Development and validation of a colorimetric antifungal susceptibility testing method for the dimorphic fungus Talaromyces marneffei.

Antifungal drug resistance is an emerging cause of treatment failure in invasive fungal infections, and antifungal susceptibility testing (AFST) may inform treatment decisions. Currently, there are no established AFST guidelines for Talaromyces marneffei (Tm) or other dimorphic fungi. We developed a colorimetric AFST method using a fluorescent redox indicator alamarBlue, which changes from blue to pink in proportion to cellular metabolic activity. We determined the optimal time for alamarBlue addition to be 24 h post-inoculation and for MIC reading to be 72 h post-inoculation. Our method allows three ways to determine minimum inhibitory concentration (MIC): visual inspection of color change, optical density, and fluorescence intensity. We validated the assay by determining the MICs for seven antifungals against 32 Tm clinical isolates and assessed the essential agreement (EA) and inter-rater reliability between our alamarBlue and the Clinical Laboratory Standard Institute (CLSI) broth microdilution methods. The MIC ranges (from low to high) were: 0.008-0.025 µg/ml for itraconazole, 0.004-0.13 µg/ml for voriconazole, 0.03-0.13 µg/ml for posaconazole, 0.06-0.5 µg/ml for flucytosine, 0.5-1 µg/ml for amphotericin B, 0.5-4 µg/ml for caspofungin, and 0.5-16 µg/ml for fluconazole. The EAs were 100% between all three MIC readouts of the alamarBlue method, and 94%-100% between the alamarBlue and CLSI methods. Our alamarBlue method had substantially higher inter-rater agreement and offers a more reliable method that can be standardized across laboratories in both high- and low-resource settings compared to the established CLSI methodology.

We developed a colorimetric alamarBlue method to determine the susceptibility of antifungal drugs against Talaromyces marneffei. We observed excellent agreement between the alamarBlue method and the Clinical Laboratory Standard Institute broth microdilution method, and the alamarBlue method had substantially higher inter-rater agreement.

Treatment Outcomes of Dolutegravir- Versus Efavirenz-Based Highly Active Antiretroviral Therapy Regimens Among Treatment-Naive People Living With HIV.

BACKGROUND: In India, following the implementation of the dolutegravir (DTG) based regimen, only a few studies compared the outcomes of DTG and efavirenz (EFV) based regimens. Therefore, this study aimed to assess virological suppression and gain in CD4+ counts of DTG and EFV-based antiretroviral therapy (ART) regimens. METHODS:  A retrospective study was conducted and the entire sample (n=140) was divided into two major classes as DTG group (n=70) and EFV group (n=70) further classified as tenofovir/lamivudine/dolutegravir (TLD) and tenofovir/lamivudine/efavirenz (TLE) regimen. Data was collected on socio-demographic characteristics, laboratory measures, and clinical and drug-related variables. For quantitative and qualitative data analysis, respectively, the T-tests and Chi-square tests were applied. RESULTS:  The mean CD4+ gain was comparable in both regimens after six months of ART but significant after 12 months of ART in the TLD group. Viral load suppression was achieved in 55.71% of clients in the TLE group after six months of ART while in the TLD group, 88.57% of clients achieved virologic suppression which was highly significant. Clients who remained on the DTG-based regimen gained significantly more weight at 12 months (mean +6.15 kg) as compared to the EFV-based regimen (mean +1.85 kg). After 12 months of ART, the majority of laboratory variables were unaffected by either regimen with the exception of serum creatinine and random blood sugar (RBS) in the TLD group. CONCLUSIONS:  Our study provides real-life evidence of better outcomes of therapy with DTG over EFV in terms of viral load suppression but immunologic recovery is equivalent in EFV-based regimens after six months of treatment. We recommend the use of DTG only in clients with a high baseline viral load as it costs approximately twice as much as EFV when cost-effectiveness is taken into account.