Search

Background: Potential risk contacts for HIV transmission may lead to presentations to the emergency department (ED) for counseling and initiation of post-exposure prophylaxis (PEP). Objective: To examine the impact of German health insurance covering pre-exposure prophylaxis (PrEP) following Sept 1st 2019 for certain risk groups on the frequency and reasons for PEP counseling in a university-based ED in Germany. Methods: In a before-after study design, all persons aged ≥18 years who presented for PEP counseling were analyzed retrospectively. We compared characteristics of presentations in the 18 months prior to PrEP coverage on Sept 1st, 2019, with those in the following 18 months. Results: 154 ED presentations occurred in the first study period, and 155 ED presentations in the second period. Regarding the reasons for ED visits, no statistically significant difference was found [occupational risk contact (18.2 vs. 26.5%, p = 0.081), sexual risk contact (74.7 vs. 69.0%, p = 0.266), other non-occupational risk contact (7.1 vs. 4.5%, p = 0.329)]. For men who have sex with men (MSM), no statistically significant differences were found [38.9 (n = 60) vs. 35.5% (n = 55), p = 0.537]. All persons presenting to the HIV outpatient clinic after ED PEP initiation (n = 60 vs. n = 52) tested negative for HIV 3 months later. Conclusion: In this study, reasons to present for PEP counseling to a university ED showed no change following the implementation of PrEP coverage by health insurances. Therefore, PEP remains an important prevention for HIV transmission and presentations to the ED for PEP counseling may provide an opportunity to educate persons at risk of HIV infection about PrEP, thereby helping to prevent new HIV infections. [ABSTRACT FROM AUTHOR]

Determining SARS-CoV-2 immunity is critical to assess COVID-19 risk and the need for prevention and mitigation strategies. We measured SARS-CoV-2 Spike/Nucleocapsid seroprevalence and serum neutralizing activity against Wu01, BA.4/5 and BQ.1.1 in a convenience sample of 1,411 patients receiving medical treatment in the emergency departments of five university hospitals in North Rhine-Westphalia, Germany, in August/September 2022. 62% reported underlying medical conditions and 67.7% were vaccinated according to German COVID-19 vaccination recommendations (13.9% fully vaccinated, 54.3% one booster, 23.4% two boosters). We detected Spike-IgG in 95.6%, Nucleocapsid-IgG in 24.0%, and neutralization against Wu01, BA.4/5 and BQ.1.1 in 94.4%, 85.0%, and 73.8% of participants, respectively. Neutralization against BA.4/5 and BQ.1.1 was 5.6- and 23.4-fold lower compared to Wu01. Accuracy of S-IgG detection for determination of neutralizing activity against BQ.1.1 was reduced substantially. We explored previous vaccinations and infections as correlates of BQ.1.1 neutralization using multivariable and Bayesian network analyses. Given a rather moderate adherence to COVID-19 vaccination recommendations, this analysis highlights the need to improve vaccine-uptake to reduce the COVID-19 risk of immune evasive variants. The study was registered as clinical trial (DRKS00029414). Dewald et al. show a high Spike-IgG seroprevalence (95%) in a multicenter study with 1,411 participants. They determined a substantially reduced serum neutralization against the SARS-CoV-2 VOCs BA.4/5 and BQ.1.1. and explored predictive factors of neutralizing activity. [ABSTRACT FROM AUTHOR]

Purpose: During resuscitation of patients with severe trauma, guidelines recommend permissive hypotension prior to surgical bleeding control. However, hypotension may be associated with reduced organ perfusion and multiple organ dysfunction, e.g. myocardial injury. The association between hypotension and myocardial injury in trauma patients is underexplored. We hypothesized that hypotension is associated with myocardial injury in this population. Materials and methods: This retrospective study included patients ≥ 18 years suffering from severe trauma [defined as Injury Severity Score (ISS) ≥ 16] that were treated in the emergency department resuscitation room between 2016 and 2019. Primary endpoint was the incidence of myocardial injury defined as high-sensitive troponin T > 14 ng/l. Main exposure was the duration of arterial hypotension during resuscitation period defined as mean arterial pressure < 65 mmHg. Results: Out of 368 patients screened, 343 were analyzed (73% male, age: 55 ± 21, ISS: 28 ± 12). Myocardial injury was detected in 143 (42%) patients. Overall in-hospital mortality was 26%. Multivariate binary logistic regression with forced entry of nine predefined covariables revealed an odds ratio of 1.29 [95% confidence interval 1.16–1.44]; p = 0.012) for the association between the duration of hypotension and myocardial injury. Conclusion: The duration of hypotension during resuscitation period is independently associated with the incidence of myocardial injury in patients with severe trauma. [ABSTRACT FROM AUTHOR]

Purpose: Severe trauma can lead to end organ damages of varying severity, including myocardial injury. In the non-cardiac surgery setting, there is extensive evidence that perioperative myocardial injury is associated with increased morbidity and mortality. The impact of myocardial injury on outcome after severe trauma has not been investigated adequately yet. We hypothesized that myocardial injury is associated with increased in-hospital mortality in patients with severe trauma. Materials/methods: This retrospective cohort study included patients ≥ 18 years with severe trauma [defined as injury severity score (ISS) ≥ 16] that were admitted to the resuscitation room of the Emergency Department of the University Hospital Duesseldorf, Germany, between 2016 and 2019. The main endpoint was in-hospital mortality. Main exposure was myocardial injury at arrival [defined as high-sensitive troponin T (hsTnT) > 14 ng/l]. For statistical analysis, receiver operating characteristic curve (ROC) and multivariate binary logistic regression were performed. Results: Out of 368 patients, 353 were included into statistical analysis (72.5% male, age: 55 ± 21, ISS: 28 ± 12). Overall in-hospital mortality was 26.1%. Myocardial injury at presentation was detected in 149 (42.2%) patients. In-hospital mortality of patients with and without myocardial injury at presentation was 45% versus 12.3%, respectively. The area under the curve (AUC) for hsTnT and mortality was 0.76 [95% confidence interval (CI) 0.71–0.82]. The adjusted odds ratio of myocardial injury for in-hospital mortality was 2.27 ([95%CI 1.16–4.45]; p = 0.017). Conclusion: Myocardial injury after severe trauma is common and independently associated with in-hospital mortality. Thus, hsTnT might serve as a new prognostic marker in this cohort. [ABSTRACT FROM AUTHOR]

By the end of the year 2016, approximately 3 billion people worldwide travelled by commercial air transport. Between 1 out of 14,000 and 1 out of 50,000 passengers will experience acute medical problems/emergencies during a flight (i.e., in-flight medical emergency). Cardiac arrest accounts for 0.3% of all in-flight medical emergencies. So far, no specific guideline exists for the management and treatment of in-flight cardiac arrest (IFCA). A task force with clinical and investigational expertise in aviation, aviation medicine, and emergency medicine was created to develop a consensus based on scientific evidence and compiled a guideline for the management and treatment of in-flight cardiac arrests. Using the GRADE, RAND, and DELPHI methods, a systematic literature search was performed in PubMed. Specific recommendations have been developed for the treatment of IFCA. A total of 29 specific recommendations for the treatment and management of in-flight cardiac arrests were generated. The main recommendations included emergency equipments as well as communication of the emergency. Training of the crew is of utmost importance, and should ideally have a focus on CPR in aircraft. The decision for a diversion should be considered very carefully. [ABSTRACT FROM AUTHOR]

Objective:Two patient-focused long-term research projects performed in the German outpatient psychotherapy system are focused on in this article. The TK (Techniker Krankenkasse) project is the first study to evaluate a quality assurance and feedback system with regard to its practical feasibility in German routine care. The other study (“Quality Assurance in Outpatient Psychotherapy in Bavaria”; QS-PSY-BAY) was designed to test a new approach for quality assurance in outpatient psychotherapy using electronic documentation of patient characteristics and outcome parameters. In addition this project provides the opportunity to analyze data on health-related costs for the patients undergoing outpatient psychotherapy.Method:Both projects and their results indicating high effect sizes are briefly described.Results:From the perspectives of the research teams, advisory boards and other stakeholders, the experiences with these projects are discussed focusing on obstacles, challenges, difficulties, and benefits in developing and implementing the studies. The triangle collaboration of therapists, researchers, and health insurance companies/health service institutions turned out to be fruitful in both studies.Conclusions:Despite some controversies between the partners the experiences indicate the importance of practiced-research collaborations to provide relevant information about the delivery of outpatient psychotherapy in the health system. [ABSTRACT FROM PUBLISHER]

ACADEMIC EMERGENCY MEDICINE 2011; 18:1358-1370 © 2011 by the Society for Academic Emergency Medicine Abstract The maturation of emergency medicine (EM) as a specialty has coincided with dramatic increases in emergency department (ED) visit rates, both in the United States and around the world. ED crowding has become a public health problem where periodic supply and demand mismatches in ED and hospital resources cause long waiting times and delays in critical treatments. ED crowding has been associated with several negative clinical outcomes, including higher complication rates and mortality. This article describes emergency care systems and the extent of crowding across 15 countries outside of the United States: Australia, Canada, Denmark, Finland, France, Germany, Hong Kong, India, Iran, Italy, The Netherlands, Saudi Arabia, Catalonia (Spain), Sweden, and the United Kingdom. The authors are local emergency care leaders with knowledge of emergency care in their particular countries. Where available, data are provided about visit patterns in each country; however, for many of these countries, no national data are available on ED visits rates or crowding. For most of the countries included, there is both objective evidence of increases in ED visit rates and ED crowding and also subjective assessments of trends toward higher crowding in the ED. ED crowding appears to be worsening in many countries despite the presence of universal health coverage. Scandinavian countries with robust systems to manage acute care outside the ED do not report crowding is a major problem. The main cause for crowding identified by many authors is the boarding of admitted patients, similar to the United States. Many hospitals in these countries have implemented operational interventions to mitigate crowding in the ED, and some countries have imposed strict limits on ED length of stay (LOS), while others have no clear plan to mitigate crowding. An understanding of the causes and potential solutions implemented in these countries can provide a lens into how to mitigate ED crowding in the United States through health policy interventions and hospital operational changes. [ABSTRACT FROM AUTHOR]

Presents a study which explained the democratic success of the Federal Republic of Germany and the relevance of comparative political economy to the study of democratization. Argument on electoral outcomes and the potential for stable democratic governance through party coalitions; Democratic potential of Eastern and Western Germany; Quality of pluralism and its ramifications for democratic breakdown.

Introduction of accredited Cardiac Arrest Centers. Patients after OHCA who were transferred to one of three university hospitals before and after CAC accreditation were analyzed retrospectively concerning treatment and outcome variables. Created with https://www.biorender.com/ [Display omitted] Out-of-hospital cardiac arrest (OHCA) remains a frequent medical emergency with low survival rates even after a return of spontaneous circulation (ROSC). Growing evidence supports formation of dedicated teams in scenarios like cardiogenic shock to improve prognosis. Thus, the European Resuscitation Council (ERC) recommended introduction of Cardiac Arrest Centers (CAC) in their 2015 guidelines. Here, we aimed to elucidate the effects of newly introduced CACs in Germany regarding survival rate and neurological outcome. A multicenter retrospective observational cohort study was performed at three university hospitals and outcomes after OHCA were compared before and after CAC accreditation. Primary outcomes were survival until discharge and favorable neurological status (CPC 1 or 2) at discharge. In total 784 patients (368 before and 416 after CAC accreditation) were analyzed. Rates of immediate percutaneous coronary intervention (40 vs. 52%, p = 0.01) and implementation of extracorporeal CPR (8 vs. 13%, p < 0.05) increased after CAC accreditation. Likelihood of favorable neurological status at discharge was higher after CAC accreditation (71 vs. 87%, p < 0.01), whereas overall survival remained similar (35 vs. 35%, p > 0.99). CAC accreditation is linked to higher rates of favorable neurological outcome and unchanged overall survival. [ABSTRACT FROM AUTHOR]

Background: Large language models (LLMs) have demonstrated impressive performances in various medical domains, prompting an exploration of their potential utility within the high-demand setting of emergency department (ED) triage. This study evaluated the triage proficiency of different LLMs and ChatGPT, an LLM-based chatbot, compared to professionally trained ED staff and untrained personnel. We further explored whether LLM responses could guide untrained staff in effective triage., Objective: This study aimed to assess the efficacy of LLMs and the associated product ChatGPT in ED triage compared to personnel of varying training status and to investigate if the models' responses can enhance the triage proficiency of untrained personnel., Methods: A total of 124 anonymized case vignettes were triaged by untrained doctors; different versions of currently available LLMs; ChatGPT; and professionally trained raters, who subsequently agreed on a consensus set according to the Manchester Triage System (MTS). The prototypical vignettes were adapted from cases at a tertiary ED in Germany. The main outcome was the level of agreement between raters' MTS level assignments, measured via quadratic-weighted Cohen κ. The extent of over- and undertriage was also determined. Notably, instances of ChatGPT were prompted using zero-shot approaches without extensive background information on the MTS. The tested LLMs included raw GPT-4, Llama 3 70B, Gemini 1.5, and Mixtral 8x7b., Results: GPT-4-based ChatGPT and untrained doctors showed substantial agreement with the consensus triage of professional raters (κ=mean 0.67, SD 0.037 and κ=mean 0.68, SD 0.056, respectively), significantly exceeding the performance of GPT-3.5-based ChatGPT (κ=mean 0.54, SD 0.024; P<.001). When untrained doctors used this LLM for second-opinion triage, there was a slight but statistically insignificant performance increase (κ=mean 0.70, SD 0.047; P=.97). Other tested LLMs performed similar to or worse than GPT-4-based ChatGPT or showed odd triaging behavior with the used parameters. LLMs and ChatGPT models tended toward overtriage, whereas untrained doctors undertriaged., Conclusions: While LLMs and the LLM-based product ChatGPT do not yet match professionally trained raters, their best models' triage proficiency equals that of untrained ED doctors. In its current form, LLMs or ChatGPT thus did not demonstrate gold-standard performance in ED triage and, in the setting of this study, failed to significantly improve untrained doctors' triage when used as decision support. Notable performance enhancements in newer LLM versions over older ones hint at future improvements with further technological development and specific training., (©Lars Masanneck, Linea Schmidt, Antonia Seifert, Tristan Kölsche, Niklas Huntemann, Robin Jansen, Mohammed Mehsin, Michael Bernhard, Sven G Meuth, Lennert Böhm, Marc Pawlitzki. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 14.06.2024.)

Background: An out-of-hospital cardiac arrest (OHCA) with return of spontaneous circulation (ROSC) may need to be treated with airway management, emergency ventilation, invasive interventions, and post-arrest sedation. We investigated the influence of the use of midazolam for post-arrest sedation on achieving postresuscitation care targets and the associated risk of hemodynamic complications., Methods: All emergency rescue missions of the Dresden, Gütersloh, and Lippe medical rescue services in the years 2019-2021 were reviewed to identify adult patients who had OHCA, unconsciousness, and sustained ROSC with spontaneous circulation until arrival at the hospital; the findings were supplemented with data from the German Resuscitation Registry. Patients who received midazolam (alone or in combination with other anesthetic agents) for post-arrest sedation were compared with those who did not. The endpoints were the regaining of a systolic blood pressure ≥ 100 mmHg, end-tidal pCO2 35-45 mmHg, and oxygen saturation (SpO2) 94-98%. A propensity score analysis was used to adjust for age, sex, and variables potentially affecting hemodynamic status or the targets for oxygenation and ventilation., Results: There were 2335 cases of OHCA among 391 305 emer - gency rescue missions. 571 patients had ROSC before arrival in the hospital (24.5%; female, 33.6%; age, 68 ± 14 years). Of the 395 among them (69.2%) who were treated with postarrest sedation, 249 (63.0%) received midazolam. Patients who received midazolam reached the guideline- recommended targets for oxygenation, ventilation, and blood pressure more frequently than those who were not sedated: the respective odds ratios and 95% confidence intervals were 2.00 [1.20; 3.34], 1.57 [0.99; 2.48], and 1.41 [0.89; 2.21]., Conclusion: The pre-hospital administration of midazolam leads to more frequent pre-hospital attainment of the oxygenation and ventilation targets in post-resuscitation care, without any evidence of an elevated risk of hemodynamic complications.

Background: Mechanical ventilation in helicopter emergency medical service (HEMS) environments is a procedure which carries a significant risk of complications. Limited data on the quality and performance of mechanical ventilation in HEMS are available in the literature., Method: We conducted an international survey to evaluate mechanical ventilation infrastructure in HEMS and collect data of transported ventilated patients. From June 20-22, 2019, the participating HEMS bases were asked to provide data via a web-based platform. Vital parameters and ventilation settings of the patients at first patient contact and at handover were compared using non-parametric statistical tests., Results: Out of 215 invited HEMS bases, 53 responded. Respondents were from Germany, Denmark, United Kingdom, Luxembourg, Austria and Switzerland. Of the HEMS bases, all teams were physician staffed, mainly anesthesiologists (79%), the majority were board certified (92.5%) and trained in intensive care medicine (89%) and had a median (range) experience in HEMS of 9 (0-25) years. HEMS may provide a high level of expertise in mechanical ventilation whereas the majority of ventilators are able to provide pressure controlled ventilation and continuous positive airway pressure modes (77%). Data of 30 ventilated patients with a median (range) age of 54 (21-100) years and 53% male gender were analyzed. Of these, 24 were primary missions and 6 interfacility transports. At handover, oxygen saturation (p < 0.01) and positive end-expiratory pressure (p = 0.04) of the patients were significantly higher compared to first patient contact., Conclusion: In this survey, the management of ventilated HEMS-patients was not associated with ventilation related serious adverse events. Patient conditions, training of medical crew and different technical and environmental resources are likely to influence management. Further studies are necessary to assess safety and process quality of mechanical ventilation in HEMS., Trial Registration: The survey was prospectively registered at Research Registry ( researchregistry2925 ).

Background: Elevated blood lactate levels were reported as useful predictors of clinical outcome and mortality in critically ill patients. To identify higher-risk patients, this investigation evaluated the relationship between patient mortality and admission lactate levels during the management of non-trauma critically ill patients in the emergency department (ED)., Methods: In this prospective, single centre observational study in a German university ED, all adult patients who were admitted to the ED resuscitation room were evaluated between September 1, 2014 and August 31, 2015. Blood samples for blood gas analysis, including lactate levels, were obtained immediately at admission. Study endpoint was 30-day mortality., Results: During the study period, 532 patients were admitted to the resuscitation room of the ED. The data of 523 patients (98.3%) were available. The overall 30-day mortality was 34.2%. Patients presenting to the resuscitation room with admission lactate levels < 2.0 mmol/l had a 30-day mortality of 22.7%, while admission lactate levels above 8.0 mmol/l were associated with higher mortality (8.0-9.9 mmol/l: OR: 2.83, 95%CI: 1.13-7.11, p = 0.03, and ≥ 10 mmol/l: OR: 7.56, 95%CI: 4.18-13.77, p < 0.001)., Conclusion: High lactate levels at admission are associated with an increased 24-h and 30-day mortality. These measurements may be used not only to predict mortality, but to help identify patients at risk for becoming critically ill. The breakpoint for mortality may be an ALL ≥8.0 mmol/l.

Background: Emergency airway management (AM) is a major key for successful resuscitation of critically ill non-traumatic (CINT) patients. Details of the AM of these patients in German emergency departments (ED) are unknown. This observational study describes epidemiology, airway techniques, success rates and complications of AM in CINT ED patients in the resuscitation room (RR)., Methods: Data was collected prospectively on adult CINT patients admitted to the RR of a single German university ED September 2014 to August 2015. Patient characteristics, out-of-hospital and in-hospital RR AM, complications and success rates were recorded using a self-developed airway registry form., Results: During the study period 34,303 patients were admitted to the ED, out of those 21,074 patients for non-trauma emergencies. Suffering from severe acute life-threatening problems, 532 CINT patients were admitted to the RR. 150 (28.2%) CINT patients had received out-of-hospital AM. In 16 of these cases (10.7%) the inserted airway needed to be changed after RR admission (unrecognized oesophageal intubation: n = 2, laryngeal tube exchange: n = 14). 136 (25.6%) CINT patients without out-of-hospital AM received RR AM immediately after admission. The first-pass and overall success rate in the RR were 71 and 100%, respectively, and multiple intubation attempts were necessary in 29%. A lower Cormack/Lehane (C/L) grade was associated with less intubation attempts (C/L1/2 vs. 3/4: 1.2 ± 0.5 vs. 1.8 ± 1.2, p = 0.0002). Complication rate was 43%., Conclusions: OcEAN demonstrates the challenges of AM in CINT patients in a German ED RR. We propose a nation-wide ED airway registry to better track outcomes in the future.

Background: Management of critically ill non-trauma patients in the resuscitation room of an emergency department (ED) is very challenging, and it is difficult to identify patients with a higher risk of death. Previous studies have shown that lactate indices can predict survival for selected diseases and syndromes., Objective: As reported for other patient populations, we set out to determine whether admission lactate or lactate dynamics (LD) within 24 h can predict 30-day mortality in unselected critically ill non-traumatic patients., Methods: In this retrospective study over a 1-year period, admission lactate, time weighted average lactate (Lac TW ) and LD of all critically ill adult patients admitted from ED to intensive care unit were analyzed. A linear regression model was implemented to estimate lactate data 1 h after admission., Results: The admission lactate, Lac TW , and LD within 24 h were analyzed from 392 critically ill patients. The overall 30-day mortality rate was around 29%. Admission lactate (4.1 ± 4.0 mmol/L vs. 6.6 ± 6.1 mmol/L; p < 0.01) and Lac TW (1.8 ± 1.7 mmol/L vs. 4.1 ± 4.8 mmol/L; p < 0.01) were different between survivors and non-survivors. LD between survivors and non-survivors did not differ at 1 h, 6 h, 12 h, or 24 h. After excluding patients with out-of-hospital or in-hospital cardiac arrest during resuscitation room management, admission lactate and LD between survivors and non-survivors did not differ at 1 h, 12 h, and 24 h. LD at 6 h (44% ± 42% vs. 33% ± 58%; p = 0.042) and Lac TW (1.7 ± 1.6 mmol/L vs. 2.6 ± 3.0 mmol/L; p < 0.01) did differ., Conclusions: In critically ill ED patients initially requiring treatment in a resuscitation room setting, LD at 6 h and Lac TW may predict their survival beyond 30 days. These findings need to be confirmed in a prospective study design., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Successful management of emergency patients with multiple trauma in the hospital resuscitation room depends on the immediate diagnosis and rapid treatment of the most life-threatening injuries. In order to reduce the time spent in the resuscitation room, an in-hospital algorithm was developed in an interdisciplinary team approach with respect to local structures. The aim of the study was to analyse whether this algorithm affects the interval between hospital admission and the completion of diagnostic procedures and the start of life-saving interventions. Moreover, in-hospital mortality was investigated before and after the algorithm was introduced., Material and Methods: In this prospective study, all consecutive trauma patients in the resuscitation room were investigated before (group I, 01/04-10/04) and after (group II, 01/05-11/05) introduction of the algorithm. The times between hospital admission and the end of the diagnostic procedures (ultrasound [sono], chest X-ray [CF], and cranial computed tomography [CCT]), and between hospital admission and the start of life-saving interventions were registered and in-hospital mortality analysed., Results: In the study period, 170 patients in group I and 199 patients in group II were investigated. Injury severity score (ISS) were comparable between the two groups. The intervals between admission and completion of diagnostic procedures were significantly lower after the algorithm was introduced (mean+/-S.D.): sono (11 +/- 10 min versus 7 +/- 6 min, p < 0.05), CF (21 +/- 12 min versus 12 +/- 9 min, p < 0.01), and CCT (55 +/- 27 min versus 32 +/- 14 min, p < 0.01). Moreover, the interval to the start of life-saving interventions was significantly shorter (126 +/- 90 min versus 51 +/- 20 min, p < 0.01). After introducing the algorithm, in-hospital mortality was reduced significantly from 33.3% to 16.7% (p < 0.05) in the most severely injured patients (ISS>or=25)., Conclusion: The introduction of an algorithm for early management of emergency patients significantly reduced the time spent in the resuscitation room. The periods to completion of sono, CF, and CCT, respectively, and the start of life-saving interventions were significantly shorter after introduction of the algorithm. Moreover, introduction of the algorithm reduced mortality in the most severely injured patients. Although further investigations are needed to evaluate the effects of the Heidelberg treatment algorithm in terms of outcome and mortality, the time reduction in the resuscitation room seems to be beneficial.

Marine aggregates are densely colonized by bacteria, and inter-specific interactions such as inhibition are important for colonization by aggregate-associated bacteria and thus affect the turnover of organic matter in the sea. In order to study antagonistic activities we carried out inhibition tests with 51 isolates obtained exclusively from aggregates of the German Wadden Sea. 16S rRNA gene sequences of all isolates revealed that 35% of the isolates affiliated with the Flavobacteria/Sphingobacteria group, 24% and 16% with alpha- and gamma-Proteobacteria, respectively, 16% with the Bacillus/Clostridium group, and 10% with Actinobacteria. The relatively high percentage of Gram-positive bacteria may be related to specific features of the Wadden Sea environment. After 11 days of incubation using Burkholder agar diffusion assays the percentage of inhibitory isolates was 54.1% and this decreased to 20.7% after 20 days of incubation but it did not decline for members of the Bacillus/Clostridium group. Inhibitory activity was expressed in strain-specific patterns even though some isolates were closely related according to their 16S rRNA gene sequences. Antagonistic activity was lowest for Flavobacteria/Sphingobacteria (35%) and highest for Actinobacteria (80%). We further examined whether growth of isolates was affected when they were placed on lawns of certain other isolates. In parallel with lowest percentage of inhibitory isolates, highest growth occurred on lawns of the Flavobacteria/Sphingobacteria group whereas it was lowest on lawns of Actinobacteria and the Bacillus/Clostridium group. The high inhibitory activity of both groups of Gram-positive bacteria fits well with data from chemical screening using matrix-assisted laser desorption ionization time of flight mass spectrometry. Hence, inhibitory activity greatly influences inter-specific interactions and may impact microbial degradation and remineralization of particulate organic matter in aquatic environments.