Allovahlkampfia spelaea Causing Keratitis in Humans

Area of Science:

• Microbiology
• Infectious Diseases
• Ophthalmology

Background:

• Free-living amoebae (FLAs) are ubiquitous microorganisms capable of causing human diseases.
• Acanthamoeba sp. is a well-known cause of severe keratitis, particularly in developing nations.
• The Vahlkampfiidae family, including the newly identified Allovahlkampfia spelaea, has rarely been associated with human infections.

Purpose of the Study:

• To identify the specific free-living amoeba responsible for a keratitis case in an Egyptian patient.
• To investigate the pathogenic potential of Allovahlkampfia spelaea in human infections.

Main Methods:

• Monoxenic culture of pathogenic amoebae.
• Morphological characterization and 18S ribosomal RNA (rRNA) gene sequencing for identification.
• Experimental induction of keratitis in a rabbit model to assess pathogenicity.

Main Results:

• Allovahlkampfia spelaea was identified as the causative agent of human keratitis.
• The Egyptian strain's 18S rRNA gene sequence showed close relation to a previously isolated Slovenian strain.
• Experimental models confirmed the organism's ability to induce keratitis.

Conclusions:

• This is the first report of Allovahlkampfia spelaea causing human keratitis, establishing it as a human pathogen.
• Integrated morphological and molecular diagnostic approaches are crucial for accurate amoebic keratitis diagnosis.
• Employing diverse primer sets and DNA sequencing is essential to avoid misdiagnosis of amoebic infections.