Mem Inst Oswaldo Cruz, Rio de Janeiro, 112(12) December 2017
Original Article

Potentially pathogenic Acanthamoeba genotype T4 isolated from dental units and emergency combination showers

Esteban Castro-Artavia1,2, Lissette Retana-Moreira1,2, Jacob Lorenzo-Morales3, Elizabeth Abrahams-Sandí1,2,+

1University of Costa Rica, Faculty of Microbiology, Department of Parasitology, San Pedro, San José, Costa Rica
2University of Costa Rica, Centro de Investigación en Enfermedades Tropicales, San Pedro, San José, Costa Rica
3University of La Laguna, Institute of Tropical Diseases and Public Health of the Canary Islands, Tenerife, Spain

DOI: 10.1590/0074-02760170147
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BACKGROUND Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae.

OBJECTIVE The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques.

METHODS Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed.

FINDINGS All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer.

MAIN CONCLUSION The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae.

Financial support: Vicerrectoría de Investigación, University of Costa Rica (project 803-B4-050). JLM was supported by the grants RICET (Project no. RD12/0018/0012), Spanish Ministry of Health, Madrid, Spain (Project PI13/00490 from the Instituto de Salud Carlos III), Project ref. AGUA3 from Caja Canarias Fundación, and the Ramón y Cajal Subprogramme from the Spanish Ministry of Economy and Competitivity (RYC-2011-08863).
+ Corresponding author:
Received 13 April 2017
Accepted 20 June 2017

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