Acridine orange fluorescent microscopy is more sensitive than India ink light microscopy in the rapid detection of cryptococcosis among CrAg positive HIV patients

Richard Kwizera, Andrew Akampurira, Darlisha Williams, David R. Boulware, David B. Meya, ASTRO-CM Study Team

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Background: India ink microscopy on cerebrospinal fluid is still utilized in resource limited settings for the diagnosis of cryptococcal meningitis despite its poor sensitivity. We hypothesized that staining fungal nucleic acids with fluorescent dyes instead of the capsule with India ink might improve sensitivity for the diagnosis of cryptococcal meningitis. Methods: We enrolled 96 HIV-infected participants with cryptococcal meningitis who provided 194 CSF specimens at serial time points in Kampala, Uganda. Cryptococcosis was diagnosed by cerebrospinal fluid (CSF) cryptococcal antigen (CrAg) test and only positive samples were included. We stained CSF with India ink and acridine orange. We cultured the same samples on standard fungal media. We compared acridine orange to CrAg, India ink and CSF culture. Results: Acridine orange was more sensitive (96%) than India ink (79%) with reference to CSF CrAg. Acridine orange and India ink had a statistically significant difference (P<0.001) with a 25% correlation for detection of Cryptococcus yeasts. India ink had more negative results (22%) than acridine orange (4%). The sensitivity for India ink increased (86%) while that of acridine orange did not change (97%) when compared to CSF culture. However, both India ink and acridine orange had poor predictive values with reference to culture. Conclusion: Acridine orange is a better alternative to India ink in the rapid detection of cryptococcosis among CrAg positive HIV patients.

Original languageEnglish (US)
Article numbere0182108
JournalPloS one
Volume12
Issue number7
DOIs
StatePublished - Jul 2017

Bibliographical note

Funding Information:
Financial support for this research was provided by the National Institutes of Health (R01NS086312, T32AI055433 R25TW009345), Grand Challenges Canada (S4 0296-01), and United Kingdom Medical Research Council (MR/M007413/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank institutional support from Drs. Richard Brough, Rosalind Parkes Ratanshi, Andrew Kambugu and Mohammed Lamorde. We also thank the entire ASTRO study team Kampala (Joshua Rhein, Edward Mpoza, Reuben Kiggundu, Lillian Tugume, Kenneth Ssebambulidde, Andrew Akampurira, Paul Kirumira, Darlisha A Williams, Jane Francis Ndyetukira, Cynthia Ahimbisibwe, Florence Kugonza, Carolyne Namuju, Alisat Sadiq, Tadeo Kiiza Kandole, Tony Luggya, Julian Kaboggoza, Eva Laker, Alice Namudde, Sarah Lofgren, Richard Kwizera, Kirsten Nielsen, Anna Stadelman, and Ananta S Bangdiwala) for patient care.

Publisher Copyright:
© 2017 Kwizera et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.

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