Free-living amoebae (FLA): detection, morphological and molecular identification ofAcanthamoebagenus in the hydraulic system of an haemodialysis unit in Tunisia

Abstract

Summary :The free-living amoebae (FLA) are ubiquitous and opportunistic protozoa. They can induce human and animal diseases. The aim of our study was to detect the FLA and Acanthamoeba genus in the hydraulic system of an hemodialysis unit. It was a prospective study of 46 water samples. The first collect (23) was before cleaning and after the haemodialysis sessions and the second (23) after cleaning and before the hemodialysis sessions. Results: the morphological study enabled us to detect morphotypic diversity. The predominant morphotypes were the acanthopodial forms (29 %). At the entrance of hemodialysis unit there were acanthopodial (44 %) and monotactic (25 %) forms; at the outlet, acanthopodial and fan-shaped forms (25 % each). In addition, Acanthamoeba genus was present in 39 % (1 st collect) and 18 % (2 nd collect). The amplification of the FLA 18S rDNA gene was negative in only one sample localized in the last stage of water treatment unit (WTU). The amplification of the 18S rDNA (ASA.A1) Acanthamoeba gene was positive in15 samples. Conclusions: we noted that, in the hemodialysis unit, the purification techniques used in the WTU were effective, but there is a problem of water stagnation in the drain, which constitutes an appropriate condition for the biofilms formation. It is then necessary to use a filter with a low porosity (0.2 µm) at the entrance of the hemodialysis unit and if possible to change the drain. Résumé

Acanthamoeba contamination of hemodialysis and dental units in Alexandria, Egypt: A neglected potential source of infection

“…Confirmation of Acanthamoeba, based on size and the presence of acanthopodia and a large central karyosome, was performed using trichrome-stained smears. Smears were examined microscopically for Acanthamoeba trophozoites and/or cysts at 1000× magnification under a light microscope [8].…”

“…Acanthamoeba spp. have also been recovered from shower heads, ventilators, hydrotherapy baths and heating, ventilation, and air conditioning units in the hospital environment and dental irrigation systems [8]. Dendana et al [8] reported that water at the entrance of hemodialysis apparatus contained FLA, with many FLA of the genus Acanthamoeba.…”

“…have also been recovered from shower heads, ventilators, hydrotherapy baths and heating, ventilation, and air conditioning units in the hospital environment and dental irrigation systems [8]. Dendana et al [8] reported that water at the entrance of hemodialysis apparatus contained FLA, with many FLA of the genus Acanthamoeba. These authors attributed this contamination to the long stagnation of water, which could lead to the development of biofilms, providing favorable conditions for the growth and proliferation of many microbes and FLA [8].…”

“…Dendana et al [8] reported that water at the entrance of hemodialysis apparatus contained FLA, with many FLA of the genus Acanthamoeba. These authors attributed this contamination to the long stagnation of water, which could lead to the development of biofilms, providing favorable conditions for the growth and proliferation of many microbes and FLA [8]. In addition, these amoebae have been found in dental water lines [9,10].…”

Free-living Amoebae (FLA): morphological and molecular identification ofAcanthamoebain dental unit water

“…A previous study was performed in a dialysis unit (Dendena et al, 2008). A wide range of microorganisms has been isolated from DUW, including fungi, FLA, opportunistic and human pathogen bacteria (Parrott et al, 1982;Pankhurst et al, 2003), but few studies were published about the diseases related to dental water.…”