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Legionella incubation

Helen Y Buse, Frank W Schaefer, Eugene W Rice
Transmission of Francisella tularensis, the etiologic agent of tularemia, has been associated with various water sources. Survival of many waterborne pathogens within free-living amoeba (FLA) is well documented; however, the role of amoebae in the environmental persistence of F. tularensis is unclear. In this study, axenic FLA cultures of Acanthamoeba castellanii, Acanthamoeba polyphaga, and Vermamoeba vermiformis were each inoculated with virulent strains of F. tularensis (Types A and B), the attenuated live vaccine strain, and Francisella novicida...
December 8, 2016: Acta Microbiologica et Immunologica Hungarica
Louise K Francois Watkins, Karrie-Ann E Toews, Aaron M Harris, Sherri Davidson, Stephanie Ayers-Millsap, Claressa E Lucas, Brian C Hubbard, Natalia A Kozak-Muiznieks, Edward Khan, Preeta K Kutty
OBJECTIVES To define the scope of an outbreak of Legionnaires' disease (LD), to identify the source, and to stop transmission. DESIGN AND SETTING Epidemiologic investigation of an LD outbreak among patients and a visitor exposed to a newly constructed hematology-oncology unit. METHODS An LD case was defined as radiographically confirmed pneumonia in a person with positive urinary antigen testing and/or respiratory culture for Legionella and exposure to the hematology-oncology unit after February 20, 2014. Cases were classified as definitely or probably healthcare-associated based on whether they were exposed to the unit for all or part of the incubation period (2-10 days)...
December 6, 2016: Infection Control and Hospital Epidemiology
Thorsten Dilger, Holger Melzl, André Gessner
Detection and enumeration of Legionella bacteria in drinking water is regulated in Germany by ISO 11731-2. The mandatory method for species identification employs parallel subculturing of suspicious colonies on selective media requiring the handling of a large number of cultivation plates. After changes to the drinking water quality regulation in Germany in 2012 the demand for Legionella contamination testing increased drastically. A more reliable, faster and less laborious method for species identification is therefore desirable...
August 2016: Journal of Microbiological Methods
Bidya Prasad, Kerry A Hamilton, Charles N Haas
A novel method was used to incorporate in vivo host-pathogen dynamics into a new robust outbreak model for legionellosis. Dose-response and time-dose-response (TDR) models were generated for Legionella longbeachae exposure to mice via the intratracheal route using a maximum likelihood estimation approach. The best-fit TDR model was then incorporated into two L. pneumophila outbreak models: an outbreak that occurred at a spa in Japan, and one that occurred in a Melbourne aquarium. The best-fit TDR from the murine dosing study was the beta-Poisson with exponential-reciprocal dependency model, which had a minimized deviance of 32...
May 26, 2016: Risk Analysis: An Official Publication of the Society for Risk Analysis
Anna Lena Jung, Cornelia Stoiber, Christina E Herkt, Christine Schulz, Wilhelm Bertrams, Bernd Schmeck
The formation and release of outer membrane vesicles (OMVs) is a phenomenon of Gram-negative bacteria. This includes Legionella pneumophila (L. pneumophila), a causative agent of severe pneumonia. Upon its transmission into the lung, L. pneumophila primarily infects and replicates within macrophages. Here, we analyzed the influence of L. pneumophila OMVs on macrophages. To this end, differentiated THP-1 cells were incubated with increasing doses of Legionella OMVs, leading to a TLR2-dependent classical activation of macrophages with the release of pro-inflammatory cytokines...
April 2016: PLoS Pathogens
María Reyes-Batlle, Carolina Wagner, Jonadab Zamora-Herrera, Alejandro Vargas-Mesa, Ines Sifaoui, Ana C González, Atteneri López-Arencibia, Basilio Valladares, Enrique Martínez-Carretero, José E Piñero, Jacob Lorenzo-Morales
Free-living amoebae (FLA) are widely distributed protozoa in the environment and have been isolated from many sources such as dust, soil and water. Furthermore, some genera/species of FLA such as Naegleria fowleri, Balamuthia mandrillaris and Acanthamoeba spp. are also able to cause opportunistic infections in humans and other animals. More recently, FLA have been reported to be environmental carriers of pathogenic bacteria, fungi and viruses, and thus have gained further importance from the public health point of view...
July 2016: Current Microbiology
Jessie A Gleason, Natalie R Kratz, Rebecca D Greeley, Jerald A Fagliano
The incidence of legionellosis, caused by the bacteria Legionella which are commonly found in the environment, has been increasing in New Jersey (NJ) over the last decade. The majority of cases are sporadic with no known source of exposure. Meteorological factors may be associated with increases in legionellosis. Time series and case-crossover study designs were used to evaluate associations of legionellosis and meteorological factors (temperature (daily minimum, maximum, and mean), precipitation, dew point, relative humidity, sea level pressure, wind speed (daily maximum and mean), gust, and visibility)...
June 2016: EcoHealth
Aruna Dorairaj, Sridharan Sathyamoorthy Kopula, Kennedy Kumar
INTRODUCTION: Pneumonia is one of the leading infectious causes of mortality and morbidity worldwide. Atypical respiratory pathogens account for 30 - 40% of these infections. The three most important atypical pathogens are Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila. AIM: To screen for atypical pathogens as cause for community acquired pneumonia. MATERIALS AND METHODS: A cross-sectional study was done with 107 patients who had clinical suspicion of atypical pneumonia...
November 2015: Journal of Clinical and Diagnostic Research: JCDR
Masoumeh Ahmadi Jalali Moghadam, Hamidreza Honarmand, Sajad Asfaram Meshginshahr
This study is designed to determine the contamination degree of hospital water supplies with Pseudomonas aeruginosa, Legionella pneumophila, and E. coli in Gilan, Iran. Samples were collected directly into sterile containers and concentrated by centrifuge. Half part of any sample transferred to yeast extract broth and the second part transferred to Trypticase Soy Broth and incubated for 3 days. DNA was extracted by using commercial kit. Four rounds of PCR were performed as follows: multiplex PCR for detecting Pseudomonas aeruginosa, Integron 1, and Metallo-β-lactamases gene; PCR for detecting Legionella pneumophila and mip gene separately; PCR for detecting E...
2015: Interdisciplinary Perspectives on Infectious Diseases
Nilmini Mendis, Peter McBride, Sébastien P Faucher
Legionella pneumophila (Lp) is the etiological agent responsible for Legionnaires' disease, a potentially fatal pulmonary infection. Lp lives and multiplies inside protozoa in a variety of natural and man-made water systems prior to human infection. Fraquil, a defined freshwater medium, was used as a highly reproducible medium to study the behaviour of Lp in water. Adopting a reductionist approach, Fraquil was used to study the impact of temperature, pH and trace metal levels on the survival and subsequent intracellular multiplication of Lp in Acanthamoeba castellanii, a freshwater protozoan and a natural host of Legionella...
2015: PloS One
Miriam Martín, Pedro Salazar, Carmen Jiménez, María Lecuona, Ma José Ramos, Jesús Ode, Julia Alcoba, Rossany Roche, Reynaldo Villalonga, Susana Campuzano, José Manuel Pingarrón, José Luis González-Mora
A novel amperometric magnetoimmunoassay, based on the use of core-shell magnetic nanoparticles and screen-printed carbon electrodes, was developed for the selective determination of Legionella pneumophila SG1. A specific capture antibody (Ab) was linked to the poly(dopamine)-modified magnetic nanoparticles (MNPs@pDA-Ab) and incubated with bacteria. The captured bacteria were sandwiched using the antibody labeled with horseradish peroxidase (Ab-HRP), and the resulting MNPs@pDA-Ab-Legionella neumophila-Ab-HRP were captured by a magnetic field on the electrode surface...
August 5, 2015: Analytica Chimica Acta
Osvalda De Giglio, Christian Napoli, Grazia Lovero, Giusy Diella, Serafina Rutigliano, Giuseppina Caggiano, Maria Teresa Montagna
OBJECTIVES: The purpose of this study was to describe the susceptibility of environmental strains of Legionella spp. to 10 antimicrobials commonly used for legionellosis therapy. A study of environmental strains could be useful to timely predict the onset of antibiotic resistance in the environment before it is evidenced in clinical specimens. METHODS: The minimum inhibitory concentrations (MICs) of 100 environmental Legionella pneumophila (Lpn) strains belonging to serogroups (sgs) 1, 6, 8, and 10 were tested using the E-test methodology on buffered charcoal yeast extract agar supplemented with α-ketoglutarate...
October 2015: Environmental Research
S Collins, F Jorgensen, C Willis, J Walker
AIMS: Culture remains the gold-standard for the enumeration of environmental Legionella. However, it has several drawbacks including long incubation and poor sensitivity, causing delays in response times to outbreaks of Legionnaires' disease. This study aimed to validate real-time PCR assays to quantify Legionella species (ssrA gene), Legionella pneumophila (mip gene) and Leg. pneumophila serogroup-1 (wzm gene) to support culture-based detection in a frontline public health laboratory...
October 2015: Journal of Applied Microbiology
David Otto Schwake, Absar Alum, Morteza Abbaszadegan
To examine the impact of environmental factors on Legionella in drinking water distribution systems, the growth and survival of Legionella under various conditions was studied. When incubated in tap water at 4 °C, 25 °C, and 32 °C, L. pneumophila survival trends varied amongst the temperatures, with the stable populations maintained for months at 25 °C and 32 °C demonstrating that survival is possible at these temperatures for extended periods in oligotrophic conditions. After inoculating coupons of PVC, copper, brass, and cast iron, L...
2015: Pathogens
David Otto Schwake, Absar Alum, Morteza Abbaszadegan
Epidemiological evidence suggesting driving cars to be a risk factor for legionellosis has prompted public health studies to investigate vehicle windshield washer fluid as a novel transmission source of this disease. The goal of the current study was to investigate whether or not windshield washer fluid could serve as a potential source of transmission for Legionella. A wide variation in the survival of L. pneumophila was observed when incubated in different washer fluids at 25 and 37 °C, however, one brand tested supported Legionella survival similar to or greater than sterilized deionized water...
September 1, 2015: Science of the Total Environment
Alicia Demirjian, Claressa E Lucas, Laurel E Garrison, Natalia A Kozak-Muiznieks, Stanley States, Ellen W Brown, Jonathan M Wortham, Amanda Beaudoin, Megan L Casey, Chandra Marriott, Alison M Ludwig, Ali F Sonel, Robert R Muder, Lauri A Hicks
BACKGROUND: Healthcare-associated Legionnaires' disease (LD) is a preventable pneumonia with a 30% case fatality rate. The Centers for Disease Control and Prevention guidelines recommend a high index of suspicion for the diagnosis of healthcare-associated LD. We characterized an outbreak and evaluated contributing factors in a hospital using copper-silver ionization for prevention of Legionella growth in water. METHODS: Through medical records review at a large, urban tertiary care hospital in November 2012, we identified patients diagnosed with LD during 2011-2012...
June 1, 2015: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
Vassilios Sandalakis, Dimosthenis Chochlakis, Ioannis Goniotakis, Yannis Tselentis, Anna Psaroulaki
In Greece standard tests are performed in the watering and cooling systems of hotels' units either as part of the surveillance scheme or following human infection. The purpose of this study was to establish the minimum inhibitory concentration (MIC) distributions of environmental Legionella isolates for six antimicrobials commonly used for the treatment of Legionella infections, by MIC-test methodology. Water samples were collected from 2004 to 2011 from 124 hotels from the four prefectures of Crete (Greece)...
December 2014: Journal of Water and Health
Helen Y Buse, Jingrang Lu, Nicholas J Ashbolt
Water conservation efforts have focused on gray water (GW) usage, especially for applications that do not require potable water quality. However, there is a need to better understand environmental pathogens and their free-living amoeba (FLA) hosts within GW, given their growth potential in stored gray water. Using synthetic gray water (sGW) we examined three strains of the water-based pathogen Legionella pneumophila and its FLA hosts Acanthamoeba polyphaga, A. castellanii, and Vermamoeba vermiformis. Exposure to sGW for 72 h resulted in significant inhibition (P < 0...
January 2015: Applied and Environmental Microbiology
Jens Jäger, Susanne Keese, Manfred Roessle, Michael Steinert, Andra B Schromm
The formation and release of outer membrane vesicles (OMVs) is a phenomenon observed in many bacteria, including Legionella pneumophila. During infection, this human pathogen primarily invades alveolar macrophages and replicates within a unique membrane-bound compartment termed Legionella-containing vacuole. In the current study, we analysed the membrane architecture of L. pneumophila OMVs by small-angle X-ray scattering and biophysically characterized OMV membranes. We investigated the interaction of L...
May 2015: Cellular Microbiology
Donica Liu-Baker, Mittal Mayank, Will Roland
SESSION TITLE: Infectious Disease Student/Resident Case Report Posters IIISESSION TYPE: Medical Student/Resident Case ReportPRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PMINTRODUCTION: This case report describes a rare presentation of histoplasmosis and emphasizes the importance of maintaining suspicion in endemic areas. CASE PRESENTATION: A 62 year old veteran from mid-Missouri was admitted with a one month history of SOB, cough productive of green sputum, and weight loss of 2...
October 1, 2014: Chest
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