Thesis (Ph. D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed Jan. 26, 2010). Additional advisors: Asim K. Bej, Gail E. Christie, Peter E. Prevelige, Jr., R. Douglas Watson. Includes bibliographical references.

Thesis (doctoral)--Universität Hohenheim, 2003.

Thesis--M. Phil., University of Hong Kong. / Typewritten.

Introduktion och bakgrund: Methicillinresistenta staphylokockus aureus finns över hela världen och sprids på både sjukhus och i samhället. Sjuksköterskor som arbetar inom hälso- och sjukvård bör vara medvetna om att det förekommer multiresistenta bakterier och ska därför arbeta preventivt mot smittspridning. Syfte: Syftet med denna litteratur studie var att belysa sjuksköterskors erfarenheter att arbeta preventivt mot MRSA-smittspridning i sjukhusmiljö. Metod: Litteraturöversikten hade sin utgångspunkt från det valda ämnesområdet. Artikelsökningarna genomfördes i vedertagna databaser som till exempel PubMed och Cinahl. 15 vetenskapliga artiklar inkluderades till resultatet efter noggrann kvalitetsgranskning och genomgång. Resultat: Områden som identifierades i resultatet var kunskap, basal hygien och kommunikation. Under dessa områdens belystes hinder, möjligheter och erfarenheter av att arbeta preventivt mot smittspridning av MRSA. Diskussion: Det behövs mer kunskap hos sjuksköterskor angående MRSA, vad det är och hur det preventiva arbetet bör gå till. Följsamheten till basalhygien varierar och tiden kan vara ett hinder till följsamhet. Bristande kommunikation uppgavs som en av de faktorer som försvårade det preventiva arbetet. Slutsats: Syftet med litteraturöversikten var att belysa sjuksköterskors erfarenheter av att arbeta preventivt mot MRSA smittspridning i sjukhusmiljö. Om sjuksköterskan har mer kunskap gällande MRSA skulle smittspridningen kunna minska ute i den kliniska verksamheten vilket skulle gagna patientsäkerheten. Bättre kommunikation, mer utbildning samt lägre arbetsbelastning kanske kan vara ett sätt att förbättra det preventiva arbetet mot smittspridning av MRSA.

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen often infecting the lungs of individuals with the heritable genetic disease cystic fibrosis and the peritoneum of those undergoing continuous 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 dissertation I used a rat dialysis membrane peritoneal model 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. Included in this analysis are genes important for iron acquisition and growth in lowoxygen 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 the environment. This lysis was shown to be dependent on antimicrobial quinolones produced by P. aeruginosa. I demonstrate that these quinolones are present in outer membrane vesicles (MVs). Not only were these quinolones present in MVs, but the quorum sensing molecule; 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas Quinolone Signal; PQS) was also packaged into MVs and was necessary for MV formation. These findings illustrate that a prokaryote possesses a signal trafficking system with features common to those used by higher organisms and outlines a novel mechanism for delivery of a signal critical for coordinating group behaviors in P. aeruginosa. Although MVs are involved in important processes besides signaling, the molecular mechanism is unknown. To provide insight into the molecular mechanism of MV formation, I examined the interaction of PQS with bacterial lipids. In this work, I demonstrated that PQS interacts strongly with the acyl chains and 4’-phosphate of bacterial lipopolysaccharide. The results of my studies provide molecular insight into P. aeruginosa MV formation and demonstrate that quorum signals serve important non-signaling functions. Finally, I propose a model of PQSmediated MV formation where PQS interacts with specific outer membrane components to allow the necessary curvature for MV formation. / text

Pseudomonas aeruginosa is a ubiquitous bacterium that is commonly isolated from soil and water. Additionally, this bacterium can cause infections in individuals with compromised immune systems and in those with underlying debilitating conditions. Individuals with cystic fibrosis, burn wounds, AIDS and diabetes are more likely to being infected by P. aeruginosa than healthy individuals. In individuals with CF, there is a marked increase in the accumulation of lung mucus that serves as a source of nutrition for P. aeruginosa and other bacterial species resulting in chronic and often fatal infections. While CF lung infections are initially caused by more than one species of bacteria, over time P. aeruginosa emerges as the dominant species. P. aeruginosa also causes chronic infections in association with other bacteria in wounds. Microbes within these infections are engaged in complex interactions with each other. Often, these interactions are synergistic resulting in infections that are recalcitrant to antimicrobial therapy. While many studies have documented the occurrence of synergistic polymicrobial infections, little is known about the molecular mechanisms prevailing in these infections. Interestingly, production of virulence factors by P. aeruginosa has been shown to correlate with the presence of specific nutrients in their growth environment. Expanding on the idea of available nutrients affecting virulence, I demonstrate the ability of N-Acetylglucosamine (GlcNAc) and GlcNAc-containing polymers such as peptidoglycan to induce production of virulence factors in P. aeruginosa. Peptidoglycan shed by Gram-positive bacteria acts as a cue for P. aeruginosa in polymicrobial environments, to enhance production of virulence factors. In the context of a polymicrobial infection, this results in enhanced pathogenesis. Here, I provide insights into mechanisms influencing such interspecies interactions between the opportunistic pathogen Pseudomonas aeruginosa and S.aureus. / text

published_or_final_version / Nursing Studies / Master / Master of Nursing

Bakgrund: Vårdrelaterade infektioner som Methicillin Resistent Staphylococcus Aureus, MRSA, ökar. Bakterien är komplicerad att avlägsna och idag är MRSA ett av de största vårdhygieniska problemen internationellt. Vid vård av personer som bär på MRSA krävs särskilda rutiner, såsom isoleringsvård och skyddskläder. Syfte: Att belysa personers upplevelser av att bära på MRSA i en vårdkontext. Metod: En litteraturstudie av åtta stycken kvalitativa, vetenskapliga artiklar. Materialet analyserades och sammanställdes med en beskrivande metasyntes, enligt Friberg (2012). Resultat: Tre teman tydliggjordes: ”Rutinernas inverkan på patientens upplevelse av vården”,” Patientens upplevelse av mötet med vårdpersonalen.” och ” Patientens känslomässiga upplevelse av att vara infekterad med MRSA”. Resultatet visade att MRSA infektionen ledde till starka känsloreaktioner samt att rutiner, föreskrifter och personalens förhållningssätt ofta upplevdes som negativt. Patienterna saknade förståelse för sin situation och fick inte adekvat information. Slutsats: Personer som bar på MRSA saknade information om sitt tillstånd. Det behövs ökad kunskap hos personalen för att kunna möta patienters psykiska och fysiska behov samt individanpassad patientinformation. Likaså behövs ytterligare forskning som studerar livssituationen hos MRSA bärare för att kunna lindra deras lidande

The susceptibility of 80 StaphyIococcus aureus isolated to oxacillin was investigated using microtitre, agar dilution and Stokes' disc diffusion methods. There was a bimodal distribution of the isolates according to the oxacillin minimum inhibitory concentration (MIC) values. For the sensitive isolates, the agar dilution method generally gave lower MIC values than the microtitre method, while for the resistant isolates the agar dilution method gave comparable to slightly lower MIC values than the microtitre method. The Stokes disc diffusion method yielding the best results when performed on Mueller-Hinton agar incubated at 30°C for 18 hours; however local strains grew poorly when incubated at 30 C for 18 hours. The next best medium which provided clear disc diffusion results plus good growth was Mueller-Hinton agar incubated at 35°C for 18 hours, on which 10 % of the sensitive isolates appeared intermediate in susceptibility, and none resistant, while all the resistant isolates (microtitre MIC >8mg/1) appeared resistant. Oxacillin resistance among strains of Staphylococcus aureus tested by Stokes' disc diffusion method correlated best with gentamicin resistance, and less often with tetracycline resistance. Therefore gentamicin- or tetracycline-resistance may indicate oxacillin resistance in Staphylococcus aureus. / Thesis (M.Med.)-University of Natal, Durban, 1988.

Staphylococci strains are among the most widespread multidrug-resistant nosocomial pathogens in Canada. Rapid and accurate identification and epidemiological typing of methicillin-resistant S. aureus (MRSA) and its discrimination from coagulase-negative staphylococci (CNS) and glycopeptide-intermediate S. aureus (GISA) are crucial for appropriate therapy and for monitoring and limiting intra- and inter-hospital spread of epidemic MRSA strains. Although pulsed-field gel electrophoresis and polymerase chain reaction methods for the identification of MRSA are reliable, they are technically demanding, time-consuming and inappropriate for routine clinical diagnosis. Moreover, no reliable method exists for discrimination of epidemic MRSA from sporadic MRSA and from GISA strains. The objective of the research described in this thesis was to investigate whether Fourier transform infrared (FTIR) spectroscopy could be used to distinguish MRSA from methicillin-susceptible S. aureus, borderline oxacillin-resistant S. aureus (BORSA), CNS, including methicillin-resistant CNS, and GISA. The application of FTIR spectroscopy for epidemiological typing of Canadian epidemic MRSA (CMRSA) strains as well as their discrimination from sporadic MRSA was also assessed. FTIR spectra were recorded from intact stationary-phase cells grown on Universal Medium (UM™) and deposited and dried on a ZnSe optical window, normalized, and converted to first-derivative spectra. Various chemometric approaches were employed to cluster the different phenotypes of staphylococci species and to subtype five CMRSA strains based on the similarity of their infrared spectral fingerprints in narrow spectral regions selected by visual inspection and by employing a singularvalue decomposition (SVD) algorithm. Pairwise separation of MRSA from MSSA, BORSA, CNS, MRCNS, and GISA was accomplished by using principal component analysis (PCA), self-organizing maps (SOM), and the K-nearest neighbors (KNN) algorithm. These chemometric techniques were also successfully employed for epidemiological typing of the five CMRSA strains and their discrimination from sporadic MRSA strains using a combination of different optimal spectral regions selected by SVD. These results demonstrate that FTIR spectroscopy has considerable potential as a rapid method for the identification of different phenotypes of staphylococci and epidemiological typing of MRSA.