Allovahlkampfia spelaea Causing Keratitis in Humans

Mohammed Essa Marghany Tolba, Enas Abdelhameed Mahmoud Huseein, Haiam Mohamed Mahmoud Farrag, Hanan El Deek Mohamed, Seiki Kobayashi, Jun Suzuki, Tarek Ahmed Mohamed Ali, Sumio Sugano

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6 Citations (Scopus)

Abstract

Background: Free-living amoebae are present worldwide. They can survive in different environment causing human diseases in some instances. Acanthamoeba sp. is known for causing sight-threatening keratitis in humans. Free-living amoeba keratitis is more common in developing countries. Amoebae of family Vahlkampfiidae are rarely reported to cause such affections. A new genus, Allovahlkampfia spelaea was recently identified from caves with no data about pathogenicity in humans. We tried to identify the causative free-living amoeba in a case of keratitis in an Egyptian patient using morphological and molecular techniques. Methods: Pathogenic amoebae were culture using monoxenic culture system. Identification through morphological features and 18S ribosomal RNA subunit DNA amplification and sequencing was done. Pathogenicity to laboratory rabbits and ability to produce keratitis were assessed experimentally. Results: Allovahlkampfia spelaea was identified as a cause of human keratitis. Whole sequence of 18S ribosomal subunit DNA was sequenced and assembled. The Egyptian strain was closely related to SK1 strain isolated in Slovenia. The ability to induce keratitis was confirmed using animal model. Conclusions: This the first time to report Allovahlkampfia spelaea as a human pathogen. Combining both molecular and morphological identification is critical to correctly diagnose amoebae causing keratitis in humans. Use of different pairs of primers and sequencing amplified DNA is needed to prevent misdiagnosis.

Original languageEnglish
Article numbere0004841
JournalPLoS Neglected Tropical Diseases
Volume10
Issue number7
DOIs
Publication statusPublished - 2016 Jul 14

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ASJC Scopus subject areas

  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Tolba, M. E. M., Huseein, E. A. M., Farrag, H. M. M., Mohamed, H. E. D., Kobayashi, S., Suzuki, J., Ali, T. A. M., & Sugano, S. (2016). Allovahlkampfia spelaea Causing Keratitis in Humans. PLoS Neglected Tropical Diseases, 10(7), [e0004841]. https://doi.org/10.1371/journal.pntd.0004841