scholarly journals Genomic investigation of a suspected outbreak of Legionella pneumophila ST82 reveals undetected heterogeneity by the present gold-standard methods, Denmark, July to November 2014

2017 ◽  
Vol 22 (25) ◽  
Author(s):  
Susanne Schjørring ◽  
Marc Stegger ◽  
Charlotte Kjelsø ◽  
Berit Lilje ◽  
Jette M Bangsborg ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Gold Standard ◽  
Phylogenetic Analyses ◽  
External Source ◽  
Sequence Type ◽  
The Other ◽  
Outbreak Investigations ◽  
Legionnaires Disease ◽  
The Uk ◽  
Suspected Outbreak

Between July and November 2014, 15 community-acquired cases of Legionnaires´ disease (LD), including four with Legionella pneumophila serogroup 1 sequence type (ST) 82, were diagnosed in Northern Zealand, Denmark. An outbreak was suspected. No ST82 isolates were found in environmental samples and no external source was established. Four putative-outbreak ST82 isolates were retrospectively subjected to whole genome sequencing (WGS) followed by phylogenetic analyses with epidemiologically unrelated ST82 sequences. The four putative-outbreak ST82 sequences fell into two clades, the two clades were separated by ca 1,700 single nt polymorphisms (SNP)s when recombination regions were included but only by 12 to 21 SNPs when these were removed. A single putative-outbreak ST82 isolate sequence segregated in the first clade. The other three clustered in the second clade, where all included sequences had < 5 SNP differences between them. Intriguingly, this clade also comprised epidemiologically unrelated isolate sequences from the UK and Denmark dating back as early as 2011. The study confirms that recombination plays a major role in L. pneumophila evolution. On the other hand, strains belonging to the same ST can have only few SNP differences despite being sampled over both large timespans and geographic distances. These are two important factors to consider in outbreak investigations.

scholarly journals Legionnaires' Disease - Results of a Multicenter Canadian Study

2003 ◽  
Vol 14 (3) ◽  
pp. 154-158 ◽  
Author(s):  
Thomas J Marrie ◽  
Emidio de Carolis ◽  
Victor L Yu ◽  
Janet Stout ◽  
Keyword(s):  
Legionella Pneumophila ◽  
Tertiary Care ◽  
Community Acquired Pneumonia ◽  
The Other ◽  
Urinary Antigen ◽  
Serum Samples ◽  
Eastern Canada ◽  
Legionnaires Disease ◽  
Canadian Provinces ◽  
A Prospective Study

BACKGROUND: There has never been a cross-Canada surveillance project to determine the rate ofLegionellaspecies as a cause of community-acquired pneumonia requiring hospitalization and to determine whether there are any regional differences in the rates of Legionnaires' disease in Canada. Anecdotally, Legionnaires' disease is thought to be uncommon in Western Canada.METHODS: From January, 1996 through to October 31, 1997, a prospective study of the etiology of community acquired pneumonia requiring admission to 15 tertiary care hospitals in eight Canadian provinces was conducted. A urine sample from each patient was tested forLegionella pneumophilaserogroup 1 antigen using a commercially available ELISA assay. A culture of sputum or other respiratory specimens for Legionellaceae was carried out at the discretion of the attending physician. Two hundred thirty-four patients had acute and 6-week convalescent serum samples tested for antibodies toL pneumophilaserogroups 1 through 6 using an ELISA method.RESULTS: 28 of the 850 patients (3.2%) had Legionnaires' disease; 18 of 823 (2.1%) were positive forL pneumophilaserogroup 1 by urinary antigen testing. The rate of Legionnaires' disease, based on urinary antigen, at the Halifax site was higher than that at the other sites (seven of 163 patients versus 11 of 660 [P=0.04]). Of the 28 cases of Legionnaires' disease identified using all methods, 11 of 277 patients (3.9%) were enrolled from Western provinces versus 17 of 573 patients (2.9%) from Eastern provinces (P=nonsignificant).CONCLUSIONS: Legionnaires' disease is just as common in Western as in Eastern Canada.L pneumophilaserogroup 1 may be more common in Halifax than at the other sites studied.

scholarly journals Results of intensified source finding efforts among community-acquired cases of Legionnaires’ disease – first results of the German LeTriWa study; Berlin, 2016−2019

2020 ◽  
Author(s):  
U. Buchholz ◽  
H. J. Jahn ◽  
B. Brodhun ◽  
A-S. Lehfeld ◽  
M. Lewandowsky ◽  
...  
Keyword(s):  
Drinking Water ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
External Source ◽  
District Health ◽  
Positive Strain ◽  
Household Water ◽  
Sources Of Infection ◽  
Legionnaires Disease ◽  
Infectious Source

AbstractIntroductionSources of infection of most cases of community-acquired Legionnaires’ disease (CALD) are unknown.ObjectiveIdentification of sources of infection of CALD.SettingBerlin; December 2016–May 2019.ParticipantsAdult cases of CALD reported to district health authorities and consenting to the study; age and hospital matched controls.Main outcome measurePercentage of cases of CALD with identified source of infection.MethodsAnalysis 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 contents of 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, residential drinking water (RDW) as source) using three evidence types (microbiological results, cluster evidence, analytical-comparative evidence (using added information from controls)).ResultsInclusion 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 (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, by cluster evidence if at least two cases were exposed to it and by analytical-comparative evidence if a case was exposed to it and the type of source was statistically significantly associated with being a case. We identified an infectious source in 53 (48 %) of 111 cases: in 16 (14 %) an external source, in 9 (8 %) a RnDW source, and in 28 (25 %) we attributed RDW. We attributed 9 cases to RnDW because cases were associated with wearing not regularly disinfected dentures (OR = 3.2, 95 % CI 1.3 to 7.8).ConclusionUsing 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.

scholarly journals Type I-F CRISPR-Cas distribution and array dynamics in Legionella pneumophila

2018 ◽  
Author(s):  
Shayna R. Deecker ◽  
Alexander W. Ensminger
Keyword(s):  
Nucleic Acid ◽  
Legionella Pneumophila ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Type I ◽  
Deletion Event ◽  
Crispr Array ◽  
Target Dna ◽  
Foreign Dna ◽  
Chromosomal Loci

AbstractIn bacteria and archaea, several distinct types of CRISPR-Cas systems provide adaptive immunity through broadly similar mechanisms: short nucleic acid sequences derived from foreign DNA, known as spacers, engage in complementary base pairing with invasive genetic elements setting the stage for nucleases to degrade the target DNA. A hallmark of type I CRISPR-Cas systems is their ability to acquire spacers in response to both new and previously encountered invaders (naïve and primed acquisition, respectively). Our phylogenetic analyses of 47 L. pneumophila type I-F CRISPR-Cas systems and their resident genomes suggest that many of these systems have been horizontally acquired. These systems are frequently encoded on plasmids and can co-occur with nearly identical chromosomal loci. We show that two such co-occurring systems are highly protective and undergo efficient primed acquisition in the lab. Furthermore, we observe that targeting by one system’s array can prime spacer acquisition in the other. Lastly, we provide experimental and genomic evidence for a model in which primed acquisition can efficiently replenish a depleted type I CRISPR array following a mass spacer deletion event.

scholarly journals 1649. That’s Not Cricket! Outbreak of Legionella pneumophila (L. pneumophila) in a Community Cricket Club in the UK, 2018: Challenges in Legionella Control in This Setting

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S603-S603
Author(s):  
Natalie Wright ◽  
Deborah Fenelon ◽  
Rachel Fleeson ◽  
Diane Coopey ◽  
Jeremy Hawker ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Disease Surveillance ◽  
Sputum Sample ◽  
Control Measures ◽  
Partial Result ◽  
Reference Laboratory ◽  
Disease Surveillance System ◽  
Increased Risk ◽  
Legionnaires Disease ◽  
The Uk

Abstract Background Cricket clubs in the UK are frequently collocated with community venues which host a range of activities, often for vulnerable members of society, such as children and elderly people. In July 2018, two cases of local laboratory-confirmed Legionnaires’ disease were notified to Public Health England (PHE). The cases were found to be players in the same cricket team (via the enhanced Legionnaires’ disease surveillance system) and had multiple shared potential exposures during their incubation periods. Methods A three-pronged outbreak investigation was conducted, with epidemiological, microbiological, and environmental components. Case-finding and potential shared exposures were identified through completion and analysis of Legionella enhanced surveillance questionnaires. Following risk assessment, environmental samples were obtained from aerosolizing outlets at identified sites. Additionally, sputum and urine samples were obtained from cases. All samples were sent to the PHE reference laboratory for confirmation of species and sequence typing. Results All cases were confirmed as L. pneumophila serogroup 1. Only one case provided a sputum sample suitable for sequence typing, which yielded a partial result. This result was consistent with a strain of L. pneumophila found in abundance at numerous water outlets at a local cricket club epidemiologically linked to all cases. On the emergence of these findings, control measures were put in place to prevent further exposure to the pathogen including shot-dosing of the water systems and closure of aerosolizing outlets. However, eradication of the organism proved challenging. Conclusion This is the first known outbreak of L. pneumophila epidemiologically and microbiologically linked to a cricket club in the UK. Control of the outbreak was challenging for two reasons. Firstly, the nature of the setting as a community venue meant that there was a large number of people potentially exposed, many with characteristics putting them at increased risk of Legionnaires’ disease. Secondly, the cricket club was run by a committee of volunteers with limited expertise and financial resource. There was a resultant lack of clarity about who was ultimately responsible for Legionella risk management and the implementation of control measures. Disclosures All authors: No reported disclosures.

scholarly journals Healthcare-associated Legionnaires’ disease: Limitations of surveillance definitions and importance of epidemiologic investigation

2017 ◽  
Vol 18 (6) ◽  
pp. 307-310 ◽  
Author(s):  
Laila M Castellino ◽  
Shantini D Gamage ◽  
Patti V Hoffman ◽  
Stephen M Kralovic ◽  
Mark Holodniy ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Sequence Type ◽  
Significant Morbidity ◽  
Urinary Antigen ◽  
Epidemiologic Investigation ◽  
Urinary Antigen Testing ◽  
Legionnaires Disease ◽  
Healthcare Associated ◽  
Antigen Testing

Healthcare-associated Legionnaires’ disease (HCA LD) causes significant morbidity and mortality, with varying guidance on prevention. We describe the evaluation of a case of possible HCA LD and note the pitfalls of relying solely on an epidemiologic definition for association of a case with a facility. Our detailed investigation led to the identification of a new Legionella pneumophila serogroup 1 sequence type, confirmed a healthcare association and helped build the framework for our ongoing preventive efforts. Our experience highlights the role of routine environmental cultures in the assessment of risk for a given facility. As clinicians increasingly rely on urinary antigen testing for the detection of L. pneumophila, our investigation emphasises the importance of clinical cultures in an epidemiologic investigation.

scholarly journals Type I-F CRISPR-Cas Distribution and Array Dynamics in Legionella pneumophila

2020 ◽  
Vol 10 (3) ◽  
pp. 1039-1050
Author(s):  
Shayna R. Deecker ◽  
Alexander W. Ensminger
Keyword(s):  
Nucleic Acid ◽  
Legionella Pneumophila ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Type I ◽  
Deletion Event ◽  
Crispr Array ◽  
Target Dna ◽  
Foreign Dna ◽  
Chromosomal Loci

In bacteria and archaea, several distinct types of CRISPR-Cas systems provide adaptive immunity through broadly similar mechanisms: short nucleic acid sequences derived from foreign DNA, known as spacers, engage in complementary base pairing with invasive genetic elements setting the stage for nucleases to degrade the target DNA. A hallmark of type I CRISPR-Cas systems is their ability to acquire spacers in response to both new and previously encountered invaders (naïve and primed acquisition, respectively). Our phylogenetic analyses of 43 L. pneumophila type I-F CRISPR-Cas systems and their resident genomes suggest that many of these systems have been horizontally acquired. These systems are frequently encoded on plasmids and can co-occur with nearly identical chromosomal loci. We show that two such co-occurring systems are highly protective and undergo efficient primed acquisition in the lab. Furthermore, we observe that targeting by one system’s array can prime spacer acquisition in the other. Lastly, we provide experimental and genomic evidence for a model in which primed acquisition can efficiently replenish a depleted type I CRISPR array following a mass spacer deletion event.

scholarly journals Acute Pneumonia Caused by Clinically Isolated Legionella pneumophila Sg 1, ST 62: Host Responses and Pathologies in Mice

2022 ◽  
Vol 10 (1) ◽  
pp. 179
Author(s):  
Jiří Trousil ◽  
Lucia Frgelecová ◽  
Pavla Kubíčková ◽  
Kristína Řeháková ◽  
Vladimír Drašar ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Lung Infection ◽  
Severe Form ◽  
Host Immunity ◽  
Sequence Type ◽  
Host Responses ◽  
Lung Pathology ◽  
Bacterial Clearance ◽  
Acute Pneumonia ◽  
Legionnaires Disease

Legionnaires’ disease is a severe form of lung infection caused by bacteria belonging to the genus Legionella. The disease severity depends on both host immunity and L. pneumophila virulence. The objective of this study was to describe the pathological spectrum of acute pneumonia caused by a virulent clinical isolate of L. pneumophila serogroup 1, sequence type 62. In A/JOlaHsd mice, we compared two infectious doses, namely, 104 and 106 CFU, and their impact on the mouse status, bacterial clearance, lung pathology, and blood count parameters was studied. Acute pneumonia resembling Legionnaires’ disease has been described in detail.

scholarly journals The Impact of Storms on Legionella pneumophila in Cooling Tower Water, Implications for Human Health

2020 ◽  
Vol 11 ◽  
Author(s):  
Robin L. Brigmon ◽  
Charles E. Turick ◽  
Anna S. Knox ◽  
Courtney E. Burckhalter
Keyword(s):  
Human Health ◽  
Legionella Pneumophila ◽  
Count Data ◽  
Distribution Systems ◽  
Cooling Tower ◽  
Water Systems ◽  
The Other ◽  
Cooling Towers ◽  
Legionnaires Disease ◽  
The Impact

At the U.S. Department of Energy’s Savannah River Site (SRS) in Aiken, SC, cooling tower water is routinely monitored for Legionella pneumophila concentrations using a direct fluorescent antibody (DFA) technique. Historically, 25–30 operating SRS cooling towers have varying concentrations of Legionella in all seasons of the year, with patterns that are unpredictable. Legionellosis, or Legionnaires’ disease (LD), is a pneumonia caused by Legionella bacteria that thrive both in man-made water distribution systems and natural surface waters including lakes, streams, and wet soil. Legionnaires’ disease is typically contracted by inhaling L. pneumophila, most often in aerosolized mists that contain the bacteria. At the SRS, L. pneumophila is typically found in cooling towers ranging from non-detectable up to 108 cells/L in cooling tower water systems. Extreme weather conditions contributed to elevations in L. pneumophila to 107–108 cells/L in SRS cooling tower water systems in July–August 2017. L. pneumophila concentrations in Cooling Tower 785-A/2A located in SRS A-Area, stayed in the 108 cells/L range despite biocide addition. During this time, other SRS cooling towers did not demonstrate this L. pneumophila increase. No significant difference was observed in the mean L. pneumophila mean concentrations for the towers (p &lt; 0.05). There was a significant variance observed in the 285-2A/A Tower L. pneumophila results (p &lt; 0.05). Looking to see if we could find “effects” led to model development by analyzing 13 months of water chemistry and microbial data for the main factors influencing the L. pneumophila concentrations in five cooling towers for this year. It indicated chlorine and dissolved oxygen had a significant impact (p &lt; 0.0002) on cooling tower 785A/2A. Thus, while the variation in the log count data for the A-area tower is statistically greater than that of the other four towers, the average of the log count data for the A-Area tower was in line with that of the other towers. It was also observed that the location of 785A/2A and basin resulted in more debris entering the system during storm events. Our results suggest that future analyses should evaluate the impact of environmental conditions and cooling tower design on L. pneumophila water concentrations and human health.

scholarly journals A supervised statistical learning approach for accurateLegionella pneumophilasource attribution during outbreaks

2017 ◽  
Author(s):  
Andrew H. Buultjens ◽  
Kyra Y. L. Chua ◽  
Sarah L. Baines ◽  
Jason Kwong ◽  
Wei Gao ◽  
...  
Keyword(s):  
Statistical Learning ◽  
Legionella Pneumophila ◽  
Core Genome ◽  
Cooling Tower ◽  
Sequence Data ◽  
Disease Outbreaks ◽  
Epidemiological Data ◽  
Learning Approach ◽  
Outbreak Investigations ◽  
Legionnaires Disease

AbstractPublic health agencies are increasingly relying on genomics during Legionnaires’ disease investigations. However, the causative bacterium (Legionella pneumophila) has an unusual population structure with extreme temporal and spatial genome sequence conservation. Furthermore, Legionnaires’ disease outbreaks can be caused by multipleL. pneumophilagenotypes in a single source. These factors can confound cluster identification using standard phylogenomic methods. Here, we show that a statistical learning approach based onL. pneumophilacore genome single nucleotide polymorphism (SNP) comparisons eliminates ambiguity for defining outbreak clusters and accurately predicts exposure sources for clinical cases. We illustrate the performance of our method by genome comparisons of 234L. pneumophilaisolates obtained from patients and cooling towers in Melbourne, Australia between 1994 and 2014. This collection included one of the largest reported Legionnaires’ disease outbreaks, involving 125 cases at an aquarium. Using only sequence data fromL. pneumophilacooling tower isolates and including all core genome variation, we built a multivariate model using discriminant analysis of principal components (DAPC) to find cooling tower-specific genomic signatures, and then used it to predict the origin of clinical isolates. Model assignments were 93% congruent with epidemiological data, including the aquarium Legionnaires’ outbreak and three other unrelated outbreak investigations. We applied the same approach to a recently described investigation of Legionnaires’ disease within a UK hospital and observed model predictive ability of 86%. We have developed a promising means to breachL. pneumophilagenetic diversity extremes and provide objective source attribution data for outbreak investigations.

Epidemiological investigation of a Legionnaires' disease outbreak in Christchurch, New Zealand: the value of spatial methods for practical public health

2012 ◽  
Vol 141 (4) ◽  
pp. 789-799 ◽  
Author(s):  
P. S. WHITE ◽  
F. F. GRAHAM ◽  
D. J. G. HARTE ◽  
M. G. BAKER ◽  
C. D. AMBROSE ◽  
...  
Keyword(s):  
New Zealand ◽  
Legionella Pneumophila ◽  
Dispersal Distance ◽  
Epidemiological Investigation ◽  
Disease Epidemiology ◽  
Infectious Disease Epidemiology ◽  
Outbreak Investigations ◽  
Legionnaires Disease ◽  
Aerosol Dispersion ◽  
Geographical Association

SUMMARYBetween April and August 2005 Christchurch, New Zealand experienced an outbreak of Legionnaires' disease. There were 19 laboratory-confirmed case including three deaths.Legionella pneumophilaserogroup 1 (Lpsg1) was identified as the causative agent for all cases. A case-control study indicated a geographical association between the cases but no specific common exposures. Rapid spatial epidemiological investigation confirmed the association and identified seven spatially significant case clusters. The clusters were all sourced in the same area and exhibited a clear anisotropic process (noticeable direction) revealing a plume effect consistent with aerosol dispersion from a prevailing southwesterly wind. Four out of five cases tested had indistinguishable allele profiles that also matched environmental isolates from a water cooling tower within the centre of the clusters. This tower was considered the most probable source for these clusters. The conclusion would suggest a maximum dispersal distance in this outbreak of 11·6 km. This work illustrated the value of geostatistical techniques for infectious disease epidemiology and for providing timely information during outbreak investigations.

Sign in / Sign up

Export Citation Format

Share Document