Surface barrier discharges for Escherichia coli biofilm inactivation: Modes of action and the importance of UV radiation.

Cold plasma generated in air at atmospheric pressure is an extremely effective antimicrobial agent, with proven efficacy against clinically relevant bacterial biofilms. The specific mode of bacterial inactivation is highly dependent upon the configuration of the plasma source used. In this study, the mode of microbial inactivation of a surface barrier discharge was investigated against Escherichia coli biofilms grown on polypropylene coupons. Different modes of exposure were considered and it was demonstrated that the long-lived reactive species created by the plasma are not solely responsible for the observed microbial inactivation. It was observed that a synergistic interaction occurs between the plasma generated long-lived reactive species and ultraviolet (UV) photons, acting to increase the antimicrobial efficacy of the approach by an order of magnitude. It is suggested that plasma generated UV is an important component for microbial inactivation when using a surface barrier discharge; however, it is not through the conventional pathway of direct DNA damage, rather through the synergistic interaction between liquid in the biofilm matrix and long-lived chemical species created by the discharge.

Is a reduction in viability enough to determine biofilm susceptibility to a biocide?

OBJECTIVE: The abundance and prevalence of dry-surface biofilms (DSBs) in hospitals constitute an emerging problem, yet studies rarely report the cleaning and disinfection efficacy against DSBs. Here, the combined impact of treatments on viability, transferability, and recovery of bacteria from DSBs has been investigated for the first time. METHODS: Staphylococcus aureus DSBs were produced in alternating 48-hour wet-dry cycles for 12 days on AISI 430 stainless steel discs. The efficacy of 11 commercially available disinfectants, 4 detergents, and 2 contactless interventions were tested using a modified standardized product test. Reduction in viability, direct transferability, cross transmission (via glove intermediate), and DSB recovery after treatment were measured. RESULTS: Of 11 disinfectants, 9 were effective in killing and removing bacteria from S. aureus DSBs with >4 log10 reduction. Only 2 disinfectants, sodium dichloroisocyanurate 1,000 ppm and peracetic acid 3,500 ppm, were able to lower both direct and cross transmission of bacteria (<2 compression contacts positive for bacterial growth). Of 11 disinfectants, 8 could not prevent DSB recovery for >2 days. Treatments not involving mechanical action (vaporized hydrogen peroxide and cold atmospheric plasma) were ineffective, producing <1 log10 reduction in viability, DSB regrowth within 1 day, and 100% transferability of DSB after treatment. CONCLUSIONS: Reduction in bacterial viability alone does not determine product performance against biofilm and might give a false sense of security to consumers, manufacturers and regulators. The ability to prevent bacterial transfer and biofilm recovery after treatment requires a better understanding of the effectiveness of biocidal products.

Computational and Experimental Investigation of Biofilm Disruption Dynamics Induced by High-Velocity Gas Jet Impingement.

Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such extreme conditions, since direct measurements of viscosity at these high shear rates are not possible using dynamic testing instruments. Here, we used computational fluid dynamics simulations to assess the complex fluid interactions of ripple patterning produced by high-speed turbulent air jets impacting perpendicular to the surface of Streptococcus mutans biofilms, a dental pathogen causing caries, captured by high-speed imaging. The numerical model involved a two-phase flow of air over a non-Newtonian biofilm, whose viscosity as a function of shear rate was estimated using the Herschel-Bulkley model. The simulation suggested that inertial, shear, and interfacial tension forces governed biofilm disruption by the air jet. Additionally, the high shear rates generated by the jet impacts coupled with shear-thinning biofilm property resulted in rapid liquefaction (within milliseconds) of the biofilm, followed by surface instability and traveling waves from the impact site. Our findings suggest that rapid shear thinning under very high shear flows causes the biofilm to behave like a fluid and elasticity can be neglected. A parametric sensitivity study confirmed that both applied force intensity (i.e., high jet nozzle air velocity) and biofilm properties (i.e., low viscosity and low air-biofilm surface tension and thickness) intensify biofilm disruption by generating large interfacial instabilities.IMPORTANCE Knowledge of mechanisms promoting disruption though mechanical forces is essential in optimizing biofilm control strategies which rely on fluid shear. Our results provide insight into how biofilm disruption dynamics is governed by applied forces and fluid properties, revealing a mechanism for ripple formation and fluid-biofilm mixing. These findings have important implications for the rational design of new biofilm cleaning strategies with fluid jets, such as determining optimal parameters (e.g., jet velocity and position) to remove the biofilm from a certain zone (e.g., in dental hygiene or debridement of surgical site infections) or using antimicrobial agents which could increase the interfacial area available for exchange, as well as causing internal mixing within the biofilm matrix, thus disrupting the localized microenvironment which is associated with antimicrobial tolerance. The developed model also has potential application in predicting drag and pressure drop caused by biofilms on bioreactor, pipeline, and ship hull surfaces.

Biofilm mechanics: Implications in infection and survival.

It has long been recognized that biofilms are viscoelastic materials, however the importance of this attribute to the survival and persistence of these microbial communities is yet to be fully realized. Here we review work, which focuses on understanding biofilm mechanics and put this knowledge in the context of biofilm survival, particularly for biofilm-associated infections. We note that biofilm viscoelasticity may be an evolved property of these communities, and that the production of multiple extracellular polymeric slime components may be a way to ensure the development of biofilms with complex viscoelastic properties. We discuss viscoelasticity facilitating biofilm survival in the context of promoting the formation of larger and stronger biofilms when exposed to shear forces, promoting fluid-like behavior of the biofilm and subsequent biofilm expansion by viscous flow, and enabling resistance to both mechanical and chemical methods of clearance. We conclude that biofilm viscoelasticity contributes to the virulence of chronic biofilm infections.

Computational Investigation of Ripple Dynamics in Biofilms in Flowing Systems.

Biofilms are collections of microorganisms that aggregate using a self-produced matrix of extracellular polymeric substance. It has been broadly demonstrated that many microbial infections in the body, including dental plaque, involve biofilms. While studying experimental models of biofilms relevant to mechanical removal of oral biofilms, distinct ripple patterns have been observed. In this work, we describe a multiphase model used to approximate the dynamics of the biofilm removal process. We show that the fully nonlinear model provides a better representation of the experimental data than the linear stability analysis. In particular, we show that the full model more accurately reflects the relationship between the apparent wavelength and the external forcing velocities, especially at mid-to-low velocities at which the linear theory neglects important interactions. Finally, the model provides a framework by which the removal process (presumably governed by highly nonlinear behavior) can be studied.

[The role of caregiver in patients at risk of difficult discharge: a needs analysis in a medical ward]. / Il caregiver del paziente a rischio di dimissione difficile: un'analisi dei bisogni in area medica.

INTRODUCTION: the continuous increase in life expectancy and the large amount of elderly population the caregiver become an important figure in domiciliary assistance. He is not often prepared to fulfil this complex role, because he has a great number of unsatisfied needs. For this reason the aim of this study is to identify and analyze the caregiver's educational needs, in anticipation of frail elderly's home discharge. METHODS: 39 caregivers of patients in the Humanitas Gradenigo Hospital in Turin, were asked to express their needs through the Caregiver Needs Assessment (CNA) questionnaire and then through semi-structured interviews, which were analyzed with Grouded Theory. RESULTS: The CNA's results showed that health care professionals were not always able to satisfy caregiver needs, in particular they needed more informations and needed to be involved in team decisions. There was a lack of communication between them and the equipe, they also needed to know how to take care of the patients and they needed emotional and social support. From the interviews, five main categories emerged: "emotion during acute event", " Strategies to face the disease", "relationship with staff ", "expressed need" and "future ". CONCLUSIONS: This study shows how the caregiver's experience impacts on different aspects of his life, including work, physical, emotional, and psychological health. Therapeutic education is an essential instrument that nursing staff can use to make caregivers more prepared for the complex management of the patient at home, sharing therapeutic aims.

Fluid-driven interfacial instabilities and turbulence in bacterial biofilms.

Biofilms are thin layers of bacteria embedded within a slime matrix that live on surfaces. They are ubiquitous in nature and responsible for many medical and dental infections, industrial fouling and are also evident in ancient fossils. A biofilm structure is shaped by growth, detachment and response to mechanical forces acting on them. The main contribution to biofilm versatility in response to physical forces is the matrix that provides a platform for the bacteria to grow. The interaction between biofilm structure and hydrodynamics remains a fundamental question concerning biofilm dynamics. Here, we document the appearance of ripples and wrinkles in biofilms grown from three species of bacteria when subjected to high-velocity fluid flows. Linear stability analysis suggested that the ripples were Kelvin-Helmholtz Instabilities. The analysis also predicted a strong dependence of the instability formation on biofilm viscosity explaining the different surface corrugations observed. Turbulence through Kelvin-Helmholtz instabilities occurring at the interface demonstrated that the biofilm flows like a viscous liquid under high flow velocities applied within milliseconds. Biofilm fluid-like behavior may have important implications for our understanding of how fluid flow influences biofilm biology since turbulence will likely disrupt metabolite and signal gradients as well as community stratification.

[Improving conseling skills in nursing students of Turin university: a pilot study]. / Migliorare le abilità di counseling in un gruppo di studenti del corso di laurea in infermieristica di Torino: uno studio pilota.

BACKGROUND: Although communication and counseling skills are essential for nursing profession, specific educational program are not so widespread. AIM: Evaluation of the improvement of Counseling skills as a result of a specific training. METHODS: A multi-center pilot study with pre-post test design with a convenience sample of 65 students was carried out. The Counseling training consisted in three consecutive levels over a period of six months for a total of six days. To measure the ability of reformulation, basic tool of Counseling, a questionnaire was used with 20 interviews (hypothetical interview between health professional and patient). RESULTS: 62 students participated. The sample is composed mainly by females (84%), the average age is 23 years. The average value of BEES (level of empathy) is 41 points (± SD 11.5), the value does not correlate with age nor gender. Before the training (PRE) most of the students identified as the most suitable approach/strategy to deal with educational problems that investigative (347-27%) and the relational one. At the end of intervention (POST) most of the students used a comprehension approach/strategy (90% of the responses), opposed to before the course (18%). CONCLUSION: The training course, shows to lead to a significant improvement in using comprehension strategies to deal with issues of educational assistance of clients.

Toward prevention of alcohol exposed pregnancies: characteristics that relate to ineffective contraception and risky drinking.

Alcohol-exposed pregnancy is a leading cause of preventable birth defects in the United States. This paper describes the motivational patterns that relate to risky drinking and ineffective contraception, two behaviors that can result in alcohol-exposed pregnancy. As part of an intervention study aimed at reducing alcohol-exposed pregnancy 124 women were recruited and reported demographic characteristics, readiness to change, stages of change, drinking, contraception, and sexual behavior history. Our results showed the following. Drinking: A significant positive correlation was found between the number of drinks consumed in 90 days and the Importance to reduce drinking (r = .23, p = .008). A significant negative correlation between number of drinks and confidence to reduce drinking (r = -.39, p = .000) was found as well. Significant differences were found in the total number of drinks consumed in 90 days between the five stages of change (F = (4,118), 3.12, p = .01). Women in Preparation reported drinking a significantly higher number of drinks than women in other stages of change. Contraception: There were significant negative correlations between ineffective contraception and Importance (r = -.38, p = .00), confidence (r = -.20, p = .02) and Readiness (r = -.43, p = .00) to use contraception effectively. Significant differences in contraception ineffectiveness were found for women in different stages of change (F = (4,115) 8.58, p = .000). Women in Precontemplation reported significantly higher levels of contraception ineffectiveness compared to women in other stages of change. Results show a clear relationship between higher alcohol consumption and higher levels of motivation to reduce drinking. In contrast, higher levels of ineffective contraception were related to lower levels of motivation to use contraception effectively. This suggests risky drinking may be better targeted with brief skills building interventions and ineffective contraception may require interventions that enhance problem awareness and motivation.

New strategies in the assessment of psychological factors affecting medical conditions.

In this article, we examine research that may lead to a better assessment of psychological factors affecting medical conditions. We performed a review of the psychosomatic literature using both Medline and manual searches. We selected papers that were judged to be relevant to new strategies of assessment, with particular reference to the use of the Diagnostic Criteria for Psychosomatic Research. We assessed 8 areas concerned with the assessment of psychological factors in the setting of medical disease: hypochondriasis, disease phobia, persistent somatization, conversion symptoms, illness denial, demoralization, irritable mood, and Type A behavior. A new subclassification of the Diagnostic and Statistical Manual of Mental Disorders (5th ed. [DSM-V]; not yet published) category of psychological factors affecting physical conditions appears to be feasible and may provide the clinician with better tools for identifying psychological distress.

Family intervention approach to loss of clinical effect during long-term antidepressant treatment: a pilot study.

BACKGROUND: The return of depressive symptoms during maintenance antidepressant treatment is a common phenomenon, but has attracted very limited research attention. The aims of this investigation were to explore the feasibility of a family intervention approach to loss of clinical effect during long-term antidepressant therapy and to compare this approach with dose increase. METHOD: Twenty outpatients with recurrent major depressive disorder (diagnosed using Research Diagnostic Criteria, i.e., patients were at their third or greater episode of major depressive disorder, with the immediately preceding episode being no more than 2.5 years before the onset of the episode which led to antidepressant treatment) who lived with a partner and relapsed while taking antidepressant drugs were randomly assigned to (1) family intervention approach according to the McMaster Model and maintenance of the anti-depressant drug at the same dosage or (2) dose increase and clinical management. A 1-year follow-up was performed. The study was conducted from January 2002 to December 2004. RESULTS: Seven of 10 patients responded to an increased dosage; all but 1 relapsed again on that dosage during follow-up. Seven of 10 patients responded to family intervention, but only 1 relapsed during follow-up. The difference in relapse was significant (p < .05). CONCLUSIONS: The data suggest that application of a family intervention approach is feasible when there is a loss of clinical effect during long-term antidepressant treatment, and this approach may carry long-term benefits. The results need to be confirmed by large-scale controlled studies but should alert the physician to explore the psychosocial correlates of loss of clinical effect.

Development of a new assessment strategy in psychosomatic medicine: the diagnostic criteria for psychosomatic research.

The Diagnostic Criteria for Psychosomatic Research (DCPR) are a diagnostic and conceptual framework that was proposed a decade ago by an international group of investigators. The DCPR's rationale was to translate psychosocial variables that derived from psychosomatic research into operational tools whereby individual patients could be identified. A set of 12 syndromes was developed: health anxiety, thanatophobia, disease phobia, illness denial, persistent somatization, conversion symptoms, functional somatic symptoms secondary to a psychiatric disorder, anniversary reaction, demoralization, irritable mood, type A behavior, and alexithymia. These criteria were meant to be used in a multiaxial approach. The aim of this work is to survey the research evidence which has accumulated on the DCPR, to provide specification for their development and validation and to examine the specific DCPR clusters. Their implications for classification purposes (DSM-V) are also discussed.

Psychological factors affecting medical condition: a new proposal for DSM-V.

The DSM category of "psychological factors affecting medical condition" had virtually no impact on clinical practice. However, several clinically relevant psychosomatic syndromes have been described in the literature: disease phobia, persistent somatization, conversion symptoms, illness denial, demoralization, and irritable mood. These syndromes, in addition to the DSM definition of hypochondriasis, can yield clinical specification in the category of "psychological factors affecting medical condition" and eliminate the need for the highly criticized DSM classification of somatoform disorders. This new classification is supported by a growing body of research evidence and is in line with psychosomatic medicine as a recognized subspecialty.

Self-exposure treatment of recurrent nightmares: waiting-list-controlled trial and 4-year follow-up.

BACKGROUND: In open and randomized controlled trials self-exposure therapy reduced the frequency of nightmares but follow-up ceased at 7 months post-entry. METHOD: Ten adults who attended an outpatient clinic and had DSM-IV nightmare disorder were put on a 3-month waiting-list. After 3 months they were given a self-exposure manual and were asked to follow its instructions for 4 weeks and were then followed up for 4 years. They were rated at 0, 3, 4, 5, 7, 10, 16, 28 and 52 months. At month 0 only, a matched control group of 10 subjects from the same clinic who had no axis I or II disorder was also rated. RESULTS: At month 0, the nightmare sufferers had more nightmares, anxiety, depression, hostility and somatic symptoms than the matched control group. All 10 nightmare sufferers completed the 3-month waiting-list, 4-week self-exposure therapy and 4-year follow-up without any dropouts. The recurrent nightmares and most associated symptoms did not improve while on the waiting-list but improved markedly after self-exposure therapy and remained improved over the 4-year follow-up. CONCLUSIONS: Adults' recurrent nightmares and associated symptoms failed to improve over a 3-month waiting-list period but reduced greatly after subsequent self-exposure therapy with minimal therapist contact over 1 month, and these gains continued over the next 4 years.

Residual symptoms in depression: an emerging therapeutic target.

Residual symptoms, despite successful response to therapy, appear to be the rule in unipolar depression. Most of the residual symptoms occur in the prodromal phase of illness. Residual symptoms are associated with biological correlates, mainly involving the hypothalamic-pituitary-adrenal (HPA) axis and the sleep architecture. They are powerful predictors of relapse. These findings have led to the hypothesis that residual symptoms upon recovery may progress to become prodromal symptoms of relapse. A sequential strategy (encompassing pharmacotherapy in the acute phase of illness and cognitive behavioral therapy in its residual phase) has been developed and was found to be effective in decreasing relapse rate in controlled studies. A largely untested assumption in unipolar depression is that pharmacological strategies that are effective in the short term are the most suitable for postacute and residual phases or maintenance. The literature on subclinical symptomatology calls for specific, stage-oriented, therapeutic approaches. The efficacy of antidepressant drugs may be assessed not only on differential remission rates, but also on differential amount of residual symptomatology after response.