scholarly journals In Vitro and In Vivo Activity of Single and Dual Antimicrobial Agents Against KPC-producing Klebsiella pneumoniae

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S379-S379
Author(s):  
Farzad Moussavi ◽  
Sarath Nath ◽  
Daniel Abraham ◽  
David Landman ◽  
John Quale
Keyword(s):  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
Survival Rates ◽  
Polymyxin B ◽  
The Other ◽  
In Vivo Model ◽  
Serious Infections ◽  
Time Kill

Abstract Background Options for treatment of infections due to KPC-producing K. pneumoniae are limited, and combination therapy is often recommended. In this report, the in vitro and in vivo activity of potential therapeutic agents and combinations was assessed against four KPC-producing K. pneumoniae isolates. Methods Using clinically-relevant concentrations, time-kill experiments and the Galleria mellonella model of infection were used to examine the activity of polymyxin B, ceftazidime-avibactam, meropenem, rifampin, and amikacin alone and in combination. Four isolates of KPC-producing K. pneumoniae were studied, including two isolates that were resistant to polymyxin B and had ceftazidime-avibactam MICs of 8 µg/mL. The other two K. pneumoniae isolates were susceptible to polymyxin B and had lower MICs of ceftazidime-avibactam. Results Two isolates that were resistant to polymyxin B and with ceftazidime-avibactam MICs of 8 µg/mL were also resistant to amikacin and meropenem. When ceftazidime-avibactam was combined with either amikacin or meropenem, synergy was observed in vitro, and these combinations were associated with improved survival with the in vivo model. The other two K. pneumoniae isolates were susceptible to polymyxin B and had lower MICs of ceftazidime-avibactam. At concentrations four times the MIC, ceftazidime-avibactam had bactericidal activity in vitro; at one fourth the MIC, synergy was observed when combined with meropenem. Improved survival rates were observed with therapy with ceftazidime-avibactam, particularly when combined with a second agent for one isolate. In the in vivo model, polymyxin B with or without rifampin or meropenem, was ineffective against polymyxin B resistant strains. Conclusion Pending clinical studies, combining ceftazidime-avibactam with another agent (e.g., a carbapenem) should be encouraged when treating serious infections due to these pathogens, especially for isolates with ceftazidime-avibactam MICs near the susceptibility breakpoint. Disclosures All authors: No reported disclosures.

scholarly journals Macrocolony of NDM-1 Producing Enterobacter hormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 49 ◽  
Author(s):  
Flávia Roberta Brust ◽  
Luana Boff ◽  
Danielle da Silva Trentin ◽  
Franciele Pedrotti Rozales ◽  
Afonso Luís Barth ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Biofilm Production ◽  
Depth Study ◽  
Enterobacter Hormaechei ◽  
Type 3

Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem–rifampicin–polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.

scholarly journals In Vitro and In Vivo Activities of Syn2836, Syn2869, Syn2903, and Syn2921: New Series of Triazole Antifungal Agents

2001 ◽  
Vol 45 (9) ◽  
pp. 2420-2426 ◽  
Author(s):  
S. M. Salama ◽  
H. Atwal ◽  
A. Gandhi ◽  
J. Simon ◽  
M. Poglod ◽  
...  
Keyword(s):  
Antifungal Agents ◽  
Survival Rates ◽  
Systemic Infection ◽  
Kinetic Studies ◽  
The Other ◽  
In Vivo Studies ◽  
Infection Model ◽  
Time Kill

ABSTRACT The in vitro and in vivo activities of four azole compounds belonging to a new series of 2(2,4-difluorophenyl)-3-(4-substituted piperazin-1-yl)-1-(1,2,4-triazol-1-yl) butanol antifungal agents is described. The compounds were selected from a library of azole compounds synthesized by our group. The in vitro activities of Syn2869, Syn2836, Syn2903, and Syn2921 against a panel of over 240 recently collected clinical isolates of yeast and molds were determined, and the results were compared with those obtained with fluconazole (FLC), itraconazole (ITC), and amphotericin B (AMB). The MICs at which 90% of the isolates were inhibited (MIC90s) for the four test compounds for strains of Candida spp. ranged from <0.048 to 0.78 μg/ml. All compounds were also active against FLC-resistant Candida albicans and otherCandida sp. strains. Moreover, MIC90s for strains of Cryptococcus neoformans,Aspergillus spp., Trichophyton spp., andMicrosporum spp. were also low and ranged from <0.048 to 0.39 μg/ml. The test compounds produced a fungistatic pattern during the time-kill kinetic studies. In vivo studies indicated that all four test compounds have good efficacies against C. albicans in a murine systemic infection model and significantly improved the survival rates of the infected mice. The results for Syn2903 were similar to those for FLC, while the other compounds were slightly less effective but had ranges of activities similar to the range of activity of ITC. The compounds were also evaluated against anAspergillus fumigatus systemic infection. Syn2903 was also superior to ITC, whereas the efficacy data for the other compounds were similar to those for ITC. It was concluded from the data generated for this new series of azole compounds in the studies described above that further pharmacokinetic and toxicologic evaluations are warranted prior to selection of a candidate compound for preclinical testing.

Exploring Galleria mellonella larval model to evaluate antibacterial efficacy of Cecropin A (1-7)- Melittin against multi-drug resistant enteroaggregative Escherichia coli

2021 ◽  
Author(s):  
Jess Vergis ◽  
S V S Malik ◽  
Richa Pathak ◽  
Manesh Kumar ◽  
Nitin V Kurkure ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
In Vivo Model ◽  
Drug Resistant ◽  
Physiological Concentration ◽  
Microbial Drug Resistance ◽  
Cecropin A ◽  
Screening And Identification

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

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 Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates: In Vivo Virulence Assessment in Galleria mellonella and Potential Therapeutics by Polycationic Oligoethyleneimine

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 56
Author(s):  
Dalila Mil-Homens ◽  
Maria Martins ◽  
José Barbosa ◽  
Gabriel Serafim ◽  
Maria J. Sarmento ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Galleria Mellonella ◽  
Multidrug Resistant ◽  
In Vitro Models ◽  
Clinical Isolates ◽  
In Vivo Model ◽  
Virulence Potential ◽  
Hospital Acquired

Klebsiella pneumoniae, one of the most common pathogens found in hospital-acquired infections, is often resistant to multiple antibiotics. In fact, multidrug-resistant (MDR) K. pneumoniae producing KPC or OXA-48-like carbapenemases are recognized as a serious global health threat. In this sense, we evaluated the virulence of K. pneumoniae KPC(+) or OXA-48(+) aiming at potential antimicrobial therapeutics. K. pneumoniae carbapenemase (KPC) and the expanded-spectrum oxacillinase OXA-48 isolates were obtained from patients treated in medical care units in Lisbon, Portugal. The virulence potential of the K. pneumonia clinical isolates was tested using the Galleria mellonella model. For that, G. mellonella larvae were inoculated using patients KPC(+) and OXA-48(+) isolates. Using this in vivo model, the KPC(+) K. pneumoniae isolates showed to be, on average, more virulent than OXA-48(+). Virulence was found attenuated when a low bacterial inoculum (one magnitude lower) was tested. In addition, we also report the use of a synthetic polycationic oligomer (L-OEI-h) as a potential antimicrobial agent to fight infectious diseases caused by MDR bacteria. L-OEI-h has a broad-spectrum antibacterial activity and exerts a significantly bactericidal activity within the first 5-30 min treatment, causing lysis of the cytoplasmic membrane. Importantly, the polycationic oligomer showed low toxicity against in vitro models and no visible cytotoxicity (measured by survival and health index) was noted on the in vivo model (G. mellonella), thus L-OEI-h is foreseen as a promising polymer therapeutic for the treatment of MDR K. pneumoniae infections.

scholarly journals Polymyxin Triple Combinations against Polymyxin-Resistant, Multidrug-Resistant, KPC-Producing Klebsiella pneumoniae

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Su Mon Aye ◽  
Irene Galani ◽  
Heidi Yu ◽  
Jiping Wang ◽  
Ke Chen ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Triple Therapy ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Infection Model ◽  
Bacterial Killing ◽  
Standard Dosage ◽  
Time Kill

ABSTRACT Resistance to polymyxin antibiotics is increasing. Without new antibiotic classes, combination therapy is often required. We systematically investigated bacterial killing with polymyxin-based combinations against multidrug-resistant (including polymyxin-resistant), carbapenemase-producing Klebsiella pneumoniae. Monotherapies and double- and triple-combination therapies were compared to identify the most efficacious treatment using static time-kill studies (24 h, six isolates), an in vitro pharmacokinetic/pharmacodynamic model (IVM; 48 h, two isolates), and the mouse thigh infection model (24 h, six isolates). In static time-kill studies, all monotherapies (polymyxin B, rifampin, amikacin, meropenem, or minocycline) were ineffective. Initial bacterial killing was enhanced with various polymyxin B-containing double combinations; however, substantial regrowth occurred in most cases by 24 h. Most polymyxin B-containing triple combinations provided greater and more sustained killing than double combinations. Standard dosage regimens of polymyxin B (2.5 mg/kg of body weight/day), rifampin (600 mg every 12 h), and amikacin (7.5 mg/kg every 12 h) were simulated in the IVM. Against isolate ATH 16, no viable bacteria were detected across 5 to 25 h with triple therapy, with regrowth to ∼2-log10 CFU/ml occurring at 48 h. Against isolate BD 32, rapid initial killing of ∼3.5-log10 CFU/ml at 5 h was followed by a slow decline to ∼2-log10 CFU/ml at 48 h. In infected mice, polymyxin B monotherapy (60 mg/kg/day) generally was ineffective. With triple therapy (polymyxin B at 60 mg/kg/day, rifampin at 120 mg/kg/day, and amikacin at 300 mg/kg/day), at 24 h there was an ∼1.7-log10 CFU/thigh reduction compared to the starting inoculum for all six isolates. Our results demonstrate that the polymyxin B-rifampin-amikacin combination significantly enhanced in vitro and in vivo bacterial killing, providing important information for the optimization of polymyxin-based combinations in patients.

scholarly journals DCTPP1, an Oncogene Regulated by miR-378a-3p, Promotes Proliferation of Breast Cancer via DNA Repair Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Ming Niu ◽  
Ming Shan ◽  
Yang Liu ◽  
Yanni Song ◽  
Ji-guang Han ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Dna Repair ◽  
Survival Rates ◽  
The Other ◽  
Poor Survival ◽  
Induced Apoptosis ◽  
Cell Growth And Proliferation

Breast cancer (BRCA) is one of the most deadly cancers worldwide, with poor survival rates that could be due to its high proliferation. Human all-alpha dCTP pyrophosphatase 1 (DCTPP1) is implicated in numerous diseases, including cancers. However, its role in BRCA is unclear. In this study, we used bioinformatic analyses of the ONCOMINE, UALCAN, and GEPIA databases to determine the expression pattern of DCTPP1 in BRCA. We found that elevated DCTPP1 levels correlate with poor BRCA prognosis. DCTPP1 silencing inhibited BRCA cell proliferation and induced apoptosis in vitro, as well as in vivo. Our data show that this tumorigenic effect depends on DNA repair signaling. Moreover, we found that DCTPP1 is directly modulated by miR-378a-3p, whose downregulation is linked to BRCA progression. Our results showed down-regulation of miR-378a-3p in BRCA. Upregulation of miR-378a-3p, on the other hand, can inhibit BRCA cell growth and proliferation. This study shows that reduced miR-378a-3p level enhances DCTPP1 expression in BRCA, which promotes proliferation by activating DNA repair signaling in BRCA.

scholarly journals Galleria mellonella: The Versatile Host for Drug Discovery, In Vivo Toxicity Testing and Characterising Host-Pathogen Interactions

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1545
Author(s):  
Magdalena Piatek ◽  
Gerard Sheehan ◽  
Kevin Kavanagh
Keyword(s):  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
Toxicity Testing ◽  
In Vivo Model ◽  
Ethical Considerations ◽  
Food Preservatives ◽  
In Vivo Toxicity ◽  
Greater Wax Moth ◽  
Development Processes

Larvae of the greater wax moth, Galleria mellonella, are a convenient in vivo model for assessing the activity and toxicity of antimicrobial agents and for studying the immune response to pathogens and provide results similar to those from mammals. G. mellonella larvae are now widely used in academia and industry and their use can assist in the identification and evaluation of novel antimicrobial agents. Galleria larvae are inexpensive to purchase and house, easy to inoculate, generate results within 24–48 h and their use is not restricted by legal or ethical considerations. This review will highlight how Galleria larvae can be used to assess the efficacy of novel antimicrobial therapies (photodynamic therapy, phage therapy, metal-based drugs, triazole-amino acid hybrids) and for determining the in vivo toxicity of compounds (e.g., food preservatives, ionic liquids) and/or solvents (polysorbate 80). In addition, the disease development processes are associated with a variety of pathogens (e.g., Staphylococcus aureus, Listeria monocytogenes, Aspergillus fumigatus, Madurella mycotomatis) in mammals are also present in Galleria larvae thus providing a simple in vivo model for characterising disease progression. The use of Galleria larvae offers many advantages and can lead to an acceleration in the development of novel antimicrobials and may be a prerequisite to mammalian testing.

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