Christian Lück

Bio: Christian Lück is an academic researcher from Dresden University of Technology. The author has contributed to research in topics: Legionella pneumophila & Legionella. The author has an hindex of 20, co-authored 65 publications receiving 1154 citations.

Community-Acquired Legionella Pneumonia: New Insights from the German Competence Network for Community Acquired Pneumonia

Abstract: Background The Competence Network for Community Acquired Pneumonia (CAPNETZ) offers a unique opportunity to study the epidemiology of legionellosis throughout Germany, applying sophisticated diagnostic tools. Methods The incidence, clinical characteristics, and outcome of Legionella pneumonia in 2503 adult patients with community-acquired pneumonia, participating in the German Multicenter Study of the CAPNETZ, were studied. Results Legionella pneumonia was diagnosed in 94 patients (3.8%), thus identifying Legionella species as one of the most common pathogens to cause community-acquired pneumonia. It was equally common among ambulatory and hospitalized patients (3.7% and 3.8%, respectively). The predominant species causing community-acquired pneumonia was Legionella pneumophila; however, 10% of cases were caused by other species not detectable by the urinary antigen test. Patients whose disease was diagnosed by urinary antigen testing experienced a more severe clinical course. Compared with hospitalized patients, ambulatory patients with Legionella pneumonia showed an equal sex distribution, were younger, had fewer comorbidities, fewer cases of discordant initial antimicrobial treatment, and a milder clinical course without fatalities. Thirty percent of patients with Legionella pneumonia received discordant initial antimicrobial treatment without increased mortality. Conclusions Legionella is a leading cause of community-acquired pneumonia in Germany. It needs to be considered equally in hospitalized and ambulatory patients. A positive result of a urine antigen test is associated with a more severe clinical course and leads to a potentially relevant underrecognition of species other than L. pneumophila. Legionella pneumonia in outpatients differs significantly from that in hospitalized patients in terms of clinical presentation and outcome. There was an unacceptably high rate of discordant initial antimicrobial treatment.

Mycoplasma pneumoniae pneumonia revisited within the German Competence Network for Community-acquired pneumonia (CAPNETZ).

Abstract: Currently, broad empiric antimicrobial treatment including atypical coverage is recommended for patients with mild to moderate community-acquired pneumonia (CAP). Therefore, the relative impact of each atypical pathogen, particularly Mycoplasma pneumoniae deserves renewed attention. Based on prospective data from 4532 patients with CAP included in the German CAP-Competence Network (CAPNETZ), we studied the incidence, clinical characteristics, and outcome of patients with Mycoplasma pneumoniae pneumonia (MPP). The diagnosis of MPP was based on a positive PCR from respiratory samples and/or a positive IgM-titer from an acute phase serum sample. 307 patients (6.8%) had definite MPP (148 with positive PCR, 204 with positive IgM, 46 with positive PCR and IgM). Compared to patients with other definite and unknown etiologies, patients with MPP were significantly younger (41 ± 16 versus 62 ± 17 and 61 ± 18 years), had fewer co-morbidities, presented with a less severe disease, showed a lower inflammatory response in terms of leukocyte counts (median 8850 versus 13200 and 11000 μL) and CRP values (60 versus 173 and 73 mg/L), and had better outcomes, including a shorter length of hospitalization (9 ± 5 versus 14 ± 11 and 12 ± 9 days), fewer patients requiring mechanical ventilation (0.3 versus 4.5 and 2.1%), and a minimal mortality (0.7 versus 8.7 and 6.5%). In this large series of patients with definite MPP according to very strict criteria, MPP appears as a condition with a high incidence, quite specific clinical presentation, and a largely benign course. In view of a widely favorable clinical outcome, recent recommendations including regular coverage of atypical pathogens in patients with mild to moderate CAP might be reconsidered for patients in Germany as well as in other countries with comparable epidemiological settings.

Sensitive Detection of Mycoplasma pneumoniae in Human Respiratory Tract Samples by Optimized Real-Time PCR Approach

Abstract: To enhance the sensitivity of the available real-time PCR systems for the detection of Mycoplasma pneumoniae, we established a method to amplify copies of the repetitive element repMp1. In a study of respiratory tract samples, we found that, compared to the use of the conserved part of the P1 adhesin gene as a monocopy target, the use of the repMp1-PCR showed an increase in the detected genome equivalents by a factor of 22.

Design and application of a core genome multilocus sequence typing scheme for investigation of Legionnaires' disease incidents

Abstract: Sequence-based typing (SBT) for Legionella pneumophila (Lp) has dramatically improved Legionnaires’ disease (LD) cluster investigation. Microbial whole genome sequencing (WGS) is a promising modality for investigation but sequence analysis methods are neither standardised, nor agreed. We sought to develop a WGS-based typing scheme for Lp using de novo assembly and a genome-wide gene-by-gene approach (core genome multilocus sequence typing, cgMLST). We analysed 17 publicly available Lp genomes covering the whole species variation to define a core genome (1,521 gene targets) which was validated using 21 additional published genomes. The genomes of 12 Lp strains implicated in three independent cases of paediatric humidifier-associated LD were subject to cgMLST together with three 'outgroup' strains. cgMLST was able to resolve clustered strains and clearly identify related and unrelated strains. Thus, a cgMLST scheme was readily achievable and provided high-resolution analysis of Lp strains. cgMLST appears to have satisfactory discriminatory power for LD cluster analysis and is advantageous over mapping followed by single nucleotide polymorphism (SNP) calling as it is portable and easier to standardise. cgMLST thus has the potential for becoming a gold standard tool for LD investigation. Humidifiers pose an ongoing risk as vehicles for LD and should be considered in cluster investigation and control efforts.

Regrowth of Legionella pneumophila in a heat-disinfected plumbing system

Abstract: We examined the factors involved in the occurrence of Legionellaceae in a hospital water system and the recontamination by Legionella pneumophila after a thermal disinfection procedure was studied. Three months after the heat treatment (70 degrees C), the regrowth of the two prevalent Legionella strains (L. pneumophila serogroup 1 [Oxford-like] and L. pneumophila serogroup 2) reached the original level of cell numbers. Genomic analysis (pulsed-field gel electrophoresis) revealed the strains to be survivors of the decontamination. Temperature tolerance experiments showed that the serogroup 1 strain exhibited a higher tolerance to 60 degrees C than the serogroup 2 strain, which could account for the order of reappearance of the strains after the heat treatment. Potential host amoebae, including Acanthamoeba spp. and Vahlkampfia spp., which are known to play a critical role in the amplification process of Legionella, were isolated from the plumbing system. In-vitro studies demonstrated both Legionella strains for a similar rate of multiplication in A. castellanii. In competitive coinfections, however, the serogroup 1 strain achieved a higher rate of multiplication if compared with the serogroup 2 strain.

Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 1: Definitions, Diagnosis, Extra-intestinal Manifestations, Pregnancy, Cancer Surveillance, Surgery, and Ileo-anal Pouch Disorders.

Abstract: aDepartment of Pharmacology and Therapeutics, University of Porto; MedInUP, Centre for Drug Discovery and Innovative Medicines; Centro Hospitalar São João, Porto, Portugal bIBD Unit, DIMEC, University of Bologna, Bologna, Italy cDepartment of Gastroenterology and Hepatology, Chaim Sheba Medical Center, Tel Hashomer, Israel dGastrointestinal Unit ASST Fatebenefratelli Sacco—University of Milan—Milan, Italy eIBD Unit Complesso Integrato Columbus, Gastroenterological and Endocrino-Metabolical Sciences Department, Fondazione Policlinico Universitario Gemelli Universita’ Cattolica del Sacro Cuore, Rome, Italy fDepartment of Gastroenterology, IBD Unit, University Hospital Santiago De Compostela (CHUS), A Coruña, Spain gDepartment of Gastroenterology, North Zealand University Hospital, Frederikssund, Denmark hFirst Department of Medicine, Semmelweis University, Budapest, Hungary iIBD Unit, St Mark’s Hospital, Middlesex, UK jDepartment of Gastroenterology, University Hospital of Ghent, Ghent, Belgium kInstitute of Pathology, Medical University of Graz, Graz, Austria lDepartment of Gastroenterology, Pennine Acute Hospitals NHS Trust; Institute of Inflammation and Repair, University of Manchester, Manchester, UK mUnit of General Surgery, Second University of Naples, Napoli, Italy nMaria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology, Department of Oncological Gastroenterology Warsaw; Medical Centre for Postgraduate Education, Department of Gastroenterology, Hepatology and Clinical Oncology, Warsaw, Poland oDepartment of Medicine, University of Cambridge, Cambridge, UK pImperial College London; Chelsea and Westminster Hospital, London, UK qDepartment of Pathobiology /NC22, Lerner Research Institute; Department of Gastroenterology, Hepatology and Nutrition/A3, Digestive Disease and Surgery Institute, Cleveland Clinic Foundation, Cleveland, OH, USA

Acanthamoeba spp. as agents of disease in humans.

Abstract: Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease.

Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications.

Abstract: Determine age-specific infection fatality rates for COVID-19 to inform public health policies and communications that help protect vulnerable age groups. Studies of COVID-19 prevalence were collected by conducting an online search of published articles, preprints, and government reports that were publicly disseminated prior to 18 September 2020. The systematic review encompassed 113 studies, of which 27 studies (covering 34 geographical locations) satisfied the inclusion criteria and were included in the meta-analysis. Age-specific IFRs were computed using the prevalence data in conjunction with reported fatalities 4 weeks after the midpoint date of the study, reflecting typical lags in fatalities and reporting. Meta-regression procedures in Stata were used to analyze the infection fatality rate (IFR) by age. Our analysis finds a exponential relationship between age and IFR for COVID-19. The estimated age-specific IFR is very low for children and younger adults (e.g., 0.002% at age 10 and 0.01% at age 25) but increases progressively to 0.4% at age 55, 1.4% at age 65, 4.6% at age 75, and 15% at age 85. Moreover, our results indicate that about 90% of the variation in population IFR across geographical locations reflects differences in the age composition of the population and the extent to which relatively vulnerable age groups were exposed to the virus. These results indicate that COVID-19 is hazardous not only for the elderly but also for middle-aged adults, for whom the infection fatality rate is two orders of magnitude greater than the annualized risk of a fatal automobile accident and far more dangerous than seasonal influenza. Moreover, the overall IFR for COVID-19 should not be viewed as a fixed parameter but as intrinsically linked to the age-specific pattern of infections. Consequently, public health measures to mitigate infections in older adults could substantially decrease total deaths.

Survey of the year 2003 commercial optical biosensor literature

Abstract: In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.