legionnaires disease

Health board fined after patient contracts Legionnaires'

2012-02-24T03:57:00.000-08:00

Sorry, I could not read the content fromt this page.Sorry, I could not read the content fromt this page.

View the original article here

Study Links Hospital Water Wall, Legionnaires' Disease

2012-02-23T23:39:00.000-08:00

View the original article here

An Outbreak of Legionnaires Disease Associated with a Decorative Water Wall Fountain in a Hospital

2012-02-23T19:07:00.000-08:00

The JSTOR site requires that your browser allows JSTOR (http://www.jstor.org/) to set and modify cookies.

JSTOR uses cookies to maintain information that will enable access to the archive and improve the response time and performance of the system. Any personal information, other than what is voluntarily submitted, is not extracted in this process, and we do not use cookies to identify what other websites or pages you have visited.

View the original article here

Innate Immune Pathways Triggered by Listeria monocytogenes and Their Role in the Induction of Cell-Mediated Immunity.

2012-02-23T14:22:00.000-08:00

Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California, USA.

Acquired cell-mediated immunity to Listeria monocytogenes is induced by infection with live, replicating bacteria that grow in the host cell cytosol, whereas killed bacteria, or those trapped in a phagosome, fail to induce protective immunity. In this chapter, we focus on how L. monocytogenes is sensed by the innate immune system, with the presumption that innate immunity affects the development of acquired immunity. Infection by L. monocytogenes induces three innate immune pathways: an MyD88-dependent pathway emanating from a phagosome leading to expression of inflammatory cytokines; a STING/IRF3-dependent pathway emanating from the cytosol leading to the expression of IFN-ß and coregulated genes; and very low levels of a Caspase-1-dependent, AIM2-dependent inflammasome pathway resulting in proteolytic activation and secretion of IL-1ß and IL-18 and pyroptotic cell death. Using a combination of genetics and biochemistry, we identified the listerial ligand that activates the STING/IRF3 pathway as secreted cyclic diadenosine monophosphate, a newly discovered conserved bacterial signaling molecule. We also identified L. monocytogenes mutants that caused robust inflammasome activation due to bacteriolysis in the cytosol, release of DNA, and activation of the AIM2 inflammasome. A strain was constructed that ectopically expressed and secreted a fusion protein containing Legionella pneumophila flagellin that robustly activated the Nlrc4-dependent inflammasome and was highly attenuated in mice, also in an Nlrc4-dependent manner. Surprisingly, this strain was a poor inducer of adaptive immunity, suggesting that inflammasome activation is not necessary to induce cell-mediated immunity and may even be detrimental under some conditions. To the best of our knowledge, no single innate immune pathway is necessary to mount a robust acquired immune response to L. monocytogenes infection.

View the original article here

Environmental surveillance and molecular characterization of Legionella in tropical Singapore.

2012-02-23T09:26:00.000-08:00

Environmental Health Institute, National Environment Agency, Singapore, 11 Biopolis Way #06-05/08 Helios Block Singapore 138667.

Legionnaires' disease is often acquired by inhalation of legionellae from a contaminated environmental source. In recent years, Singapore has seen an increase in the use of aerosol-generating fixtures such as mist fans and spa pools. Poorly maintained and designed water fixtures could pose a public health threat to the community. In this study, we provided an update on the prevalence of Legionella in mist fans (N=28), household water heaters with storage tanks (N=19) and instantaneous heaters (N=30); and extended the survey to spa pools (N=29) and aerosol-generating fixtures in nursing homes (N=116). The prevalence of Legionella were 21.1% in water heaters with storage tanks, 24.1% in spa pools, 14.2% in mist fans and 3.3% in instantaneous heaters. Legionella was not detected in nursing homes. A total of 37 isolates were subjected to molecular characterization using Sequence-Based Typing (SBT) protocol from the European Working Group on Legionella Infections (EWGLI). This is the first study on the use of SBT protocol on environmental strains isolated from tropical South East Asia. The Legionella flora was very heterogenous. The overall diversity of the allelic profile was found to be 0.970 (95% CI 0.946 - 0.994). All known STs of our isolates have been associated with clinical cases in EWGLI database. The phylogenetic analysis showed that our novel environmental isolates were clustered with clinical STs that were previously reported in Europe, Japan, United Kingdom and United States etc. (in EWGLI database), suggesting that Legionella found in the environment of Singapore may potentially cause human disease.

View the original article here

Domain organization of Legionella effector SetA

2012-02-23T04:42:00.000-08:00

Domain organization of Legionella effector SetA - Jank - 2012 - Cellular Microbiology - Wiley Online LibrarySkip to Main Content

Home Help

PUBLICATIONSBROWSE BY SUBJECTRESOURCESABOUT US LOGIN Enter e-mail address Enter password REMEMBER ME NOT REGISTERED ?FORGOTTEN PASSWORD ?INSTITUTIONAL LOGIN > Home > Microbiology & Virology > Microbiology & Virology > Journal Home > Early View > Abstract JOURNAL TOOLS Get New Content Alerts Get RSS feed Save to My Profile Get Sample Copy Recommend to Your Librarian JOURNAL MENUJournal HomeFIND ISSUESCurrent IssueAll Issues FIND ARTICLES Early ViewAccepted Articles GET ACCESS Subscribe / Renew FOR CONTRIBUTORS Author GuidelinesSubmit an Article ABOUT THIS JOURNAL NewsOverviewEditorial BoardPermissionsAdvertiseContact SPECIAL FEATURES Faculty of 1000Parasitology Virtual Special IssuePostersVirology Virtual Special IssueWiley Job Network Domain organization of Legionella effector SetAThomas Jank1, Kira E. Böhmer1, Tina Tzivelekidis1, Carsten Schwan1, Yury Belyi2, Klaus Aktories1,*Article first published online: 21 FEB 2012

DOI: 10.1111/j.1462-5822.2012.01761.x

Issue

Cellular MicrobiologyEarly View (Online Version of Record published before inclusion in an issue)

Additional Information

How to CiteJank, T., Böhmer, K. E., Tzivelekidis, T., Schwan, C., Belyi, Y. and Aktories, K. (2012), Domain organization of Legionella effector SetA. Cellular Microbiology. doi: 10.1111/j.1462-5822.2012.01761.x

Author Information1

Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, Freiburg D-79104, Germany

Gamaleya Research Institute, Ulitsa Gamalei 18, Moscow 123098, Russia

* E-mail klaus.aktories@pharmakol.uni-freiburg.de; Tel. (+49) 761 203 5301; Fax (+49) 761 203 5311.

Publication HistoryArticle first published online: 21 FEB 2012Accepted manuscript online: 31 JAN 2012 04:43AM ESTReceived 25 November, 2011; revised 13 January, 2012; accepted 17 January, 2012. SEARCH Search Scope All contentPublication titlesIn this journalIn this issue Search String Advanced >Saved Searches > SEARCH BY CITATION Volume: Issue: Page: ARTICLE TOOLSGet PDF (2198K)Save to My ProfileE-mail Link to this ArticleExport Citation for this ArticleGet Citation AlertsRequest Permissions AbstractArticleReferencesSupporting InformationCited By View Full Article with Supporting Information (HTML) Get PDF (2198K) Summary

Legionella pneumophila is a human pathogen causing severe pneumonia called Legionnaires' disease. Multiple Legionella effectors are type IV-secreted into the host cell to establish a specific vesicular compartment for pathogen replication. Recently, it has been reported that the Legionella effector SetA shares sequence similarity with glycosyltransferases and interferes with vesicular trafficking of host cells. Here we show that SetA possesses glycohydrolase and mono-O-glucosyltransferase activity by using UDP-glucose as a donor substrate. Whereas the catalytic activity is located at the N terminus of SetA, the C terminus (amino acids 401–644) is essential for guidance of SetA to vesicular compartments of host cells. EGFP-SetA expressed in HeLa cells localizes to early endosomes by interacting with phosphatidylinositol 3-phosphate. EGFP-SetA, transiently expressed in RAW 264.7 macrophages, associates with early phagosomes after infection with Escherichia coli and L. pneumophila. Only the combined expression of the C- and N-terminal domains induces growth defects in yeast similar to full-length SetA. The data indicate that SetA is a multidomain protein with an N-terminal glucosyltransferase domain and a C-terminal phosphatidylinositol 3-phosphate-binding domain, which guides the Legionella effector to the surface of the Legionella-containing vacuole. Both, the localization and the glucosyltransferase domains of SetA are crucial for cellular functions.

View Full Article with Supporting Information (HTML) Get PDF (2198K) More content like this Find more content: like this article Find more content written by:Thomas JankKira E. BöhmerTina TzivelekidisCarsten SchwanYury BelyiKlaus AktoriesAll Authors ABOUT USHELPCONTACT USAGENTSADVERTISERSMEDIAPRIVACYTERMS & CONDITIONSSITE MAP

View the original article here

Purdue scientists reveal how bacteria build homes inside healthy cells

2012-02-23T01:37:00.000-08:00

Public release date: 20-Dec-2011
[ | E-mail | Share ]

Contact: Elizabeth K. Gardner
ekgardner@purdue.edu
765-494-2081
Purdue University

WEST LAFAYETTE, Ind. - Bacteria are able to build camouflaged homes for themselves inside healthy cells - and cause disease - by manipulating a natural cellular process.

Purdue University biologists led a team that revealed how a pair of proteins from the bacteria Legionella pneumophila, which causes Legionnaires disease, alters a host protein in order to divert raw materials within the cell for use in building and disguising a large structure that houses the bacteria as it replicates.

Zhao-Qing Luo, the associate professor of biological sciences who headed the study, said the modification of the host protein creates a dam, blocking proteins that would be used as bricks in cellular construction from reaching their destination. The protein "bricks" are then diverted and incorporated into a bacterial structure called a vacuole that houses bacteria as it replicates within the cell. Because the vacuole contains materials natural to the cell, it goes unrecognized as a foreign structure.

"The bacterial proteins use the cellular membrane proteins to build their house, which is sort of like a balloon," Luo said. "It needs to stretch and grow bigger as more bacterial replication occurs. The membrane material helps the vacuole be more rubbery and stretchy, and it also camouflages the structure. The bacteria is stealing material from the cell to build their own house and then disguising it so it blends in with the neighborhood."

The method by which the bacteria achieve this theft is what was most surprising to Luo.

The bacterial proteins, named AnkX and Lem3, modify the host protein through a biochemical process called phosphorylcholination that is used by healthy cells to regulate immune response. Phosphorylcholination is known to happen in many organisms and involves adding a small chemical group, called the phosphorylcholine moiety, to a target molecule, he said.

The team discovered that AnkX adds the phosphorylcholine moiety to a host protein involved in moving proteins from the cell's endoplasmic reticulum to their cellular destinations. The modification effectively shuts down this process and creates a dam that blocks the proteins from reaching their destination.

The bacterial protein Lem3 is positioned outside the vacuole and reverses the modification of the host protein to ensure that the protein "bricks" are free to be used in creation of the bacterial structure.

This study was the first to identify proteins that directly add and remove the phosphorylcholine moiety, Luo said.

"We were surprised to find that the bacterial proteins use the phosphorylcholination process and to discover that this process is reversible," he said. "This is evidence of a new way signals are relayed within cells, and we are eager to investigate it."

The team also found that the phosphorylcholination reaction is carried out at a specific site on the protein called the Fic domain. Previous studies had shown this site induced a different reaction called AMPylation.

It is rare for a domain to catalyze more than one reaction, and it was thought this site's only responsibility was to transfer the chemical group necessary for AMPylation, Luo said.

"Revealing that this domain has dual roles is very important to identify or screen for compounds to inhibit its activity and fight disease," he said. "This domain has a much broader involvement in biochemical reactions than we thought and may be a promising target for effective treatments."

During infection bacteria deliver hundreds of proteins into healthy cells that alter cellular processes to turn the hostile environment into one hospitable to bacterial replication, but the specific roles of only about 20 proteins are known, Luo said.

"In order to pinpoint proteins that would be good targets for new antibiotics, we need to determine their roles and importance to the success of infection," he said. "We need to understand at the biochemical level exactly what these proteins do and how they take over natural cellular processes. Then we can work on finding ways to block these activities, stop the infection and save lives."

A paper detailing their National Institutes of Health-funded work is published in the current issue of the Proceedings of National Academy of Sciences. In addition to Luo, Purdue graduate student Yunhao Tan and Randy Ronald of Indiana University co-authored the paper. Luo next plans to use the bacterial proteins as a tool to learn more about the complex cellular processes controlled by phosphorylcholination and to determine the biochemical processes role in cell signaling.

Writer: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu Source: Zhao-Wing Luo, 765-496-6697, luoz@purdue.edu

Related website:
Luo lab: http://bilbo.bio.purdue.edu/luolab/

Related news release:
Purdue biologists identify new strategy used by bacteria during infection: http://www.purdue.edu/newsroom/research/2011/110712LuoNature.html

PHOTO CAPTION:
Purdue associate professor of biological sciences Zhao-Qing Luo, at right, and graduate student Yunhao Tan look at the growth of Legionella pneumophila bacteria in a petri dish. (Purdue University photo provided by Laurie Iten and Rodney McPhail)

A publication-quality photo is available at http://news.uns.purdue.edu/images/2011/luo-legionella.jpg

Abstract on the research in this release can be found at: http://www.purdue.edu/newsroom/research/2011/111220LuoPNAS.html

[ | E-mail | Share ]
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.

View the original article here

3rd Briton dies of Legionnaires' disease in Spanish hotel

2012-02-22T21:12:00.000-08:00

Home : Health : 3rd Briton dies of Legionnaires' disease in Spanish hotel

SLIDES.showHideViewT();The Associated Press

Date: Friday Feb. 3, 2012 6:22 AM ET

MADRID, Spain — Spanish health officials say a third British national has died from Legionnaires' disease while vacationing in Spain.

A Valencia regional government statement Friday said the three, aged between 73 and 78, had contracted the disease at a hotel in the eastern town of Calpe.

The Valencia statement said a further 10 Britons and four Spaniards are being treated for the disease.

The U.K.-based company Saga Holidays reported the first two deaths Thursday, saying the Britons had stayed at the Diamante Beach Hotel in Calpe.

The names of the three victims were not released.

The regional government said authorities have taken measures to control the outbreak, including closing the hotel.

Share with your social Network:

View the original article here

Legionnaires' Disease

2011-12-11T18:42:00.000-08:00

Legionellosis is an infection that is caused by a bacterium.The bacterium thrives in the mist that is sprayed from air-conditioning ducts.The bacterium can infest an entire building.The illness takes two distinct forms: Legionnaires' disease and Pontiac fever.Legionnaires' disease is the more severe form and can be fatal.Pontiac fever is the far milder form of the illness.Symptoms of Legionnaires' disease include fever, chills, and a cough.At its worst, Legionnaires' disease can cause severe pneumonia and respiratory failure.Although antibiotics are effective for treatment, the most useful approach is prevention.

Legionellosis is an infection that is caused by the bacterium Legionella pneumophila. The disease has two distinct forms:

Pneumonia Pneumonia is inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.Diarrhea Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.Headache Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.Chronic Cough Chronic cough is a cough that does not go away and is generally a symptom of another disorder such as asthma, allergic rhinitis, sinus infection, cigarette smoking, GERD, postnasal drip, bronchitis, pneumonia, medications, and less frequently tumors or other lung disease. Treatment of chronic cough is dependant upon the cause.Fever Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.ARDS (Acute Respiratory Distress Syndrome) Acute respiratory distress syndrome (ARDS) is a lung condition in which trauma to the lungs leads to inflammation of the lungs, accumulation of fluid in the alveolar air sacs, low blood oxygen, and respiratory distress. Causes of ARDS include: pneumonia, aspiration, severe blow to the chest, sepsis, severe injury with shock, drug overdose, and/or inflamed pancreas. Treatment for ARDS include extra oxygen, and/or medication.

Chronic Cough »

Chronic cough is a cough that persists. Chronic cough is not a disease in itself; rather it is a symptom of an underlying condition. Chronic cough is a common problem and the reason for many doctor visits.

Some common causes of chronic cough include asthma, allergic rhinitis, sinus problems (for example sinus infection), and esophageal reflux of stomach contents. In rare occasions, chronic cough may be the result of aspiration of foreign objects into the lungs (usually in children). It is very important to see a doctor who may order a chest X-ray if a chronic cough is present. The following are common causes of chronic coughing.

Cigarette smoking actually is the most common cause of chronic cough. Asthma is a disease of airways, resulting in difficulty breathing or wheezing often characterized by abnormal breathing...

Read the Chronic Cough article »

View the original article here

Cluster of travel-associated Legionnaires' disease in Lazise, Italy, July to August 2011

2011-12-11T14:58:00.000-08:00

Sorry, I could not read the content fromt this page.Sorry, I could not read the content fromt this page.

View the original article here

How Legionnaires' bacteria proliferate, cause disease

2011-12-11T10:04:00.000-08:00

ScienceDaily (Nov. 17, 2011) — A University of Louisville scientist has determined for the first time how the bacterium that causes Legionnaires' disease manipulates our cells to generate the amino acids it needs to grow and cause infection and inflammation in the lungs.

The results are published online on Nov. 17 in Science.

Yousef Abu Kwaik, Ph.D., the Bumgardner Endowed Professor in Molecular Pathogenesis of Microbial Infections at UofL, and his team believe their work could help lead to development of new antibiotics and vaccines.

"It is possible that the process we have identified presents a great target for new research in antibiotic and vaccine candidates, not only for Legionnaires' disease but in other bacteria that cause illness," he said.

According to the Centers for Disease Control and Prevention, Legionnaires' disease is a lung infection caused by the bacterium called Legionella. The bacterium got its name in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from an outbreak of pneumonia of unknown causes that was later determined to be caused by the bacterium. Each year, between 8,000 and 18,000 people are hospitalized with Legionnaires' disease in the U.S. There is no vaccine currently available for it.

For two years, the researchers examined Legionella which is an intracellular bacterium that exists in amoebae in the water systems; it is transmitted to humans through inhalation of water droplets. Cooling towers and whirlpools are the major sources of transmission. The bacterium uses the amoeba's cellular process to "tag" proteins, causing them to degrade into their basic elements of amino acids. These amino acids are used by the bacteria as the main source of energy to grow and cause disease.

"The bacteria live on an 'Atkins diet' of low carbs and high protein, and they trick the host cell to provide that specialized diet," Abu Kwaik said.

The same process occurs in a host -- animal or human -- who inhales the bacterium and is diagnosed with Legionnaires' disease. However, the bacteria do not tag the proteins, but rather trick the host into tagging the proteins for degradation to generate the amino acids.

In the laboratory, Abu Kwaik and his team saw that by inactivating the bacterial virulence factor responsible for tricking the cell into tagging proteins for degradation in mice models, the pulmonary disease was totally prevented. This was totally due to disabling the bacteria from generating amino acids, he said.

The process was then reversed, and the disease became evident when the mice, infected by the disabled bacteria, were injected with amino acids to compensate for the inability of the altered bacteria.

"Bacteria need to live on high protein and amino acids as sources of nutrition and energy in order to replicate in a host. This is what causes pulmonary disease," Abu Kwaik said. "No one has known how they generate sufficient sources of nutrients from the host to proliferate. Our work is the first to identify this process for any bacteria that cause disease."

He added that the type of host infected does not appear to affect the process. "Whether in a single-cell amoeba or a multi-cellular mammal, Legionella seems to know what to do; the process is the same, and is highly conserved through evolution. By interfering with the bacterium's sources of nutrients, we can stop it from thriving and causing disease."

Examining nutrient sources for organisms with the goal of stopping them from acquiring nutrients is a relatively new arena of basic research that deserves further study, he said. "We went after the basics -- the food and energy source -- which are prerequisite for the bacteria to grow and cause disease. It is not a process that is well understood yet, but by first discovering how an organism gets nutrients by tricking the host into degrading proteins, and then interfering with that process, we can, in effect, starve it to death and prevent or treat the disease."

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by University of Louisville.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Christopher T. D. Price, Tasneem Al-Quadan, Marina Santic, Ilan Rosenshine, and Yousef Abu Kwaik. Host Proteasomal Degradation Generates Amino Acids Essential for Intracellular Bacterial Growth. Science, 17 November 2011 DOI: 10.1126/science.1212868

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Correction for O'Connor et al., Minimization of the Legionella pneumophila genome reveals chromosomal regions involved in host range expansion [Correction]

2011-12-11T06:58:00.000-08:00

MICROBIOLOGY Correction for “Minimization of the Legionella pneumophila genome reveals chromosomal regions involved in host …

View the original article here

Legionella secreted effectors and innate immune responses

2011-12-11T02:13:00.000-08:00

Legionella secreted effectors and innate immune responses - Luo - 2011 - Cellular Microbiology - Wiley Online LibrarySkip to Main Content

Home Help

PUBLICATIONSBROWSE BY SUBJECTRESOURCESABOUT US LOGIN Enter e-mail address Enter password REMEMBER ME NOT REGISTERED ?FORGOTTEN PASSWORD ?INSTITUTIONAL LOGIN > Home > Microbiology & Virology > Microbiology & Virology > Journal Home > Early View > Abstract JOURNAL TOOLS Get New Content Alerts Get RSS feed Save to My Profile Get Sample Copy Recommend to Your Librarian JOURNAL MENUJournal HomeFIND ISSUESCurrent IssueAll Issues FIND ARTICLES Early ViewAccepted Articles GET ACCESS Subscribe / Renew FOR CONTRIBUTORS Author GuidelinesSubmit an Article ABOUT THIS JOURNAL NewsOverviewEditorial BoardPermissionsAdvertiseContact SPECIAL FEATURES Virology Virtual Special IssueFaculty of 1000PostersWiley Job NetworkParasitology Virtual Special Issue You have free access to this contentLegionella secreted effectors and innate immune responsesZhao-Qing LuoArticle first published online: 10 NOV 2011

DOI: 10.1111/j.1462-5822.2011.01713.x

Issue

Cellular MicrobiologyEarly View (Online Version of Record published before inclusion in an issue)

Additional Information

How to CiteLuo, Z.-Q. (2011), Legionella secreted effectors and innate immune responses. Cellular Microbiology. doi: 10.1111/j.1462-5822.2011.01713.x

Author Information

Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA

*Correspondence: Zhao-Qing Luo,

*Correspondence: E-mail luoz@purdue.edu; Tel. (+1) 765 496 6697; Fax (+1) 765 494 0876.

Publication HistoryArticle first published online: 10 NOV 2011Accepted manuscript online: 11 OCT 2011 03:50AM ESTReceived 1 August, 2011; revised 3 October, 2011; accepted 5 October, 2011. SEARCH Search Scope All contentPublication titlesIn this journalIn this issue Search String Advanced >Saved Searches > SEARCH BY CITATION Volume: Issue: Page: ARTICLE TOOLSGet PDF (300K)Save to My ProfileE-mail Link to this ArticleExport Citation for this ArticleGet Citation AlertsRequest Permissions AbstractArticleReferencesCited By View Full Article (HTML) Get PDF (300K) Summary

Legionella pneumophila is a facultative intracellular pathogen capable of replicating in a wide spectrum of cells. Successful infection by Legionella requires the Dot/Icm type IV secretion system, which translocates a large number of effector proteins into infected cells. By co-opting numerous host cellular processes, these proteins function to establish a specialized organelle that allows bacterial survival and proliferation. Even within the vacuole, L. pneumophila triggers robust immune responses. Recent studies reveal that a subset of Legionella effectors directly target some basic components of the host innate immunity systems such as phagosome maturation. Others play essential roles in engaging the host innate immune surveillance system. This review will highlight recent progress in our understanding of these interactions and discuss implications for the study of the immune detection mechanisms.

View Full Article (HTML) Get PDF (300K) More content like this Find more content: like this article Find more content written by:Zhao-Qing Luo ABOUT USHELPCONTACT USAGENTSADVERTISERSMEDIAPRIVACYTERMS & CONDITIONSSITE MAP

View the original article here

Tumor Necrosis Factor-alpha (TNFα) Blockers: Label Change - Boxed Warning Updated for Risk of Infection from Legionella and Listeria

2011-12-10T21:17:00.000-08:00

including Remicade (infliximab), Enbrel (etanercept), Humira (adalimumab), Cimzia (certolizumab pegol), and Simponi (golimumab)

AUDIENCE: Rheumatology, Gastroenterology, Oncology

ISSUE: FDA notified healthcare professionals that the Boxed Warning for the entire class of Tumor Necrosis Factor-alpha (TNFa) blockers has been updated to include the risk of infection from two bacterial pathogens, Legionella and Listeria. In addition, the Boxed Warning and Warnings and Precautions sections of the labels for all of the TNFa blockers have been revised so that they contain consistent information about the risk for serious infections and the associated disease-causing pathogens.

Patients treated with TNFa blockers are at increased risk for developing serious infections involving multiple organ systems and sites that may lead to hospitalization or death due to bacterial, mycobacterial, fungal, viral, parasitic, and other opportunistic pathogens.

BACKGROUND: The class of TNFa blockers are used to treat Crohn's disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, plaque psoriasis, and/or juvenile idiopathic arthritis.

RECOMMENDATION: The risks and the benefits of TNFa blockers should be considered prior to initiating therapy in patients with chronic or recurrent infection and patients with underlying conditions that may predispose them to infection. See the Drug Safety Communication for a listing of recommendations for healthcare professionals and patients, as well as a data summary.

Healthcare professionals and patients are encouraged to report adverse events or side effects related to the use of these products to the FDA's MedWatch Safety Information and Adverse Event Reporting Program:

Complete and submit the report Online: www.fda.gov/MedWatch/report.htm
Download form or call 1-800-332-1088 to request a reporting form, then complete and return to the address on the pre-addressed form, or submit by fax to 1-800-FDA-0178
Read the MedWatch safety alert, including a link to the FDA Drug Safety Communication, at:

http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm270977.htm

Posted: September 2011

View the original article here

Disease cases in Britain linked to travel

2011-12-10T17:32:00.000-08:00

Published: Oct. 7, 2011 at 6:27 PM

LONDON, Oct. 7 (UPI) -- Nine cases of Legionnaire's disease in Britain have been linked to travel to the Greek island of Corfu since August, health authorities say.

The Health Protection Agency advising people to be aware of the symptoms of Legionnaire's disease -- which can lead to pneumonia and is sometimes fatal -- if they are traveling to the island, the BBC reported Friday.

"We are concerned that U.K. residents traveling to Corfu should be aware of this potential risk, however we are not suggesting that people change their holiday plans," Nick Phin of the Legionnaire's disease department at the HPA said.

The HPA cannot rule out a U.K. source of the infections and is still investigating, he said.

Symptoms may not appear until two weeks after infection and generally start as a "flu-like" illness, the HPA said, but the disease can be treated with antibiotics.

View the original article here

Recovery of Legionella species from water samples using an internal method based on ISO 11731: suggestions for revision and implementation

2011-12-10T12:57:00.000-08:00

European Online Customer Service
The Boulevard
Langford Lane, Kidlington
Oxford. OX5 1GB
UK
Hours: Monday - Friday, 8:30am - 5:00pm (Greenwich Mean Time/British Summer Time)
Tel: +44 (0) 1865-843177 (Within Europe)
Fax: +44 (0) 1865-843970
E-mail: eurosupport@elsevier.com

North American and Rest of World Online Customer Service
6277 Sea Harbor Drive
Orlando. FL 32887-4800
USA
Hours: Monday - Friday, 7:30am - 6:00pm EST (Eastern Standard/Daylight Time)
Tel: (800) 654-2452 (Toll Free US & Canada)
Tel: (407) 345-4299 (Outside US & Canada)
Fax: (407) 363-9661
E-mail: elspcs@elsevier.com

View the original article here

The htpAB operon of Legionella pneumophila cannot be deleted in the presence of the groE chaperonin operon of Escherichia coli

2011-12-10T08:13:00.000-08:00

Gheyath K. Nasrallah,a Elizabeth Gagnon,a,* Dennis J. Orton,a,† Rafael A. Garduñoa,b aDepartment of Microbiology and Immunology, Dalhousie University, Sir Charles Tupper Medical Building, 7th Floor, 5850 College Street, Halifax, NS B3H 1X5, Canada.

bDepartment of Medicine — Division of Infectious Diseases, Dalhousie University, Dickson Building, 1276 South Park Street, Halifax, NS B3H 2Y9, Canada.

*Present address: Department of Microbiology and Immunology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada

†Present address: Department of Pathology, Dalhousie University, Sir Charles Tupper Medical Building, NS B3H 1X5, Canada

Published on the web 27 October 2011.

Canadian Journal of Microbiology, 2011, 57:(11) 943-952, 10.1139/w11-086

Allan, D.S. 2002. Secretion of Hsp60 chaperonin (GroEL) homologs by Legionella pneumophila. M.Sc. thesis, Dalhousie University, Nova Scotia, Canada. Berger KH, Isberg RR. 1993. Two distinct defects in intracellular growth complemented by a single genetic locus in Legionella pneumophila. Mol. Microbiol. 7(1): 7-19 .Bethke K, Staib F, Distler M, Schmitt U, Jonuleit H, Enk AH, et al.. 2002. Different efficiency of heat shock proteins (HSP) to activate human monocytes and dendritic cells: superiority of Hsp60. J. Immunol. 169(11): 6141-6148 .Blander SJ, Horwitz MA. 1993. Major cytoplasmic membrane protein of Legionella pneumophila, a genus common antigen and member of the hsp60 family of heat shock proteins, induces protective immunity in a guinea pig model of Legionnaires’ disease. J. Clin. Invest. 91(2): 717-723 .Brassinga, A.K., Mathew, A.C., Hoemaker, C.J., Morash, M.G., LeBlanc, J.J., and Hoffman, P.S. 2006. Novel use of Helicobacter pylori nitroreductase(rdxA) as a counterselectable marker in allelic vector exchange to create Legionella pneumophila Philadelphia-1 mutants. InLegionella — state of the art 30 years after its recognition. Edited by N.P. Cianciotto, Y. AbuKwaik, P.H. Edelstein, B.S. Fields, D.F. Geary, T.G. Harrison, C.A. Joseph, R.M. Ratcliff, J.E. Stout, and M.S. Swanson. ASM Press, Washington, D.C. pp. 339–342. Buchmeier NA, Heffron F. 1990. Induction of Salmonella stress proteins upon infection of macrophages. Science 248(4956): 730-732 .Carreiro MM, Laux DC, Nelson DR. 1990. Characterization of the heat shock response and identification of heat shock protein antigens of Borrelia burgdorferi. Infect. Immun. 58(7): 2186-2191 .Cazalet C, Rusniok C, Brüggemann H, Zidane N, Magnier A, Ma L, et al.. 2004. Evidence in the Legionella pneumophila genome for exploitation of host cell functions and high genome plasticity. Nat. Genet. 36(11): 1165-1173 .Chien M, Morozova I, Shi S, Sheng H, Chen J, Gomez SM, et al.. 2004. The genomic sequence of the accidental pathogen Legionella pneumophila. Science 305(5692): 1966-1968 .Chong A, Lima CA, Allan DS, Nasrallah GK, Garduno RA. 2009. The purified and recombinant Legionella pneumophila chaperonin alters mitochondrial trafficking and microfilament organization. Infect. Immun. 77(11): 4724-4739 .D’Auria G, Jimenez-Hernandez N, Peris-Bondia F, Moya A, Latorre A. 2010. Legionella pneumophila pangenome reveals strain-specific virulence factors. BMC Genomics 11(1) .Ewann, F., and Hoffman, P.S. 2006. Antisense strategy. InLegionella — state of the art 30 years after its recognition. Edited by N.P. Cianciotto, Y. AbuKwaik, P.H. Edelstein, B.S. Fields, D.F. Geary, T.G. Harrison, C.A. Joseph, R.M. Ratcliff, J.E. Stout, and M.S. Swanson. ASM Press, Washington, DC. pp. 336–338. Fernandez RC, Logan SM, Lee SH, Hoffman PS. 1996. Elevated levels of Legionella pneumophila stress protein Hsp60 early in infection of human monocytes and L929 cells correlate with virulence. Infect. Immun. 64(6): 1968-1976 .Fields BS. 1996. The molecular ecology of legionellae. Trends Microbiol. 4(7): 286-290 .Fields BS, Benson RF, Besser RE. 2002. Legionella and Legionnaires’ disease: 25 years of investigation. Clin. Microbiol. Rev. 15(3): 506-526 .Fujiwara K, Ishihama Y, Nakahigashi K, Soga T, Taguchi H. 2010. A systematic survey of in vivo obligate chaperonin-dependent substrates. EMBO J. 29(9): 1552-1564 .Gabay JE, Horwitz MA. 1985. Isolation and characterization of the cytoplasmic and outer membranes of the Legionnaires’ disease bacterium (Legionella pneumophila). J. Exp. Med. 161(2): 409-422 .Garduño RA, Faulkner G, Trevors MA, Vats N, Hoffman PS. 1998a. Immunolocalization of Hsp60 in Legionella pneumophila. J. Bacteriol. 180(3): 505-513 .Garduño RA, Garduño E, Hoffman PS. 1998b. Surface-associated Hsp60 chaperonin of Legionella pneumophila mediates invasion in a HeLa cell model. Infect. Immun. 66(10): 4602-4610 .Garduño RA, Chong A, Nasrallah GK, Allan DS. 2011. The Legionella pneumophila chaperonin — an unusual multifunctional protein in unusual locations. Front. Microbiol. 2 .Glöckner G, Albert-Weissenberger C, Weinmann E, Jacobi S, Schunder E, Steinert M, et al.. 2008. Identification and characterization of a new conjugation/type IVA secretion system (trb/tra) of Legionella pneumophila Corby localized on two mobile genomic islands. Int. J. Med. Microbiol. 298(5–6): 411-428 .Gupta RS. 1995. Evolution of the chaperonin families (Hsp60, Hsp10 and Tcp-1) of proteins and the origin of eukaryotic cells. Mol. Microbiol. 15(1): 1-11 .Helsel LO, Bibb WF, Butler CA, Hoffman PS, Mckinney RM. 1988. Recognition of a genus-wide antigen of Legionella by a monoclonal antibody. Curr. Microbiol. 16(4): 201-208 .Hirsch PR, Beringer JE. 1984. A physical map of pPH1JI and pJB4JI. Plasmid 12(2): 139-141 .Hoffman PS, Butler CA, Quinn FD. 1989. Cloning and temperature-dependent expression in Escherichia coli of a Legionella pneumophila gene coding for a genus-common 60-kilodalton antigen. Infect. Immun. 57(6): 1731-1739 .Hoffman PS, Houston L, Butler CA. 1990. Legionella pneumophila htpAB heat shock operon: nucleotide sequence and expression of the 60-kilodalton antigen in L. pneumophila-infected HeLa cells. Infect. Immun. 58(10): 3380-3387 .Horwich AL, Fenton WA, Chapman E, Farr GW. 2007. Two families of chaperonin: physiology and mechanism. Annu. Rev. Cell Dev. Biol. 23(1): 115-145 .Karlin S, Brocchieri L. 2000. Heat shock protein 60 sequence comparisons: duplications, lateral transfer, and mitochondrial evolution. Proc. Natl. Acad. Sci. U.S.A. 97(21): 11348-11353 .Karunakaran KP, Noguchi Y, Read TD, Cherkasov A, Kwee J, Shen C, et al.. 2003. Molecular analysis of the multiple GroEL proteins of Chlamydia. J. Bacteriol. 185(6): 1958-1966 .Kaufmann SH. 1990. Heat shock proteins and the immune response. Immunol. Today 11(4): 129-136 .Kaufmann SHE, Schoel B, v. Embden JDA, Koga T, Wand-Württenberger A, Munk ME, Steinhoff U. 1991. Heat-shock protein 60: implications for pathogenesis of and protection against bacterial infections. Immunol. Rev. 121(1): 67-90 .Laemmli UK. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227(5259): 680-685 .Lathigra RB, Butcher PD, Garbe TR, Young DB. 1991. Heat shock proteins as virulence factors of pathogens. Curr. Top. Microbiol. Immunol. 167: 125-143 .LeBlanc JJ, Davidson RJ, Hoffman PS. 2006. Compensatory functions of two alkyl hydroperoxide reductases in the oxidative defense system of Legionella pneumophila. J. Bacteriol. 188(17): 6235-6244 .Lema MW, Brown A. 1995. Legionella pneumophila has two 60-kilodalton heat-shock proteins. Curr. Microbiol. 31(6): 332-335 .Lund PA. 2009. Multiple chaperonins in bacteria — Why so many? FEMS Microbiol. Rev. 33(4): 785-800 .Macellaro A, Tujulin E, Hjalmarsson K, Norlander L. 1998. Identification of a 71-kilodalton surface-associated Hsp70 homologue in Coxiella burnetii. Infect. Immun. 66(12): 5882-5888 .Maguire M, Coates ARM, Henderson B. 2002. Chaperonin 60 unfolds its secrets of cellular communication. Cell Stress Chaperones 7(4): 317-329 .Morash MG, Brassinga AK, Warthan M, Gourabathini P, Garduño RA, Goodman SD, Hoffman PS. 2009. Reciprocal expression of integration host factor and HU in the developmental cycle and infectivity of Legionella pneumophila. Appl. Environ. Microbiol. 75(7): 1826-1837 .Nasrallah GK, Riveroll AL, Chong A, Murray LE, Lewis PJ, Garduño RA. 2011. Legionella pneumophila requires polyamines for optimal intracellular growth. J. Bacteriol. 193(17): 4346-4360 .Pasculle AW, Feeley JC, Gibson RJ, Cordes LG, Myerowitz RL, Patton CM, et al.. 1980. Pittsburgh pneumonia agent: direct isolation from human lung tissue. J. Infect. Dis. 141(6): 727-732 .Sadosky AB, Wiater LA, Shuman HA. 1993. Identification of Legionella pneumophila genes required for growth within and killing of human macrophages. Infect. Immun. 61(12): 5361-5373 .Sambrook, J., and Russell, D.W. 2001. Molecular cloning: a laboratory manual. 3rd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. Sandegren L, Andersson DI. 2009. Bacterial gene amplification: implications for the evolution of antibiotic resistance. Nat. Rev. Microbiol. 7(8): 578-588 .Sigler PB, Xu Z, Rye HS, Burston SG, Fenton WA, Horwich AL. 1998. Structure and function in GroEL-mediated protein folding. Annu. Rev. Biochem. 67(1): 581-608 .Singh B, Gupta RS. 2009. Conserved inserts in the Hsp60 (GroEL) and Hsp70 (DnaK) proteins are essential for cellular growth. Mol. Genet. Genomics 281(4): 361-373 .Taylor JS, Raes J. 2004. Duplication and divergence: the evolution of new genes and old ideas. Annu. Rev. Genet. 38(1): 615-643 .Towbin H, Staehelin T, Gordon J. 1979. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc. Natl. Acad. Sci. U.S.A. 76(9): 4350-4354 .Viswanathan, V.K., and Cianciotto, N.P. 2001. Electroporation of Legionella species. In Electro-transformation of bacteria. Edited by N. Eynard and J. Teissie. Springer-Verlag Publications, Heidelberg, Germany. pp. 203–211. Young RA, Elliott TJ. 1989. Stress proteins, infection, and immune surveillance. Cell 59(1): 5-8 .Zhang J. 2003. Evolution by gene duplication: an update. Trends Ecol. Evol. 18(6): 292-298 .

View the original article here

Legionella - Every Infection Preventionist's Dream—Or Is It?

2011-12-10T04:23:00.000-08:00

View the original article here

Update on Legionnaires' cluster in UK travellers returning from Corfu

2011-12-10T01:18:00.000-08:00

The Health Protection Agency (HPA) has issued an update on the Legionnaire’s cluster – three further cases have now been confirmed, which brings the total to 12 confirmed cases in people who have travelled to Corfu since August. Another three possible cases with travel history to Corfu are currently under investigation.

Laboratory tests have identified three different subtypes of Legionnella from the patients’ samples, suggesting that one common source is unlikely. In addition, detailed questioning of the people who became unwell has also failed to reveal a common source.

The HPA is continuing to advise people going on holiday to Corfu to be aware of the signs and symptoms of Legionnaires’ disease – please see the link below for details. A briefing note was recently issued to GPs asking them to be alert to returning travellers from Corfu with relevant symptoms.

View the original article here

How Legionnaires' bacteria cause disease

2011-12-09T20:53:00.000-08:00

Published: Nov. 18, 2011 at 11:05 PM

LOUISVILLE, Ky., Nov. 18 (UPI) -- A bacterium that causes Legionnaires' disease manipulates cells to generate amino acids it needs to grow and infect the lungs, U.S. researchers say.

Yousef Abu Kwaik of the University of Louisville and his team said their work could help lead to development of new antibiotics and vaccines for the disease.

For two years, the researchers examined Legionella, which is an intercellular bacterium that exists in amoebae in the water systems; it is transmitted to humans through inhalation of water droplets. Cooling towers and whirlpools are the major sources of transmission.

The study, published in the journal Science, said the bacterium uses the amoeba's cellular process to "tag" proteins, causing them to degrade into their basic elements of amino acids, which are used by the bacteria as the main source of energy to grow and cause disease.

"The bacteria live on an 'Atkins diet' of low carbs and high protein and they trick the host cell to provide that specialized diet," Abu Kwaik said.

View the original article here

[Interdisciplinary management of a large Legionella outbreak in Germany].

2011-12-09T16:15:00.000-08:00

Landratsamt Alb-Donau-Kreis, Alb-Donau-Kreis, Deutschland.

Between December 2009 and the end of January 2010, the largest hitherto known outbreak of Legionella in Germany took place in the cities of Ulm and Neu-Ulm. Of a total of 64 patients involved, 60 patients had to be hospitalized, and 5 patients died from the infection. This event was caused by a wet cooling tower of a large air conditioning system in the city center of Ulm. The search for the source of the Legionella emission was extremely difficult, since these plants are neither notifiable nor subject to authorization in Germany. We report about the search for the source and the measures to control the outbreak. We also discuss communication and coordination during these investigations. Regulatory measures as proposed by the World Health Organization (WHO) and the European Network for Legionellosis (EWGLI) and already implemented in numerous other European countries would be desirable to prevent such outbreaks in the future.

View the original article here

Detection of Legionella by quantitative-Polymerase Chain Reaction (qPCR) for monitoring and risk assessment

2011-12-09T11:43:00.000-08:00

Research article Louise H Krojgaard, Karen A Krogfelt, Hans-Jorgen Albrechtsen and Soren A Uldum

For all author emails, please log on.

BMC Microbiology 2011, 11:254 doi:10.1186/1471-2180-11-254

Published: 21 November 2011

Background Culture and quantitative polymerase chain reaction (qPCR) assays for the detection of Legionella were compared on samples from a residential area before and after two interventions. A total of 84 samples were collected from shower hoses and taps as first flush samples and at constant temperature. Samples were grouped according to the origin of the sample, a) circulation water b) water from empty apartments c) water from shower hoses. The aims were to investigate the usefulness of qPCR compared to culture for monitoring remedial actions for elimination of Legionella bacteria and as a tool for risk assessment.

In water collected from the apartments Legionella spp were detected by qPCR in the concentration range from LOQ to 9.6*105GU/L while L. pneumophila were detected in a range from LOQ to 6.8 *105 GU/L. By culturing, the legionellae were detected in the range from below detection limit (> 10 CFU/L) to 1.6 * 106 CFU/L. In circulating water and in first flush water from shower hoses, culture and qPCR showed the same tendencies. The overall correlation between the bacteria number detected by culture and the two developed qPCR assays (L. spp and L. pneumophila) was relatively poor (r2 =0.31 for culture and Legionella spp. assay, r2 = 0.20 for culture and L. pneumophila assay).

Detection by qPCR was suitable for monitoring changes in the concentration of Legionella but the precise determination of bacteria is difficult. Risk assessment by qPCR only on samples without any background information regarding treatment, timing, etc is dubious. However, the rapid detection by qPCR of high concentrations of Legionella - especially Legionella pneumophila - is valuable as an indicator of risk, although it may be false positive compared to culture results. On the other hand, the detection of a low number of bacteria by qPCR is a strong indication for the absence of risk.

View the original article here

Identification of Legionella pneumophila serogroups and other Legionella species by mip gene sequencing

2011-12-09T08:42:00.000-08:00

Journal Article

PCR methods for the rapid detection and identification of four pathogenic Legionella spp. and two Legionella pneumophila subspecies based on the gene amplification of gyrB

Guangpeng Zhou, Boyang Cao, Yan Dou, Yanwei Liu and Lu Feng, et al.

Applied Microbiology and Biotechnology, 2011, Volume 91, Number 3, Pages 777-787

Journal Article

Legionella pneumophila DNA in serum samples during Legionnaires’ disease in relation to C-reactive protein levels

F. L. van de Veerdonk, C. P. C. de Jager, J. J. A. Schellekens, C. J. J. Huijsmans and F. Beaumont, et al.

European Journal of Clinical Microbiology & Infectious Diseases, 2009, Volume 28, Number 4, Pages 371-376

Journal Article

LAMP-based method for a rapid identification of Legionella spp. and Legionella pneumophila

Xi Lu, Zi-Yao Mo, Hong-Bo Zhao, He Yan and Lei Shi

Applied Microbiology and Biotechnology, 2011, Volume 92, Number 1, Pages 179-187

Journal Article

Profiling of environmental Legionella pneumophila strains by randomly amplified polymorphic DNA method isolated from geographically nearby buildings

Zuhal Zeybek, Irfan Türetgen, Ayten Kimiran Erdem, Gönül Filoglu and Aysin Çotuk

Environmental Monitoring and Assessment, 2009, Volume 149, Numbers 1-4, Pages 323-327

Journal Article

Anin vitro evaluation of the interactions ofLegionella pneumophila serogroups 2 to 14 strains with other bacteria in the same habitat

Ayten Kimiran Erdem and Aysegül Yazici

Annals of Microbiology, 2008, Volume 58, Number 3, Pages 395-401

Reference Work Entry

Legionella Species and Legionnaires’ Disease

Paul Edelstein and Nicholas Cianciotto

2006, The Prokaryotes, PART 3, SECTION 3.3, Pages 988-1033

Journal Article

Screening-level assays for potentially human-infectious environmental Legionella spp.

Helen Y. Buse, Abby Brehm, Jorge W. Santo Domingo and Nicholas J. Ashbolt

The Journal of Microbiology, 2011, Volume 49, Number 2, Pages 200-207

Journal Article

Online First™ Efficacy of Colloidal Silver-Hydrogen Peroxide and 2-Bromo-2-nitroporopane-1,3-diol Compounds Against Different Serogroups of Legionella pneumophila Strains

N. O. Sanli-Yurudu, A. Kimiran-Erdem, E. O. Arslan-Aydogdu, Z. Zeybek and S. Gurun

Indian Journal of Microbiology, Online First™, 28 June 2011

View the original article here

UofL researcher determines how Legionnaires' bacteria proliferate, cause disease

2011-12-09T04:09:00.000-08:00

Public release date: 17-Nov-2011
[ | E-mail | Share ]

Contact: Jill Scoggins
jill.scoggins@louisville.edu
502-852-7461
University of Louisville

LOUISVILLE, Ky. ? A University of Louisville scientist has determined for the first time how the bacterium that causes Legionnaires' disease manipulates our cells to generate the amino acids it needs to grow and cause infection and inflammation in the lungs. The results are published online today (Nov. 17) in "Science."

For two years, the researchers examined Legionella which is an intercellular bacterium that exists in amoebae in the water systems; it is transmitted to humans through inhalation of water droplets. Cooling towers and whirlpools are the major sources of transmission. The bacterium uses the amoeba's cellular process to "tag" proteins, causing them to degrade into their basic elements of amino acids. These amino acids are used by the bacteria as the main source of energy to grow and cause disease.

"The bacteria live on an 'Atkins diet' of low carbs and high protein, and they trick the host cell to provide that specialized diet," Abu Kwaik said.

The same process occurs in a host ? animal or human ? who inhales the bacterium and is diagnosed with Legionnaires' disease. However, the bacteria do not tag the proteins, but rather trick the host into tagging the proteins for degradation to generate the amino acids.

The process was then reversed, and the disease became evident when the mice, infected by the disabled bacteria, were injected with amino acids to compensate for the inability of the altered bacteria.

Examining nutrient sources for organisms with the goal of stopping them from acquiring nutrients is a relatively new arena of basic research that deserves further study, he said. "We went after the basics ? the food and energy source ? which are prerequisite for the bacteria to grow and cause disease. It is not a process that is well understood yet, but by first discovering how an organism gets nutrients by tricking the host into degrading proteins, and then interfering with that process, we can, in effect, starve it to death and prevent or treat the disease."

With Abu Kwaik, authors of the paper are Christopher T.D. Price, Ph.D. and Tasneem Al-Quadan, a doctoral student, in UofL's Department of Microbiology and Immunology; Marina Santic, Ph.D., of the University of Rijeka, Croatia; and Ilan Rosenshine, Ph.D., of the Hebrew University Medical School in Jerusalem, Israel.

The work was funded by a grant from the National Institute of Allergy and Infectious Diseases.

View the original article here

Researcher Determines How Legionnaires' Bacteria Proliferate, Cause Disease

2011-12-09T00:33:00.000-08:00

Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Respiratory / Asthma
Article Date: 21 Nov 2011 - 0:00 PST

email to a friend printer friendly opinions

A University of Louisville scientist has determined for the first time how the bacterium that causes Legionnaires' disease manipulates our cells to generate the amino acids it needs to grow and cause infection and inflammation in the lungs. The results are published online in Science.

"The bacteria live on an 'Atkins diet' of low carbs and high protein, and they trick the host cell to provide that specialized diet," Abu Kwaik said.

The same process occurs in a host - animal or human - who inhales the bacterium and is diagnosed with Legionnaires' disease. However, the bacteria do not tag the proteins, but rather trick the host into tagging the proteins for degradation to generate the amino acids.

The process was then reversed, and the disease became evident when the mice, infected by the disabled bacteria, were injected with amino acids to compensate for the inability of the altered bacteria.

Examining nutrient sources for organisms with the goal of stopping them from acquiring nutrients is a relatively new arena of basic research that deserves further study, he said. "We went after the basics - the food and energy source - which are prerequisite for the bacteria to grow and cause disease. It is not a process that is well understood yet, but by first discovering how an organism gets nutrients by tricking the host into degrading proteins, and then interfering with that process, we can, in effect, starve it to death and prevent or treat the disease."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our infectious diseases / bacteria / viruses section for the latest news on this subject. With Abu Kwaik, authors of the paper are Christopher T.D. Price, Ph.D. and Tasneem Al-Quadan, a doctoral student, in UofL’s Department of Microbiology and Immunology; Marina Santic, Ph.D., of the University of Rijeka, Croatia; and Ilan Rosenshine, Ph.D., of the Hebrew University Medical School in Jerusalem, Israel.
The work was funded by a grant from the National Institute of Allergy and Infectious Diseases.
University of Louisville Please use one of the following formats to cite this article in your essay, paper or report:

MLA

University of Louisville. "Researcher Determines How Legionnaires' Bacteria Proliferate, Cause Disease." Medical News Today. MediLexicon, Intl., 21 Nov. 2011. Web.
8 Dec. 2011. APA

Please note: If no author information is provided, the source is cited instead.

Rate this article:
(Hover over the stars then click to rate)

Please note that we publish your name, but we do not publish your email address. It is only used to let you know when your message is published. We do not use it for any other purpose. Please see our privacy policy for more information.

If you write about specific medications or operations, please do not name health care professionals by name.

All opinions are moderated before being included (to stop spam)

Contact Our News Editors

For any corrections of factual information, or to contact the editors please use our feedback form.

Please send any medical news or health news press releases to:

Note: Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional. For more information, please read our terms and conditions.

View the original article here