Epidemiology and Control of Legionellosis, Singapore

Lam, Meng

doi:10.3201/eid1707.101509

Cited by 24 publications

(21 citation statements)

References 24 publications

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“…These symptoms have been reported previously as a common clinical signs of legionellosis caused by L. pneumophila [27]. Chon Lam et al (2011) [24] reported that the main clinical features of reported cases of RTIs caused by L. pneumophila were cough (77.9%), fever (72.7%), shortness of breath (32.5%), chest pain (13.3%) and nausea (11.8%) which was similar to our results.…”

Section: Resultssupporting

confidence: 92%

“…A total of 202 patients hospitalized with a diagnosis of CAP were enrolled in a Korean study and 3 samples (2.4%) were positive for L. pneumophila which also was lower than our results [23]. Total incidence of L. pneumophila in Southeast Asia was 0.28 cases per 100,000 population (0.1%) [24], while its incidence among European countries were 1.18% (100,000 cases in 2008) [25]. The above investigations highlight large differences in the prevalence of L. pneumophila.…”

Section: Resultscontrasting

confidence: 74%

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Molecular depiction of lepA, lidA, ralF, rtxA and lvhB virulence factors of Legionella pneumophila isolated from respiratory tract infections

2015

Int Arch Med

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Background: Among all bacterial species in the genus Legionella, Legionella pneumophila is responsible for 90% of Legionella infections in humans. Putative virulence genes are the main factors in pathogenesis of L. pneumophila. The aim of this study was to determine the incidence of L. pneumophila in the broncho alveolar lavages of patients hospitalized due to respiratory tract infections as well as study the distribution of lepA, lidA, ralF, rtxA and lvhB virulence factors in bacterial strains. Methods:One hundred fifty BAL samples were collected from patients who were referred to several Iranian health centers. Samples were cultured and those that were L. pneumophila positive were subjected to PCR method targeting the 16S rRNA gene. Samples positive for Legionella were analyzed for presence of latent virulence factors.Results: Thirteen out of 90 male BAL samples (14.4%) and 5 out of 60 female BAL samples (8.3%) were positive for L. pneumophila (P =0.046). Patients older than 50 years had the highest incidence of L. pneumophila (20%), while patients younger than 15 years old had the lowest (4.16%) (P =0.017). All patients positive for L. pneumophila had fever, while the distribution of cough, dyspnea, chest pain and headache were 77.7%, 77.7%, 66.6% and 44.4%, respectively. The most commonly detected virulence factors among L. pneumophila isolates were lidA (50%) and ralF (27.77%). . RTIs are usually caused by viruses, however the roles of bacteria are also significant. One of the most commonly considered pathogens in the cases of RTIs and pneumonia is Legionella species (Legionella spp.). Although several species of the genus Legionella were subsequently identified in the cases of RTIs, Legionella pneumophila (L. pneumophila) is the most frequent cause of human legionellosis or Legionnaires Disease (LD) and also a comparatively common cause of community-acquired and nosocomial pneumonia in adults [2]. In children, L pneumophila is also a significant, although quite scarce, cause of pneumonia. It has been estimated that 18,000 patients are admitted annually in the United States due to the LD which is quite significant [3].L. pneumophila are gram-negative, fastidious and aerobic bacilli, catalase-positive, heterotrophic, motile, non-fermentative and urease and nitrate negative bacterium [4]. RTIs caused by this bacterium are usually known by fever, confusion, headache, abdominal pain, diarrhea, chills, and myalgia as well as a non-productive cough [5]. Mortality rate of L. pneumophila RTIs is reported to be 15-25% [5,6].Most outbreaks and sporadic cases of RTIs caused by L. pneumophila have been attributed to presence of certain virulence factors. The products of genes are involved in the initial attachment to host cells and early stages of intracellular infection like the pore formation protein rtxA [7]. Another group of genes are those required for bacterial survival and intracellular replication like a number of effectors including ralF, lidA and lepA [8]. Legionella vir homolog (lvh) is a type IV sec...

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Section: Resultssupporting

confidence: 92%

Section: Resultscontrasting

confidence: 74%

Molecular depiction of lepA, lidA, ralF, rtxA and lvhB virulence factors of Legionella pneumophila isolated from respiratory tract infections

2015

Int Arch Med

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“…La legionelosis (Enfermedad del legionario y Fiebre de Pontiac) es una infección respiratoria aguda vinculada al medio ambiente. Su origen es la bacteria Legionella, de la que en la actualidad se han descrito 52 especies y 70 serogrupos, 25 conocidas como causantes de enfermedad [1]. Fundamentalmente es Legionella pneumophila la responsable de la mayoría de las infecciones humanas, con serogrupo 1 como el principal.…”

Section: Introductionunclassified

Legionelosis asociada con viajes en España, serie 1997-2002

Gea-Izquierdo

2017

archmed

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Objetivo: analizar el desarrollo de la legionelosis en España durante los años 1997-2002, mediante números crudos, y su relación con el European Surveillance Scheme for Travel Associated Legionnaires’ Disease. La legionelosis es una enfermedad respiratoria que puede resultar mortal. En España es considerada como de declaración obligatoria desde 1995. En 1986 se creó The European Working Group for Legionella Infections y al año siguiente el European Surveillance Scheme for Travel Associated Legionnaires’ Disease. Materiales y métodos: estudio de carácter descriptivo mediante la recopilación de los casos, brotes y defunciones por legionelosis, para la serie indicada, a través de las notificaciones efectuadas al Centro Nacional de Epidemiología. Resultados: se determina la implicación en el ámbito comunitario, nosocomial y el European Surveillance Scheme for Travel Associated Legionnaires’ Disease. Esta afecta al número total en todos los ámbitos y, en especial, en los brotes, casos y defunciones en los años 1997, 1998 y 2000; mientras que los mayores registros para estos eventos en la serie estudiada acontecieron en los años 2002 (62), 2001 (772) y 2000 (25), respectivamente. Conclusiones: la vigilancia epidemiológica constituye una herramienta muy valiosa para la prevención y control de la enfermedad. El análisis de las series temporales puede arrojar información relevante del comportamiento de la legionelosis y de las fuentes de desarrollo del agente inductor de la enfermedad.

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“…is ubiquitous in the aquatic environment, particularly in warm (25–42°C) stagnant water (Kool et al ). Over 50 species and 70 serotypes have been identified (Lam et al , Yarom et al ), with Legionella pneumophila serotype 1 as the strain with the greatest public health significance in North America (http://www.cdc.gov/vitalsigns/legionnaires/). Since 2001, reported outbreaks of legionellosis in the US have increased 400%, and it has become the most commonly reported waterborne pathogen—responsible for two‐thirds of all drinking water outbreaks (http://www.cdc.gov/vitalsigns/legionnaires/).…”

mentioning

confidence: 99%

Occurrence of Legionella in Nonpotable Reclaimed Water

et al. 2018

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Legionella was monitored in reclaimed water systems and were detected by culture in 50% of 115 samples, while 80% of the samples were positive by quantitative polymerase chain reaction (qPCR). The lowest level of Legionella was in a system that practiced biological nutrient removal and maintained an average 0.3 mg/L free chlorine residual. The difference between qPCR and ethidium monoazide treated samples was used as an indicator of viability, and the greatest difference was in a chloraminated system, where the molecular method indicated a 9% viability. Ninety-six percent of the species were L. pneumophila, and 87% were identified as L. pneumophila serotype 1. Total amoebae (summed as cysts or trophozoites) were detected in 100% of samples from all six systems, and were mostly (50-95%) in the active trophozoite phase. In the chloraminated system, 87% of the mesophilic amoebae and 66% of the thermophilic amoebae were in the cyst phase.

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Epidemiology and Control of Legionellosis, Singapore

Cited by 24 publications

References 24 publications

Molecular depiction of lepA, lidA, ralF, rtxA and lvhB virulence factors of Legionella pneumophila isolated from respiratory tract infections

Molecular depiction of lepA, lidA, ralF, rtxA and lvhB virulence factors of Legionella pneumophila isolated from respiratory tract infections

Legionelosis asociada con viajes en España, serie 1997-2002

Occurrence of Legionella in Nonpotable Reclaimed Water

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