scholarly journals A Functional Phenylacetic Acid Catabolic Pathway Is Required for Full Pathogenicity of Burkholderia cenocepacia in the Caenorhabditis elegans Host Model

2008 ◽  
Vol 190 (21) ◽  
pp. 7209-7218 ◽  
Author(s):  
Robyn J. Law ◽  
Jason N. R. Hamlin ◽  
Aida Sivro ◽  
Stuart J. McCorrister ◽  
Georgina A. Cardama ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Phenylacetic Acid ◽  
Gene Clusters ◽  
Degradation Pathway ◽  
Burkholderia Cenocepacia ◽  
Insertion Mutagenesis ◽  
Infection Model ◽  
Catabolic Pathway ◽  
C Elegans ◽  
Ring Hydroxylation

ABSTRACT Burkholderia cenocepacia is a member of the Burkholderia cepacia complex, a group of metabolically versatile bacteria that have emerged as opportunistic pathogens in cystic fibrosis and immunocompromised patients. Previously a screen of transposon mutants in a rat pulmonary infection model identified an attenuated mutant with an insertion in paaE, a gene related to the phenylacetic acid (PA) catabolic pathway. In this study, we characterized gene clusters involved in the PA degradation pathway of B. cenocepacia K56-2 in relation to its pathogenicity in the Caenorhabditis elegans model of infection. We demonstrated that targeted-insertion mutagenesis of paaA and paaE, which encode part of the putative PA-coenzyme A (CoA) ring hydroxylation system, paaZ, coding for a putative ring opening enzyme, and paaF, encoding part of the putative beta-oxidation system, severely reduces growth on PA as a sole carbon source. paaA and paaE insertional mutants were attenuated for virulence, and expression of paaE in trans restored pathogenicity of the paaE mutant to wild-type levels. Interruption of paaZ and paaF slightly increased virulence. Using gene interference by ingested double-stranded RNA, we showed that the attenuated phenotype of the paaA and paaE mutants is dependent on a functional p38 mitogen-activated protein kinase pathway in C. elegans. Taken together, our results demonstrate that B. cenocepacia possesses a functional PA degradation pathway and that the putative PA-CoA ring hydroxylation system is required for full pathogenicity in C. elegans.

scholarly journals A Genomic Virulence Reference Map of Enterococcus faecalis Reveals an Important Contribution of Phage03-Like Elements in Nosocomial Genetic Lineages to Pathogenicity in a Caenorhabditis elegans Infection Model

2015 ◽  
Vol 83 (5) ◽  
pp. 2156-2167 ◽  
Author(s):  
Sabina Leanti La Rosa ◽  
Lars-Gustav Snipen ◽  
Barbara E. Murray ◽  
Rob J. L. Willems ◽  
Michael S. Gilmore ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Enterococcus Faecalis ◽  
Principal Component ◽  
Gene Clusters ◽  
Clinical Strain ◽  
Comparative Genomic ◽  
Infection Model ◽  
Content Type ◽  
C Elegans ◽  
Virulence Traits

In the present study, the commensal and pathogenic host-microbe interaction ofEnterococcus faecaliswas explored using aCaenorhabditis elegansmodel system. The virulence of 28E. faecalisisolates representing 24 multilocus sequence types (MLSTs), including human commensal and clinical isolates as well as isolates from animals and of insect origin, was investigated usingC. elegansstrainglp-4(bn2ts);sek-1(km4). This revealed that 6E. faecalisisolates behaved in a commensal manner with no nematocidal effect, while the remaining strains showed a time to 50% lethality ranging from 47 to 120 h. Principal component analysis showed that the difference in nematocidal activity explained 94% of the variance in the data. Assessment of known virulence traits revealed that gelatinase and cytolysin production accounted for 40.8% and 36.5% of the observed pathogenicity, respectively. However, coproduction of gelatinase and cytolysin did not increase virulence additively, accounting for 50.6% of the pathogenicity and therefore indicating a significant (26.7%) saturation effect. We employed a comparative genomic analysis approach using the 28 isolates comprising a collection of 82,356 annotated coding sequences (CDS) to identify 2,325 patterns of presence or absence among the investigated strains. Univariate statistical analysis of variance (ANOVA) established that individual patterns positively correlated (n= 61) with virulence. The patterns were investigated to identify potential new virulence traits, among which we found five patterns consisting of the phage03-like gene clusters. Strains harboring phage03 showed, on average, 17% higher killing ofC. elegans(P= 4.4e−6). The phage03 gene cluster was also present in gelatinase-and-cytolysin-negative strainE. faecalisJH2-2. Deletion of this phage element from the JH2-2 clinical strain rendered the mutant apathogenic inC. elegans, and a similar mutant of the nosocomial V583 isolate showed significantly attenuated virulence. Bioinformatics investigation indicated that, unlike otherE. faecalisvirulence traits, phage03-like elements were found at a higher frequency among nosocomial isolates. In conclusion, our report provides a valuable virulence map that explains enhancement inE. faecalisvirulence and contributes to a deeper comprehension of the genetic mechanism leading to the transition from commensalism to a pathogenic lifestyle.

scholarly journals Iron Acquisition of Urinary Tract Infection Escherichia coli Involves Pathogenicity in Caenorhabditis elegans

2021 ◽  
Vol 9 (2) ◽  
pp. 310
Author(s):  
Masayuki Hashimoto ◽  
Yi-Fen Ma ◽  
Sin-Tian Wang ◽  
Chang-Shi Chen ◽  
Ching-Hao Teng
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Caenorhabditis Elegans ◽  
Large Scale ◽  
Iron Acquisition ◽  
Infection Model ◽  
High Throughput Analysis ◽  
E Coli ◽  
C Elegans ◽  
Tract Infections

Uropathogenic Escherichia coli (UPEC) is a major bacterial pathogen that causes urinary tract infections (UTIs). The mouse is an available UTI model for studying the pathogenicity; however, Caenorhabditis elegans represents as an alternative surrogate host with the capacity for high-throughput analysis. Then, we established a simple assay for a UPEC infection model with C. elegans for large-scale screening. A total of 133 clinically isolated E. coli strains, which included UTI-associated and fecal isolates, were applied to demonstrate the simple pathogenicity assay. From the screening, several virulence factors (VFs) involved with iron acquisition (chuA, fyuA, and irp2) were significantly associated with high pathogenicity. We then evaluated whether the VFs in UPEC were involved in the pathogenicity. Mutants of E. coli UTI89 with defective iron acquisition systems were applied to a solid killing assay with C. elegans. As a result, the survival rate of C. elegans fed with the mutants significantly increased compared to when fed with the parent strain. The results demonstrated, the simple assay with C. elegans was useful as a UPEC infectious model. To our knowledge, this is the first report of the involvement of iron acquisition in the pathogenicity of UPEC in a C. elegans model.

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 Identification of a Novel Virulence Factor in Burkholderia cenocepacia H111 Required for Efficient Slow Killing of Caenorhabditis elegans

2004 ◽  
Vol 72 (12) ◽  
pp. 7220-7230 ◽  
Author(s):  
Birgit Huber ◽  
Friederike Feldmann ◽  
Manuela Köthe ◽  
Peter Vandamme ◽  
Julia Wopperer ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Burkholderia Cepacia ◽  
Bacterial Population ◽  
Wild Type Strain ◽  
Polyclonal Antibodies ◽  
Burkholderia Cenocepacia ◽  
Predicted Amino Acid Sequence ◽  
C Elegans

ABSTRACT Burkholderia cenocepacia H111, which was isolated from a cystic fibrosis patient, employs a quorum-sensing (QS) system, encoded by cep, to control the expression of virulence factors as well as the formation of biofilms. The QS system is thought to ensure that pathogenic traits are expressed only when the bacterial population density is high enough to overwhelm the host before it is able to mount an efficient response. While the wild-type strain effectively kills the nematode Caenorhabditis elegans, the pathogenicity of mutants with defective quorum sensing is attenuated. To date, very little is known about the cep-regulated virulence factors required for nematode killing. Here we report the identification of a cep-regulated gene, whose predicted amino acid sequence is highly similar to the QS-regulated protein AidA of the plant pathogen Ralstonia solanacearum. By use of polyclonal antibodies directed against AidA, it is demonstrated that the protein is expressed in the late-exponential phase and accumulates during growth arrest. We show that B. cenocepacia H111 AidA is essential for slow killing of C. elegans but has little effect on fast killing, suggesting that the protein plays a role in the accumulation of the strain in the nematode gut. Thus, AidA appears to be required for establishing an infection-like process rather than acting as a toxin. Furthermore, evidence is provided that AidA is produced not only by B. cenocepacia but also by many other strains of the Burkholderia cepacia complex.

scholarly journals Candida albicans Hyphal Formation and Virulence Assessed Using a Caenorhabditis elegans Infection Model

2009 ◽  
Vol 8 (11) ◽  
pp. 1750-1758 ◽  
Author(s):  
Read Pukkila-Worley ◽  
Anton Y. Peleg ◽  
Emmanouil Tampakakis ◽  
Eleftherios Mylonakis
Keyword(s):  
Candida Albicans ◽  
Caenorhabditis Elegans ◽  
Debaryomyces Hansenii ◽  
Yeast Cells ◽  
Infection Model ◽  
Virulence Determinants ◽  
Tissue Destruction ◽  
C Elegans ◽  
Hyphal Formation

ABSTRACT Candida albicans colonizes the human gastrointestinal tract and can cause life-threatening systemic infection in susceptible hosts. We study here C. albicans virulence determinants using the nematode Caenorhabditis elegans in a pathogenesis system that models candidiasis. The yeast form of C. albicans is ingested into the C. elegans digestive tract. In liquid media, the yeast cells then undergo morphological change to form hyphae, which results in aggressive tissue destruction and death of the nematode. Several lines of evidence demonstrate that hyphal formation is critical for C. albicans pathogenesis in C. elegans. First, two yeast species unable to form hyphae (Debaryomyces hansenii and Candida lusitaniae) were less virulent than C. albicans in the C. elegans assay. Second, three C. albicans mutant strains compromised in their ability to form hyphae (efg1Δ/efg1Δ, flo8Δ/flo8Δ, and cph1Δ/cph1Δ efg1Δ/efg1Δ) were dramatically attenuated for virulence. Third, the conditional tet-NRG1 strain, which enables the external manipulation of morphogenesis in vivo, was more virulent toward C. elegans when the assay was conducted under conditions that permit hyphal growth. Finally, we demonstrate the utility of the C. elegans assay in a screen for C. albicans virulence determinants, which identified several genes important for both hyphal formation in vivo and the killing of C. elegans, including the recently described CAS5 and ADA2 genes. These studies in a C. elegans-C. albicans infection model provide insights into the virulence mechanisms of an important human pathogen.

scholarly journals Caenorhabditis elegans as an Infection Model for Pathogenic Mold and Dimorphic Fungi: Applications and Challenges

2021 ◽  
Vol 11 ◽  
Author(s):  
Chukwuemeka Samson Ahamefule ◽  
Blessing C. Ezeuduji ◽  
James C. Ogbonna ◽  
Anene N. Moneke ◽  
Anthony C. Ike ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Filamentous Fungi ◽  
Virulence Factors ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Infection Model ◽  
Dimorphic Fungi ◽  
C Elegans

The threat burden from pathogenic fungi is universal and increasing with alarming high mortality and morbidity rates from invasive fungal infections. Understanding the virulence factors of these fungi, screening effective antifungal agents and exploring appropriate treatment approaches in in vivo modeling organisms are vital research projects for controlling mycoses. Caenorhabditis elegans has been proven to be a valuable tool in studies of most clinically relevant dimorphic fungi, helping to identify a number of virulence factors and immune-regulators and screen effective antifungal agents without cytotoxic effects. However, little has been achieved and reported with regard to pathogenic filamentous fungi (molds) in the nematode model. In this review, we have summarized the enormous breakthrough of applying a C. elegans infection model for dimorphic fungi studies and the very few reports for filamentous fungi. We have also identified and discussed the challenges in C. elegans-mold modeling applications as well as the possible approaches to conquer these challenges from our practical knowledge in C. elegans-Aspergillus fumigatus model.

scholarly journals Feeding behaviour of Caenorhabditis elegans is an indicator of Pseudomonas aeruginosa PAO1 virulence

2014 ◽  
Author(s):  
Shawn Lewenza ◽  
Laetitia Charron-Mazenod ◽  
Lauriane Giroux ◽  
Alexandra D Zamponi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Caenorhabditis Elegans ◽  
Feeding Behaviour ◽  
Food Sources ◽  
Infection Model ◽  
Bacterial Strains ◽  
Type Iii Effectors ◽  
Type Iii ◽  
C Elegans ◽  
Transposon Mutants

Caenorhabditis elegans is commonly used as an infection model for pathogenesis studies in Pseudomonas aeruginosa. While the standard virulence assays rely on the slow and fast killing or paralysis of nematodes, here we developed a behaviour assay to monitor the preferred bacterial food sources of C. elegans. The type III secretion system is a well-conserved virulence trait that is not required for slow or fast killing of C. elegans. However, ΔexsE mutants that are competent for hypersecretion of ExoS, ExoT and ExoY effectors were avoided as food sources in binary assays. Conversely, mutants lacking the secretion machinery or type III effectors were preferred food sources for PAO1. In binary feeding assays, both food sources were ingested and observed in the gastrointestinal tract, but non-preferred food sources were ultimately avoided. Next we developed a high throughput feeding behaviour assay to test a library of 2370 transposon mutants in order to identify preferred food sources. After primary and secondary screens, 37 mutants were identified as preferred food sources, which included mutations in many known virulence genes and that showed reduced virulence in the slow killing assay. We propose that C. elegans feeding behaviour can be used as a sensitive indicator of virulence for bacterial strains that have moderate worm killing activity.

scholarly journals Feeding behaviour of Caenorhabditis elegans is an indicator of Pseudomonas aeruginosa PAO1 virulence

2014 ◽  
Author(s):  
Shawn Lewenza ◽  
Laetitia Charron-Mazenod ◽  
Lauriane Giroux ◽  
Alexandra D Zamponi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Caenorhabditis Elegans ◽  
Feeding Behaviour ◽  
Food Sources ◽  
Infection Model ◽  
Bacterial Strains ◽  
Type Iii Effectors ◽  
Type Iii ◽  
C Elegans ◽  
Transposon Mutants

Caenorhabditis elegans is commonly used as an infection model for pathogenesis studies in Pseudomonas aeruginosa. While the standard virulence assays rely on the slow and fast killing or paralysis of nematodes, here we developed a behaviour assay to monitor the preferred bacterial food sources of C. elegans. The type III secretion system is a well-conserved virulence trait that is not required for slow or fast killing of C. elegans. However, ΔexsE mutants that are competent for hypersecretion of ExoS, ExoT and ExoY effectors were avoided as food sources in binary assays. Conversely, mutants lacking the secretion machinery or type III effectors were preferred food sources for PAO1. In binary feeding assays, both food sources were ingested and observed in the gastrointestinal tract, but non-preferred food sources were ultimately avoided. Next we developed a high throughput feeding behaviour assay to test a library of 2370 transposon mutants in order to identify preferred food sources. After primary and secondary screens, 37 mutants were identified as preferred food sources, which included mutations in many known virulence genes and that showed reduced virulence in the slow killing assay. We propose that C. elegans feeding behaviour can be used as a sensitive indicator of virulence for bacterial strains that have moderate worm killing activity.

154 Virulence Potential of Antimicrobial Resistant Extraintestinal Pathogenic Escherichia coli from Poultry in a Caenorhabditis Elegans Model

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 84-84
Author(s):  
Chongwu Yang ◽  
Moussa Diarra ◽  
Muhammad Attiq Rehman ◽  
Linyan Li ◽  
Hai Yu ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Life Span ◽  
Negative Control ◽  
Coli Strain ◽  
Poultry Meat ◽  
Infection Model ◽  
E Coli ◽  
C Elegans ◽  
Virulence Potential ◽  
Retail Meats

Abstract This study investigated virulence potential of poultry antimicrobial resistant extraintestinal pathogenic E. coli (ExPEC). A total of 46 E. coli isolates from poultry meat, feces, or humans were sequenced and identified as ExPEC. Based on their characteristics, eight of these ExPEC isolates were evaluated for their potentials using a Caenorhabditis elegans infection model. The life-span of C. elegans in response to these eight isolates was examined in three life-span experiments: 1) E. coli OP 50 (negative control), K88+ enterotoxigenic E. coli strain JG280 (positive control), and an ExPEC isolate from human urinal tract infection; 2) three ExPEC isolates from chicken and turkey retail meats; 3) four ExPEC isolates from chicken feces with different antimicrobial resistance (AMR) profiles or a various number of virulence genes (VGs). All 46 isolates belonged to 24 serotypes among which 6 were of serotype O25:H4 Sequence Type 131 (ST131). Interestingly, all ST 131 isolates from chicken or turkey retail meats clustered with a human UTI isolate belonging to the similar serotype and ST type. The types and numbers of AGRs and VGs varied among the eight selected isolates for C. elegans model. The human ExPEC induced a similar effect as the JG280 on reducing (P < 0.05) survival of C. elegans. Interestingly, chicken and turkey meat ExPEC isolates, caused similar negative impacts on the survival of worms as the human ExPEC. Additionally, fecal ExPEC isolates reduced (P < 0.05) the survival of C. elegans compared to OP50. However, the survival of C. elegans was not reduced with an increasing number of VGs and did not seem to be affected by AMR profiles. This study indicated the virulence potential of ExPEC isolates from retail poultry meat or feces. The relationship between specific AMR profiles and/or numbers of VGs with pathogenicity in these E. coli isolates deserves further investigations.

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