scholarly journals Staphylococcus epidermidis un Pseudomonas aeruginosa adhēzijas un kolonizācijas intensitātes noteikšana uz oriģināli sintezētu biomateriālu virsmas in vitro un in vivo pētījumos un to ietekme uz iekaisuma citokīnu ekspresiju audos. Promocijas darbs

2016 ◽  
Author(s):  
◽  
Reinis Aigars
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Staphylococcus Epidermidis

Interferences bacteriennes au niveau cutane chez la souris «hairless» dixénique

1986 ◽  
Vol 32 (9) ◽  
pp. 751-755 ◽  
Author(s):  
M. C. Barc ◽  
P. Bourlioux ◽  
H. Boureau ◽  
F. Nerbone ◽  
E. Wasconcellos da Costa
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Digestive Tract ◽  
Staphylococcus Epidermidis ◽  
Bacteriocin Production ◽  
In Vitro Assays ◽  
Adherence Inhibition

Bacterial colonizaion of the digestive tract and the skin was studied over a 3-week period in a group of 10 germfree HRS mice using Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. Sequential utilization of two strains allowed us to carry out six assays and to show the presence of interference phenomena during colonization of the skin. When P. aeruginosa was given after challenge with S. aureus or S. epidermidis, it did not colonize the skin. If the first challenge was done with P. aeruginosa, this bacteria was eliminated within 10 days by S. aureus and S. epidermidis on the skin, but it succeeded in colonizing the digestive tract. When the first challenge was done with S. aureus, colonization of the skin and the digestive tract with S. epidermidis was prevented, whereas these two species were found in association when S. aureus was given in second place. None of the in vitro assays (mixed culture, bacteriocin production, adherence inhibition, antimicrobial activity) could explain the in vivo observations.

scholarly journals Σύνθεση, χαρακτηρισμός και μελέτη νέων συμπλόκων ενώσεων, αλάτων του υδραργύρου(ΙΙ) και μολύβδου(ΙΙ) με υποκαταστάτες παράγωγα της θειουρίας και αμινοξέων

2018 ◽  
Author(s):  
Βασίλειος Μπαλάς
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Allium Cepa ◽  
1H Nmr ◽  
Staphylococcus Epidermidis

H παρούσα διατριβή πραγματεύεται τη σύνθεση νέων συμπλόκων ενώσεων του ανόργανου υδραργύρου (ΙΙ) και μολύβδου(ΙΙ) με υποκαταστάτες παράγωγα της θειουρίας και αμινοξέα. Ο χαρακτηρισμός των ενώσεων έγινε σε στερεά κατάσταση με κρυσταλλογραφία φθορισμού (XRF) και κόνεος (XRPD), με φασματοσκοπία υπερύθρου (IR) και με θερμοσταθμική ανάλυση. Σε διάλυμα οι ενώσεις χαρακτηρίστηκαν με φασματοσκοπία υπεριώδους-ορατού (UV-Vis) και πυρηνικού μαγνητικού συντονισμού πυρήνων υδρογόνου (1H-NMR) ενώ πραγματοποιήθηκε και μελέτη φθορισμού σε στερεά κατάσταση και σε διάλυμα. Οι ενώσεις: Hg(tpp)2(pmt-)2, Hg(pmt-)3(pmtH)Cl, Hg2(pmt)2(pmtH)2Br2, Hg(pmtH)2I2, Hg(tpp)2I2, [Hg(tu)4]2+2[Cl]-, [glyH]+[HgCl3]- και (Hg(cysH2)(cysH-)Cl.H2O, [Et3NH]+ [Cl(HgCl2)6]-, [Et3NH]+ [Hg2Cl5)]-, [na-onaH]+ [HgI3]-, [HSCH2CHNH3+COO-], [Et3NH+][CH2SCSNHCHCOO-], [Et3NH]+ [tbaH]-.H2O και [naH+][NO3-] χαρακτηρίστηκαν με κρυσταλλογραφία περίθλασης ακτίνων Χ μονοκρυστάλλου. Επίσης προσδιορίστηκε και η δομή του προϊόντος Hg(pmt-)2 από την αντίδραση του HgCl2 με την αποπρωτονιομένη 2-μερκαπτοπυριμιδίνη. Για τις ενώσεις αυτές μελετήθηκε η σχέση δομής με το είδος και το μέγεθος των τοξικών επιδράσεων που προκαλούνται in vitro σε βιολογικά συστήματα προκαρυωτικών κυττάρων (Gram +: Staphylococcus aureus, Staphylococcus epidermidis, Gram –: Pseudomonas aeruginosa). Επίσης εκτιμήθηκε η in vitro τοξική τους δράση έναντι υγιών ευκαρυωτικών κυττάρων δέρματος (HaCaT) και ινοβλαστών πνεύμονα (MRC5) ως πρότυπα διαφορετικών κύριων οδών απορρόφησης των βαρέων μετάλλων από τον ανθρώπινο οργανισμό. Τέλος, στο πλαίσιο διερεύνησης της πιθανής γενοτοξικής τους δράσης πραγματοποιήθηκε αξιολόγηση: α) in vitro με την ανιχνεύση μικροπυρηνίσκων σε κύτταρα HaCaT που βρίσκονται στη φάση της μεσόφασης και β) in vivo με την ανίχνευση χρωμοσωμικών ανωμαλιών και εκτίμηση του μιτωτικού δείκτη σύμφωνα με το πρωτόκολλο Allium cepa.

scholarly journals A Novel Infection Protocol in Zebrafish Embryo to Assess Pseudomonas aeruginosa Virulence and Validate Efficacy of a Quorum Sensing Inhibitor In Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 401
Author(s):  
Pauline Nogaret ◽  
Fatima El El Garah ◽  
Anne-Béatrice Blanc-Potard
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Animal Model ◽  
Quorum Sensing ◽  
Drug Testing ◽  
Drug Efficacy ◽  
Embryo Viability ◽  
Immersion Method ◽  
Opportunistic Human Pathogen

The opportunistic human pathogen Pseudomonas aeruginosa is responsible for a variety of acute infections and is a major cause of mortality in chronically infected cystic fibrosis patients. Due to increased resistance to antibiotics, new therapeutic strategies against P. aeruginosa are urgently needed. In this context, we aimed to develop a simple vertebrate animal model to rapidly assess in vivo drug efficacy against P. aeruginosa. Zebrafish are increasingly considered for modeling human infections caused by bacterial pathogens, which are commonly microinjected in embryos. In the present study, we established a novel protocol for zebrafish infection by P. aeruginosa based on bath immersion in 96-well plates of tail-injured embryos. The immersion method, followed by a 48-hour survey of embryo viability, was first validated to assess the virulence of P. aeruginosa wild-type PAO1 and a known attenuated mutant. We then validated its relevance for antipseudomonal drug testing by first using a clinically used antibiotic, ciprofloxacin. Secondly, we used a novel quorum sensing (QS) inhibitory molecule, N-(2-pyrimidyl)butanamide (C11), the activity of which had been validated in vitro but not previously tested in any animal model. A significant protective effect of C11 was observed on infected embryos, supporting the ability of C11 to attenuate in vivo P. aeruginosa pathogenicity. In conclusion, we present here a new and reliable method to compare the virulence of P. aeruginosa strains in vivo and to rapidly assess the efficacy of clinically relevant drugs against P. aeruginosa, including new antivirulence compounds.

Antimicrobial and antibiofilm activities of meropenem loaded-mesoporous silica nanoparticles against carbapenem-resistant Pseudomonas aeruginosa

2021 ◽  
pp. 088532822110038
Author(s):  
Mohammad Yousef Memar ◽  
Mina Yekani ◽  
Hadi Ghanbari ◽  
Edris Nabizadeh ◽  
Sepideh Zununi Vahed ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Carbapenem Resistant ◽  
Toxicity In Vitro ◽  
Different Levels

The aims of the present study were the determination of antimicrobial and antibiofilm effects of meropenem-loaded mesoporous silica nanoparticles (MSNs) on carbapenem resistant Pseudomonas aeruginosa ( P. aeruginosa) and cytotoxicity properties in vitro. The meropenem-loaded MSNs had shown antibacterial and biofilm inhibitory activities on all isolates at different levels lower than MICs and BICs of meropenem. The viability of HC-04 cells treated with serial concentrations as MICs and BICs of meropenem-loaded MSNs was 92–100%. According to the obtained results, meropenem-loaded MSNs display the significant antibacterial and antibiofilm effects against carbapenem resistant and biofilm forming P. aeruginosa and low cell toxicity in vitro. Then, the prepared system can be an appropriate option for the delivery of carbapenem for further evaluation in vivo assays.

scholarly journals Exogenous Alginate Protects Staphylococcus aureus from Killing by Pseudomonas aeruginosa

2019 ◽  
Vol 202 (8) ◽  
Author(s):  
Courtney E. Price ◽  
Dustin G. Brown ◽  
Dominique H. Limoli ◽  
Vanessa V. Phelan ◽  
George A. O’Toole
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Physical Space ◽  
Late Time ◽  
Protective Effects ◽  
Content Type ◽  
Alginate Production ◽  
The Impact

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.

scholarly journals In-vivo assessment of in-vitro killing patterns of Pseudomonas aeruginosa

1985 ◽  
Vol 15 (suppl A) ◽  
pp. 201-206 ◽  
Author(s):  
A. U. Gerber ◽  
C. Feller-Segessenmann
Keyword(s):  
Pseudomonas Aeruginosa ◽  
In Vivo Assessment

scholarly journals Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

2005 ◽  
Vol 187 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Lauren M. Mashburn ◽  
Amy M. Jett ◽  
Darrin R. Akins ◽  
Marvin Whiteley
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Iron Acquisition ◽  
Low Oxygen ◽  
Dialysis Membrane ◽  
Opportunistic Human Pathogen ◽  
The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

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