Johannes Boyer

Dr. Johannes Boyer


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
18 October 2022 in Transplant Infectious Disease
Verified
Journal Article
Open access
LKLisa Kriegl
Lisa Kriegl
JBJohannes Boyer
Johannes Boyer
MEMatthias Egger
Matthias Egger
MHMartin Hoenigl
Martin Hoenigl
Background: Antifungal stewardship (AFS) has emerged as an important component of quality in managing invasive fungal infections (IFIs), and cost‐benefit calculations suggest regular training in AFS is well worth the effort.Methods: This review will discuss the most common IFIs in solid organ transplantation (SOT)‐recipients, how to diagnose them, and current recommendations for antifungal treatment and prophylaxis before demonstrating key takeaway points of AFS in this high‐risk population.Results: Effective AFS starts before a patient is admitted for SOT, through education and regular interactions of the interdisciplinary clinical team involved in patient management, considering local factors such as epidemiological data and knowledge of diagnostic options including local turnaround times. Understanding the spectrum of antifungal agents, their efficacy and safety profiles, and pharmacokinetics, as well as duration of therapy is hereby essential.The most frequent IFIs in SOT recipients are caused by Candida species, followed by Aspergillus species, both with increasing resistance rates. Diagnosis of IFI can be challenging due to unspecific clinical presentation and difficult interpretation of microbiological findings and biomarkers. Prophylactic strategies, such as those for invasive aspergillosis in lung transplantation or invasive candidiasis (IC) in certain liver transplant settings, as well as the selection of the appropriate therapeutic agents require detailed knowledge on the pharmacokinetics and drug–drug interactions of antifungals.Conclusions: Here in this review, we address what constitutes good AFS in this heterogeneous field of solid organ transplant recipients.

1 April 2023 in Infection and Drug Resistance
Verified
Journal Article
Open access
PDF file
MEMatthias Egger
Matthias Egger
RBRomuald Bellmann
Romuald Bellmann
Robert KrauseRobert Krause
Robert Krause
JBJohannes Boyer
Johannes Boyer
Daniela JakšićDaniela Jakšić
Daniela Jakšić
MHMartin Hoenigl
Martin Hoenigl
Invasive mold diseases are devastating systemic infections which demand meticulous care in selection, dosing, and therapy monitoring of antifungal drugs. Various circumstances regarding PK/PD properties of the applied drug, resistance/tolerance of the causative pathogen or host intolerability can lead to failure of the initial antifungal therapy. This necessitates treatment adaption in the sense of switching antifungal drug class or potentially adding another drug for a combination therapy approach. In the current state of drastically limited options of antifungal drug classes adaption of therapy remains challenging. Current guidelines provide restricted recommendations only and emphasize individual approaches. However, novel antifungals, incorporating innovative mechanisms of action, show promising results in late stage clinical development. These will expand options for salvage therapy in the future potentially as monotherapy or in combination with conventional or other novel antifungals. We outline current recommendations for salvage therapy including PK/PD considerations as well as elucidate possible future treatment options for invasive aspergillosis and mucormycosis.

14 December 2021 in Frontiers in Digital Health
Verified
Journal Article
Open access
JBJohannes Boyer
Johannes Boyer
JEJakob Eckmann
Jakob Eckmann
KSKarl Strohmayer
Karl Strohmayer
WKWerner Koele
Werner Koele
MFMoritz Federspiel
Moritz Federspiel
RKRobert Krause
Robert Krause
Since the human body reacts to a variety of different diseases with elevated body temperature, measurement of body temperature remains relevant in clinical practice. The absolute temperature value for fever definition is still arbitrary and depends on the measuring site, as well as underlying disease and individual factors. Hence, a simple threshold for fever definition is outdated and a definition which relies on the relative changes in the individual seems reasonable as it takes these individual factors into account. In this prospective multicentric study we validate an adhesive axillary thermometer (SteadyTemp®) which allows continuous non-invasive temperature measurements. It consists of a patch to measure temperature and a smartphone application to process and visualize gathered data. This article provides information of the new diagnostic possibilities when using this wearable device and where it could be beneficial. Furthermore, it discusses how to interpret the generated data and when it is not practical to use, based on its characteristics and physiological phenomena.

5 June 2023 in Vaccines
Verified
Journal Article
Open access
PDF file
JBJohannes Boyer
Johannes Boyer
EKElisabeth König
Elisabeth König
HFHerwig Friedl
Herwig Friedl
CPChristian Pux
Christian Pux
MUMichael Uhlmann
Michael Uhlmann
ZSZollner Schwetz
Zollner Schwetz
Residents of long-term care facilities (LTCFs) are particularly at risk for influenza infections. We aimed to improve influenza vaccination coverage among residents and healthcare workers (HCWs) in four LTCFs by implementing educational programs and enhanced vaccination services. We compared vaccination coverage before and after the interventions (2017/18 and 2018/19 seasons). Data on vaccination adherence were recorded during a four-year observational period (2019/20 to 2022/23 seasons). Following the interventions, vaccination coverage increased significantly from 5.8% (22/377) to 19.1% (71/371) in residents and from 1.3% (3/234) to 19.7% (46/233) in HCWs (p < 0.001). During the observational period (2019/20 to 2022/23 seasons), vaccination coverage remained high in residents but decreased in HCWs. Vaccination adherence was significantly higher in residents and HCWs in LTCF 1 compared to the other three LTCFs. Our study suggests that a bundle of educational interventions and enhanced vaccination services can be an effective method for improving influenza vaccination coverage in LTCFs in both residents and HCWs. However, vaccination rates are still well below the recommended targets and further efforts are needed to increase vaccine coverage in our LTCFs.

6 June 2020 in Journal Of Hypertension
Verified
Journal Article
Closed access
FSFalko Skrabal
Falko Skrabal
TWThomas Weber
Thomas Weber
KSKatharina Skrabal
Katharina Skrabal
JWJana Windhaber
Jana Windhaber
HEHasibullah Ehsas
Hasibullah Ehsas
JBJohannes Boyer
Johannes Boyer
Objective: Measurements of pulse wave velocity are generally thought to be too impractical for clinical routine. This study aimed to develop a method that can be performed during routine 12-channel ECG. Methods: A 12-channel ECG simultaneously supplies arterial impedance plethysmographic signals from the extremities beside segmental multifrequency impedance measurements for obtaining body composition. The origin of the plethysmographic signal (volume wave) at the arms and legs was determined at the level of the elbows and the knees. The volume wave velocity (VWV) at the aorta and femoral arteries was calculated from the time difference of the plethysmographic signals between arms and legs. Results: Automated measurement of VWV was highly reproducible (r = 0.96). In 107 participants in perfect health, VWV in different models was positively related to age, physiological hemoglobin A 1C, triglycerides, normal standardized unattended blood pressure, but not to physiological low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol. Aortofemoral VWV was significantly higher in patients with established coronary artery disease than in healthy controls of the same age group (18.1 ± 5.8 vs. 11.9 ± 1.7 m/s, P < 0.001). VWV in study participants was higher than tonometrically determined pulse wave velocity as muscular arteries are included (13.2 ± 5.81 vs. 8.8 ± 2.98 m/s, n = 115, P < 0.001). Conclusion: These background arterial impedance plethysmographic measurements for the measurement of VWV made simultaneously during 12-channel ECG show promise for large-scale, routine clinical assessment of large artery function.

5 October 2023 in Clinical Microbiology and Infection
Verified
Journal Article
Closed access
JBJohannes Boyer
Johannes Boyer
LKLisa Kriegl
Lisa Kriegl
TVThomas Valentin
Thomas Valentin
RKRobert Krause
Robert Krause