scholarly journals Development of Galleria mellonella as an Alternative Infection Model for the Burkholderia cepacia Complex

2008 ◽  
Vol 76 (3) ◽  
pp. 1267-1275 ◽  
Author(s):  
Kimberley D. Seed ◽  
Jonathan J. Dennis
Keyword(s):  
Burkholderia Cepacia ◽  
Galleria Mellonella ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Experimental Conditions ◽  
Closely Related Species ◽  
Infection Models ◽  
Concomitant Reduction ◽  
Mammalian Infection ◽  
Bacterial Complex

ABSTRACT Burkholderia is an important bacterial genus with a complex taxonomy that contains species of both ecological and pathogenic importance, including nine closely related species collectively termed the Burkholderia cepacia complex (BCC). In order to more thoroughly investigate the virulence of this bacterial complex of microorganisms, alternative infection models would be useful. To this end, we have adapted and developed the use of the Galleria mellonella wax moth larvae as a host for examining BCC infections. The experimental conditions affecting the BCC killing of the “wax worm” were optimized. BCC virulence levels were determined using 50% lethal doses, and differences were observed between both species and strains of the BCC. The BCC pathogenicity trends obtained compare favorably with results acquired using other published alternative infection models, as well as mammalian infection models. In addition, BCC killing activity was determined by directly measuring relative bacterial loads in three different BCC strains, thus demonstrating innate differences in BCC strain virulence. Finally, genetically mutated BCC strains were compared to a wild-type BCC strain in order to show concomitant reduction of BCC virulence and increased wax worm survival. For experimentation examining the virulent properties of the BCC, the wax worm has proven to be a useful alternative infection model.

scholarly journals Experimental Bacteriophage Therapy Increases Survival of Galleria mellonella Larvae Infected with Clinically Relevant Strains of the Burkholderia cepacia Complex

2009 ◽  
Vol 53 (5) ◽  
pp. 2205-2208 ◽  
Author(s):  
Kimberley D. Seed ◽  
Jonathan J. Dennis
Keyword(s):  
Alternative Treatment ◽  
Burkholderia Cepacia ◽  
Phage Therapy ◽  
Galleria Mellonella ◽  
Respiratory Infections ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Bacteriophage Therapy ◽  
Antibiotic Resistant

ABSTRACT The Burkholderia cepacia complex (BCC) is a group of bacterial pathogens that are highly antibiotic resistant and associated with debilitating respiratory infections. Although bacteriophages of the BCC have been isolated and characterized, no studies have yet examined phage therapy against the BCC in vivo. In a caterpillar infection model, we show that BCC phage therapy is an alternative treatment possibility and is highly effective under specific conditions.

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 Evaluation of the electron transfer flavoprotein as an antibacterial target in Burkholderia cenocepacia

2017 ◽  
Vol 63 (10) ◽  
pp. 857-863 ◽  
Author(s):  
Maria S. Stietz ◽  
Christina Lopez ◽  
Osasumwen Osifo ◽  
Marcelo E. Tolmasky ◽  
Silvia T. Cardona
Keyword(s):  
Electron Transfer ◽  
Burkholderia Cepacia ◽  
Multidrug Resistant ◽  
Burkholderia Cenocepacia ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Electron Transfer Flavoprotein ◽  
C Elegans

There are hundreds of essential genes in multidrug-resistant bacterial genomes, but only a few of their products are exploited as antibacterial targets. An example is the electron transfer flavoprotein (ETF), which is required for growth and viability in Burkholderia cenocepacia. Here, we evaluated ETF as an antibiotic target for Burkholderia cepacia complex (Bcc). Depletion of the bacterial ETF during infection of Caenorhabditis elegans significantly extended survival of the nematodes, proving that ETF is essential for survival of B. cenocepacia in this host model. In spite of the arrest in respiration in ETF mutants, the inhibition of etf expression did not increase the formation of persister cells, when treated with high doses of ciprofloxacin or meropenem. To test if etf translation could be inhibited by RNA interference, antisense oligonucleotides that target the etfBA operon were synthesized. One antisense oligonucleotide was effective in inhibiting etfB translation in vitro but not in vivo, highlighting the challenge of reduced membrane permeability for the design of drugs against B. cenocepacia. This work contributes to the validation of ETF of B. cenocepacia as a target for antibacterial therapy and demonstrates the utility of a C. elegans liquid killing assay to validate gene essentiality in an in vivo infection model.

scholarly journals Galleria mellonella as an infection model: an in-depth look at why it works and practical considerations for successful application

2020 ◽  
Vol 78 (8) ◽  
Author(s):  
Monalessa Fábia Pereira ◽  
Ciro César Rossi ◽  
Giarlã Cunha da Silva ◽  
Jéssica Nogueira Rosa ◽  
Denise Mara Soares Bazzolli
Keyword(s):  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
State Of The Art ◽  
Infection Model ◽  
Larval Rearing ◽  
Greater Wax Moth ◽  
Infection Models ◽  
Interlaboratory Reproducibility ◽  
Practical Recommendations ◽  
Wax Moth

ABSTRACT The larva of the greater wax moth Galleria mellonella is an increasingly popular model for assessing the virulence of bacterial pathogens and the effectiveness of antimicrobial agents. In this review, we discuss details of the components of the G. mellonella larval immune system that underpin its use as an alternative infection model, and provide an updated overview of the state of the art of research with G. mellonella infection models to study bacterial virulence, and in the evaluation of antimicrobial efficacy. Emphasis is given to virulence studies with relevant human and veterinary pathogens, especially Escherichia coli and bacteria of the ESKAPE group. In addition, we make practical recommendations for larval rearing and testing, and overcoming potential limitations of the use of the model, which facilitate intra- and interlaboratory reproducibility.

scholarly journals Lysogeny and bacteriophage host range within the Burkholderia cepacia complex

2003 ◽  
Vol 52 (6) ◽  
pp. 483-490 ◽  
Author(s):  
Ross Langley ◽  
Dervla T. Kenna ◽  
Peter Vandamme ◽  
Rebecca Ure ◽  
John R. W. Govan
Keyword(s):  
Host Range ◽  
Burkholderia Cepacia ◽  
Potential Role ◽  
River Sediments ◽  
Burkholderia Cepacia Complex ◽  
Potential Contribution ◽  
Closely Related Species ◽  
Burkholderia Gladioli ◽  
Life Threatening ◽  
Species Specific

The Burkholderia cepacia complex comprises a group of nine closely related species that have emerged as life-threatening pulmonary pathogens in immunocompromised patients, particularly individuals with cystic fibrosis or chronic granulomatous disease. Attempts to explain the genomic plasticity, adaptability and virulence of the complex have paid little attention to bacteriophages, particularly the potential contribution of lysogenic conversion and transduction. In this study, lysogeny was observed in 10 of 20 representative strains of the B. cepacia complex. Three temperate phages and five lytic phages isolated from soils, river sediments or the plant rhizosphere were chosen for further study. Six phages exhibited T-even morphology and two were lambda-like. The host range of individual phages, when tested against 66 strains of the B. cepacia complex and a representative panel of other pseudomonads, was not species-specific within the B. cepacia complex and, in some phages, included Burkholderia gladioli and Pseudomonas aeruginosa. These new data indicate a potential role for phages of the B. cepacia complex in the evolution of these soil bacteria as pathogens of plants, humans and animals, and as novel therapeutic agents.

scholarly journals Burkholderia cepacia Complex Phage-Antibiotic Synergy (PAS): Antibiotics Stimulate Lytic Phage Activity

2014 ◽  
Vol 81 (3) ◽  
pp. 1132-1138 ◽  
Author(s):  
Fatima Kamal ◽  
Jonathan J. Dennis
Keyword(s):  
Burkholderia Cepacia ◽  
Galleria Mellonella ◽  
Burkholderia Cenocepacia ◽  
Burkholderia Cepacia Complex ◽  
Lytic Phage ◽  
Bacterial Killing ◽  
Content Type ◽  
Drug Classes ◽  
Phage Production ◽  
A Chain

ABSTRACTTheBurkholderia cepaciacomplex (Bcc) is a group of at least 18 species of Gram-negative opportunistic pathogens that can cause chronic lung infection in cystic fibrosis (CF) patients. Bcc organisms possess high levels of innate antimicrobial resistance, and alternative therapeutic strategies are urgently needed. One proposed alternative treatment is phage therapy, the therapeutic application of bacterial viruses (or bacteriophages). Recently, some phages have been observed to form larger plaques in the presence of sublethal concentrations of certain antibiotics; this effect has been termed phage-antibiotic synergy (PAS). Those reports suggest that some antibiotics stimulate increased production of phages under certain conditions. The aim of this study is to examine PAS in phages that infectBurkholderia cenocepaciastrains C6433 and K56-2. Bcc phages KS12 and KS14 were tested for PAS, using 6 antibiotics representing 4 different drug classes. Of the antibiotics tested, the most pronounced effects were observed for meropenem, ciprofloxacin, and tetracycline. When grown with subinhibitory concentrations of these three antibiotics, cells developed a chain-like arrangement, an elongated morphology, and a clustered arrangement, respectively. When treated with progressively higher antibiotic concentrations, both the sizes of plaques and phage titers increased, up to a maximum.B. cenocepaciaK56-2-infectedGalleria mellonellalarvae treated with phage KS12 and low-dose meropenem demonstrated increased survival over controls treated with KS12 or antibiotic alone. These results suggest that antibiotics can be combined with phages to stimulate increased phage production and/or activity and thus improve the efficacy of bacterial killing.

scholarly journals Mucoid morphotype variation of Burkholderia multivorans during chronic cystic fibrosis lung infection is correlated with changes in metabolism, motility, biofilm formation and virulence

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3124-3137 ◽  
Author(s):  
Inês N. Silva ◽  
Ana S. Ferreira ◽  
Jörg D. Becker ◽  
James E. A. Zlosnik ◽  
David P. Speert ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Phenotypic Variation ◽  
Biofilm Formation ◽  
Burkholderia Cepacia ◽  
Galleria Mellonella ◽  
Acute Infection ◽  
Lung Infection ◽  
Infection Model ◽  
Burkholderia Multivorans ◽  
Expression Of Genes

Burkholderia cepacia complex (Bcc) bacteria are opportunistic pathogens infecting hosts such as cystic fibrosis (CF) patients. Long-term Bcc infection of CF patients’ airways has been associated with emergence of phenotypic variation. Here we studied two Burkholderia multivorans clonal isolates displaying different morphotypes from a chronically infected CF patient to evaluate trait development during lung infection. Expression profiling of mucoid D2095 and non-mucoid D2214 isolates revealed decreased expression of genes encoding products related to virulence-associated traits and metabolism in D2214. Furthermore, D2214 showed no exopolysaccharide production, lower motility and chemotaxis, and more biofilm formation, particularly under microaerophilic conditions, than the clonal mucoid isolate D2095. When Galleria mellonella was used as acute infection model, D2214 at a cell number of approximately 7×106 c.f.u. caused a higher survival rate than D2095, although 6 days post-infection most of the larvae were dead. Infection with the same number of cells by mucoid D2095 caused larval death by day 4. The decreased expression of genes involved in carbon and nitrogen metabolism may reflect lower metabolic needs of D2214 caused by lack of exopolysaccharide, but also by the attenuation of pathways not required for survival. As a result, D2214 showed higher survival than D2095 in minimal medium for 28 days under aerobic conditions. Overall, adaptation during Bcc chronic lung infections gave rise to genotypic and phenotypic variation among isolates, contributing to their fitness while maintaining their capacity for survival in this opportunistic human niche.

scholarly journals Identification of Specific and Universal Virulence Factors in Burkholderia cenocepacia Strains by Using Multiple Infection Hosts

2009 ◽  
Vol 77 (9) ◽  
pp. 4102-4110 ◽  
Author(s):  
Susanne Uehlinger ◽  
Stephan Schwager ◽  
Steve P. Bernier ◽  
Kathrin Riedel ◽  
David T. Nguyen ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Burkholderia Cepacia ◽  
Galleria Mellonella ◽  
Burkholderia Cenocepacia ◽  
Model Organisms ◽  
Multiple Infection ◽  
Pathogenic Potential ◽  
The Past ◽  
Infection Models ◽  
Lipopolysaccharide Biosynthesis

ABSTRACT Over the past few decades, strains of the Burkholderia cepacia complex have emerged as important pathogens for patients suffering from cystic fibrosis. Identification of virulence factors and assessment of the pathogenic potential of Burkholderia strains have increased the need for appropriate infection models. In previous studies, different infection hosts, including mammals, nematodes, insects, and plants, have been used. At present, however, the extent to which the virulence factors required to infect different hosts overlap is not known. The aim of this study was to analyze the roles of various virulence factors of two closely related Burkholderia cenocepacia strains, H111 and the epidemic strain K56-2, in a multihost pathogenesis system using four different model organisms, namely, Caenorhabditis elegans, Galleria mellonella, the alfalfa plant, and mice or rats. We demonstrate that most of the identified virulence factors are specific for one of the infection models, and only three factors were found to be essential for full pathogenicity in several hosts: mutants defective in (i) quorum sensing, (ii) siderophore production, and (iii) lipopolysaccharide biosynthesis were attenuated in at least three of the infection models and thus may represent promising targets for the development of novel anti-infectives.

scholarly journals Potent modulation of the CepR quorum sensing receptor and virulence in a Burkholderia cepacia complex member using non-native lactone ligands

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Betty L. Slinger ◽  
Jacqueline J. Deay ◽  
Josephine R. Chandler ◽  
Helen E. Blackwell
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Cepacia ◽  
Homoserine Lactone ◽  
Communication Process ◽  
Burkholderia Cepacia Complex ◽  
Infection Model ◽  
Bacterial Communication ◽  
Human Infections ◽  
Chemical Strategies

Abstract The Burkholderia cepacia complex (Bcc) is a family of closely related bacterial pathogens that are the causative agent of deadly human infections. Virulence in Bcc species has been shown to be controlled by the CepI/CepR quorum sensing (QS) system, which is mediated by an N-acyl L-homoserine lactone (AHL) signal (C8-AHL) and its cognate LuxR-type receptor (CepR). Chemical strategies to block QS in Bcc members would represent an approach to intercept this bacterial communication process and further delineate its role in infection. In the current study, we sought to identify non-native AHLs capable of agonizing or antagonizing CepR, and thereby QS, in a Bcc member. We screened a library of AHL analogs in cell-based reporters for CepR, and identified numerous highly potent CepR agonists and antagonists. These compounds remain active in a Bcc member, B. multivorans, with one agonist 250-fold more potent than the native ligand C8-AHL, and can affect QS-controlled motility. Further, the CepR antagonists prolong C. elegans survival in an infection model. These AHL analogs are the first reported non-native molecules that both directly modulate CepR and impact QS-controlled phenotypes in a Bcc member, and represent valuable chemical tools to assess the role of QS in Bcc infections.

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