Delirium en centros residenciales para personas mayores. Estudio de la prevalencia y los factores asociados

Objectives

To study the prevalence of delirium in the residential environment and to analyse the associated clinical, functional and mental factors.

Material and methods

A cross-sectional epidemic study was conducted on a population of elderly persons institutionalised in 2011 in 6 nursing homes in Asturias. Socio-demographic, clinical, functional (Barthel Index [BI]) and mental (Mini-Mental State Examination [MMSE]) variables were collected. Delirium was defined by the Confusion Assessment Method.

Results

A total of 505 elderly were included in the study (age 83.30 ± 7.33 years, with 67.70% women), and scores on the MMSE of 17.19 ± 10.35 and a BI score of 55.11 ± 35.82. The prevalence of delirium was 11.70%. On examining the risk of delirium among the studied variables, there was statistical significance when considering: BI, MMSE, dementia, pressure ulcers, or urinary catheter, and the prescribing of clomethiazole, ACTH-I or trazodone. In the analysis of the variables in the logistic regression with BI, diagnosis of dementia, the prescribing of clomethiazole or trazodone, in the equation, there was a statistical significance associated with delirium.

Conclusions

The prevalence of delirium in a residential environment in our study population was 11.7%. The results show that BI, diagnosis of dementia, and prescribing of clomethiazole or trazodone were associated with risk of delirium in institutionalised patients.     

Role of hydrogen peroxide in loss of culturability mediated by visible light in Escherichia coli in a freshwater ecosystem.

A study was made of the mechanisms by which visible light produces cell dormancy in Escherichia coli, resulting in loss of culturability. Visible light may act directly on the cells or generate photoproducts with a negative effect on the cells. In nonilluminated microcosms the addition of increasing concentrations of hydrogen peroxide, one of the photoproducts formed in natural aquatic systems, gave rise to the formation of nonculturable cells and injured culturable cells, and this negative effect depended on the concentration of peroxide. On the other hand, in illuminated microcosms the addition of compounds which eliminate hydrogen peroxide (i.e., catalase, sodium pyruvate, and thioglycolate) had a protective effect on the E. coli cells, as the CFU counts on minimal medium and on recuperation medium were significantly higher (P < 0.05) than those detected in the absence of these compounds. Furthermore, when hydrogen peroxide was eliminated, the CFU counts on recuperation medium did not fall significantly, indicating that nonculturable cells did not form. These results rule out the direct effect of visible light on the cells and show that hydrogen peroxide, generated photochemically, may be the cause of the loss of culturability of E. coli in illuminated systems.     

Influence of a Survival Process in a Freshwater System upon Plasmid Transfer Between Escherichia coli Strains

Abstract Survival and potential ability to act as recipient or donor during the survival process for one plasmid-free and four plasmid-bearing Escherichia coli strains under nonilluminated and illuminated conditions in freshwater systems were studied. The five E. coli strains showed the same behavior with respect to the microbial parameters used to characterize the survival process (culturability and viability). Under nonilluminated conditions, recipient cells did not show variation in the ability to receive and express plasmid material, while the culturability of the recipient strain remained stable. Under the same conditions, donor cells lost their ability for plasmid transfer during the survival process, in all cases more than a 90% decrease of the number of transconjugants was found after 4 days of experimentation, although viable and culturable cells of donor strains maintained the capacity to express some plasmidic genes. Under illuminated conditions, transconjugants were not detected after 2 days of experimentation. The number of transconjugants formed was dependent not only on the time donor strains remained in the water but also on the temperature (20 or 37°C) at which the mating assays were conducted. Received: 15 August 1995; Accepted: 28 November 1995     

Biotic and abiotic factors affecting plasmid transfer in Escherichia coli strains.

The influence of biotic and abiotic factors on plasmid transfer between Escherichia coli strains in terms of the variation in the number of transconjugants formed and the variation in transfer frequency was investigated. The density of parent cells affected the number of transconjugants, reaching a maximum when the cell density was on the order of 10(8) CFU ml-1. As the donor-to-recipient ratios varied from 10(-4) to 10(4), the number of transconjugants varied significantly (P less than 0.001), reaching a maximum with donor-to-recipient ratios between 1 and 10. The concentration of total organic carbon in the mating medium affects both the number of transconjugants and the transfer frequency, being significantly higher (P less than 0.001) when the total organic carbon concentration was higher than 1,139 mg of C liter-1. However, the transconjugants were detected even with less than 1 mg of C liter-1. Linear regression of log10 transconjugants versus mating temperature showed a highly significant regression line (P less than 0.001). Neither the transfer frequency nor the transconjugant number varied significantly in the range of pHs assayed. We can conclude that plasmid transfer by conjugation can take place within a wide range of conditions, even in such adverse conditions as the absence of nutrients and low temperatures.     

Hominin lower second premolar morphology: evolutionary inferences through geometric morphometric analysis

Mandibular premolars are increasingly used in taxon-specific diagnostic analyses of hominins. Among the principal difficulties in these evaluations is the absence of discrete, discernible, and comparable anatomical structures for rigorous quantitative assessment. Previous research has addressed either internal crown surface features (such as cusps and fossae) or the morphology of the crown outline. In the present paper, we integrate both types of information in the examination of morphological variation of lower P4s (n = 96) among various fossil hominin species with an emphasis on genus Homo. We use a set of 34 2D landmarks combining coordinate data from four classical dental landmarks on the occlusal surface and 30 sliding semilandmarks of the crown outline. Our results indicate that external shape variation is closely related to the configuration of the occlusal morphological features and influenced by dental size. The external and internal shapes of P4 are polymorphic but still useful in depicting a primitive-derived gradient. The primitive pattern seems to have been an asymmetrical contour with a mesially displaced metaconid, development of a bulging talonid, and a broad occlusal polygon. The trend toward dental reduction during the Pleistocene produced different morphological variants with a reduced occlusal polygon and decreased lingual occlusal surface in later Homo species. Homo heidelbergensis/neanderthalensis have fixed plesiomorphic traits in high percentages, whereas in modern humans a symmetrical outline with a centered metaconid and talonid reduction evolved.     

Microbiological parameters as an additional tool to improve wastewater treatment plant monitoring

The operation of an activated sludge wastewater treatment plant (WWTP) was assessed by determining the removal efficiency of treatment processes. For that purpose, different physicochemical and microbiological parameters, including total, active and culturable bacteria, were measured along a year. Values of both physicochemical and microbiological parameters were significantly reduced by biological treatment but no relation between these groups of parameters was obtained. Besides, results suggest that microbiological parameters were more sensitive than physicochemical ones to changes in WWTP conditions (i.e. influent quality). Additionally, high percentages of noncultured (>88%) and noncultured remaining active (until 50%) cells were detected before and after treatment. Therefore, ISO standards adopted to enumerate indicator bacteria by Spanish legislation, and based on culturability, underestimate the bacterial population present in wastewater. We have compared two culture-independent methods for bacterial enumeration, microscopy and flow cytometry (FCM) and results indicate that FCM provides a rapid and automated quantification in WWTP. We conclude that microbiological parameters are essential to monitor the correct WWTP operation and we propose quantification of active bacteria as indicator of wastewater microbiological quality.     

Changes in Escherichia coli outer membrane subproteome under environmental conditions inducing the viable but nonculturable state

Changes in the outer membrane subproteome of Escherichia coli along the transition to the viable but nonculturable state (VBNC) were studied. The VBNC state was triggered by exposure of E. coli cells to adverse conditions such as aquatic systems, starvation, suboptimal temperature, visible light irradiation and seawater. The subproteome, obtained according to Molloy et al ., was analysed at the beginning of exposure (inoculum, phase 1), after a variable exposure time (95% of population culturable, phase 2) and when populations were mainly in the VBNC state (95% of cells VBNC, phase 3). Proteome changes were dependent on adverse conditions inducing the transition and were detected mainly in phase 2. The permanence of E. coli cells in seawater under illumination conditions entailed a dramatic rearrangement of the outer membrane subproteome involving 106 new spots, some of which could be identified by peptide fingerprinting. However, proteins exclusive to the VBNC state were not detected.     

Participation of oxygen and role of exogenous and endogenous sensitizers in the photoinactivation of Escherichia coli by photosynthetically active radiation,UV-A and UV-B

We studied the mechanisms by which photosynthetically active radiation (PAR) and ultraviolet (UV-A and UV-B) radiation damage Escherichia coli suspended in water. The roles played by oxygen and exogenous and endogenous sensitizers were analyzed by monitoring changes in the physiological state of irradiated cells. Impairment of the cellular functions was more severe in the case of UV radiations. Radiation caused cellular damage in the absence of oxygen. PAR, UV-A, and UV-B radiation induced photobiological and photodynamic reactions mediated by endogenous sensitizers, which significantly shortened the T90 (time needed to reduce a cellular parameter by 90%) based on the growth ability of the cells. In addition, when exogenous sensitizers were present, the photodynamic reactions also had a negative effect on the operation of the electron transport chains. The presence of oxygen might enhance photoinactivation, affecting both the growth ability and the electron transport chains. Endogenous sensitizers were responsible for the noxious action of oxygen. The presence of dissolved organic material played a protective role against the oxygen by absorbing the incident radiation, thereby reducing the energy that reached the endogenous sensitizers.     

Effect of disinfection upon dissolved organic carbon (DOC) in wastewater: bacterial bioassays

Quantitative and qualitative changes in organic matter content of wastewater effluents attributable to chlorination and ozonation have been analysed using bioassays as well as organic carbon direct measures. Bioassays were carried out using the bacterial populations of wastewater and two Escherichia coli strains as test micro-organisms. Our results indicate that pure strains present some advantages over indigenous bacteria. Although wastewater bacterial populations are better adapted to growth in wastewater, E. coli strains are more sensitive to changes in dissolved organic carbon (DOC) content. Moreover, the use of pure cultures allows estimation of the portion of DOC which can be converted in cell biomass, the assimilable organic carbon (AOC). Finally, the results obtained using prototrophic and the auxotrophic strains of E. coli suggested that ozonation alters the amino acid composition of wastewater while chlorination does not change the quantity nor the quality of the DOC present in effluents.