Molecular epidemiology and antimicrobial resistance of vaginal Candida glabrata isolates in Namibia.

Candida glabrata is the most common non-albicans Candida species that causes vulvovaginal candidiasis (VVC). Given the intrinsically low susceptibility of C. glabrata to azole drugs, investigations into C. glabrata prevalence, fungal susceptibility profile, and molecular epidemiology are necessary to optimise the treatment of VVC. This molecular epidemiological study was conducted to determine antifungal drug profile, single nucleotide polymorphisms (SNPs) associated with phenotypic antifungal resistance and epidemic diversity of C. glabrata isolates from women with VVC in Namibia. Candida glabrata isolates were identified using phenotypic and molecular methods. Antifungal susceptibility of strains was determined for fluconazole, itraconazole, amphotericin B, and anidulafungin. Whole genome sequencing was used to determine SNPs in antifungal resistance genes and sequence type (ST) allocation. Among C. glabrata isolates, all (20/20; 100%) exhibited phenotypic resistance to the azole class antifungal drug, (fluconazole), and phenotypic susceptibility to the polyene class (amphotericin B), and the echinocandins (anidulafungin). Non-synonymous SNPs were identified in antifungal resistance genes of all fluconazole-resistant C. glabrata isolates including ERG6 (15%), ERG7 (15%), CgCDR1 (25%), CgPDR1 (60%), SNQ2 (10%), FKS1 (5.0%), FKS2 (5.0%), CgFPS1 (5.0%), and MSH2 (15%). ST15 (n = 8/20, 40%) was predominant. This study provides important insight into phenotypic and genotypic antifungal resistance across C. glabrata isolates from women with VVC in Namibia. In this study, azole resistance is determined by an extensive range of SNPs, while the observed polyene and echinocandin resistance-associated SNPs despite phenotypic susceptibility require further investigation.

Candida glabrata is inherently resistant to azole drugs. In this study, we identified a clone that was predominant in women with vulvovaginal candidiasis in Namibia, and that harboured various mutations in resistance-associated genes. This study provides important insight into antifungal resistance across C. glabrata isolates in a sub-Sahara African setting.

Prospective cohort study of treatment outcomes of vaginal discharge syndrome in women in Windhoek, Namibia.

BACKGROUND: Syndromic treatment is the standard of care for vaginal discharge syndrome (VDS) in resource-constrained settings. However, the outcomes of VDS treatment have not been well documented. This study aimed to determine the incidence, risk factors, and microbial etiology of treatment failure in women with VDS. METHODS: This prospective cohort study of women with VDS was conducted between September 2021 and March 2022 at Katutura Intermediate Hospital in Windhoek, Namibia. Microbiological analyses of sexually transmitted infections (STI) (Chlamydia trachomatis; Neisseria gonorrhoeae; Trichomonas vaginalis; Mycoplasma genitalium), bacterial vaginosis (BV), and vulvovaginal candidiasis (VVC) were performed. Treatment outcomes were assessed at 7 and 30 days after treatment, followed by microbial investigation in case of treatment failure. RESULTS: One hundred and nine women were enrolled and 94 (86%) completed the follow-up. At baseline, 37/109 (40%) women were diagnosed with STI, 47/109 (43%) with BV and 45/109 (41%) with VVC. Candida albicans (33/45; 73%) was the main pathogen in VVC, with fluconazole resistance detected in 8/33 (24%) isolates; 10/12 (80%) of non-albicans Candida species showed resistance. The incidence of treatment failure was 3.6 per 100 person-years at 7 days and 1.0 per 100 person-years at 30 days follow-up; 17/94 (18%) women had recurrent VDS and 12/94 (13%) women had persistent VDS. VVC (OR 4.3; 95% CI 1.7-11, p = 0.002) at baseline was associated with treatment failure. CONCLUSIONS: Treatment failure after syndromic management of VDS is common in resource-constrained settings. Access to diagnostic testing, including fungal culture and susceptibility testing, is recommended to improve outcomes.

Importance of Candida infection and fluconazole resistance in women with vaginal discharge syndrome in Namibia.

BACKGROUND: Vaginal discharge syndrome (VDS) is a common condition. Clinical management targets sexually transmitted infections (STIs) and bacterial vaginosis (BV); there is limited focus on Candida infection as cause of VDS. Lack of Candida treatment coverage and, if present, antifungal resistance may result in VDS treatment failure. This study aimed to determine the prevalence of Candida infection, antifungal resistance, and coinfections in Namibian women with VDS. METHODS: A cross-sectional study was performed using 253 vaginal swabs from women with VDS in Namibia. Demographic data was collected, and phenotypic and molecular detection of Candida species was performed followed by fluconazole susceptibility testing of Candida isolates. BV was diagnosed using Nugent score microscopy; molecular detection of Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis was performed. RESULTS: Candida species was detected in 110/253 women (43%). Ninety women (36%) had Candida albicans and 24 (9.5%) had non-albicans Candida species. The non-albicans species detected were 19 (17%) Candida glabrata, 4.0 (3.5%) Candida krusei, and 1.0 (0.9%) Candida parapsilosis. Candida albicans were more frequently isolated in younger (p = 0.004) and pregnant women (p = 0.04) compared to non-albicans Candida species. Almost all (98%) Candida albicans isolates were susceptible to fluconazole while all non-albicans Candida species were fluconazole resistant. STIs were diagnosed in 92 women (36%): 30 (12%) with C. trachomatis, 11 (4.3%) N. gonorrhoeae, and 70 (28%) T. vaginalis; 98 (39%) women had BV. Candida infection alone was diagnosed in 30 women (12%), combined with STIs in 42 women (17%) and was concurrent with BV in 38 women (15%). Candida infection was more often detected in swabs from women without C. trachomatis detected (6.4% vs. 16%; OR 0.30; 95% CI 0.10-0.77, p = 0.006). CONCLUSIONS: The high prevalence of Candida infection, especially those due to non-albicans Candida species that are resistant to fluconazole, is a great concern in our setting and may lead to poor treatment outcomes. Access to microbiological testing for Candida species in the context of syndromic management is warranted.

Estimated Burden of Fungal Infections in Namibia.

Namibia is a sub-Saharan country with one of the highest HIV infection rates in the world. Although care and support services are available that cater for opportunistic infections related to HIV, the main focus is narrow and predominantly aimed at tuberculosis. We aimed to estimate the burden of serious fungal infections in Namibia, currently unknown, based on the size of the population at risk and available epidemiological data. Data were obtained from the World Health Organization (WHO), Joint United Nations Programme on HIV/AIDS (UNAIDS), and published reports. When no data existed, risk populations were used to estimate the frequencies of fungal infections, using the previously described methodology. The population of Namibia in 2011 was estimated at 2,459,000 and 37% were children. Among approximately 516,390 adult women, recurrent vulvovaginal candidiasis (≥4 episodes /year) is estimated to occur in 37,390 (3003/100,000 females). Using a low international average rate of 5/100,000, we estimated 125 cases of candidemia, and 19 patients with intra-abdominal candidiasis. Among survivors of pulmonary tuberculosis (TB) in Namibia 2017, 112 new cases of chronic pulmonary aspergillosis (CPA) are likely, a prevalence of 354 post-TB and a total prevalence estimate of 453 CPA patients in all. Asthma affects 11.2% of adults, 178,483 people, and so allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitization (SAFS) were estimated in approximately 179/100,000 and 237/100,000 people, respectively. Invasive aspergillosis (IA) is estimated to affect 15 patients following leukaemia therapy, and an estimated 0.13% patients admitted to hospital with chronic obstructive pulmonary disease (COPD) (259) and 4% of HIV-related deaths (108) - a total of 383 people. The total HIV-infected population is estimated at 200,000, with 32,371 not on antiretroviral therapy (ART). Among HIV-infected patients, 543 cases of cryptococcal meningitis and 836 cases of Pneumocystis pneumonia are estimated each year. Tinea capitis infections were estimated at 53,784 cases, and mucormycosis at five cases. Data were missing for fungal keratitis and skin neglected fungal tropical diseases such as mycetoma. The present study indicates that approximately 5% of the Namibian population is affected by fungal infections. This study is not an epidemiological study-it illustrates estimates based on assumptions derived from similar studies. The estimates are incomplete and need further epidemiological and diagnostic studies to corroborate, amend them, and improve the diagnosis and management of these diseases.