Showing posts with label method. Show all posts
Showing posts with label method. Show all posts
Monday, August 29, 2016
Confirming Legionnaires’ Disease Outbreak by Genome Based Method Germany 2012 Volume 22 Number 7—July 2016 Emerging Infectious Disease journal CDC
Confirming Legionnaires’ Disease Outbreak by Genome Based Method Germany 2012 Volume 22 Number 7—July 2016 Emerging Infectious Disease journal CDC
Confirming Legionnaires’ Disease Outbreak by Genome-Based Method, Germany, 2012 - Volume 22, Number 7—July 2016 - Emerging Infectious Disease journal - CDC
Volume 22, Number 7—July 2016
Letter
Confirming Legionnaires’ Disease Outbreak by Genome-Based Method, Germany, 2012
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- Letter
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To the Editor: We report an outbreak of Legionnaires’ disease in southwestern Germany. On July 31, 2012, the State Health Agency of Rhineland-Palatinate was informed by the local health department of the city of Zweibrücken that 10 patients tested positive for Legionella pneumophila, the bacterium that causes Legionnaires’ disease. The onset of disease for all case-patients was from June 26 through July 25, which exceeded the yearly average of 1–4 patients a month. By August 23, we had received notifications of 19 patients with pneumonia and notification of 1 patient who did not exhibit pneumonia. We set 3 parameters for reporting a patient as a Legionnaires’ disease case-patient. First, the patient had to either live in or have been visiting the city of Zweibrücken in June 2012 before onset of disease. Second, the respiratory samples from the patient had to contain L. pneumophila or the results of patient’s serogroup 1 urinary antigen test had to be positive for the bacterium (1). Finally, clinical or radiologic confirmation of the disease was required. Of 20 patients who fit the case definition, 14 were male and 6 were female. Nine smoked and 2 were immunocompromised; none died.
All case-patients were positive for L. pneumophila serogroup 1 urinary antigen. From clinical samples of 2 patients, legionellae were cultured, and the infecting strain was confirmed as L. pneumophila serogroup 1, monoclonal subgroup Allentown-France, sequence type (ST) 82 (2,3). Currently, 118 strains of this ST are found in the European database for sequence-based typing of L. pneumophila (2). Most ST82 strains were isolated from clinical samples; thus, this ST appears more likely than other strains to infect humans. Further, 3 respiratory samples from case-patients were positive in a PCR for L. pneumophila serogroup 1 (4) but were negative by culture. These samples were investigated with the nested sequence-based typing protocol, which allows typing data to be obtained directly from clinical samples (2). Of the 3 samples, 2 were confirmed as ST82.
The local health authority did not initially identify likely sources of transmission such as cooling towers, public spas, or warm water supply systems in the vicinity of the patients (5). Environmental samples were taken from the homes of 15 of the 20 patients; all samples tested negative for Legionella (6).
Figure. Geographic distribution of cooling tower and home and work addresses (n = 23) of patients; 1 patient may be represented twice with home and work address, because place of infection is...
To find the source of the outbreak, we plotted 20 home and 7 work addresses of patients using Quantum-GIS software (7) and found that 18 addresses were within a 2-km radius of each other, including 2 patients who had limited mobility and had not left their homes during their incubation period (Figure). We conducted a site visit on August 22 to inspect a sewage plant and 2 large manufacturing plants (A and B) that were within the same 2-km radius. Neither the sewage plant nor plant A had a potential Legionella source. Plant B had a cooling tower mounted on a rooftop that was described by the company as a closed circuit cooling system, indicating that no aerosols would be released, and thus was missed by the initial local health department inquiry. However, closed circuit referred only to the primary cooling circuitry, whereas excess heat was exchanged through wet surface cooling, allowing release of aerosols into the atmosphere. The local health department immediately shut down the cooling tower, and plant B used shot-dose chlorine to disinfect it. Before disinfection, we obtained 3 swab specimens and 250-mL samples of water from the reservoir and plated them in dilutions with and without acid wash (6,8). Samples without acid wash were completely overgrown, whereas a single 1-mL sample with acid wash showed 20 Legionella colonies after 7 days. Three colonies were typed and found to belong to the epidemic strain. Of the 27 work and home addresses, 6 were within a 1-km radius of the cooling tower, and 18 were within a 4-km radius (Figure). No further cases occurred within the incubation period (up to 14 days after closure of the cooling tower).
To further confirm this cooling tower as the source of the outbreak, we applied core genome multilocus sequence typing (cgMLST) (3). We analyzed allelic differences of 1,521 gene targets of the core genome of L. pneumophila using the pairwise ignore missing values option in SeqSphere+ software (Ridom GmbH, Münster, Germany). Results showed that the strains from 2 patients with culture-positive test results and the 3 environmental ST82 strains were identical in their cgMLST profile, which covers 47% of the Philadelphia-1 reference genome.
Currently, no German law requires a registry for cooling towers; such a registry would accelerate identification of potential L. pneumophila emission during outbreaks (9). In January 2015, a code of conduct for maintenance of cooling towers went into effect (10). Modern typing methods such as cgMLST can serve as supporting tools in confirming infection origin. However, this method must be validated on a larger scale, and its discriminatory power compared with that of current typing methods. Further cgMLST studies with other ST82 strains are underway.
Florian Burckhardt
, Andre Brion, Jeanette Lahm, Heinz-Ulrich Koch, Karola Prior, Markus Petzold, Dag Harmsen, and Christian Lück
, Andre Brion, Jeanette Lahm, Heinz-Ulrich Koch, Karola Prior, Markus Petzold, Dag Harmsen, and Christian LückAcknowledgments
We acknowledge the support of Jürgen Blanz of the Regional Trade Control, Rhineland Palatinate, and thank the visited companies for their full and unconditional cooperation. We also acknowledge the contribution of all those individuals involved in the outbreak—local, regional and national Health Protection Agency staff, the Local Authority, the Health and Safety Executive, Environmental Health Officers, hospital staff and microbiologists —for their dedication and professionalism in the face of the outbreak.
This work received financial support from the Robert Koch Institute (BMG/RKI 1369-464).
References
- European Center for Disease Control. Stockholm, Sweden. Case definitions for Legionnaires’ disease: 2014 [cited 2016 Apr 29].http://www.ecdc.europa.eu/en/activities/surveillance/ELDSNet/Pages/EU%20case%20definition.aspx
- European Study Group for. Legionella Infections (ESGLI). The EWGLI SBT database for the typing of Legionella pneumophila: 2015 [cited 2016 Apr 29]. http://www.hpa-bioinformatics.org.uk/legionella/legionella_sbt/php/sbt_homepage.php
- Moran-Gilad J, Prior K, Yakunin E, Harrison TG, Underwood A, Lazarovitch T, Design and application of a core genome multilocus sequence typing scheme for investigation of Legionnaires’ disease incidents. Euro Surveill. 2015;20:21186. DOIPubMed
- Mérault N, Rusniok C, Jarraud S, Gomez-Valero L, Cazalet C, Marin M, Specific real-time PCR for simultaneous detection and identification ofLegionella pneumophila serogroup 1 in water and clinical samples. Appl Environ Microbiol. 2011;77:1708–17. DOIPubMed
- Mercante JW, Winchell JM. Current and emerging Legionella diagnostics for laboratory and outbreak investigations. Clin Microbiol Rev.2015;28:95–133. DOIPubMed
- International Standardisation Organisation. ISO 11731. Water quality—detection and enumeration of Legionella. International Standardisation Organisation; 1998 [cited 2016 Apr 29]. http://www.iso.org/iso/catalogue_detail?csnumber=19653
- Quantum Geographic Information System Team (QGDT). Open Source Geospatial Foundation Project, 2012 [cited 2016 Mar 27].http://qgis.osgeo.org
- Deutsche Industrie Norm. EN ISO 11731–2. Water quality—detection and enumeration of Legionella. Part 2: direct membrane filtration method for waters with low bacterial counts. Deutsche Industrie Norm, Berlin; 2008 [cited 2016 Apr 29]. http://www.beuth.de/de/norm/din-en-iso-11731-2/107294968
- Maisa A, Brockmann A, Renken F, Luck C, Pleischl S, Exner M, Epidemiological investigation and case-control study: a Legionnaires’ disease outbreak associated with cooling towers in Warstein, Germany, August–September 2013. Euro Surveill. 2015;20:30064. DOIPubMed
- Verein Deutscher Ingenieure. Securing hygienically sound operation of evaporative cooling systems (VDI Cooling Tower Code of Practice). Verein Deutscher Ingenieure, Berlin; 2015 [cited 2016 Apr 29]. http://www.beuth.de/de/technische-regel/vdi-2047-blatt-2/224206933
Figure
Suggested citation for this article: Burckhardt F, Brion A, Lahm J, Koch HL, Prior K, Petzold M, et al. Confirming Legionnaires’ disease outbreak by genome-based method, Germany, 2012. Emerg Infect Dis. 2016 Jul [date cited]. http://dx.doi.org/10.3201/eid2207.151738
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Thursday, August 4, 2016
New imaging method may predict risk of post treatment brain bleeding after stroke National Institutes of Health NIH
New imaging method may predict risk of post treatment brain bleeding after stroke National Institutes of Health NIH
New imaging method may predict risk of post-treatment brain bleeding after stroke | National Institutes of Health (NIH)
Institute/Center
National Institute of Neurological Disorders and Stroke (NINDS)
Contact
Barbara McMakin
301-496-5751
New imaging method may predict risk of post-treatment brain bleeding after stroke
NIH scientists develop technique that provides new insight into stroke.
In a study of stroke patients, investigators confirmed through MRI brain scans that there was an association between the extent of disruption to the brain’s protective blood-brain barrier and the severity of bleeding following invasive stroke therapy. The results of the National Institutes of Health-funded study were published in Neurology.
These findings are part of the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE)-2 Study, which was designed to see how MRIs can help determine which patients undergo endovascular therapy following ischemic stroke caused by a clot blocking blood flow to the brain. Endovascular treatment targets the ischemic clot itself, either removing it or breaking it up with a stent.
The blood-brain barrier is a layer of cells that protects the brain from harmful molecules passing through the bloodstream. After stroke, the barrier is disrupted, becoming permeable and losing control over what gets into the brain.
“The biggest impact of this research is that information from MRI scans routinely collected at a number of research hospitals and stroke centers can inform treating physicians on the risk of bleeding,” said Richard Leigh, M.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and an author on the study.
In this study, brain scans were collected from more than 100 patients before they underwent endovascular therapy, within 12 hours of stroke onset. Dr. Leigh and his team obtained the images from DEFUSE-2 investigators.
Using a new method of image processing, Dr. Leigh’s group was able to get detailed measurements on the extent to which the blood-brain barrier is disrupted following a stroke. Combining that data with findings from the DEFUSE-2 study revealed that large degrees of blood-brain barrier disruption were associated with severe bleeding following endovascular therapy. Extensive breakdown of the blood-brain barrier was associated with parenchymal hematoma, a form of bleeding in the brain that carries the greatest risk for the patient. In addition, the results showed a link between the location of blood-brain barrier damage and post-treatment brain bleeding.
Ischemic stroke patients are increasingly receiving combination therapy, endovascular treatment along with an intravenous drug known as tissue plasminogen activator (t-PA), to effectively break up clots in the brain. However, bleeding into the damaged brain tissue is a serious complication of both acute stroke therapies. t-PA has been shown to be most effective when given within a few hours of stroke onset, but the treatment window for endovascular therapy is unknown.
“With the growing precision of brain imaging technology, researchers are able to get a detailed look at what is going on in the brain during a stroke. Innovative studies, such as DEFUSE-2, can help patients and their doctors make more informed decisions about medical care,” said Walter Koroshetz, M.D., director of NINDS.
According to the authors, examining blood-brain barrier disruption on brain images may potentially help doctors identify patients not likely to benefit from endovascular therapy. “It is too early to say how these images will be able to help guide clinical decisions, but they can expand how we think about stroke, especially as we try to broaden treatment options for this disease that can have devastating consequences,” said Dr. Leigh.
The DEFUSE-3 trial is currently underway, in which researchers will use imaging data to select patients for endovascular therapy up to 16 hours after stroke onset. The patients’ recovery will be closely monitored for three months following the treatment.
This study was supported by the NIH (NS039325, NS051372, NIH Intramural Program).
The NINDS is the nation’s leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease.
About the National Institutes of Health (NIH): NIH, the nations medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
NIH…Turning Discovery Into Health®
Reference
R. Leigh et al. “Pretreatment blood–brain barrier disruption and postendovascular intracranial hemorrhage.” Neurology, June 17, 2016.download now
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