Allovahlkampfia spelaea Causing Keratitis in Humans

作者：Tolba Mohammed Essa Marghany^*; Huseein Enas Abdelhameed Mahmoud; Farrag Haiam Mohamed Mahmoud; Mohamed Hanan El Deek; Kobayashi Seiki; Suzuki Jun; Ali Tarek Ahmed Mohamed; Sugano Sumio

来源：PLoS Neglected Tropical Diseases, 2016, 10(7): e0004841.

DOI：10.1371/journal.pntd.0004841

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 sightthreatening 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.

• 出版日期2016-7