Naegleria lovaniensis new species: Isolation and identification of six thermophilic strains of a new species found in association with Naegleria fowleri

Stevens, A. R.; Jonckheere, J. De; Willaert, E

doi:10.1016/0020-7519(80)90064-8

Cited by 85 publications

(56 citation statements)

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“…For example, attachment to the nasal epithelium by N. fowleri has been reported to be an important early event in the pathogenesis of PAM (Martinez et al, 1973). Studies characterizing experimentally induced PAM in mice have shown that deep invasion occurs after N. fowleri amoebae penetrate the basement membrane (Martinez et al, 1973).In the present study, two species within the genus Naegleria, one linked to pathogenicity in humans (Carter, 1968; Cerva & Novȃk, 1968;Martinez, 1985) and the other a non-pathogen (Stevens et al, 1980;Marciano-Cabral & Fulford, 1986), were selected for assessment of differences in attachment to, and invasion of, ECM components. A differential level of binding to laminin-1, collagen I and fibronectin was observed for N. fowleri versus N. lovaniensis.…”

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confidence: 84%

“…Thermotolerance is not seen with N. gruberi, and it has been proposed that this lack of heat tolerance results in humans and other mammals, such as mice, being non-permissive hosts (Marciano-Cabral & Fulford, 1986). Furthermore, N. lovaniensis is thermotolerant and can survive at temperatures of 37 u C and higher (Stevens et al, 1980), yet has not been associated with human infection.The interaction of cells with ECM components plays an important role in mediating cell adhesion and migration (Berrier & Yamada, 2007), and promoting invasion of host tissue. Binding to, and passage through, ECM components by micro-organisms have been implicated in the pathogenesis of bacterial, viral, protozoan and fungal infections (Alderete et al, 2002;Boshuizen et al, 2004;de Bentzmann et al, 2004; Gozalbo et al, 1998;Hostetter, 1999;Kottom et al, 2008;Lama et al, 2009;Casta e Silva Filho et al, 1988).…”

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Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins

et al. 2012

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Naegleria fowleri and Naegleria lovaniensis are closely related free-living amoebae found in the environment. N. fowleri causes primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system, while N. lovaniensis is non-pathogenic. N. fowleri infection occurs when the amoebae access the nasal passages, attach to the nasal mucosa and its epithelial lining, and migrate to the brain. This process involves interaction with components of the host extracellular matrix (ECM). Since the ability to invade tissues can be a characteristic that distinguishes pathogenic from non-pathogenic amoebae, the objective of this study was to assess adhesion to, and invasion of, the ECM by these two related but distinct Naegleria species. N. fowleri exhibited a higher level of adhesion to the ECM components laminin-1, fibronectin and collagen I. Scanning electron microscopy revealed that N. fowleri attached on ECM substrata exhibited a spread-out appearance that included the presence of focal adhesion-like structures. Western immunoblotting revealed two integrin-like proteins for both species, but one of these, with a molecular mass of approximately 70 kDa, was detected at a higher level in N. fowleri. Confocal microscopy indicated that the integrin-like proteins co-localized to the focal adhesionlike structures. Furthermore, anti-integrin antibody decreased adhesion of N. fowleri to ECM components. Finally, N. fowleri disrupted 3D ECM scaffolds, while N. lovaniensis had a minimal effect. Collectively, these results indicate a distinction in adhesion to, and invasion of, ECM proteins between N. fowleri and N. lovaniensis. INTRODUCTIONThe genus Naegleria consists of species of free-living amoebae that are found worldwide in soil, and freshwater lakes and ponds Martinez & Visvesvara, 1997). Although numerous species from this genus have been identified in the environment and in domestic water supplies (Anderson & Jamieson, 1972;Craun et al., 2005;Gyori, 2003;Jamerson et al., 2009;Marciano-Cabral et al., 2003;Yoder et al., 2004), only one species, Naegleria fowleri, has been linked to disease in humans (Carter, 1968; Cerva & Novȃk, 1968;Martinez, 1985). N. fowleri is the causative agent of primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system (CNS) that occurs in individuals who have been engaged recently in activities such as swimming or diving in warm freshwater bodies (Carter, 1968;Martinez, 1985). Infection occurs when amoebae enter the nasal passages and attach to the nasal mucosa (Carter, 1972;Martinez, 1985). Following contact with the nasal epithelium, amoebae penetrate the underlying basement membrane and migrate to the brain, wherein they multiply and destroy tissues, resulting in haemorrhagic necrosis and death (Jarolim et al., 2000;Martinez et al., 1973;Martinez, 1985). While the attachment process may induce an innate immune response, N. fowleri appears to be resistant. For example, it has been reported that it activates the complement system but is...

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Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins

et al. 2012

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“…The correct identification of N. fowleri is difficult because several genera of amoebae found in the same ecological habitat are morphologically similar (33,39). Furthermore, pathogenic N. fowleri and nonpathogenic Naegleria lovaniensis are antigenically related (39).…”

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confidence: 99%

“…Furthermore, pathogenic N. fowleri and nonpathogenic Naegleria lovaniensis are antigenically related (39). Therefore, a sensitive and specific nested-PCR assay was developed in our laboratory to identify N. fowleri in water and soil samples (35; R. MacLean, D. J. Richardson, R. LePardo, and F. Marciano-Cabral, submitted for publication).…”

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Identification of Naegleria fowleri in Domestic Water Sources by Nested PCR

Marciano‐Cabral

MacLean

Mensah

et al. 2003

Appl Environ Microbiol

101

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The free-living amoeboflagellate Naegleria fowleri is the causative agent of primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system. In the United States, the disease is generally acquired while swimming and diving in freshwater lakes and ponds. In addition to swimming, exposure to N. fowleri and the associated disease can occur by total submersion in bathwater or small backyard wading pools. In the present study, swipe samples and residual pipe water from homes in Arizona were examined for N. fowleri by nested PCR due to the death of two previously healthy children from PAM. Since neither child had a history of swimming in a freshwater lake or pond prior to the onset of disease symptoms, the domestic water supply was the suspected source of infection. Of 19 samples collected from bathroom and kitchen pipes and sink traps, 17 samples were positive for N. fowleri by PCR. A sample from a Micro-Wynd II filter was obtained by passing water from bathtubs through the filter. Organisms attached to the filter also tested positive by PCR. The two samples that tested negative for N. fowleri were one that was obtained from a kitchen sink trap and a swipe sample from the garbage disposal of one home.

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“…Naegleria è stata anche isolata da impianti idrici domestici, torri di raffreddamento ed effluenti di processi industriali (41). La capacità di resistere alle alte temperature non è tuttavia direttamente correlata alla patogenicità; infatti, la specie N. lovaniensis, pur termotollerante, risulta non patogena in modelli animali (58). La presenza di questo genere di amebe in acque ad uso ricreativo costituisce un pericolo per la salute umana.…”

Section: Introduzioneunclassified

Free living amoebae in water environment: health implications

Briancesco¹,

Bonadonna²

2014

Microbiol Med

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INTRODUZIONETra gli agenti microbici responsabili di patologie umane trasmesse attraverso l'acqua le amebe a vita libera rivestono un ruolo particolare. Infatti, oltre ad essere note per la patogenicità di alcuni generi e specie, manifestano anche la potenzialità di veicolare microrganismi patogeni presenti nell'ambiente idrico. Le amebe a vita libera sono protozoi unicellulari che possono vivere all'interno di un ospite in condizioni di parassitismo facoltativo o avere un'esistenza autonoma. Per tale proprietà sono anche indicate col termine di amebe anfizoiche. Nell'ambiente possono essere rinvenute nella forma vegetativa, il trofozoite, che si alimenta di microrganismi presenti nell'acqua e nel suolo, e sotto forma di cisti metabolicamente inattiva, che rappresenta la forma di resistenza ambientale. Non dipendendo da un ospite per la trasmissione e diffusione, sono ubiquitarie e ampiamente rinvenibili in natura; il loro habitat naturale è costituito da bacini d'acqua naturali ed artificiali, fango e suoli. Ne esistono centinaia di specie ma quelle di interesse sanitario sono in numero limitato ed includono le specie Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris e Sappinia diploidea che possono essere responsabili di patologie anche ad esito fatale, in taluni casi persino in individui immunocompetenti. Per la capacità di sopravvivere nei mammiferi, possono essere considerate pseudo-parassiti con un ciclo biologico potenzialmente patogeno. Il primo caso di meningoencefalite amebica fu descritto nel 1965 in Australia (16), dapprima impropriamente attribuito ad Acanthamoeba e, solo successivamente, ascritto ad amebe del genere Naegleria. Cheratiti da Acanthamoeba sono state per la prima volta diagnosticate nel 1974 nel Regno Unito e nel 1975 negli Stati Uniti, rispettivamente da Naginton e da Jones (26, 45). Il primo caso di infezione umana attribuito a Balamuthia risale invece al 1993. Ad Hartmannella, termine che originariamente veniva usato come sinonimo del genere Acanthamoeba e che, solo in seguito, è stato utilizzato per indicare amebe di un genere distinto, non sono state ad oggi associate patologie umane. Per il basso numero di infezioni riscontrate, le amebe non hanno mai rappresentato un argomento sanitario di interesse prioritario, anche se la mancanza di farmaci efficaci e l'esito quasi sempre fatale delle malattie indotte da alcune specie, le hanno sempre rese oggetto di interesse e di studio nell'area della microbiologia ambientale. Negli anni più recenti tuttavia, un'attenzione particolare è loro rivolta per il potenziale ruolo di veicolo all'uomo di microrganismi patogeni presenti nell'ambiente idrico. Infatti, sembra che circa un quarto degli isolati di origine ambientale, clinica o derivanti da lenti a contatto contengono batteri endosimbionti (17). Di seguito viene pertanto presentato lo stato dell'arte sulle specie amebiche la cui diffusione nell'ambiente idrico potrebbe costituire un rischio per la salute umana. Verranno descritte le caratteristiche ecologiche di questi organi...

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Naegleria lovaniensis new species: Isolation and identification of six thermophilic strains of a new species found in association with Naegleria fowleri

Cited by 85 publications

References 16 publications

Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins

Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins

Identification of Naegleria fowleri in Domestic Water Sources by Nested PCR

Free living amoebae in water environment: health implications

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