Comparative analysis of Gram's stain, PNA-FISH and Sepsityper with MALDI-TOF MS for the identification of yeast direct from positive blood cultures.

Fungaemia diagnosis could be improved by reducing the time to identification of yeast from blood cultures. This study aimed to evaluate three rapid methods for the identification of yeast direct from blood cultures; Gram's stain analysis, the AdvanDX Peptide Nucleic Acid in Situ Hybridisation Yeast Traffic Light system (PNA-FISH YTL) and Bruker Sepsityper alongside matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS). Fifty blood cultures spiked with a known single yeast strain were analysed by blinded operators experienced in each method. Identifications were compared with MALDI-TOF MS CHROMagar Candida culture and ITS rRNA sequence-based identifications. On first attempt, success rates of 96% (48/50) and 76% (36/50) were achieved using PNA-FISH YTL and Gram's stain respectively. MALDI-TOF MS demonstrated a success rate of 56% (28/50) when applying manufacturer's species log score thresholds and 76% (38/50) using in-house parameters, including lowering the species log score threshold to >1.5. In conclusion, PNA-FISH YTL demonstrated a high success rate successfully identifying yeast commonly encountered in fungaemia. Sepsityper(™) with MALDI-TOF MS was accurate but increased sensitivity is required. Due to the misidentification of commonly encountered yeast Gram's stain analysis demonstrated limited utility in this setting.

Evaluation of PNA-FISH yeast traffic light for rapid identification of yeast directly from positive blood cultures and assessment of clinical impact.

The PNA-FISH Yeast Traffic Light assay was performed on 54 clinical isolates of yeasts inoculated into blood culture bottles. The assay showed high sensitivity (Candida albicans/C. parapsilosis, 100%; C. glabrata/C. krusei, 92.3%; C. tropicalis, 100%) and specificity (C. albicans/C. parapsilosis, 100%; C. glabrata/C. krusei, 94.8%; C. tropicalis, 100%). Case note review estimated a change in therapy in 29% of cases had the PNA-FISH result been available to the clinician.

Approaches to Effectively Documenting Prior Single Dose Nevirapine Exposure among Women in Africa

Background: Single dose nevirapine (sdNVP) is widely used in resource-limited settings for the prevention of mother to child transmission of HIV; but can result in NVP resistance that negatively impacts the subsequent efficacy of maternal antiretroviral therapy (ART). It is important to determine prior sdNVP exposure status to help guide treatment decisions; but systematic data on approaches to documenting previous sdNVP ingestion are lacking. Aim: With the growing body of evidence of the effects of sdNVP exposure on subsequent choices of ART; we aim to highlight some of the practical challenges that exist in documenting prior sdNVP exposure or lack thereof. Materials and Methods: ACTG A5208 Optimized Combination Therapy after Nevirapine Exposure (OCTANE) is a randomized treatment trial of protease inhibitor vs. NVP-based ART that enrolled 745 HIV-infected women in 7 African countries. Documentation of previous exposure to sdNVP (or lack thereof) was collected prospectively and intensively; as were locally-available sources of such data. Results: All 243 women who were exposed to sdNVP recalled having taken sdNVP; written documentation of sdNVP exposure was found for 73 and an additional 20 identified having ingested a NVP tablet when the tablet was shown to them. Among 502 women not exposed to sdNVP; only 10 (2) had written documentation of lack of sdNVP exposure. NVP resistance was detected in 33 (13.8) of sdNVP-exposed and 1 of non-exposed women. Conclusion: Maternal self-report of prior sdNVP exposure was corroborated by supporting evidence in the majority of women participating in the trial