Search results for "Legionella"
showing 10 items of 52 documents
Phylogenetic analysis of environmental Legionella pneumophila isolates from an endemic area (Alcoy, Spain).
2015
Environmental surveillance of Legionella pneumophila is a key component of the control measures established in urban settlements to ensure water safety and quality, with the aim of minimizing and limiting opportunistic infections in humans. In this work, we present results on the detection and genetic characterization of these bacteria in the outbreak-recurrent region of Alcoy (Comunidad Valenciana, Spain) using water and biofilm samples. We were particularly interested in studying the presence and distribution of L. pneumophila in the absence of outbreak or sporadic cases of legionellosis and in comparing the efficacy of culturing from water samples with a biofilm-based detection procedure…
Comparative evaluation of three different genotyping methods for investigation of nosocomial outbreaks of Legionnaires' disease in hospitals.
2000
ABSTRACT The increased incidence of nosocomial Legionnaires' disease in two hospitals prompted investigation of possible environmental sources. In the search for an effective DNA-typing technique for use in hospital epidemiology, the performance and convenience of three methods— Sfi I macrorestriction analysis (MRA), amplified fragment length polymorphism (AFLP), and arbitrarily primed PCR (AP-PCR)—were compared. Twenty-nine outbreak-associated and eight nonassociated strains of Legionella pneumophila with 13 MRA types and subtypes were investigated. These strains comprised isolates from bronchoalveolar lavages, from environmental, patient-related sources, and type strains. All three typing…
Comparison of clinical and environmental samples of Legionella pneumophila at the nucleotide sequence level
2009
Legionella pneumophila serogroup 1 is the most common etiological agent of legionellosis. We have used clinical and environmental isolates from different sources to compare their genetic variability. We have obtained the nucleotide sequence for six protein-coding loci, included in the SBT scheme for L. pneumophila, and three intergenic regions from 127 samples, 47 of environmental origin and 80 from clinical samples. Levels of genetic variability were found to be higher in the environmental than in the clinical samples, but these did not represent a mere subset of the former. Not a single case of full identity between clinical and environmental isolates was found, which raises the possibili…
GyrA sequence-based typing of Legionella.
2000
Comparative sequence analysis of a 423-bp segment of the gyrA gene including a region homologous to the quinolone resistance-determining region (QRDR) of other species was evaluated as a novel typing method for Legionella strains. The study was performed with 29 reference strains representing 11 different Legionella species, with various serogroups, and with 13 clinical isolates of L. pneumophila. Pulsed-field gel electrophoresis and serotyping were employed for comparison of the clinical isolates. QRDR sequencing proved to be a highly discriminative tool for typing Legionellae, and permitted identification of species, serogroups and even different strains within serogroup 1. None of the is…
Four-Year Environmental Surveillance Program of Legionella spp. in One of Palermo’s Largest Hospitals
2022
Legionella is a ubiquitous bacterium that lives in freshwater environments and colonizes human-made water systems. Legionella pneumophila is the most virulent species, and risk factors for Legionnaires’ disease include increasing age, smoking, chronic diseases, and immunodeficiency. For this reason, it is very important to assess and monitor hospital water systems in order to prevent legionellosis. We have monitored a large hospital in Palermo for four years. To determine the presence of microorganisms, according to national guidelines, we used the culture method, which is considered the gold standard for Legionella detection. Sampling was divided into five macro-areas, and a total of 251 s…
Detection and quantification of Streptococcus pneumoniae from Iranian patients with pneumonia and individual carriers by real time PCR
2011
The aim of this study was to develop a real time polymerase chain reaction (PCR) for quantitative detection of Streptococcus pneumoniae from clinical respiratory specimens. Initially, 184 respiratory specimens from patients with community acquired pneumonia (CAP) (n = 129) and 55 cases with hospital associated pneumonia (HAP) were bacteriologically investigated. To check the colonization status among the healthy individuals, 32 preschool and 31 adults were screened in parallel. All specimens were cultured on selective culture media to isolate S. pneumoniae, Legionella spp. and Mycoplasma spp. A 166 bp fragment corresponding to cbp A gene of S. pneumoniae was amplified from clinical specimen…
Enfermedad del legionario con afectación hepática predominante
2002
Like other pneumonias due to atypical agents, pneumonia due to Legionela Pneumophila has no characteristic clinical facts, although fever and non-productive cough are almost constant and diarrhea with changes in mental status are common. Hyponatremia and moderate transient hypertransaminasemia are common too. Severe systemic affectation after hematogenous dissemination similar to those described with typical bacterial pneumonias is a prominent difference with other atypical agents, with high mortality rates in the absence of appropriate treatment. Etiological diagnosis is very difficult and it is normally achieved late in the course of the infection. Because of diagnostic difficulties and p…
Procesos puntuales como herramienta para el análisis de posibles fuentes de contaminación
2002
El análisis de un patrón puntual engloba una serie de técnicas que permiten estudiar la distribución de un conjunto de eventos ocurridos sobre una región del plano. Este problema surge en epidemiología cuando se investiga una potencial fuente de contaminación ambiental alrededor de la cual se sospecha que surgen casos de una determinada enfermedad. En el presente trabajo, se explica brevemente en qué consiste el análisis de un patrón puntual y se ilustra con una aplicación a la determinación del origen medioambiental y al estudio de las zonas de mayor riesgo de incidencia en un brote de neumonía por Legionella ocurrido entre mediados de septiembre y principios de octubre en la ciudad de Alc…
Photocatalytic inactivation of Legionella Pneumophila and aerobic bacteria consortium in water over TiO2/SiO2 fibres in a continuous reactor
2005
A continuous photoreactor, working in a total recycle mode and irradiated by a low-pressure Hg lamp, has been used to study the bactericidal effect of a photocatalyst, formed by TiO2 embedded in SiO2 fibres, on Legionella pneumophila and a consortium of common gram-negative aerobic bacteria: (Escherichia coli, Klebsiella sp., Pseudomona sp. and Proteus sp.) in water. The kinetic modeling of the inactivation process, carried out with the measured values of viable bacteria concentration at the outlet of photoreactor, evidenced that for each pass inside the photoreactor the ratio between the outlet and inlet cell concentrations was of order of 0.01 for the inactivation of L. pneumophila. For t…
A combined molecular typing approach does not discriminate Legionella pneumophila serogroup 1 strains of a predominant sequence-based type in Palermo…
2009
Summary: The sequence-based type 1,4,3,1,1,1 of Legionella pneumophila sg.1 is predominant in the Palermo city environment since several years. In this study, extended sequence-based typing and pulsed field gel electrophoresis were used in a combined approach in the aim to enhance discriminatory power of the molecular typing procedures. However, probably due to a common environmental reservoir and genetic stability, most of the strains circulating in the geographic area under study belong to the same clone and are, consequently, indistinguishable by molecular typing. Investigations of clinical cases and tracing to their environmental source require caution and support from sound epidemiolog…