Viability test exclusively is not adequate to evaluate the T4 Acanthamoeba keratitis’ treatment
Nenhuma Miniatura disponível
Data
2020
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Acanthamoeba keratitis is a serious corneal infection and can lead to blindness. Cysts and
recurrence of infection represent a challenge in the treatment of keratitis due to its high
resistance to adverse conditions and to most medications. This intriguing property can
lead to late diagnosis and can explain absence of cyst removal during and after therapy
regimen. So the evaluation of Acanthamoeba cysts viability after exposure to drugs used in
Acanthamoeba keratitis treatment is so important.
Material and methods: Cysts (105
/mL) of two clinical and an environmental T4 isolates
were separately incubated with polyhexamethylene biguanide (0.02%), chlorhexidine
digluconate (0.02%) or propamidine isethionate (0.1%) at 37 °C for a period of 1h or 24h.
Cysts were quantified, stained with trypan blue and inoculated in agar plates covered with
inactivated Escherichia coli.
Results: None of the treatment regimens induced complete cysts elimination. The
environmental isolate had no reduction on cysts quantification compared to clinical
isolates. The trypan blue exclusion method demonstrated non-viable cysts in the treatment
with chlorhexidine digluconate and propamidine isethionate. In the treatment with
polyhemamethylene biguanide, viable and non-viable cysts were observed after 24h of
incubation. The cultures were positive for all treatment protocols except for clinical isolate
ATCC 30461 with chlorhexidine digluconate regimen after 24 h.
Conclusions: The presence of cysts observed in cultures reiterates cysts viability even after
treatment demonstrating the demonstrating the need to follow up this form of development
during treatment. The trypan blue staining is not adequate to evaluate the Acanthamoeba
cysts viability due to its recovery in culture. With these results, we conclude that the
viability test exclusively is not adequate to evaluate the Acanthamoeba keratitis treatment
and that its always necessary to perform culture technique.
Descrição
Palavras-chave
Acanthamoeba, Viability, Culture, Polyhexamethylene biguanide, Chlorhexidine digluconate, Propamidine isethionate, Trypan blue
Citação
BERNARDES, Geisa et al. Viability test exclusively is not adequate to evaluate the T4 Acanthamoeba keratitis treatment. Journal of Microbiology & Experimentation, Budapeste, v. 8, n. 1, p. 1-5, 2020. DOI: 10.15406/jmen.2020.08.00278. Disponível em: https://medcraveonline.com/JMEN/viability-test-exclusively-is-not-adequate-to-evaluate-the-t4-acanthamoeba-keratitis-treatment.html. Acesso em: 20 fev. 2025.