scholarly journals Pancreatic Amylase Is an Environmental Signal for Regulation of Biofilm Formation and Host Interaction in Campylobacter jejuni

2015 ◽  
Vol 83 (12) ◽  
pp. 4884-4895 ◽  
Author(s):  
Waheed Jowiya ◽  
Katja Brunner ◽  
Sherif Abouelhadid ◽  
Haitham A. Hussain ◽  
Sean P. Nair ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Infection Model ◽  
Pancreatic Amylase ◽  
Content Type ◽  
Host Interaction ◽  
Food Borne ◽  
Epithelial Cell Lines

Campylobacter jejuniis a commensal bacterium in the intestines of animals and birds and a major cause of food-borne gastroenteritis in humans worldwide. Here we show that exposure to pancreatic amylase leads to secretion of an α-dextran byC. jejuniand that a secreted protease, Cj0511, is required. Exposure ofC. jejunito pancreatic amylase promotes biofilm formationin vitro, increases interaction with human epithelial cell lines, increases virulence in theGalleria mellonellainfection model, and promotes colonization of the chicken ileum. We also show that exposure to pancreatic amylase protectsC. jejunifrom stress conditionsin vitro, suggesting that the induced α-dextran may be important during transmission between hosts. This is the first evidence that pancreatic amylase functions as an interkingdom signal in an enteric microorganism.

scholarly journals Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

2015 ◽  
Vol 14 (8) ◽  
pp. 834-844 ◽  
Author(s):  
Ranjith Rajendran ◽  
Elisa Borghi ◽  
Monica Falleni ◽  
Federica Perdoni ◽  
Delfina Tosi ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Inflammatory Responses ◽  
Fungal Infections ◽  
Infection Model ◽  
Content Type

ABSTRACT Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo . In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

scholarly journals Activity of Telavancin against Staphylococcus aureus Isolates, Including Those with Decreased Susceptibility to Ceftaroline, from Cystic Fibrosis Patients

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Melanie Roch ◽  
Maria Celeste Varela ◽  
Agustina Taglialegna ◽  
Warren E. Rose ◽  
Adriana E. Rosato
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Galleria Mellonella ◽  
Therapeutic Option ◽  
The United States ◽  
Infection Model ◽  
Content Type ◽  
Complicated Skin ◽  
Hospital Acquired

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) acquisition in cystic fibrosis (CF) patients confers a clinical outcome worse than that in non-CF patients with an increased rate of declined lung function. Telavancin, an approved lipoglycopeptide used to treat infections due to S. aureus, has a dual mode of action causing inhibition of peptidoglycan synthesis and membrane depolarization. MRSA infections in CF patients remain an important problem with no foreseeable decline in prevalence rates. Although telavancin is currently in clinical use for the treatment of complicated skin infections and hospital-acquired pneumonia, the activity against S. aureus infections in CF patients has not been investigated. In this work, we studied the activity of telavancin against CF patient-derived S. aureus strains collected from geographically diverse CF centers in the United States. We found that the telavancin MIC90 was 0.06 μg/ml, 8-fold lower than the ceftaroline or daptomycin MIC90 and 25-fold lower than the linezolid and vancomycin MIC90. We demonstrate that telavancin at serum free concentrations has rapid bactericidal activity, with a decrease of more than 3 log10 CFU/ml being achieved during the first 4 to 6 h of treatment, performing better in this assay than vancomycin and ceftaroline, including against S. aureus strains resistant to ceftaroline. Telavancin resistance was infrequent (0.3%), although we found that it can occur in vitro in both CF- and non-CF patient-derived S. aureus strains by progressive passages with subinhibitory concentrations. Genetic analysis of telavancin-resistant in vitro mutants showed gene polymorphisms in cell wall and virulence genes and increased survival in a Galleria mellonella infection model. Thus, we conclude that telavancin represents a promising therapeutic option for infections in CF patients with potent in vitro activity and a low resistance development potential.

scholarly journals Development of in Vitro Resistance to Daptomycin in Enterococcus Faecium and Estimation of Its Fitness Cost

2020 ◽  
Author(s):  
Weiliang Zeng ◽  
Tao Chen ◽  
Qing Wu ◽  
Ye Xu ◽  
Kaihang Yu ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Resistance Mechanisms ◽  
Fitness Cost ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Dynamic Resistance ◽  
Vancomycin Resistant

Abstract BackgroundDaptomycin has broad-spectrum antibacterial activity against Gram-positive pathogens, but recent studies have revealed cases where daptomycin has failed to treat multidrug-resistant bacteria, such as vancomycin-resistant Enterococcus faecium. However, the resistance evolution of E. faecium to daptomycin in vitro and fitness cost remain unclear. In this study, we sought to analyze the resistance development and mechanism of E. faecium to datomycin, and futher to investigate the relationship between daptomycin resistance and fitness cost.MethodsTo investigate the development of daptomycin resistance in E. faecium, 6 daptomycin-susceptible (DAP-S) clinical isolates, including 3 vancomycin-resistant E. faecium (VRE) and 3 vancomycin-susceptible E. faecium (VSE), were exposured to daptomycin in vitro by serial passage experiment. Then the different resistance mechanisms of daptomycin-resistant (DAP-R) mutants were analyzed by polymerase chain reaction (PCR), cytochrome C binding assay and transmission electron microscopy. Furthermore, we also estimated the changes of fitness cost among each highly DAP-R mutants by bacterial growth curve measurement, in vitro competition experiments, infection model of Galleria mellonella larvae and biofilm formation assays.ResultsIn vitro, a total of 21 DAP-R mutants with minimal inhibitory concentration (MIC) of 4 to 512 μg/mL were obtained, and these mutants carried more than one mutation of LiaFSR and YycFG system encoding genes. More positive charges were detected among highly DAP-R mutants than parent isolates, and the cell walls of SC1174-D and SC1762-D mutants were remarkly thicker than those of the parent isolates. In comparison with parent isolates, besides, the growth, competition ability and virulence were significantly reduced, while the biofilm formation capacity was markedly elevated among each highly DAP-R mutants.ConclusionsOur findings suggest that E. faecium isolates are able to rapidly acquire DAP resistance in vitro through different dynamic resistance mechanisms, which often accompany by significant fitness cost. Intriguingly, DAP and glycopeptide antibiotics may present collateral-sensitivity during E. faecium acquired DAP resistance in vitro.

scholarly journals The Heat-Induced Molecular Disaggregase Hsp104 of Candida albicans Plays a Role in Biofilm Formation and Pathogenicity in a Worm Infection Model

2012 ◽  
Vol 11 (8) ◽  
pp. 1012-1020 ◽  
Author(s):  
Alessandro Fiori ◽  
Soňa Kucharíková ◽  
Gilmer Govaert ◽  
Bruno P. A. Cammue ◽  
Karin Thevissen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Stress Responses ◽  
Biofilm Formation ◽  
Fungal Pathogens ◽  
Elevated Temperatures ◽  
Structural Defects ◽  
Infection Model ◽  
Content Type

ABSTRACT The consequences of deprivation of the molecular chaperone Hsp104 in the fungal pathogen Candida albicans were investigated. Mutants lacking HSP104 became hypersusceptible to lethally high temperatures, similarly to the corresponding mutants of Saccharomyces cerevisiae , whereas normal susceptibility was restored upon reintroduction of the gene. By use of a strain whose only copy of HSP104 is an ectopic gene under the control of a tetracycline-regulated promoter, expression of Hsp104 prior to the administration of heat shock could be demonstrated to be sufficient to confer protection from the subsequent temperature increase. This result points to a key role for Hsp104 in orchestrating the cell response to elevated temperatures. Despite their not showing evident growth or morphological defects, biofilm formation by cells lacking HSP104 proved to be defective in two established in vitro models that use polystyrene and polyurethane as the substrates. Biofilms formed by the wild-type and HSP104 -reconstituted strains showed patterns of intertwined hyphae in the extracellular matrix. In contrast, biofilm formed by the hsp104 Δ/ hsp104 Δ mutant showed structural defects and appeared patchy and loose. Decreased virulence of the hsp104 Δ/ hsp104 Δ mutant was observed in the Caenorhabditis elegans infection model, in which high in vivo temperature does not play a role. In agreement with the view that stress responses in fungal pathogens may have evolved to provide niche-specific adaptation to environmental conditions, these results provide an indication of a temperature-independent role for Hsp104 in support of Candida albicans virulence, in addition to its key role in governing thermotolerance.

scholarly journals Anti-adhesive and anti-biofilm activity of NC-E08. In vitro and in vivo study using Galleria mellonella infection model

2019 ◽  
Author(s):  
Gabriela Fernanda Bombarda ◽  
Janaina de Cássia Orlandi Sardi ◽  
Pedro L. Rosalen ◽  
Josy G. Lazarini ◽  
Eder R. Paganini ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Early Childhood Caries ◽  
Galleria Mellonella ◽  
Infection Model ◽  
Oral Diseases ◽  
Antimicrobial Drugs ◽  
Structural Analogues

Biofilms are organized microbial communities formed from an ecological succession. Biofilm formation functions as a mechanism of virulence and favors the development of diseases, including oral diseases such as dental caries and periodontal disease, in which the microorganisms Streptococcus mutans and Candida albicans are closely related. Previous studies have shown that interactions between S. mutans and C. albicans are associated with the pathogenesis of early childhood caries (ECC). Therefore, there is a great interest in finding new prototypes for antimicrobial drugs, mainly for the development of structural analogues of chalcones, which constitute one of the largest classes of natural products belonging to the flavonoid family and are considered strategic molecules for this purpose.

scholarly journals Narrow-Spectrum Inhibitors of Campylobacter jejuni Flagellar Expression and Growth

2015 ◽  
Vol 59 (7) ◽  
pp. 3880-3886 ◽  
Author(s):  
Jeremiah G. Johnson ◽  
Caroline Yuhas ◽  
Thomas J. McQuade ◽  
Martha J. Larsen ◽  
Victor J. DiRita
Keyword(s):  
Small Molecules ◽  
Campylobacter Jejuni ◽  
Campylobacter Coli ◽  
Content Type ◽  
Food Borne ◽  
Food Borne Illness ◽  
Inhibitor Screen

ABSTRACTCampylobacter jejuniis a major cause of food-borne illness due to its ability to reside within the gastrointestinal tracts of chickens. Multiple studies have identified the flagella ofC. jejunias a major determinant of chicken colonization. An inhibitor screen of approximately 147,000 small molecules was performed to identify compounds that are able to inhibit flagellar expression in a reporter strain ofC. jejuni. Several compounds that modestly inhibited motility of wild-typeC. jejuniin standard assays were identified, as were a number of small molecules that robustly inhibitedC. jejunigrowth,in vitro. Examination of similar bacterial screens found that many of these small molecules inhibited only the growth ofC. jejuni. Follow-up assays demonstrated inhibition of other strains ofC. jejuniandCampylobacter colibut no inhibition of the closely relatedHelicobacter pylori. The compounds were determined to be bacteriostatic and nontoxic to eukaryotic cells. Preliminary results from a day-of-hatch chick model of colonization suggest that at least one of the compounds demonstrates promise for reducingCampylobactercolonization loadsin vivo, although further medicinal chemistry may be required to enhance bioavailability.

scholarly journals Hyaluronan Modulation Impacts Staphylococcus aureus Biofilm Infection

2016 ◽  
Vol 84 (6) ◽  
pp. 1917-1929 ◽  
Author(s):  
Carolyn B. Ibberson ◽  
Corey P. Parlet ◽  
Jakub Kwiecinski ◽  
Heidi A. Crosby ◽  
David K. Meyerholz ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Infection Model ◽  
Wild Type ◽  
Content Type ◽  
Joint Infections ◽  
The Impact ◽  
Biofilm Infection ◽  
Biofilm Matrix

Staphylococcus aureusis a leading cause of chronic biofilm infections. Hyaluronic acid (HA) is a large glycosaminoglycan abundant in mammalian tissues that has been shown to enhance biofilm formation in multiple Gram-positive pathogens. We observed that HA accumulated in anS. aureusbiofilm infection using a murine implant-associated infection model and that HA levels increased in a mutant strain lacking hyaluronidase (HysA).S. aureussecretes HysA in order to cleave HA during infection. Throughin vitrobiofilm studies with HA, thehysAmutant was found to accumulate increased biofilm biomass compared to the wild type, and confocal microscopy showed that HA is incorporated into the biofilm matrix. Exogenous addition of purified HysA enzyme dispersed HA-containing biofilms, while catalytically inactive enzyme had no impact. Additionally, induction ofhysAexpression prevented biofilm formation and also dispersed an established biofilm in the presence of HA. These observations were corroborated in the implant model, where there was decreased dissemination from anhysAmutant biofilm infection compared to theS. aureuswild type. Histopathology demonstrated that infection with anhysAmutant caused significantly reduced distribution of tissue inflammation compared to wild-type infection. To extend these studies, the impact of HA andS. aureusHysA on biofilm-like aggregates found in joint infections was examined. We found that HA contributes to the formation of synovial fluid aggregates, and HysA can disrupt aggregate formation. Taken together, these studies demonstrate that HA is a relevant component of theS. aureusbiofilm matrix and HysA is important for dissemination from a biofilm infection.

scholarly journals Does Campylobacter jejuni Form Biofilms in Food-Related Environments?

2014 ◽  
Vol 80 (17) ◽  
pp. 5154-5160 ◽  
Author(s):  
Amy Huei Teen Teh ◽  
Sui Mae Lee ◽  
Gary A. Dykes
Keyword(s):  
Campylobacter Jejuni ◽  
Food Processing ◽  
Biofilm Formation ◽  
Food Production ◽  
Significant Risk ◽  
Primary Source ◽  
Content Type ◽  
Food Borne ◽  
Processing Plants ◽  
Atmosphere Temperature

ABSTRACTCampylobacter jejuniis one of the most frequent causes of bacterial gastrointestinal food-borne infection worldwide. This species is part of the normal flora of the gastrointestinal tracts of animals used for food production, including poultry, which is regarded as the primary source of humanCampylobacterinfections. The survival and persistence ofC. jejuniin food processing environments, especially in poultry processing plants, represent significant risk factors that contribute to the spread of this pathogen through the food chain. Compared to other food-borne pathogens,C. jejuniis more fastidious in its growth requirements and is very susceptible to various environmental stressors. Biofilm formation is suggested to play a significant role in the survival ofC. jejuniin the food production and processing environment. The aims of this minireview were (i) to examine the evidence thatC. jejuniforms biofilms and (ii) to establish the extent to which reported and largely laboratory-based studies ofC. jejunibiofilms provide evidence for biofilm formation by this pathogen in food processing environments. Overall existing studies do not provide strong evidence for biofilm formation (as usually defined) by mostC. jejunistrains in food-related environments under the combined conditions of atmosphere, temperature, and shear that they are likely to encounter. Simple attachment to and survival on surfaces and in existing biofilms of other species are far more likely to contribute toC. jejunisurvival in food-related environments based on our current understanding of this species.

scholarly journals Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species

mSphere ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Andrew M. Borman ◽  
Adrien Szekely ◽  
Elizabeth M. Johnson
Keyword(s):  
Invasive Candidiasis ◽  
Fungal Pathogen ◽  
Galleria Mellonella ◽  
Systemic Infection ◽  
Mortality Rates ◽  
Infection Model ◽  
Candida Auris ◽  
Deep Tissue ◽  
Content Type

ABSTRACT The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain-specific differences in the virulence of C. auris, with the most virulent isolates exhibiting pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus. Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain-specific differences in the virulence of C. auris, with the most virulent isolates exhibiting pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus.

scholarly journals Chitosan Ameliorates Candida auris Virulence in a Galleria mellonella Infection Model

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Laís Salomão Arias ◽  
Mark C. Butcher ◽  
Bryn Short ◽  
Emily McKloud ◽  
Chris Delaney ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Survival Rates ◽  
Health Care Facilities ◽  
Antifungal Drugs ◽  
Infection Model ◽  
Candida Auris ◽  
Gene Expression Response ◽  
Content Type

ABSTRACT Candida auris has emerged as a multidrug-resistant nosocomial pathogen over the last decade. Outbreaks of the organism in health care facilities have resulted in life-threatening invasive candidiasis in over 40 countries worldwide. Resistance by C. auris to conventional antifungal drugs such as fluconazole and amphotericin B means that alternative therapeutics must be explored. As such, this study served to investigate the efficacy of a naturally derived polysaccharide called chitosan against aggregative (Agg) and nonaggregative (non-Agg) isolates of C. auris in vitro and in vivo. In vitro results indicated that chitosan was effective against planktonic and sessile forms of Agg and non-Agg C. auris. In a Galleria mellonella model to assess C. auris virulence, chitosan treatment was shown to ameliorate killing effects of both C. auris phenotypes (NCPF 8973 and NCPF 8978, respectively) in vivo. Specifically, chitosan reduced the fungal load and increased survival rates of infected Galleria, while treatment alone was nontoxic to the larvae. Finally, chitosan treatment appeared to induce a stress-like gene expression response in NCPF 8973 in the larvae likely arising from a protective response by the organism to resist antifungal activity of the compound. Taken together, results from this study demonstrate that naturally derived compounds such as chitosan may be useful alternatives to conventional antifungals against C. auris.

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