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Aim To summarize the scientific literature on the elements essential to understanding a nursing definition of patient satisfaction. Design Whittemore and Knafl's methodology was used for this integrative review. Methods Articles were included if the studies they explored patient satisfaction in patient populations and measured patient satisfaction using standardized, validated instruments. Elements in this review were defined as the essential components that create the complex concept of patient satisfaction. Results Thirty articles were found and analysed in full. Five definitions of patient satisfaction were used, all of which were at least 20 years old. Twenty‐two different measures of patient satisfaction were used, six of which were nursing‐specific. Sixty‐eight elements of patient satisfaction were studied in the included articles. Forty‐three elements were reported as having a significant relationship with patient satisfaction, 25 were reported as having no significant relationship. Eight elements had both significant and non‐significant relationships.

It has been widely reported that quorum-sensing incapable strains of Pseudomonas aeruginosa are less virulent than wild type strains. However, quorum sensing mutants of P. aeruginosa have been shown to develop other spontaneous mutations under prolonged culture conditions, and one of the phenotypes of P. aeruginosa that is frequently affected by this phenomenon is type IV pili-dependent motility, referred to as twitching motility. As twitching motility has been reported to be important for adhesion and colonisation, we aimed to generate a quorum-sensing knockout for which the heritage was recorded and the virulence factor production in areas unrelated to quorum sensing was known to be intact. We created a lasIRrhlIR quadruple knockout in PAO1 using a published technique that allows for the deletion of antibiotic resistance cartridges following mutagenesis, to create an unmarked QS knockout of PAO1, thereby avoiding the need for use of antibiotics in culturing, which can have subtle effects on bacterial phenotype. We phenotyped this mutant demonstrating that it produced reduced levels of protease and elastase, barely detectable levels of pyoverdin and undetectable levels of the quorum sensing signal molecules N-3-oxododecanoly-L-homoserine lactone and N-butyryl homoserine lactone, but retained full twitching motility. We then used a mouse model of acute lung infection with P. aeruginosa to demonstrate that the lasIRrhlIR knockout strain showed equal persistence to wild type parental PAO1, induced equal or greater neutrophil infiltration to the lungs, and induced similar levels of expression of inflammatory cytokines in the lungs and similar antibody responses, both in terms of magnitude and isotype. Our results suggest, in contrast to previous reports, that lack of quorum sensing alone does not significantly affect the immunogenicity, infectiveness and persistence of P. aeruginosa in a mouse model of acute lung infection.

The emergence of widespread antimicrobial resistance has led to the need for development of novel therapeutic interventions. Antivirulence strategies are an attractive alternative to classic antimicrobial therapy; however, they require identification of new specific targets which can be exploited in drug discovery programs. The opportunistic pathogen Pseudomonas aeruginosa produces an arsenal of virulence factors causing a wide range of diseases in multiple hosts and is difficult to eradicate due to its intrinsic resistance to antibiotics. With the antibacterial pipeline drying up, antivirulence therapy has become an attractive alternative strategy to the traditional use of antibiotics to treat P. aeruginosa infections. To identify P. aeruginosa genes required for virulence in multiple hosts, a random library of Tn 5 mutants in strain PAO1-L was previously screened in vitro for those showing pleiotropic effects in the production of virulence phenotypes. Using this strategy, we identified a Tn 5 mutant with an insertion in PA4130 showing reduced levels of a number of virulence traits in vitro . Construction of an isogenic mutant in this gene presented results similar to those for the Tn 5 mutant. Furthermore, the PA4130 isogenic mutant showed substantial attenuation in disease models of Drosophila melanogaster and Caenorhabditis elegans as well as reduced toxicity in human cell lines. Mice infected with this mutant demonstrated an 80% increased survival rate in acute and agar bead lung infection models. PA4130 codes for a protein with homology to nitrite and sulfite reductases. Overexpression of PA4130 in the presence of the siroheme synthase CysG enabled its purification as a soluble protein. Methyl viologen oxidation assays with purified PA4130 showed that this enzyme is a nitrite reductase operating in a ferredoxin-dependent manner. The preference for nitrite and production of ammonium revealed that PA4130 is an ammonia:ferredoxin nitrite reductase and hence was named NirA. IMPORTANCE The emergence of widespread antimicrobial resistance has led to the need for development of novel therapeutic interventions. Antivirulence strategies are an attractive alternative to classic antimicrobial therapy; however, they require identification of new specific targets which can be exploited in drug discovery programs. The host-specific nature of P. aeruginosa virulence adds complexity to the discovery of these types of targets. Using a sequence of in vitro assays and phylogenetically diverse in vivo disease models, we have identified a PA4130 mutant with reduced production in a number of virulence traits and severe attenuation across all infection models tested. Characterization of PA4130 revealed that it is a ferredoxin-nitrite reductase and hence was named NirA. These results, together with attenuation of nirA mutants in different clinical isolates, high level conservation of its gene product in P. aeruginosa genomes, and the lack of orthologues in human genomes, make NirA an attractive antivirulence target.

The threat of antimicrobial resistance to human health has prompted interest in complex, natural products with antimicrobial activity. Honey has been an effective topical wound treatment throughout history, predominantly due to its broad-spectrum antimicrobial activity. Unlike traditional antibiotics, honey-resistant bacteria have not been reported; however, honey remains underutilized in the clinic in part due to a lack of understanding of its mechanism of action. Here, we demonstrate that honey affects multiple processes in bacteria, and this is not explained by its major antibacterial components. Honey also uniquely affects bacterial membranes, and this can be exploited for combination therapy with antibiotics that are otherwise ineffective on their own. We argue that honey should be included as part of the current array of wound treatments due to its effective antibacterial activity that does not promote resistance in bacteria. Manuka honey has broad-spectrum antimicrobial activity, and unlike traditional antibiotics, resistance to its killing effects has not been reported. However, its mechanism of action remains unclear. Here, we investigated the mechanism of action of manuka honey and its key antibacterial components using a transcriptomic approach in a model organism, Pseudomonas aeruginosa . We show that no single component of honey can account for its total antimicrobial action, and that honey affects the expression of genes in the SOS response, oxidative damage, and quorum sensing. Manuka honey uniquely affects genes involved in the explosive cell lysis process and in maintaining the electron transport chain, causing protons to leak across membranes and collapsing the proton motive force, and it induces membrane depolarization and permeabilization in P. aeruginosa . These data indicate that the activity of manuka honey comes from multiple mechanisms of action that do not engender bacterial resistance. IMPORTANCE The threat of antimicrobial resistance to human health has prompted interest in complex, natural products with antimicrobial activity. Honey has been an effective topical wound treatment throughout history, predominantly due to its broad-spectrum antimicrobial activity. Unlike traditional antibiotics, honey-resistant bacteria have not been reported; however, honey remains underutilized in the clinic in part due to a lack of understanding of its mechanism of action. Here, we demonstrate that honey affects multiple processes in bacteria, and this is not explained by its major antibacterial components. Honey also uniquely affects bacterial membranes, and this can be exploited for combination therapy with antibiotics that are otherwise ineffective on their own. We argue that honey should be included as part of the current array of wound treatments due to its effective antibacterial activity that does not promote resistance in bacteria.

Pseudomonas aeruginosa uses multiple protein regulators that work in tandem to control the production of a wide range of virulence factors and facilitate rapid adaptation to diverse environmental conditions. In this opportunistic pathogen, ToxR was known to positively regulate the production of the major virulence factor exotoxin A and now, through analysis of genetic changes between two sublines of P. aeruginosa PAO1 and functional complementation of swarming, we have identified a previously unknown role of ToxR in surface-associated motility in P. aeruginosa. Further analysis revealed that ToxR had an impact on swarming motility by regulating the Rhl quorum sensing system and subsequent production of rhamnolipid surfactants. Additionally, ToxR was found to tightly bind cyclic diguanylate (c-di-GMP) and negatively affect traits controlled by this second messenger including reducing biofilm formation and the expression of Psl and Pel exopolysaccharides, necessary for attachment and sessile communities matrix scaffolding, in P. aeruginosa. Moreover, a link between the post-transcriptional regulator RsmA and toxR expression via the alternative sigma factor PvdS, induced under iron-limiting conditions, is established. This study reveals the importance of ToxR in a sophisticated regulation of free-living and biofilm-associated lifestyles, appropriate for establishing acute or chronic P. aeruginosa infections.

The Pseudomonas aeruginosa quorum‐sensing signal molecule N‐3‐oxododecanoyl)‐l‐homoserine lactone (OdDHL) has been reported to affect the function of a wide range of mammalian cell types, including cells of the immune system. In T cells, it has been reported to inhibit the production of most cytokines, and it has been reported to inhibit the function of antigen‐presenting cells. The intracellular target of OdDHL in these cells remains to be identified, although the lipophilic nature of the molecule suggested that the target could be membrane associated. We explored the association of radiolabelled OdDHL with the membrane and cytoplasm of Jurkat T‐cell lines and of primary murine T cells and dendritic cells. We found that not only did 3H‐OdDHL enter the cytoplasm of Jurkat cells without disproportionate association with the cell membrane, it also reached maximum levels in the cytoplasm very quickly, and that the intracellular concentration was proportional to the extracellular concentration. Similar results were obtained when 3H‐OdDHL was incubated with primary murine T cells or cultured dendritic cells. In addition, we show that the cellular distribution of OdDHL does not significantly alter after stimulation of Jurkat cells or primary murine CD4 T cells with immobilized anti‐CD3, with little activity being associated with nuclear fractions. Together, these data strongly suggest that OdDHL enters mammalian cells by passive mechanisms, and that it does not preferentially associate with the membrane or nucleus upon T‐cell receptor ligation.

Manuka honey has broad-spectrum antimicrobial activity, and unlike traditional antibiotics, resistance to its killing effects has not been reported. However, its mechanism of action remains unclear. Here, we investigated the mechanism of action of manuka honey and its key antibacterial components using a transcriptomic approach in a model organism, Pseudomonas aeruginosa. We show that no single component of honey can account for its total antimicrobial action, and that honey affects the expression of genes in the SOS response, oxidative damage, and quorum sensing. Manuka honey uniquely affects genes involved in the explosive cell lysis process and in maintaining the electron transport chain, causing protons to leak across membranes and collapsing the proton motive force, and it induces membrane depolarization and permeabilization in P. aeruginosa. These data indicate that the activity of manuka honey comes from multiple mechanisms of action that do not engender bacterial resistance. IMPORTANCE The threat of antimicrobial resistance to human health has prompted interest in complex, natural products with antimicrobial activity. Honey has been an effective topical wound treatment throughout history, predominantly due to its broad-spectrum antimicrobial activity. Unlike traditional antibiotics, honey-resistant bacteria have not been reported; however, honey remains underutilized in the clinic in part due to a lack of understanding of its mechanism of action. Here, we demonstrate that honey affects multiple processes in bacteria, and this is not explained by its major antibacterial components. Honey also uniquely affects bacterial membranes, and this can be exploited for combination therapy with antibiotics that are otherwise ineffective on their own. We argue that honey should be included as part of the current array of wound treatments due to its effective antibacterial activity that does not promote resistance in bacteria.

Background: We have recently determined that explosive cell lysis events account for the biogenesis of membrane vesicles (MVs) in biofilms by the Gram-negative bacterium Pseudomonas aeruginosa. Livecell super-resolution microscopy (OMX 3D-SIM) revealed that explosive cell lysis liberates shattered membrane fragments that rapidly vesicularize into MVs. This vesicularization process also captures cellular content that has been released into the extracellular milieu, thereby packaging it as MV cargo. We have determined that explosive cell lysis is mediated by the endolysin Lys that degrades the peptidoglycan of the bacterial cell wall. As Lys-deficient mutants are severely abrogated in the formation of MVs, explosive cell lysis appears to be the major mechanism for MV biogenesis, at least in P. aeruginosa biofilms. The endolysin Lys is encoded within the highly conserved R- and F-pyocin gene cluster. The R- and F-pyocins resemble headless bacteriophage tails and are related to lytic bacteriophage. Endolysins of lytic bacteriophage are transported from the cytoplasm to the periplasm via holins that form pores in the inner membrane. P. aeruginosa possesses three putative holins encoded by hol, alpB and cidA. Hol is likely to be the cognate holin for Lys as it is also encoded in the R- and F-pyocin gene cluster and has been previously shown to mediate Lys translocation. However, both AlpB and CidA have also been previously implicated in lytic processes, but an endolysin associated with these systems has not been described. Methods: Isogenic single, double and triple deletion mutants were generated in hol, alpB and cidA by allelic exchange. Results: We found that all three holin systems contribute to explosive cell lysis in P. aeruginosa biofilms. However, each holin appears to have a unique contribution to explosive cell lysis as complementation of a single holin deletion with another of the holins was not always sufficient to restore explosive cell lysis to wild-type levels. Summary/Conclusion: Our findings have revealed that explosive cell lysis is a novel mechanism for the production of MVs and other cell-derived public goods in P. aeruginosa biofilms. Furthermore, we have found that three holin systems contribute to explosive cell lysis in P. aeruginosa.