• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 283
  • 42
  • 32
  • 25
  • 20
  • 9
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 575
  • 575
  • 95
  • 66
  • 62
  • 49
  • 47
  • 46
  • 44
  • 44
  • 44
  • 40
  • 39
  • 37
  • 37
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Topical formulation of antimicrobials for wound care

Cederwall, Ida January 2022 (has links)
The increasing spread of antibiotic resistance among bacteria poses a major threat to the public health. There is an urge for the development of innovative formulations of existing and new antibiotics. One area of interest is in wound care, where two interesting antimicrobials are the conventional antibiotic amoxicillin and the antimicrobial peptide AP114. The objective of this work was to systemically evaluate topical gel formulations of these APIs by following a Quality by Design approach. A short excipient compatibility study was performed and the thickening agents poloxamer 407 and HPMC were chosen to be included in the following Design of Experiment (DoE) study of formulation composition and storage climate. The DoE set up was generated by the software MODDE Pro® and a short stability study of four weeks was performed, including analysis of the apparent pH, rheology stability, appearance, BCA assay, UV-Vis and FTIR spectroscopy and Franz cell diffusion. The results showed that AP114 formulations stored at 2-8˚C with poloxamer 407 should be with buffer pH 5-6 and 5-15 wt% organic phase to maximize stability, while HPMC based AP114 gels should be with buffer pH 6-8 and 10-40 wt% organic phase. Poloxamer 407 was not preferrable for amoxicillin formulations. The optimal HPMC based amoxicillin formulations included the storage temperature 25˚C, a buffer pH 7-8 and 40-60 wt% organic phase. HPMC based amoxicillin gels stored at 2-8˚C should be composed with buffer pH 6-8 and 10-40 wt% organic phase.
482

Sjuksköterskans förebyggande roll vid antibiotikaresistens : En litteraturöversikt / The nurse’s preventive roll in antibiotic resistance : A literature review

Palmkvist, Amanda, Weijnblad, Mikaela January 2022 (has links)
Bakgrund: Behandlingen av bakteriella infektioner med antibiotika har lett till ett ökat problem av antibiotikaresistens. Antibiotikaresistensens konsekvenser har resulterat i problem för både individer och sjukvård världen över. Både etiska aspekter och sjuksköterskans roll inom omvårdnaden behöver ses över för att finna lösningar till detta globala hot.   Syfte: Att beskriva sjuksköterskans förebyggande roll vid antibiotikaresistens.  Metod: En litteraturöversikt   Resultat: Sjuksköterskans roll i förebyggandet av antibiotikaresistens ansågs var otydliga. Sjuksköterskor belyste att utbildningen innehöll moment om förebyggande åtgärder för antibiotika resistens lika så i praktiken. Däremot upplevde sjuksköterskor i arbetslivet att de var exkluderade.   Sammanfattning: Författarna fann att det fanns en tydlig koppling mellan betydelsen av sjuksköterskans arbetsroll och det förebyggande arbetet kring antibiotikaresistens. Det fanns även en kunskapsbrist hos sjuksköterskorna kring antibiotikaresistensen och de förebyggande rutinerna samt att vikten av en fungerande kommunikation mellan vårdprofessionerna spelade stor roll. / Background: The treatment of bacterial infections with antibiotics has led to an increased problem with antibiotic resistance. The antibiotic resistance has had consequences that resulted in problems for both individuals as well as health care worldwide. Both ethical aspects and the nurse’s role within nursing needs to be reviewed to find solutions to this global threat.   Aim: To describe the nurse’s preventive roll in antibiotic resistance.  Method: Literature review  Results: The nurse’s role in the prevention of antibiotic resistance was seen as vague. Nurses illustrated that education contained elements on the prevention of antibiotic resistance as well as in practice. On the other hand, in the work life, nurses rather felt that they were excluded.   Summary: The authors found that there was a clear connection between the importance of the nurse’s work role and the preventative work regarding antibiotic resistance. There was a knowledge gap between the nurses when it came to antibiotic resistance and the preventative routines as well as bearing that a functioning communication between the nursing professions was of big importance.
483

Model Development and Investigation of Antibiotic Cross Resistance and Decay in <i>E. Coli</i>

Boyette, Rachel A. 22 June 2022 (has links)
No description available.
484

Development of a Model for Bacterial Antibiotic Resistance in <i>E. coli</i>

DeWeese, Claire 22 June 2022 (has links)
No description available.
485

Evolution and Selection: From Suppression of Metabolic Deficiencies to Bacteriophage Host Range and Resistance

Arens, Daniel Kurt 14 April 2021 (has links)
The evolution and adaptation of microorganisms is so rapid it can be seen in the time frame of days. The root cause for their evolution comes from selective environmental pressures that see organisms with beneficial mutations survive otherwise deadly encounters or outperform members of its population who fail to adapt. This does not always result in strict improvement of the individual as in the case of antibiotic resistant bacteria who often display fitness tradeoffs to avoid death (see Reviews [1-3]). For example, when an ampicillin resistance gene (ampC) containing plasmid that is occasionally found in the wild was transformed into S. typhimurium the bacteria had slower growth and impaired invasiveness [4]. In another example, capreomycin use with mycobacteria resulted in lower binding of the drug to the ribosome through mutations in rRNA methylase TlyA 16S rRNA, which decreases the overall fitness of the mycobacteria [5]. The evolutionary interactomes between bacteria and antibiotics do not end there, as antibiotic resistant bacteria often accumulate compensatory mechanisms to regain fitness. These range in effect with some altering individual cellular pathways and others having systemic affects [1]. My work has focused on the intersection of diabetes and related antibiotic resistant bacterial infections. Diabetes is one of the leading health issues in the United States, with over 10% of the adult population and over 26% of the elderly diagnosed (American Diabetes Association) [6]. Herein I further characterize the molecular pathways involved in diabetes, through the study of PAS kinase (PASK) function. PAS kinase is a serine-threonine protein kinase which regulates the pathways disrupted in diabetes, namely triglyceride accumulation, metabolic rate (respiration), adiposity and insulin production and sensitivity [7-9]. In this study I specifically focus on the effects of PAS kinase and its substrate, USF1/Cbf1p, and how their altered metabolic deficiencies can be suppressed using yeast cells. Through this study I further characterized the molecular function of USF1/Cbf1p through the identification of putative co-transcriptional regulators, identify novel genes involved in the regulation of respiration, and uncover a function or a previous uncharacterized protein, Pal1p. Part of the diabetes healthcare challenge results from the wide range of diseases that are associated with diabetes, including obesity [10, 11], renal failure [12, 13], neuropathies and neurodegeneration [14, 15], endocrine dysfunctions [16, 17], and cancers [18]. In addition, diabetes is a leading cause of lower limb amputations, due to poor circulation and the prevalence of ulcers [19-21], many of which are antibiotic resistant [22-25]. Phage therapy, based on the administration of bacterial viruses, is a viable option for the treatment of these diseases, with our lab recently isolating bacteriophages for several clinical cases. In the second half of my thesis, I present the study of the adaptation of bacteriophages to their hosts as well as report contributions of local ecology to their evolution.
486

High genomic diversity of multi-drug resistant wastewater Escherichia coli

Mahfouz, Norhan, Caucci, Serena, Achatz, Eric, Semmler, Torsten, Guenther, Sebastian, Berendonk, Thomas U., Schroeder, Michael 13 December 2018 (has links)
Wastewater treatment plants play an important role in the emergence of antibiotic resistance. They provide a hot spot for exchange of resistance within and between species. Here, we analyse and quantify the genomic diversity of the indicator Escherichia coli in a German wastewater treatment plant and we relate it to isolates’ antibiotic resistance. Our results show a surprisingly large pan-genome, which mirrors how rich an environment a treatment plant is. We link the genomic analysis to a phenotypic resistance screen and pinpoint genomic hot spots, which correlate with a resistance phenotype. Besides well-known resistance genes, this forward genomics approach generates many novel genes, which correlated with resistance and which are partly completely unknown. A surprising overall finding of our analyses is that we do not see any difference in resistance and pan genome size between isolates taken from the inflow of the treatment plant and from the outflow. This means that while treatment plants reduce the amount of bacteria released into the environment, they do not reduce the potential for antibiotic resistance of these bacteria.
487

Verifiering av mikrobuljongspädning med Sensititre™-paneler för MIC-bestämning av grampositiva kocker / Verification of broth microdilution with Sensititre™ panels for MIC determination of gram-positive cocci

Bengtsson, Moa, Jacobsson, Hanna January 2021 (has links)
Resistensbestämningar som genererar ett kvantitativt MIC-värde är värdefullt för att kunna välja adekvat antibiotikabehandling. Referensmetoden för MIC-bestämning är mikrobuljongspädning där kommersiella antibiotikapaneler underlättar handhavandet av metoden på kliniska laboratorier. Syftet med studien var att verifiera mikrobuljongspädning med Sensititre™-panelerna SEMSE7 och SEMST7 avsedda för grampositiva kocker, genom att jämföra erhållet resultat med tidigare uppmätta referensvärden av MIC samt SIR-kategorier. Mikrobuljongspädning utfördes med SEMSE7-panel och MH-buljong för Staphylococcus spp. (n=21) och Enterococcus spp. (n=13) samt med SEMST7-panel och MH-F buljong för Streptococcus pneumoniae (n=20). Avläsning av MIC utfördes samt tolkades enligt SIR-systemet. Resultaten jämfördes mot kända referensvärden tidigare uppmätta med mikrobuljongspädning. Isolat analyserade med SEMSE7-panel och SEMST7-panel erhöll en överensstämmelse av MIC på 88,2% respektive 96,7%. Motsvarande kategorisk överensstämmelse av SIR var 92,5% respektive 92,6%. Resultatet visar att Sensititre™-panelen SEMST7 är godkänd i verifieringen av mikrobuljongspädning med god överensstämmelse med referensvärden av MIC samt SIR-kategorier. Vidare bedöms att fortsatt verifiering krävs av SEMSE7-panelen eftersom ej tillfredställande överenstämmelse med referensvärden av MIC erhölls, trots god överenstämmelse av SIR-kategorier. Studien visar att SEMST7-panelen kan implementeras för Streptococcus pneumoniae i den kliniska verksamheten på mikrobiologilaboratoriet, Jönköping. / Antimicrobial susceptibility testing methods generating a quantitative MIC are valuable for choosing adequate antibiotic treatment. Broth microdilution is the reference method for MIC determination and commercial panels with antibiotics facilitate the procedure in clinical laboratories. The aim of the study was to verify broth microdilution with the Sensititre™ panels SEMSE7 and SEMST7 designed for gram-positive cocci, by comparing results with previously measured reference values of MIC and SIR. Broth microdilution was performed using the SEMSE7 panel with MH broth for Staphylococcus spp. (n=21) and Enterococcus spp. (n=13), and using the SEMST7 panel with MH-F broth for Streptococcus pneumoniae (n=20). Reading MIC endpoints was performed and interpreted according to SIR system. Isolates analysed with the SEMSE7 and SEMST7 panel obtained essential agreement of 88,2% and 96,7%, and categorical agreement of 92,5% and 92,6% respectively. In conclusion, the Sensititre™ panel SEMST7 is approved in the verification of broth microdilution with satisfactory essential agreement and categorical agreement. Furthermore, it is considered that further verification is required for the SEMSE7 panel as unsatisfactory essential agreement was obtained, despite satisfactory categorical agreement. The study shows that the SEMST7 panel can be implemented for Streptococcus pneumoniae in the clinical practice at the microbiology laboratory, Jönköping.
488

Analysis of Bacterial Communities Using Droplets Based Millifluidics

Zhao, Xinne 06 April 2022 (has links)
Microbes typically form highly complex and diverse communities that account for a significant portion of life's genetic diversity. Analysis of living systems, e.g. bacterial or cell population, plays a significant role in detecting and identifying pathogens, testing antibiotic susceptibility, and the fundamental research of population diversity and evolution. This work focuses on the analysis of bacterial communities using droplets based millifluidics. To monitor the bacteria growth, we designed an optofluidic system, combining the encapsulation of bacteria in numerous emulsion droplets to monitor their long-term behavior and relationship in a co-culture environment using fluorescent signals. In the first part of this work, we co-encapsulated and cultured two isogenic strains of Escherichia coli (E. coli) in numerous emulsion droplets to reveal their competition and cooperation relationship. Since two strains of E. coli express blue and yellow fluorescent proteins (BFP and YFP, respectively), we quantified their growth by integrating a fluorescence detection system. We analyzed the following parameters: doubling time, population yield, final biomass ratio, correlation map of doubling time and competition coefficient to characterize and compare the bacterial growth kinetics and behavior in mono and co-cultures. In addition, the experimental observations were compared with the predictions from a single growth model. Finally, we employed the millifluidic device to verify the appearance of cross-protection between antibiotic-sensitive bacteria and antibiotic-resistant bacteria. It is one of the mechanisms by which different bacteria, sharing the same environment, protect each other to survive in the presence of antibiotics. For this purpose, the E.coli YFP strain was chosen as an antibiotic-sensitive group. Simultaneously, the E.coli BFP strain with β-lactam and its mutations were selected as resistant strains. Combining the millifluidic droplet reactor method with other detection strategies, e.g. fluorescence microscopy, fluorescence flow cytometry, and plate reader, we proved the appearance of cross-protection by detecting the filamentary cells, the fluorescence of cell-free media, viable cell rates, cell shape and size, as well as β-lactamase activity. All these results obtained by millifluidic devices proved that this strategy could be used in a high-throughput bacterial coexistence study. In addition, the research of these general fields, such as bacterial community and antibiotic impact, can help us to reveal the interaction between microbial species and determine the right dose of antibiotics to inhibit bacterial growth in a co-existent environment efficiently.
489

The effect of the efflux pump inhibitor Carbonyl Cyanide m- Chlorophenylhydrazone (CCCP) on the susceptibility to imipenem and cefepime in clinical strains of Acinetobacter Baumannii / The effect of the efflux pump inhibitor Carbonyl Cyanide m- Chlorophenylhydrazone (CCCP) on the susceptibility to imipenem and cefepime in clinical strains of Acinetobacter Baumannii

Mondragón Ticlla, María Belén, Sánchez Carbonel, Alejandra 05 April 2022 (has links)
Introducción: Durante los XX últimos años, Acinetobacter baumannii se ha posicionado como una de las principales infecciones intrahospitalarias resistentes a antibióticos. A. baumannii multidrogoresistente (MDR) está considerado por la OMS dentro del grupo más crítico de resistencia. Uno de los mecanismos de resistencia identificados en dicho patógeno son las bombas de eflujo, por lo que, se han desarrollado inhibidores de las mismas, generando así menos resistencia por parte de las bacterias hacia los antibióticos. Objetivos: En nuestro estudio, el objetivo fue evaluar el efecto de la adición del inhibidor de bomba de eflujo CCCP sobre la actividad bactericida de imipenem y cefepime en cepas de A. baumannii Métodos: 49 cepas aisladas como A. baumannii fueron obtenidas en el Hospital Regional de Cajamarca. Mediante técnicas moleculares en el laboratorio de Biología Molecular de la Universidad Peruana de Ciencias Aplicadas (UPC) se confirmaron 47 cepas positivas para A. baumannii. Se utilizó PCR- en tiempo real para identificar el gen blaOXA-51-like y para la determinación de la CMI el método de microdilución en caldo. Finalmente se añadió el inhibidor CCCP para poder evaluar si efecto sobre los antibióticos Resultados: Un total de 49 cepas aisladas de A. baumannii fueron obtenidas en el Hospital Regional de Cajamarca. Se determinó la susceptibilidad antimicrobiana mediante la concentración mínima inhibitoria y la actividad de la bomba de eflujo fue evaluada usando CCCP. Conclusiones: Las bombas de eflujo puede jugar un rol importante en la resistencia antibiótica de A. baumannii. El inhibidor CCCP junto a imipenem y cefepime, mejora la sensibilidad antibiótica. Asimismo, nuevas estrategias terapéuticas son requeridas para eliminar el transporte de eflujo de las cepas resistentes que causan infecciones nosocomiales / Introduction: In the last years the rapid expansion of multidrug-resistant A. baumannii strains have become a major health problem. Efflux pumps are a group of transport proteins that contribute to the development of antibiotic resistance. The aim of this study was to evaluate the effect of the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) on the antimicrobial action of imipenem and cefepime on clinical strains of A. baumannii. Materials and methods: A total of 49 non-duplicate clinical samples were collected during January through December of 2018 from patients hospitalized in the Hospital Regional Docente de Cajamarca. Of the 49 samples obtained, the confirmatory identification of A. baumannii was performed on 47 samples by molecular methods. The amplification of the blaOXA-51-like gene was carried out by polymerase chain reaction (PCR). The determination of the minimum inhibitory concentration (MIC) was calculated using the microdilution method in culture broth. The susceptibility to both antibiotics (cefepime and imipenem) was evaluated in the presence and absence of the inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Results: A total of 47 strains of A. baumannii were isolated: 97.87% (46/47) were resistant to Imipenem, 2.13% (1/47) of them were classified as intermediate and none of these strains were susceptible. On the other hand, 51.06% (24/47) of isolates were resistant to cefepime; 19.15% (9/47) intermediate and 29.79% (14/47) susceptible. We considered a significant difference in antibiotic susceptibility if the MIC changed at least 4 dilutions, after the addition of the inhibitor. In the case of CCCP in addition to imipenem, 2.1% (1/47) had a significant change of 4 or more reductions in MIC, 59.6% (28/47) achieved a change equal or less than 3 dilutions and 17.0% (8/47) did not have any change. In the case of CCCP with cefepime the percentage of strains with the significant change of MIC was 8.5% (4/47). On the other hand, 53.2% (24/47) presented a reduction equal or less than 3 dilutions and 12.8% (6/47) did not show changes. Conclusion: In conclusion, our results demonstrate that the use of CCCP may improve the antibiotic effect of imipenem and cefepime on clinical strains of A. baumannii. The relevance of this study is that it provides evidence that this efflux pump inhibitor may be an alternative treatment against multidrug-resistant A. baumannii. / Tesis
490

Communicating Antibiotic Resistance to the Public: How effective was Public Health England’s 2018 ‘Keep Antibiotics Working’ campaign TV advertisement at increasing public understanding of antibiotic resistance and motivating a change in antibiotic seeking behaviours?

Anjuli, Borgonha January 2019 (has links)
Antibiotic resistance is one of the greatest global threats we face today. Human overuse ofantibiotics is a contributing factor and major behaviour change around antibioticconsumption is needed, but several challenges exist in communicating antibiotic resistanceto the public. In 2018 the UK Government relaunched a national television advertisement aspart of the ‘Keep Antibiotics Working’ campaign which aimed to raise awareness of antibioticresistance and reduce public demand for antibiotics. This study evaluates what role theframing of antibiotic resistance in the advertisement played in increasing publicunderstanding of antibiotic resistance and motivating behaviour change. The study isgrounded in behaviour change and health communication theory from the field ofCommunication for Development, and health and social psychology theory, reflecting theneed for multidisciplinary approaches to addressing antibiotic resistance. A textual analysisidentified how the issue was framed in the advertisement and surveys and interviews wereconducted with members of the target audience groups to analyse what effect theadvertisement had on their understanding of, and attitude towards antibiotic resistance.The findings show that the framing of antibiotic resistance in the TV advertisement led to anincrease in misunderstandings of what becomes resistant to antibiotics. The advertisementwas helpful in highlighting the vulnerability of antibiotics and for creating a new social normaround being a responsible antibiotic user, however was interpreted as childish byparticipants. It did not communicate the severity of antibiotic resistance or specific risk ofantibiotic overuse to the audience, or accurately reflect the audience’s existing knowledge ofantibiotic resistance and current behaviours. As the severity of antibiotic resistance was notconveyed, the advertisement did not motivate a change in antibiotic seeking behaviours orattitude amongst the majority of participants. The findings did highlight knowledge gapsamongst study participants including the importance of completing a course of antibiotics asprescribed, and that it is the bacteria itself, not the person, that develops resistance, andhopes this research can inform the development of future campaigns.

Page generated in 0.0921 seconds