Patient-reported outcome measures on mental health and psychosocial factors in patients with Brugada syndrome

AIMS

Brugada syndrome (BrS) is a hereditary arrhythmic disease, associated with sudden cardiac death. To date, little is known about the psychosocial correlates and impacts associated with this disease. The aim of this study was to assess a set of patient-reported psychosocial outcomes, to better profile these patients, and to propose a tailored psychosocial care.

METHODS AND RESULTS

Patients were recruited at the European reference Centre for BrS at Universitair Ziekenhuis Brussel, Belgium. Recruitment was undertaken in two phases: phase 1 (retrospective), patients with confirmed BrS, and phase 2 (prospective), patients referred for ajmaline testing who had an either positive or negative diagnosis. BrS patients were compared to controls from the general population. Two hundred and nine questionnaires were analysed (144 retrospective and 65 prospective). Collected patient-reported outcomes were on mental health (12 item General Health Questionnaire; GHQ-12), social support (Oslo Social Support Scale), health-related quality of life, presence of Type-D personality (Type-D Scale; DS14), coping styles (Brief-COPE), and personality dimensions (Ten Item Personality Inventory). Results showed higher mental distress (GHQ-12) in BrS patients (2.53 ± 3.03) than in the general population (P < 0.001) and higher prevalence (32.7%) of Type D personality (P < 0.001) in patients with confirmed Brugada syndrome (BrS +). A strong correlation was found in the BrS + group (0.611, P < 0.001) between DS14 negative affectivity subscale and mental distress (GHQ-12).

CONCLUSION

Mental distress and type D personality are significantly more common in BrS patients compared to the general population. This clearly illustrates the necessity to include mental health screening and care as standard for BrS.

Dealing with cultural diversity in palliative care

Palliative care is increasingly confronted with cultural diversity. This can lead to various problems in practice. In this perspective article, the authors discuss in more detail which issues play a role in culture-sensitive palliative care, why naive culturalism will not solve such problems and in which direction research into this aspect of care can be further elaborated.

Threat through the Screen? Association between Proximity and/or Watching Media Coverage of a Terrorist Attack and Health

INTRODUCTION

After terrorist attacks, media coverage of the attacks is extensive. There are some indications that there is an association between watching the media coverage and certain health reactions, both mental and somatic. Most studies occur in the United States and often months after the initial attack. In the current study, we investigated the terrorist attacks in Belgium on 22 March 2016.

METHODS

An online cross-sectional survey was conducted one week after the attacks among the general population of Belgium. We measured hours of media watching of the terrorist attacks (hereafter media watching), adjusted scales of the Patient Health Questionaire-4 (PHQ-4) to measure mental symptoms and the Patient Health Questionaire-15 (PHQ-15) to measure somatic symptoms, proximity to Brussels (home, work and overall proximity) and background factors such as gender, age and level of education. Respondents were included if they answered the survey between 29 March 2016 and 5 April 2016.

RESULTS

A total of 2972 respondents were included. Overall, media watching was significantly associated with both mental symptoms (p < 0.001) and somatic symptoms (p < 0.001), while controlling for age, gender, level of education and proximity. Watching more than three hours of media was associated with more mental and somatic symptoms (p < 0.001). Compared to proximity, media watching was, in general, a better association. For geographical factors, watching more than three hours of media indicated equally high scores for mental symptoms and somatic symptoms as work proximity (p = 0.015) and overall proximity to the attacks (p = 0.024).

CONCLUSION

Media-watching is associated with acute health reactions after terrorist attacks. However, the direction of the relationship is unclear, as it might also be that people with health issues seek out more media.

Aggression in mental health care: Opportunities for the future-A qualitative study on the challenges when defining and managing aggression across inpatient disciplines

WHAT IS KNOWN ON THE SUBJECT?: Aggression towards caregivers is a global phenomenon in mental health care. Although attempts have been made to define aggression, there is no globally accepted definition. Discrepancies in defining aggression can lead to differences in judgement and a sub-par management of aggression. The fact that different disciplines work together in mental health care makes it an even more pressing matter as no research was found regarding a multidisciplinary definition of aggression. Currently, coercive measures, such as isolation, sedation or restraints, are the most common ways of managing aggression. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Mental healthcare nurses and psychologists defined aggression by previous experiences, and they also agree that there are no alternatives in managing aggression when non-coercive techniques do not work. Several opportunities and examples of best practice were given by the participants, but the consensus was that caregivers are in need of alternatives when they are face to face with acute aggression. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: It is vital for residential units to agree on a definition of aggression and acute aggression. It is our belief that this can aid them in preventing and de-escalating aggression as well as diminishing the use of coercive measures. Further primary research exploring the opportunities of non-coercive techniques, a multidisciplinary approach and the relationship between a workplace culture normalizing aggression and the mental well-being of healthcare workers is also needed.

ABSTRACT

INTRODUCTION: Aggression by patients against healthcare workers is a global recurring phenomenon in mental health care. Discrepancies in defining aggression can lead to differences in judgement, which in turn causes difficulties in managing aggression. The multidisciplinary nature of mental healthcare makes a standardized definition an even more pressing matter. No studies, however, were found exploring the way different disciplines approach the definition of aggression. Although traditional methods of managing aggression rely on coercive methods, current research favours the use of non-coercive measures.

AIM

The aim of this study was to explore the different ways mental healthcare nurses and psychologists define and manage aggression in a residential unit.

METHOD

A qualitative research design was used, consisting of interviews and focus groups. Transcripts were analysed using a reflexive thematic approach.

RESULTS

Three major themes were found: (1) approaches towards defining aggression, (2) experiencing aggression and (3) managing aggression: the need for alternatives.

DISCUSSION

In this study, aggression is defined by how aggression has been experienced, both mental health nurses and psychologists agree that there are no alternatives in managing aggression when non-coercive techniques do not work. Aggression is considered an integral part of the job indicating an "aggression-tolerating" workplace.

IMPLICATIONS FOR PRACTICE

Three implications for practice were identified: (1) It is vital for residential units to agree on a broad-based definition of aggression, (2) further primary research exploring the opportunities of non-coercive techniques and a multidisciplinary approach is crucial and (3) the relationship between a workplace culture normalizing aggression and the mental well-being of healthcare workers also needs further study.

Association Between Feeling Threatened, Behaviour and Symptoms of Anxiety and Depression: Two and a Half Years After the Terrorist Attacks in Belgium

Feeling threatened by terrorism can be associated with mental health problems and behavioural changes. However, few studies look at the association in the long-term. Using a survey, the population in Brussels, Belgium was studied using a representative database delivered by the national post service. The Patient Health Questionnaire-4 (PHQ-4) assessed mental health, and self-made questions avoidance behaviour. 170 people answered: 60% women and 50% higher educated, 28.2% between 56 and 65 years and 62.4% had a partner. 43.5% felt threatened by the terrorist attacks and 45.9% experienced no mental health problems. Both terrorist threat (p < 0.001) and avoidance behaviour (p < 0.001) significantly predicted PHQ-4 scores, while controlling for gender, age, social support, education level, and traumatic events. There is a relation between terrorist threat and anxiety/depressive symptoms 2.5 years after the last study on terrorist threat in Brussels, but it has weakened. Avoidance behaviour seems to be more present than threat.

Reporting of Palliative Sedation and Use of Opioids at the End of Life in a Belgian University Hospital: A Pilot Study

Background: Palliative sedation requires no formal registration in Belgium. For euthanasia, however, there are clear guidelines in certain countries, including mandatory registration and evaluation of cases. Official guidelines have been developed for palliative sedation, but research still shows unskilled use of sedation and unclear demarcation between palliative sedation and euthanasia. Registration could be used to avoid unskilled use of sedation and to avoid use or abuse of sedation to hasten the patient's death (described as "slow/passive euthanasia"). Objective: To evaluate the current practice of palliative sedation and use of opioids and sedatives at the end of life by using a registration document. Design: Retrospective observational study. Setting/Subjects: We included all in-hospital deaths at an academic hospital in Belgium of patients (age ≥18 years) who had received parenteral opioids, benzodiazepines, barbiturates, or other anesthetics during the last 24 hours. Measurements: We investigated indications for palliative sedation, patients' and physicians' characteristics, types of medication used, and the decision-making process with the patients and family. The questionnaires were collected between July 9 and November 25, 2016. The study was approved by the Biomedical Ethics Committee of UZ Brussel (B.U.N. 1432016293). Results: In a population of 124 patients, refractory symptoms were reported in 94.4%. All patients received parenteral opioids (intravenously). Benzodiazepines were used in 51.6%. In 75.8%, physicians reported no change in treatment plan during end of life. Hastening death by increasing analgesics and/or sedatives was mentioned in 19.3%. The treatment plan was discussed with patients in 26.6% of cases. In 6 cases, an explicit intention to hasten death was mentioned; in 36 cases, doses of opioids/sedatives may not have been strictly proportional to symptoms. Conclusion: This Belgian study shows that objective reporting of palliative sedation can be used as a tool to ensure good clinical practice where patients receive the most appropriate end-of-life care, avoiding abusive and injudicious or unskilled use of sedation.

Suicide in Flanders, Belgium, after terrorist attacks

Little is known about the association between terrorism and suicide. This study investigates suicide numbers in Flanders, Belgium before and after the Paris-attacks (13/11/2015) and Brussels-attacks (22/03/2016). Population mortality data for suicide were gathered from the Agency for healthcare. Suicides in Flanders, Belgium, were higher after both attacks. The increase was higher after the Paris-attacks, compared to the attacks in Brussels, Belgium. The effect of a close-by, but still foreign attack (the Paris-attacks in France) on suicide numbers is larger than that of an attack inside the country (the Brussels-attacks), possibly due to a difference in threat experience and coping possibilities.

High incidence of Epstein-Barr virus, cytomegalovirus, and human-herpes virus-6 reactivations in critically ill patients with COVID-19

Background

Systemic reactivation of herpesviruses may occur in intensive care unit (ICU) patients and is associated with morbidity and mortality. Data on severe Coronavirus disease-19 (COVID-19) and concomitant reactivation of herpesviruses are lacking.

Methods

We selected patients admitted to ICU for confirmed COVID-19 who underwent systematic testing for Epstein–Barr virus (EBV), cytomegalovirus (CMV) and human-herpes virus-6 (HHV-6) DNAemia while in the ICU. We retrospectively analysed frequency, timing, duration and co-occurrence of viral DNAemia.

Results

Thirty-four patients were included. Viremia with EBV, CMV, and HHV-6 was detected in 28 (82%), 5 (15%), and 7 (22%) patients, respectively. EBV reactivation occurred early after ICU admission and was associated with longer ICU length-of-stay.

Conclusions

While in the ICU, critically ill patients with COVID-19 are prone to develop reactivations due to various types of herpesviruses.

Neurophysiological Assessments During Continuous Sedation Until Death Put Validity of Observational Assessments Into Question: A Prospective Observational Study

Introduction

In case of untreatable suffering at the end of life, continuous sedation until death (CSD) may be the only treatment option left. Because these patients cannot communicate anymore, caregivers have to rely on behavioral observation to assess the patient’s comfort. Recently, however, a number of studies from the neurosciences have shown that sometimes consciousness and pain are undetectable with these traditional behavioral methods. The aim of this study was to find out if subjective caregiver assessments of consciousness and pain would be confirmed by objective neurophysiological measures.

Methods

In this prospective observational study, we observed patients from the start of palliative sedation until death. Subjective caregiver assessments of level of consciousness and pain based on behavioral observations were compared with objective measures from neurophysiological monitoring devices.

Results

We collected and analyzed 108 subjective caregiver assessments in a sample of 12 patients and 32 assessments by traditionally used observational scales. We compared these with objective neurophysiological measures. Sensitivity and specificity of caregivers’ subjective assessments of consciousness was 23.6 and 91.1% respectively, with an accuracy of 54.0% and interrater reliability (κ) of 0.13. For pain, this was 0 and 94.79%, respectively, an accuracy of 88%, and an inter-rater reliability (κ) of − 0.063. Agreement between caregivers’ subjective assessments and objective neurophysiological measures of consciousness and pain was very poor.

Conclusions

Caregivers’ subjective assessment of level of consciousness and pain during CSD is unreliable compared with objective neurophysiological monitoring. Our results suggest that assessments of patient comfort during CSD could have been improved substantially by including objective monitoring of level of consciousness and pain.

Trial Registration

The protocol for this observational study has been registered retrospectively at Clinical-Trials.gov (ID NCT03273244).

Attitudes of Professional Caregivers and Family Members Regarding the Use of Monitoring Devices to Improve Assessments of Pain and Discomfort During Continuous Sedation Until Death

CONTEXT

Assessing consciousness and pain during continuous sedation until death (CSD) by behavior-based observational scales alone has recently been put into question. Instead, the use of monitoring technology has been suggested to make more objective and reliable assessments. Insights into which factors influence attitudes toward using these monitoring devices in a context of CSD is a first step in formulating recommendations to inform future practice.

OBJECTIVES

The aim of this study was to find out what influences professional caregivers' and family members' (FMs) attitudes regarding the use of monitors during CSD.

METHODS

We conducted semistructured face-to-face interviews with 20 professional caregivers and 15 FMs, who cared for a patient or had an FM, respectively, who took part in a study using monitoring devices. Recruitment took place in an academic hospital, a locoregional hospital, and two nursing homes, all located in Belgium. Two researchers independently analyzed the data, using grounded theory to inductively develop a model that represents the emerging attitude toward use of monitors during CSD.

RESULTS

Our model shows that the emerging attitudes toward using monitors during CSD is determined by view on CSD, desire for peace of mind, emotional valence attached to using monitors, and the realization that the sole use of behavior-based observational measures could be unreliable in a CSD context. We identified several facilitators and barriers to inform future implementation strategies.

CONCLUSION

Most participants had no objections, and all participants found the use of monitoring devices during CSD feasible and acceptable. We identified a number of facilitators and barriers and suggested that being aware that care can be improved, good communication, shared decision making, and continuing professional education can overcome the identified barriers. We suggest future research would focus on developing implementation strategies and guidelines for introducing objective monitoring devices in diverse palliative care settings.

Questions and Emotions of Minors After Terrorist Attacks: A Qualitative Study Using Data from a Belgian Youth-Helpline

Until now, there is little research on the experiences of indirectly exposed minors after terrorist attacks. This study sheds light on the emotions and questions of such indirectly exposed minors. A qualitative content analysis of secondary data gained from Awel, a youth-helpline, was performed until saturation. Data contained emotions and questions in chat conversations, with 30 minors (8-18 years old). Emotions included guilt, sadness, and especially fear of attacks on themselves, their family, or at school. Questions mostly focused on making sense of the attacks, and how to distinguish fantasy from reality. After an attack children and adolescents experienced a wide range of emotions, and seem to have difficulty to make sense of what happened. Teachers and parents can play an important role in buffering fears, and in offering contextual information and concrete answers.

Psychosocial aid provided to and sought by rescue workers after the March 2016 terrorist attacks in Brussels, Belgium. A qualitative analysis

Background

During the terrorist attacks of 22/03/2016 in Brussels, Belgium, hundreds of rescue workers were present or came to the sites to give aid to the victims. However, until now, there is little research about these first responders’ own need for aid and support immediately after their work or later, and about how they experienced that aid.

Methods

Using half-structured interviews, we collected data from 31 first responders including 4 nurses, 5 soldiers, 7 firefighters, 11 airport police officers and 4 Red Cross volunteers. Interviews were transcribed, coded and analyzed by two researchers.

Results

Generally, debriefings were organized at hoc, informal and at the day of the event. Sometimes, an additional group conversation was organized in the week or weeks later. Further initiative was left to the rescue workers themselves to find psychosocial aid, whether inside or outside their organization. Because of many contextual factors (macho culture, no sense of normality of reactions on traumatic experiences, (lack of) social support, stigma of psychosocial health, lack of understanding of those who did not experience it...) rescue workers (mostly police officers and soldiers) often did not find the necessary psychosocial aid. Some workers simply accepted that they have changed due to the attacks. Those who did search for psychological help, experience several problems: the type of help, the financial costs, a lack of recognition of the psychosocial problems, etc.

Conclusions

Psychosocial aid of first responders is often too short-term, ad hoc, and poorly prepared and organized. Awareness of adverse changes in health or personality can come long after the debriefing sessions. Furthermore, the quality of the debriefings is not always up to standard.

Main message

Psychosocial aid must not only be aimed at the short term, and must be better prepared and organized.

Should we include monitors to improve assessment of awareness and pain in unconscious palliatively sedated patients? A case report

BACKGROUND

Awareness and pain during palliative sedation is typically assessed by observational scales, but the use of such scales has been put into question.

CASE PRESENTATION

A woman in her mid-80s was admitted to a palliative care unit, presenting with chronic lymphatic leukemia, depression, and a cerebrovascular accident, with right-sided hemiplegia and aphasia. The patient was unable to eat and was suffering from nausea and vomiting. Before admission, the patient had expressed her desire to discontinue treatment on several occasions.

CASE MANAGEMENT

The decision was made to initiate palliative sedation. The patient consented to take part in a study to assess level of comfort and pain using two monitoring devices (NeuroSense monitor and Analgesia Nociception Index monitor).

CASE OUTCOME

The patient died 90 h after initiation of palliative sedation. Titration of the medication was challenging and sedation was not deep enough during the first 2 days. Thirteen assessments made with the Ramsay Sedation Scale showed that the patient was considered to be in a deep sleep, while in fact the NeuroSense monitor indicated otherwise.

CONCLUSION

This case demonstrates the feasibility and potential advantages of using monitoring devices to objectify assessments of pain and discomfort in palliatively sedated patients.

Are the Elderly Perceived as a Burden to Society? The Perspective of Family Caregivers in Belgium and Kenya: A Comparative Study

Introduction: It is estimated that 70% to 80% of informal care for frail and disabled elders is provided by family caregivers (FCGs). Aim: To better understand how caregiving for the elderly has affected FCGs lives and to compare the perspective of these caregivers in Belgium and Kenya. Method: Semistructured interviews were undertaken with 15 FCGs in Kenya and 15 FCGs in Belgium. Interpretative phenomenological analysis was used to identify themes. Results: Themes discovered in the experience of family caregiving included profile of the care receiver, impact of caregiving on the FCG, cultural values and norms, challenges in caregiving, coping strategies and caregiver well-being. Discussion: FCGs in both Kenya and Belgium identified experiencing serious concerns. In Kenya, the lack of resources and formal structures play a more important role than in Belgium. Despite this difference, culture-specific views and norms are paramount to explaining the FCG experience in the two countries.

Comfort in palliative sedation (Compas): a transdisciplinary mixed method study protocol for linking objective assessments to subjective experiences

BACKGROUND

In case of untreatable suffering at the end of life, palliative sedation may be chosen to assure comfort by reducing the patient's level of consciousness. An important question here is whether such sedated patients are completely free of pain. Because these patients cannot communicate anymore, caregivers have to rely on observation to assess the patient's comfort. Recently however, more sophisticated techniques from the neurosciences have shown that sometimes consciousness and pain are undetectable with these traditional behavioral methods. The aim of this study is to better understand how unconscious palliative sedated patients experience the last days of their life and to find out if they are really free of pain.

METHODS

In this study we will observe 40 patients starting with initiation of palliative sedation until death. Assessment of comfort based on behavioral observations will be related with the results from a NeuroSense monitor, an EEG-based monitor used for evaluation of the adequacy of anesthesia and sedation in the operating room and an ECG-based Analgesia Nociception Index (ANI) monitor, which informs about comfort or discomfort condition, based on the parasympathetic tone. An innovative and challenging aspect of this study is its qualitative approach; "objective" and "subjective" data will be linked to achieve a holistic understanding of the study topic. The following data will be collected: assessment of pain/comfort by the patients themselves (if possible) by scoring a Visual Analogue Scale (VAS); brain function monitoring; monitoring of parasympathetic tone; caregivers' assessment (pain, awareness, communication); relatives' perception of the quality of the dying process; assessment by 2 trained investigators using observational scales; video and audio registration.

DISCUSSION

Measuring pain and awareness in non-communicative dying patients is both technically and ethically challenging. ANI and EEG have shown to be promising technologies to detect pain that otherwise cannot be detected with the "traditional" methods. Although these technologies have the potential to provide objective quantifiable indicators for distress and awareness in non-communicative patients, strikingly they have not yet been used to check whether the current assessments for non-communicative patients are reliable.

TRIAL REGISTRATION

The study is registered on ClinicalTrials.gov (Identifier: NCT03273244 ; registration date: 7.9.2017).

Association between feeling threatened by a terrorist attack and subjective health: a web survey a week after the attacks of 22 March 2016 in Belgium

Background: The wave of terrorist attacks over the past years in Europe and other regions may cause problems such as anxiety and depressive symptoms. Some studies suggest that perceived threat might also trigger physical health problems. Objective: To investigate the association between feeling threatened and subjective health during the week following a terrorist attack. Method: Online survey with a self-selected sample in the Belgian population one week after the terrorist attacks in 2016. Participants were invited through the Belgian media to fill in a questionnaire in Dutch, French or English on a website. The main outcomes were the association between 'feeling threatened' and subjective health problems. Perceived threat was measured with the question 'During the week after the attacks … Did you feel threatened?' Subjective health was measured by using standardized scales (ACSA, PHQ-4, PHQ-15). Results: A total of 2620 respondents completed the questionnaire, of whom 69.8% were female, 27.7% lived and 43.1% worked in Brussels. Gender, age, place of living and working, media exposure, religiousness and religious affiliation were associated significantly with higher perceived threat. A total of 21% of the respondents felt much or very much threatened during the week after the attacks. They reported significantly higher levels of mental and physical health problems. The most frequently reported problems were anxiety and depressive symptoms. The health problems that differentiated most markedly between those with low and high levels of perceived threat were fainting spells, chest pain and shortness of breath. Conclusion: In a self-selected sample of respondents, 'feeling threatened' was strongly associated with lower level of wellbeing and higher levels of mental and physical health problems. The most prevalent health problems were mental health problems but the most pronounced differences between people with low versus high levels of perceived threat were physical health problems.

Linking numbers to perceptions and experiences: Why we need transdisciplinary mixed-methods combining neurophysiological and qualitative data

Today, more and more problems that scientists need to tackle are complex problems. Many examples of these can be found in the health sciences, medicine and ecology. Typical features of complex problems are that they cannot be studied by one discipline and that they need to take into account subjective data as well as objective data. Two promising responses to deal with complex problems are Transdisciplinary and Mixed Method approaches. However, there is still a lacuna to fill, with transdisciplinary studies bridging the social sciences and biomedical sciences. More specifically, we need more and better studies that combine qualitative data about subjective experiences, perception and so on with objective, quantitative, neurophysiological data. We believe that the combination of qualitative and neurophysiological data is a good example of what we would like to call transdisciplinary mixed methods. In this article, we aim to explore the opportunities of transdisciplinary mixed-methods studies in which qualitative and neurophysiological data are used. We give a brief overview of what is characteristic for this kind of studies and illustrate this with examples; we point out strengths and limitations and propose an agenda for the future. We conclude that transdisciplinary mixed-methods studies in which qualitative and neurophysiological data are used have the potential to improve our knowledge about complex problems. A main obstacle seems to be that most scientists from the biomedical sciences are not familiar with the (qualitative) methods from the social sciences and vice versa. To end this ‘clash of paradigms’™, we urgently need to cultivate transdisciplinary thinking.

Impact of a targeted isolation strategy at intensive-care-unit-admission on intensive-care-unit-acquired infection related to multidrug-resistant bacteria: a prospective uncontrolled before-after study

Isolation of patients with multidrug resistant (MDR) bacteria is recommended to reduce cross-transmission of these bacteria. However, isolation of critically ill patients has several negative side effects. Therefore, we hypothesized that a targeted isolation strategy, based on the presence of at least one risk factor for MDR bacteria, would be not inferior to a systematic isolation strategy at intensive-care unit (ICU) admission. This prospective before-after study was conducted in a mixed ICU, during two 12-month periods, separated by a 1-month 'wash-out' period. During the before period, isolation was systematically performed in all patients at admission. During the after period, isolation was only performed in patients with at least one risk factor for MDR bacteria at admission. During the two periods, routine screening for MDR bacteria was performed at ICU admission, and isolation prescription was modified after receipt of screening result. Primary outcome was the percentage of patients with ICU-acquired infection (ICUAI) related to MDR bacteria, measured from ICU admission until ICU discharge or day 28, whatever happens first. A total of 1221 patients were included. No significant difference was found in ICUAI related to MDR bacteria (85 of 585 (14.5%) vs. 84 of 636 (13.2%) patients, risk difference, -1.3%, 95% confidence interval [-5.2 to 2.6%]) between the two periods, confirming the non-inferiority hypothesis. Our results suggest that targeted isolation of patients at ICU admission is not inferior to systematic isolation, regarding the percentage of patients with ICUAI related to MDR bacteria. Further randomized controlled multicentre studies are needed to confirm our results.

Functioning of DcuC as the C4-dicarboxylate carrier during glucose fermentation by Escherichia coli

The dcuC gene of Escherichia coli encodes an alternative C4-dicarboxylate carrier (DcuC) with low transport activity. The expression of dcuC was investigated. dcuC was expressed only under anaerobic conditions; nitrate and fumarate caused slight repression and stimulation of expression, respectively. Anaerobic induction depended mainly on the transcriptional regulator FNR. Fumarate stimulation was independent of the fumarate response regulator DcuR. The expression of dcuC was not significantly inhibited by glucose, assigning a role to DcuC during glucose fermentation. The inactivation of dcuC increased fumarate-succinate exchange and fumarate uptake by DcuA and DcuB, suggesting a preferential function of DcuC in succinate efflux during glucose fermentation. Upon overexpression in a dcuC promoter mutant (dcuC*), DcuC was able to compensate for DcuA and DcuB in fumarate-succinate exchange and fumarate uptake.

Identification of a third secondary carrier (DcuC) for anaerobic C4-dicarboxylate transport in Escherichia coli: roles of the three Dcu carriers in uptake and exchange

In Escherichia coli, two carriers (DcuA and DcuB) for the transport of C4 dicarboxylates in anaerobic growth were known. Here a novel gene dcuC was identified encoding a secondary carrier (DcuC) for C4 dicarboxylates which is functional in anaerobic growth. The dcuC gene is located at min 14.1 of the E. coli map in the counterclockwise orientation. The dcuC gene combines two open reading frames found in other strains of E. coli K-12. The gene product (DcuC) is responsible for the transport of C4 dicarboxylates in DcuA-DcuB-deficient cells. The triple mutant (dcuA dcuB dcuC) is completely devoid of C4-dicarboxylate transport (exchange and uptake) during anaerobic growth, and the bacteria are no longer capable of growth by fumarate respiration. DcuC, however, is not required for C4-dicarboxylate uptake in aerobic growth. The dcuC gene encodes a putative protein of 461 amino acid residues with properties typical for secondary procaryotic carriers. DcuC shows sequence similarity to the two major anaerobic C4-dicarboxylate carriers DcuA and DcuB. Mutants producing only DcuA, DcuB, or DcuC were prepared. In the mutants, DcuA, DcuB, and DcuC were each able to operate in the exchange and uptake mode.

Reactivity of the N-terminal cysteine residues in active and inactive forms of FNR, and O2-responsive, Fe containing transcriptional regulator of Escherichia coli

FNR, the O2-responsive gene regulator of anaerobic respiratory genes in Escherichia coli, contains an N-terminal cluster of four cysteine residues (Cys16-X3-Cys20-X2-Cys23-X5-Cys29), three of which are thought to be involved in the binding of an iron cofactor. The accessibility of the cysteine residues for iodoacetate is known to increase upon switch from the active (anaerobic) to the inactive (aerobic or metal depleted) state. It was analyzed which residues become accessible under either condition. Up to four modified forms, FNR-I, FNR-II, FNR-III, and FNR-IV, containing approximately 1, 2, 3.5, and 5 carboxymethyl groups, were obtained either by reaction in vivo and in vitro under conditions of aerobiosis, anaerobiosis, or iron limitation. By N-terminal sequencing, the carboxymethylated cysteine residues were identified. The amount of label in each of the four cysteine residues increased rather uniformly and gradually from FNR-I to FNR-IV irrespective of the condition of labeling; only Cys16 was preferentially labeled to some extent. It is concluded that the four essential cysteine residues change their accessibility in a similar way in the switch from active to inactive (aerobic or metal depleted) FNR, without specific differences in their reaction or function. Potential modes of Fe-binding by the cysteine residues are discussed. In addition, a different type of interaction of Fe(II) with FNR is described. The interaction occurred also in FNR carboxymethylated at approximately three cysteine residues.

A third periplasmic transport system for L-arginine in Escherichia coli: molecular characterization of the artPIQMJ genes, arginine binding and transport

A new binding-protein-dependent transport system of Escherichia coli specific for L-arginine was characterized by genetic and biochemical means. The system is encoded by five adjacent genes, artPIQMJ (art standing for arginine transport), which are organized in two transcriptional units (artPIQM and artJ). The artl and artJ gene products (Artl and ArtJ) are periplasmic binding proteins with sequence similarity to binding proteins for polar (basic) amino acids. The artQ, artM and artP products are similar to the transmembraneous proteins and the ATPase of binding-protein-dependent carriers. The mature Artl and J proteins were localized in the periplasm and lacked signal peptides of 19 amino acid residues. Artl and ArtJ were isolated from overproducing strains. ArtJ specifically binds L-arginine with high affinity and overproduction of ArtJ stimulated L-arginine uptake by the bacteria. The substrate for Artl is not known, and isolated Artl did not bind common amino acids, various basic uncommon amino acids or amines. It is concluded that the artPIQM artJ genes encode a third arginine-uptake system in addition to the known argT hisJQMP system of Salmonella typhimurium and E. coli and the arginine (-ornithine) carrier (aps) of E. coli.

O2-sensing and O2-dependent gene regulation in facultatively anaerobic bacteria

Availability of O2 is one of the most important regulatory signals in facultatively anaerobic bacteria. Various two- or one-component sensor/regulator systems control the expression of aerobic and anaerobic metabolism in response to O2. Most of the sensor proteins contain heme or Fe as cofactors that interact with O2 either by binding or by a redox reaction. The ArcA/ArcB regulator of aerobic metabolism in Escherichia coli may use a different sensory mechanism. In two-component regulators, the sensor is located in the cytoplasmic membrane, whereas one-component regulators are located in the cytoplasm. Under most conditions, O2 can readily reach the cytoplasm and could provide the signal in the cytoplasm. The transcriptional regulator FNR of E. Coli controls the expression of many genes required for anaerobic metabolism in response to O2. Functional homologs of FNR are present in facultatively anaerobic Proteobacteria and presumably also in gram-positive bacteria. The target genes of FNR are mostly under multiple regulation by FNR and other regulators that respond to O2, nitrate, or glucose. FNR represents a 'one-component' sensor/regulator and contains Fe for signal perception. In response to O2 availability, FNR is converted reversibly from the aerobic (inactive) state to the anaerobic (active) state. Experiments suggest that the Fe cofactor is bound by four essential cysteine residues. The O2-triggered transformation between active and inactive FNR presumably is due to a redox reaction at the Fe cofactor, but other modes of interaction cannot be excluded. O2 seems to affect the site-specific DNA binding of FNR at target genes or the formation of an active transcriptional complex with RNA polymerase.

Escherichia coli possesses two homologous anaerobic C4-dicarboxylate membrane transporters (DcuA and DcuB) distinct from the aerobic dicarboxylate transport system (Dct)

The nucleotide sequences of two Escherichia coli genes, dcuA and dcuB (formerly designated genA and genF), have been shown to encode highly homologous products, M(r) 45,751 and 47,935 (434 and 446 amino acid residues) with 36% sequence identity (63% similarity). These proteins have a high proportion (approximately 61%) of hydrophobic residues and are probably members of a new group of integral inner membrane proteins. The locations of the dcu genes, one upstream of the aspartase gene (dcuA-aspA) and the other downstream of the anaerobic fumarase gene (fumB-dcuB), suggested that they may function in the anaerobic transport of C4-dicarboxylic acids. Growth tests and transport studies with mutants containing insertionally inactivated chromosomal dcuA and dcuB genes show that their products perform analogous and mutually complementary roles as anaerobic dicarboxylate carriers. The anaerobic dicarboxylate transport systems (Dcu) are genetically and functionally distinct from the aerobic system (Dct).

Oxygen regulated gene expression in facultatively anaerobic bacteria

In facultatively anaerobic bacteria such as Escherichia coli, oxygen and other electron acceptors fundamentally influence catabolic and anabolic pathways. E. coli is able to grow aerobically by respiration and in the absence of O2 by anaerobic respiration with nitrate, nitrite, fumarate, dimethylsulfoxide and trimethylamine N-oxide as acceptors or by fermentation. The expression of the various catabolic pathways occurs according to a hierarchy with 3 or 4 levels. Aerobic respiration at the highest level is followed by nitrate respiration (level 2), anaerobic respiration with the other acceptors (level 3) and fermentation. In other bacteria, different regulatory cascades with other underlying principles can be observed. Regulation of anabolism in response to O2 availability is important, too. It is caused by different requirements of cofactors or coenzymes in aerobic and anaerobic metabolism and by the requirement for different O2-independent biosynthetic routes under anoxia. The regulation mainly occurs at the transcriptional level. In E. coli, 4 global regulatory systems are known to be essential for the aerobic/anaerobic switch and the described hierarchy. A two-component sensor/regulator system comprising ArcB (sensor) and ArcA (transcriptional regulator) is responsible for regulation of aerobic metabolism. The FNR protein is a transcriptional sensor-regulator protein which regulates anaerobic respiratory genes in response to O2 availability. The gene activator FhlA regulates fermentative formate and hydrogen metabolism with formate as the inductor. ArcA/B and FNR directly respond to O2, FhlA indirectly by decreased levels of formate in the presence of O2. Regulation of nitrate/nitrite catabolism is effected by two 2-component sensor/regulator systems NarX(Q)/NarL(P) in response to nitrate/nitrite. Co-operation of the different regulatory systems at the target promoters which are in part under dual (or manifold) transcriptional control causes the expression according to the hierarchy. The sensing of the environmental signals by the sensor proteins or domains is not well understood so far. FNR, which acts presumably as a cytoplasmic 'one component' sensor-regulator, is suggested to sense directly cytoplasmic O2-levels corresponding to the environmental O2-levels.

Characterization of the FNR protein of Escherichia coli, an iron-binding transcriptional regulator

FNR is a transcriptional regulator mediating the activation or repression of a variety of Escherichia coli genes in response to anoxia. The FNR protein resembles CRP (the cyclic-AMP receptor protein) except for the presence of a cysteine-rich N-terminal segment which may form part of an iron-binding redoxsensing domain. The FNR protein was purified by a new procedure. It was monomeric (Mr = 30,000) and contained as much as 1.1 mol of iron per monomer when purified in the presence of added iron. This iron was associated with cysteine residues, because there was an inverse relation between iron content and titratable sulphydryl groups. Other physical and chemical properties are reported including evidence for a potential disulphide group or analogous modification. The interaction between FNR protein and target DNA appeared weak and non-specific in gel-retardation assays, but specific binding to the proposed DNA-binding site was shown for the first time in footprinting studies. A role for iron in FNR-mediated gene expression was confirmed by using cultures in which FNR was inactivated by growth in the presence of the specific chelator, ferrozine, but protected by ferrous iron.