Browsing by Author "on behalf of the ASTRO-CM Study Team"

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    Acridine Orange Fluorescent Microscopy is more Sensitive than India Ink Light Microscopy in the Rapid Detection of Cryptococcosis among Crag Positive HIV Patients
    (PLoS One, 2017) Akampurira, Andrew; Kwizera, Richard; Williams, Darlisha; Boulware, David R.; Meya, David B.; on behalf of the ASTRO-CM Study Team
    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.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.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. Acridine orange is a better alternative to India ink in the rapid detection of cryptococcosis among CrAg positive HIV patients.
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    Evaluation of Trypan Blue Stain in a Haemocytometer for Rapid Detection of Cerebrospinal Fluid Sterility in HIV Patients with Cryptococcal Meningitis
    (BMC microbiology, 2017) Kwizera, Richard; Akampurira, Andrew; Kandole, Tadeo K.; Kambugu, Andrew; Kambugu, Andrew; Meya, David B.; Boulware, David R.; Rhein, Joshua; on behalf of the ASTRO-CM Study Team
    Quantitative culture is the most common method to determine the fungal burden and sterility of cerebrospinal fluid (CSF) among persons with cryptococcal meningitis. A major drawback of cultures is a long turnaround-time. Recent evidence demonstrates that live and dead Cryptococcus yeasts can be distinguished using trypan blue staining. We hypothesized that trypan blue staining combined with haemocytometer counting may provide a rapid estimation of quantitative culture count and detection of CSF sterility. To test this, we evaluated 194 CSF specimens from 96 HIV-infected participants with cryptococcal meningitis in Kampala, Uganda. Cryptococcal meningitis was diagnosed by CSF cryptococcal antigen (CRAG). We stained CSF with trypan blue and quantified yeasts using a haemocytometer. We compared the haemocytometer readings versus quantitative Cryptococcus CSF cultures. Haemocytometer counting with trypan blue staining had a sensitivity of 98% (64/65), while CSF cultures had a sensitivity of 95% (62/65) with reference to CSF CRAG for diagnostic CSF specimens. For samples that were positive in both tests, the haemocytometer had higher readings compared to culture. For diagnostic specimens, the median of log10 transformed counts were 5.59 (n = 64, IQR = 5.09 to 6.05) for haemocytometer and 4.98 (n = 62, IQR = 3.75 to 5.79) for culture; while the overall median counts were 5.35 (n = 189, IQR = 4.78–5.84) for haemocytometer and 3.99 (n = 151, IQR = 2.59–5.14) for cultures. The percentage agreement with culture sterility was 2.4% (1/42). Counts among non-sterile follow-up specimens had a median of 5.38 (n = 86, IQR = 4.74 to 6.03) for haemocytometer and 2.89 (n = 89, IQR = 2.11 to 4.38) for culture. At diagnosis, CSF quantitative cultures correlated with haemocytometer counts (R2 = 0.59, P < 0.001). At 7–14 days, quantitative cultures did not correlate with haemocytometer counts (R2 = 0.43, P = 0.4). Despite a positive correlation, the haemocytometer counts with trypan blue staining did not predict the outcome of quantitative cultures in patients receiving antifungal therapy.