Twenty Years of Acanthamoeba Diagnostics in Austria

Abstract

Acanthamoebae are the causative agents of an often seriously progressing keratitis (AK) occurring predominantly in contact lens wearers and can cause several disseminating infections potentially resulting in granulomatous amoebic encephalitis (GAE) in the immunocompromised host. Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics and the aim of this study was to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 yr. All samples of patients with suspected AK or GAE were screened for Acanthamoeba spp. by culture and/or PCR and the detected amoebae were genotyped. Altogether, 154 cases of AK and three cases of GAE were diagnosed. Age of the AK patients ranged from 8 to 82 yr (mean 37.8) and 58% of the patients were female. Approximately 89% of the AK patients were contact lens wearers, almost all cases were unilateral and 19% of the patients required a keratoplasty. Age of the GAE patients ranged from 2 to 25 yr (mean 14.7), all were HIV‐negative, but two were severely immunosuppressed at the time of diagnosis. The predominant genotype in the AK cases was T4, other genotypes found were T3, T5, T6, T10 and T11. The three GAE cases involved genotypes T2, T4 and T5.

Genotyping of Acanthamoeba spp. and characterization of the prevalent T4 type along with T10 and unassigned genotypes from amoebic keratitis patients in India

“…isolate of genotype T6 was also found associated with Acanthamoeba keratitis in 2012 (Blaschitz et al, 2006). In a 20 year study by Walochnik et al (2015) it was reported that, apart from the predominant genotype T4, several other genotypes, such as T3, T4, T5, T6, T10 and T11, were associated with Acanthamoeba keratitis . Genotype T15, mostly reported from environmental sources, was found as a causative agent of protracted keratitis in humans (Sharifi et al, 2010).…”

Update on Acanthamoeba Keratitis

“…Typically, amebas inhabit the lens case via tap water, rapidly multiply if the case is not cleaned properly and regularly, and then infect the eye via the CLs. 36 …”

Status of the diagnosis of Amebic Keratitis in Paraguay

“…E n u n e s t u d i o r e a l i z a d o p o r Wa l o c h n i k y colaboradores, se observó que en las muestras de pacientes que recibieron tratamiento antimicótico o antibiótico tardaban más en detectar el parásito y en algunos casos los cultivos permanecieron negativos por completo, mientras que al realizar un seguimiento del paciente a medida que avanzaba con el tratamiento observaron una variada sensibilidad respecto a las muestras iniciales de 85% (primera muestra) a 10% (muestras de seguimiento) por el método de cultivo, lo que sugiere la necesidad de contar con métodos más sensibles y específicos para asegurar la detección del (35) parásito .…”

“…La dificultad para eliminar completamente el parásito se debe a los quistes altamente resistentes. Otro estudio realizado por Antonelli y colaboradores reportó el caso de un paciente que seguía dando positivo por cultivo y PCR tras ser sometido a 8 meses de terapia continua, lo que demuestra la alta persistencia y resistencia de (24,35,38) Acanthamoeba .…”