Source attribution of community-acquired cases of Legionnaires’ disease–results from the German LeTriWa study; Berlin, 2016–2019
Open Access
- 25 November 2020
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 15 (11), e0241724
- https://doi.org/10.1371/journal.pone.0241724
Abstract
Sources of infection of most cases of community-acquired Legionnaires’ disease (CALD) are unknown. Identification of sources of infection of CALD. Berlin; December 2016–May 2019. Adult cases of CALD reported to district health authorities and consenting to the study; age and hospital matched controls. Percentage of cases of CALD with attributed source of infection. Analysis of secondary patient samples for monoclonal antibody (MAb) type (and sequence type); questionnaire-based interviews, analysis of standard household water samples for Legionella concentration followed by MAb (and sequence) typing of Legionella pneumophila serogroup 1 (Lp1) isolates; among cases taking of additional water samples to identify the infectious source as appropriate; recruitment of control persons for comparison of exposure history and Legionella in standard household water samples. For each case an appraisal matrix was filled in to attribute any of three source types (external (non-residence) source, residential non-drinking water (RnDW) source (not directly from drinking water outlet), residential drinking water (RDW) as source) using three evidence types (microbiological results, cluster evidence, analytical-comparative evidence (using added information from controls)). Inclusion of 111 study cases and 202 controls. Median age of cases was 67 years (range 25–93 years), 74 (67%) were male. Among 65 patients with urine typable for MAb type we found a MAb 3/1-positive strain in all of them. Compared to controls being a case was not associated with a higher Legionella concentration in standard household water samples, however, the presence of a MAb 3/1-positive strain was significantly associated (odds ratio (OR) = 4.9, 95% confidence interval (CI) 1.7 to 11). Thus, a source was attributed by microbiological evidence if it contained a MAb 3/1-positive strain. A source was attributed by cluster evidence if at least two cases were exposed to the same source. Statistically significant general source types were attributed by calculating the population attributable risk (analytical-comparative evidence). We identified an external source in 16 (14%) cases, and RDW as source in 28 (25%). Wearing inadequately disinfected dentures was the only RnDW source significantly associated with cases (OR = 3.2, 95% CI 1.3 to 7.8) and led to an additional 8% of cases with source attribution, for a total of 48% of cases attributed. Using the appraisal matrix we attributed almost half of all cases of CALD to an infectious source, predominantly RDW. Risk for LD seems to be conferred primarily by the type of Legionella rather than the amount. Dentures as a new infectious source needs further, in particular, integrated microbiological, molecular and epidemiological confirmation.Funding Information
- Bundesministerium für Gesundheit
This publication has 22 references indexed in Scilit:
- Legionella pneumophila urinary antigen subtyping using monoclonal antibodies as a tool for epidemiological investigationsEuropean Journal of Clinical Microbiology & Infectious Diseases, 2011
- Wet cooling systems as a source of sporadic Legionnaires' disease: a geographical analysis of data for England and Wales, 1996–2006Journal of Epidemiology and Community Health, 2011
- Progress in the surveillance and control of Legionella infection in France, 1998–2008International Journal of Infectious Diseases, 2011
- Distribution of Legionella pneumophila serogroups, monoclonal antibody subgroups and DNA sequence types in recent clinical and environmental isolates from England and Wales (2000–2008)European Journal of Clinical Microbiology & Infectious Diseases, 2009
- Occurrence and distribution of sequence types among Legionella pneumophila strains isolated from patients in Germany: common features and differences to other regions of the worldEuropean Journal of Clinical Microbiology & Infectious Diseases, 2007
- Outbreak detection and secondary prevention of Legionnaires’ disease: A national approachInternational Journal of Hygiene and Environmental Health, 2007
- Legionnaires' disease outbreak associated with a cruise liner, August 2003: epidemiological and microbiological findingsEpidemiology and Infection, 2006
- Consensus Sequence-Based Scheme for Epidemiological Typing of Clinical and Environmental Isolates ofLegionella pneumophilaJournal of Clinical Microbiology, 2005
- Clinical Utility of Urinary Antigen Detection for Diagnosis of Community-Acquired, Travel-Associated, and Nosocomial Legionnaires' DiseaseJournal of Clinical Microbiology, 2003
- Association of Shower Use With Legionnaires' DiseaseJAMA, 1990