibacterial silver nanoclusters to Pseudomonas aeruginosa using species-specific DNA aptamers

Journal of Medical Microbiology ◽

10.1099/jmm.0.001174 ◽

2020 ◽

Vol 69 (4) ◽

pp. 640-652 ◽

Cited By ~ 3

Author(s):

Jennifer Soundy ◽

Darren Day

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Activity ◽

Type Species ◽

Galleria Mellonella ◽

Host Cells ◽

Silver Nanoclusters ◽

Bacterial Cells ◽

Content Type ◽

Link Type

Introduction. The use of silver as an antimicrobial therapeutic is limited by its toxicity to host cells compared with that required to kill bacterial pathogens. Aim. To use aptamer targeting of DNA scaffolded silver nanoclusters as an antimicrobial agent for treating Pseudomonas aeruginosa infections. Methodology. Antimicrobial activity was assessed in planktonic cultures and in vivo using an invertebrate model of infection. Results. The aptamer conjugates that we call aptabiotics have potent antimicrobial activity. Targeted silver nanoclusters were more effective at killing P. aeruginosa than the equivalent quantity of untargeted silver nanoclusters. The aptabiotics have an IC50 of 1.3–2.6 µM against planktonically grown bacteria. Propidium iodide staining showed that they rapidly depolarize bacterial cells to kill approximately 50 % of the population within 10 min following treatment. In vivo testing in the Galleria mellonella model of infection prolonged survival from an otherwise lethal infection. Conclusion. Using P. aeruginosa as a model, we show that targeting of DNA-scaffolded silver nanoclusters with an aptamer has effective fast-acting antimicrobial activity in vitro and in an in vivo animal model.

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Komodo-dragon cathelicidin-inspired peptides are antibacterial against carbapenem-resistant Klebsiella pneumoniae

Journal of Medical Microbiology ◽

10.1099/jmm.0.001260 ◽

2020 ◽

Vol 69 (11) ◽

pp. 1262-1272

Author(s):

Samantha J. Hitt ◽

Barney M. Bishop ◽

Monique L. van Hoek

Keyword(s):

Antimicrobial Activity ◽

Klebsiella Pneumoniae ◽

Antimicrobial Peptides ◽

Galleria Mellonella ◽

Content Type ◽

Carbapenem Resistant ◽

Level Of Activity ◽

Improvement In Survival ◽

Synthetic Antimicrobial Peptides

Introduction. The rise of carbapenem-resistant enterobacteriaceae (CRE) is a growing crisis that requires development of novel therapeutics. Hypothesis. To this end, cationic antimicrobial peptides (CAMPs) represent a possible source of new potential therapeutics to treat difficult pathogens such as carbapenem-resistant Klebsiella pneumoniae (CRKP), which has gained resistance to many if not all currently approved antibiotics, making treatment difficult. Aim. To examine the anti-CRKP antimicrobial activity of the predicted cathelicidins derived from Varanus komodoensis (Komodo dragon) as well as synthetic antimicrobial peptides that we created. Methodology. We determined the minimum inhibitory concentrations of the peptides against CRKP. We also characterized the abilities of these peptides to disrupt the hyperpolarization of the bacterial membrane as well as their ability to form pores in the membrane. Results. We did not observe significant anti-CRKP activity for the predicted native Komodo cathelicidin peptides. We found that the novel peptides DRGN-6,-7 and -8 displayed significant antimicrobial activity against CRKP with MICs of 4–8 µg ml−1. DRGN-6 peptide was the most effective peptide against CRKP. Unfortunately, these peptides showed higher than desired levels of hemolysis, although in vivo testing in the waxworm Galleria mellonella showed no mortality associated with treatment by the peptide; however, CRKP-infected waxworms treated with peptide did not show an improvement in survival. Conclusion. Given the challenges of treating CRKP, identification of peptides with activity against it represents a promising avenue for further research. Given DRGN-6′s similar level of activity to colistin, DRGN-6 is a promising template for the development of novel antimicrobial peptide-based therapeutics.

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In vitro and in vivo efficacy of the combination of colistin and endolysins against clinical strains of Multi-Drug Resistant (MDR) pathogens

10.1101/662460 ◽

2019 ◽

Author(s):

L. Blasco ◽

A. Ambroa ◽

R. Trastoy ◽

E. Perez-Nadales ◽

F. Fernández-Cuenca ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Activity ◽

Klebsiella Pneumoniae ◽

Acinetobacter Baumannii ◽

Bactericidal Activity ◽

Pathogenic Bacteria ◽

Galleria Mellonella ◽

Clinical Strain

ABSTRACTThe multidrug resistance (MDR) among pathogenic bacteria is jeopardizing the worth of antimicrobials, which had previously changed medical sciences. In this study, we used bioinformatic tools to identify the endolysins ElyA1 and ElyA2 (GH108-PG3 family) present in the genome of bacteriophages Ab1051Φ and Ab1052Φ, respectively. The muralytic activity of these endolysins over MDR clinical isolates (Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae) was tested using the turbidity reduction assay. The minimal inhibitory concentrations (MICs) of endolysin, colistin and their combination were determined using the microdilution checkerboard method. The antimicrobial activity of the combinations was confirmed by time kill curves and in vivo assays in larvae of Galleria mellonella. Our results showed that ElyA1 displayed activity against all 25 strains of A. baumannii and P. aeruginosa tested and against 13 out of 17 strains of K. pneumoniae. No activity was detected when assays were done with endolysin ElyA2. The combined antimicrobial activity of colistin and endolysin ElyA1 yielded a reduction in the colistin MIC for all strains studied, except K. pneumoniae. These results were confirmed in vivo in G. mellonella survival assays. In conclusion, the combination of colistin with new endolysins such as ElyA1 could increase the bactericidal activity and reduce the MIC of the antibiotic, thus also reducing the associated toxicity.IMPORTANCEThe development of multiresistance by pathogen bacteria increases the necessity of the development of new antimicrobial strategies. In this work, we combined the effect of the colistin with a new endolysin, ElyA1, from a bacteriophage present in the clinical strain of Acinetobacter baumannii Ab105. ElyA1 is a lysozyme-like family (GH108-GP3), whose antimicrobial activity was described for first time in this work. Also, another endolysin, ElyA2, with the same origin and family, was characterized but in this case no activity was detected. ElyA1 presented lytic activity over a broad spectrum of strains from A. baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. When colistin was combined with ElyA1 an increase of the antimicrobial activity was observed with a reduced concentration of colistin, and this observation was also confirmed in vivo in Galleria mellonella larvae. The combination of colistin with new endolysins as ElyA1 could increase the bactericidal activity and lowering the MIC of the antibiotic, thus also reducing the associated toxicity.

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Punica granatum L. (Pomegranate) Extract: In Vivo Study of Antimicrobial Activity against Porphyromonas gingivalis in Galleria mellonella Model

The Scientific World JOURNAL ◽

10.1155/2016/8626987 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Livia Aparecida Procópio Gomes ◽

Lívia Mara Alves Figueiredo ◽

Ana Luiza do Rosário Palma ◽

Barbara Maria Corrêa Geraldo ◽

Kelly Cristine Isler Castro ◽

...

Keyword(s):

Antimicrobial Activity ◽

Porphyromonas Gingivalis ◽

Galleria Mellonella ◽

Survival Rates ◽

Punica Granatum ◽

Herbal Extract ◽

Periodontal Pathogen ◽

Rank Test ◽

Control Group

Due to the increase of bacterial resistance, medicinal alternatives are being explored. Punica granatum L. is an effective herbal extract with broad spectrum of action and bactericidal, antifungal, anthelmintic potential and being able to modulate the immune response. The aim was to evaluate the antimicrobial activity of pomegranate glycolic extract (PGE) against the periodontal pathogen Porphyromonas gingivalis by using Galleria mellonella as in vivo model. Fifteen larvae were used per group. Injection of high concentration (200, 100, and 25 mg/mL) of PGE showed a toxic effect, leading them to death. A suspension of P. gingivalis (106 cells/mL) was inoculated in the left last proleg and PGE (12.5, 6.25, 3.1, and 2.5 mg/mL) were injected into the right proleg. The larvae were then kept at 37°C under the dark. Injection of PGE at any dose statistically improved larvae survival rates. The data were analysed (log-rank test, Mantel-Cox, P<0.05) and showed that all concentrations of PGE (12.5, 6.25, 3.1, and 2.5 mg/mL) presented higher larval survival rates, with significant statistical difference in relation to control group (P. gingivalis). In conclusion, the PGE had antimicrobial action against P. gingivalis in vivo model using G. mellonella.

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Assessment of in vitro and in vivo Antimicrobial Activity of an Isonitrosomalononitrile Silver(I) Salt

Journal of Medicinal Chemistry and Drug Design ◽

10.16966/2578-9589.117 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Colmont M ◽

Brunel JM

Keyword(s):

Antimicrobial Activity ◽

Animal Model ◽

Galleria Mellonella ◽

Silver Salt ◽

Antimicrobial Activities ◽

Water Soluble ◽

Gram Positive ◽

Minimum Inhibitory Concentrations

The design and evaluation of antimicrobial activities of an isonitrosomalononitrile silver(I) salt was reported. This highly stable water-soluble silver salt shows Minimum Inhibitory Concentrations (MIC) values ranging from 0.15 to 5 µg/mL towards both sensitive and resistant Gram-positive and negative bacteria. Furthermore, this silver salt has been investigated for its ability to treat a S. aureus infected Galleria mellonella larvae animal model with promising results. Thus, our results demonstrated that 80% of the treated larvae survived after 24h with respect to 10% of the untreated ones, respectively.

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ANTIMICROBIAL ACTIVITY OF Aloe vera EXTRACT ON CASES OF KERATOCONJUNCTIVITISIN SHEEP (IN VIVO AND INVITRO STUDY)AND COMPARED WITH PENICILLIN –STREPTOMYCIN.

Basrah Journal of veterinary Research ◽

10.33762/bvetr.2016.124301 ◽

2016 ◽

Vol 15 (2) ◽

pp. 227-245

Author(s):

A H.H.Al-Ahbabi ◽

M. H. Al-Ahbab ◽

Marwa amer ◽

S. O. Hasson ◽

A W.F.abed ◽

...

Keyword(s):

Antimicrobial Activity ◽

Aloe Vera

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INFLUÊNCIA DO SUBSTRATO E DA LUMINOSIDADE NA INFECÇÃO DE NEMATOIDES ENTOMOPATOGÊNICOS EM Galleria mellonella (LEPIDOPTERA: PYRALIDAE)

Revista Científica Rural ◽

10.30945/rcr-v20i2.307 ◽

2018 ◽

Vol 20 (2) ◽

pp. 91-101

Author(s):

Andressa Lima de Brida ◽

Silvia Renata Siciliano Wilcken ◽

Luis Garrigós Leite

Keyword(s):

Galleria Mellonella ◽

Steinernema Carpocapsae ◽

Steinernema Feltiae ◽

Lepidoptera Pyralidae

Nematoides entomopatogênicos (NEPs) são alternativas eficientes para o controle de pragas. O emprego de novas técnicas da produção in vivo, permite o progresso da tecnologia de formulação de bioinseticidas. O objetivo do trabalho, foi avaliar a influência da luminosidade e do substrato na capacidade de infecção de juvenis infectantes (JIs) de Steinernema brazilense IBCBn 06, Steinernema carpocapsae IBCBn 02, Steinernema feltiae IBCBn 47 e Heterorhabditis amazonensis IBCBn 24 em lagartas de Galleria mellonella (Lepidoptera: Pyralidae). O delineamento experimental foi inteiramente casualizado com quatro tratamentos e oito repetições. As parcelas, constituídas por placa de Petri com, substrato-areia e substrato-papel filtro, com e sem luminosidade, inoculados com suspensão de 1,5 mL contendo 400JIs e quatro lagartas de G. mellonella. O número de JIs foi quantificado após a mortalidade das lagartas. A taxa de infecção de JIs de S. carpocapsae IBCBn 02 e S. feltiae IBCBn 47 variaram de 2,14 a 3,28 e de 11,04 a 13,09 JIs/lagarta. O substrato-areia com e sem luminosidade permitiu a maior taxa de infeção dos JIs de S. brazilense IBCBn 06 de 7,86 e 9,44 JIs/lagarta, e 13,49 JIs/lagarta com luminosidade para H. amazonensis IBCBn 24. O substrato-areia, permite a maior taxa de infecção por JIs de NEPs.

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