title: Investigations of an extraordinary endocytobiont in Acanthamoeba sp.: development and replication.
abstract: In this article, the results of investigations concerning a parasitic endocytobiont within the host amoebae (Acanthamoeba sp.) are presented. The endocytobiont was recently isolated from the contact lens and the inflamed eye of a patient with keratitis. Light microscopy and electron microscopy were performed to provide morphological details: Light microscopy revealed the presence of ovoid microorganisms developing and proliferating within the cytoplasm of the amoebic trophozoites. Details of the unusual development of these endocytobionts within the amoebae could be studied and demonstrated by means of electron microscopy. Foldings and morphological reorganization of the microorganisms took place exclusively within the host cytoplasm. The intracellularly aggregating organisms led to the rupture of the Acanthamoeba trophozoites after proliferation. Numerous microorganisms were released, which were infectious and were subsequently ingested by hitherto uninfected acanthamoebic trophozoites. To evaluate the in vitro growth of the isolated endocytobionts (without their hosts), they were transferred to several different culture plates. There was no growth of these unique organisms on five different common cultural plates suitable for the growth of bacteria and fungi.
authors.affiliation: Laboratory of Medical Parasitology, Central Institute of the Bundeswehr Medical Service Koblenz, Andernacherstr 100, 56070 Koblenz, Germany. patrickscheid@bundeswehr.org
authors.forename: Patrick
authors.initials: P
authors.lastname: Scheid
authors.forename: Bärbel
authors.initials: B
authors.lastname: Hauröder
authors.forename: Rolf
authors.initials: R
authors.lastname: Michel
mesh_terms: D000048:Acanthamoeba / Q000469:parasitology*; D000818:Animals; D003593:Cytoplasm / Q000469:parasitology*; D008854:Microscopy, Electron; D010271:Parasites / Q000254:growth & development* / Q000302:isolation & purification / Q000648:ultrastructure*; D013559:Symbiosis
references.citation: Appl Environ Microbiol. 1980 Apr;39(4):681-5
references.pmid: 6769389
references.citation: Infect Immun. 1993 Aug;61(8):3503-10
references.pmid: 8335382
references.citation: Parasitol Res. 2008 Apr;102(5):945-50
references.pmid: 18210154
references.citation: Parasitol Res. 2000 Jun;86(6):514-20
references.pmid: 10894481
references.citation: Parasitol Res. 2007 Sep;101(4):1097-102
references.pmid: 17579885
references.citation: J Clin Pathol. 1980 Dec;33(12):1179-83
references.pmid: 7451664
references.citation: Parasitol Res. 2003 May;90(1):52-6
references.pmid: 12743804
references.citation: Appl Environ Microbiol. 1977 Apr;33(4):751-7
references.pmid: 869525
references.citation: Lancet. 1995 Sep 2;346(8975):637-8
references.pmid: 7651023