Ana Margarida Pereira

Physiological changes induced by the quaternary ammonium compound benzyldimethyldodecylammonium chloride on Pseudomonas fluorescens

OBJECTIVES Antimicrobial resistance is a major public health concern, particularly in hospitals and other healthcare settings. For the rational design of disinfection strategies, it is of utmost importance to understand the mechanisms of action of antimicrobials. In this study, the mechanism of action of benzyldimethyldodecylammonium chloride (BDMDAC) was assessed against Pseudomonas fluorescens. METHODS The targets of antimicrobial action were studied using different bacterial physiological indices. The MIC, MBC, membrane permeabilization, intracellular potassium release, physico-chemical surface properties, surface charge, outer membrane protein (OMP) expression and morphological changes were assessed after BDMDAC exposure. RESULTS The MIC was found to be 20 mg/L and the MBC was 10 mg/L. BDMDAC led to a significant change in cell surface hydrophobicity and induced propidium iodide uptake. Such results suggest cytoplasmic membrane damage, corroborated by the release of intracellular potassium. The results obtained from the zeta potential measurement demonstrate a -31.2 mV value for untreated cells and -21.0 mV for cells at the MIC. Scanning electron microscopy revealed that cells treated with 20 mg/L were less bulky, and their membrane seemed to be rougher, wrinkled and deformed when compared with untreated cells. The overall bactericidal events occurred without detectable changes in OMP expression. CONCLUSIONS BDMDAC is an effective biocide against P. fluorescens. It binds by ionic and hydrophobic interactions to the cell membrane, causing changes in membrane properties and function, as manifested by phenomena such as cellular disruption and loss of membrane integrity with consequent leakage of essential intracellular constituents.

Prevalence and classification of rhinitis in preschool children in Portugal: a nationwide study.

Information on rhinitis epidemiology in preschool children is scarce.

Asthma costs and social impact

In recent decades, both asthma prevalence and incidence have been increasing worldwide, not only due to the genetic background, but mainly because of the effect of a wide number of environmental and lifestyle risk factors.In many countries noncommunicable diseases, like asthma, are not yet considered a healthcare priority. This review will analyze and discuss disparities in asthma management in several countries and regions, such as access to healthcare human resources and medications, due to limited financial capacity to develop strategies to control and prevent this chronic disease.This review tries to explore the social and economic burden of asthma impact on society. Although asthma is generally accepted as a costly illness, the total costs to society (direct, indirect and intangible asthma costs) are difficult to estimate, mainly due to different disease definitions and characterizations but also to the use of different methodologies to assess the asthma socio-economic impact in different societies.The asthma costs are very variables from country to country, however we can estimate that a mean cost per patient per year, including all asthmatics (intermittent, mild, moderate and severe asthma) in Europe is

Inhaler devices in asthma and COPD – An assessment of inhaler technique and patient preferences

USD 1,900, which seems lower than USA, estimated mean

Persister cells in a biofilm treated with a biocide

USD 3,100.

Prevalence and classification of rhinitis in the elderly: a nationwide survey in Portugal.

BACKGROUND Incorrect use of inhaler devices remains an obstacle for respiratory diseases management. We aimed to evaluate the frequency of inhaler technique errors; to determine the devices perceived as the easiest and favourite to use; to study the association of device type, demographics and patient preferences with inhaler technique (IT). METHODS Cross-sectional assessment of 301 adults, with asthma (194) or chronic pulmonary obstructive disease, undergoing treatment with Aerolizer®, Autohaler®, Breezehaler®, Diskus®, Handihaler®, MDI without spacer, Miat-haler®, Novolizer®, Respimat® and/or Turbohaler®. Patients completed self-assessment questionnaires and face-to-face interview, with demonstration of inhaler technique. The rate of wrong steps (number of wrong steps ÷ number of total steps; RWS) was the primary outcome. Adjusted odds ratio (aOR) (95% confidence intervals [CI]) for presenting ≥1 IT errors were computed. RESULTS From the 464 inhaler technique performances, the median RWS was 18%. Turbohaler® (21%) and Diskus® (19%) were chosen as easiest and Novolizer® (18%), Diskus® (18%), Turbohaler® (17%) as favourite for daily use. Females (aOR 2.68 [95% CI 1.55-4.65]; vs. males], patients with >64 yr (aOR 2.73 [95% CI 1.15-6.48]; vs <45 yr) and patients using Aerolizer® or Handihaler® (aOR 3.24 [95% CI 1.13-9.32] and aOR 3.71 [95% CI 1.38-10.2], respectively) were more likely to perform IT errors; otherwise, no association was found, including with using the favourite device (aOR 1.43 [95% CI 0.84-2.42]). CONCLUSION The frequency of inhaler technique errors was high and no device was clearly preferred over the others. Using the preferred inhaler device was not associated with less errors.

Control of Allergic Rhinitis and Asthma Test (CARAT): dissemination and applications in primary care

This study investigated the physiology and behaviour following treatment with ortho-phthalaldehyde (OPA), of Pseudomonas fluorescens in both the planktonic and sessile states. Steady-state biofilms and planktonic cells were collected from a bioreactor and their extracellular polymeric substances (EPS) were extracted using a method that did not destroy the cells. Cell structure and physiology after EPS extraction were compared in terms of respiratory activity, morphology, cell protein and polysaccharide content, and expression of the outer membrane proteins (OMP). Significant differences were found between the physiological parameters analysed. Planktonic cells were more metabolically active, and contained greater amounts of proteins and polysaccharides than biofilm cells. Moreover, biofilm formation promoted the expression of distinct OMP. Additional experiments were performed with cells after EPS extraction in order to compare the susceptibility of planktonic and biofilm cells to OPA. Cells were completely inactivated after exposure to the biocide (minimum bactericidal concentration, MBC = 0.55 ± 0.20 mM for planktonic cells; MBC = 1.7 ± 0.30 mM for biofilm cells). After treatment, the potential of inactivated cells to recover from antimicrobial exposure was evaluated over time. Planktonic cells remained inactive over 48 h while cells from biofilms recovered 24 h after exposure to OPA, and the number of viable and culturable cells increased over time. The MBC of the recovered biofilm cells after a second exposure to OPA was 0.58 ± 0.40 mM, a concentration similar to the MBC of planktonic cells. This study demonstrates that persister cells may survive in biocide-treated biofilms, even in the absence of EPS.

Prevalence of asthma and its association with rhinitis in the elderly.

Nationwide epidemiologic data on rhinitis in the elderly do not exist. This study aimed to estimate the prevalence of rhinitis in the population aged 65 years or above in mainland Portugal and to characterize and classify rhinitis in this age group.

Pilot study of mobile phone technology in allergic rhinitis in European countries. The MASK-rhinitis study.

Asthma frequently occurs in association with allergic rhinitis and a combined management approach has been suggested. The Control of Allergic Rhinitis and Asthma Test (CARAT) is the first questionnaire to assess control of both diseases concurrently. However, to have an impact on healthcare it needs to be disseminated and adopted. In this paper we discuss the dissemination of CARAT in different countries and its possible applications in primary care. At present, the adaptation of CARAT for use in different languages and cultures is being led by volunteer researchers and clinicians in 15 countries. Website and smartphone applications have been developed, and a free open model of distribution was adopted to contribute to the dissemination of CARAT. Examples of dissemination activities include distribution of leaflets and posters, educational sessions on the use of the questionnaire in the follow-up of patients, development of clinical studies, collaborations with professional organisations and health authorities, and the inclusion of CARAT in clinical guidelines. The adoption of innovations is an important challenge in healthcare today, and research on the degree of success of dissemination strategies using suitable methods and metrics is much needed. We propose that CARAT can be used in a range of settings and circumstances in primary care for clinical, research and audit purposes, within the overall aim of increasing awareness of the level of disease control and strengthening the partnership between patients and doctors in the management of asthma and rhinitis.

The effects of glutaraldehyde on the control of single and dual biofilms of Bacillus cereus and Pseudomonas fluorescens

BACKGROUND Asthma and rhinitis are frequent respiratory diseases in children and adults. Despite the increase in the aging population, there are few epidemiologic data on both diseases in the elderly. So far, no population-based study has analyzed the association between asthma and rhinitis symptoms and severity in this age group. This study aimed to estimate the prevalence of physician-diagnosed asthma in the population aged ≥65 years in mainland Portugal and to evaluate its association with the presence and classification of rhinitis according to ARIA recommendations, in this age group. METHODS A cross-sectional, nationwide, population-based survey of individuals aged ≥65 years, living in mainland Portugal was performed. RESULTS Data were obtained from 3678 respondents. The prevalence of physician-diagnosed asthma was 10.9% (95% confidence interval (95%CI) 9.9-11.9). The frequency of asthma diagnosis increased with the number of nasal symptoms (p < 0.001). A strong association between asthma and rhinitis was found (odds ratio (OR) 13.86 (95%CI 10.66-18.02)). The strength of this association increased with the persistence and severity of rhinitis, being particularly high in elderly subjects with moderate-severe persistent rhinitis (OR 39.9 (95%CI 27.5-58.0)). CONCLUSIONS Asthma is common in the elderly and strongly associated with rhinitis. The OR for asthma is especially high in persistent and severe ARIA classification rhinitis types. This study strengthens the need for an integrated assessment of asthma together with rhinitis in the elderly.