Estimation of the Burden of Serious Human Fungal Infections in Malaysia

A review of the epidemiology of invasive fungal infections in Asian patients with hematological malignancies (2011-2021)

The incidence of invasive fungal infection (IFI) is increasing, especially among patients diagnosed with hematological malignancies due to their immunocompromised nature. Other risk factors include advanced age, exposure to immunosuppressants, neutropenia, and catheter use. Some of the most common IFI organisms reported are Candida and Aspergillus species, and other fungal species, including Scedosporium, Trichosporon, Cryptococcus, and Fusarium have also increasingly been reported in the past years. However, the epidemiologic data on IFI among patients with hematological malignancies in Asian countries are lacking. Therefore, we investigated published epidemiologic data on such cases from the past 10 years (2011-2021) and discuss the challenges faced in the diagnosis and management of IFIs in Asia.

Paving the way for affordable and equitable liposomal amphotericin B access worldwide

Amphotericin B has long been crucial for treating many serious infectious diseases, such as invasive fungal infections and visceral leishmaniasis, particularly for patients who are immunocompromised, including those with advanced HIV infection. The conventional amphotericin B deoxycholate formulation has largely been replaced in high-income countries with liposomal amphotericin B (LAmB), which has many advantages, including lower rates of adverse events, such as nephrotoxicity and anaemia. Despite an evident need for LAmB in low-income and middle-income countries, where mortality from invasive fungal infections is still substantial, many low-income and middle-income countries still often use the amphotericin B deoxycholate formulation because of a small number of generic formulations and the high price of the originator LAmB. The pricing of LAmB is also highly variable between countries. Overcoming supply barriers through the availability of additional quality-assured, generic formulations of LAmB at accessible prices would substantially facilitate equitable access and have a substantial effect on mortality attributable to deadly fungal infections.

Candida albicans skin infection in diabetic patients: An updated review of pathogenesis and management

Candida species, commensal residents of human skin, are recognized as the cause of cutaneous candidiasis across various body surfaces. Individuals with weakened immune systems, particularly those with immunosuppressive conditions, are significantly more susceptible to this infection. Diabetes mellitus, a major metabolic disorder, has emerged as a critical factor inducing immunosuppression, thereby facilitating Candida colonization and subsequent skin infections. This comprehensive review examines the prevalence of different types of Candida albicans-induced cutaneous candidiasis in diabetic patients. It explores the underlying mechanisms of pathogenicity and offers insights into recommended preventive measures and treatment strategies. Diabetes notably increases vulnerability to oral and oesophageal candidiasis. Additionally, it can precipitate vulvovaginal candidiasis in females, Candida balanitis in males, and diaper candidiasis in young children with diabetes. Diabetic individuals may also experience candidal infections on their nails, hands and feet. Notably, diabetes appears to be a risk factor for intertrigo syndrome in obese individuals and periodontal disorders in denture wearers. In conclusion, the intricate relationship between diabetes and cutaneous candidiasis necessitates a comprehensive understanding to strategize effective management planning. Further investigation and interdisciplinary collaborative efforts are crucial to address this multifaceted challenge and uncover novel approaches for the treatment, management and prevention of both health conditions, including the development of safer and more effective antifungal agents.

Antifungal Susceptibility and Genotypic Analysis of cyp51A Mutations in Aspergillus fumigatus Isolates in Malaysia

Purpose

Azole resistance in Aspergillus fumigatus poses a significant challenge in the management of invasive aspergillosis. This study aimed to investigate the antifungal susceptibility and cyp51A mutation profiles of A. fumigatus isolates in Malaysia.

Patients and Methods

Sixty clinical A. fumigatus isolates were collected and subjected to antifungal susceptibility testing (AFST) and molecular analysis. The antifungal susceptibility testing was performed according to CLSI M38 guideline. The geometric mean (GM) minimum inhibitory concentration (MIC), MIC50/MIC90 for voriconazole, itraconazole, posaconazole, amphotericin B, and isavuconazole against A. fumigatus in non-invasive cases and invasive cases were calculated. In addition, the presence of cyp51A mutations was also identified.

Results

The present study revealed an overall resistance rate of 6.7% among the isolates. In non-invasive cases, isavuconazole and posaconazole demonstrated the lowest GM MIC of 0.08 µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.15µg/mL, 0.16µg/mL and 0.90µg/mL, respectively. Similarly, in invasive cases, isavuconazole and posaconazole exhibited the lowest GM MIC of 0.09µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.14µg/mL, 0.17µg/mL and 0.80µg/mL, respectively. Genotypic analysis revealed various cyp51A mutations, including F46Y, M172V, N248K, R34L, V244A, V244S, and E427K. However, not all mutations corresponded to antifungal resistance.

Conclusion

The majority of clinical Aspergillus fumigatus isolates demonstrated susceptibility to the antifungal agents tested, with isavuconazole and posaconazole demonstrating the lowest MIC values. However, cyp51A mutations were discovered without a consistent correlation to antifungal resistance, emphasising the need for additional research.

Updated estimation of the burden of fungal disease in Vietnam

BACKGROUND

Anecdotally, the burden of fungal diseases in Vietnam is rapidly rising, but there has been no updated estimate on this issue since a previous report in 2015.

OBJECTIVES

In this study, we aimed at estimating the incidence and prevalence of serious fungal infections for the year 2020.

METHODS

We made estimates with a previously described methodology, using reports on the incidence and prevalence of various established risk factors for fungal infections from local, regional or global sources.

RESULTS

We estimated 2,389,661 cases of serious fungal infection occurred in Vietnam in 2020. The most common condition was recurrent vaginal candidiasis (4047/100,000 women annually). Among people living with HIV, we estimated 451 cases of cryptococcal meningitis, 1030 of pneumocystis pneumonia, 166 of histoplasmosis and 1612 of talaromycosis annually. Candidaemia incidence was estimated at 12/100,000 population each year. Owing to its high burden of tuberculosis and respiratory diseases, Vietnam had high rates of severe infections caused by Aspergillus species. Incidence of invasive aspergillosis is 24/100,000 population, allergic bronchopulmonary aspergillosis 78/100,000 and severe asthma with fungal sensitisation 102/100,000. Five-year period prevalence of chronic pulmonary aspergillosis is 120/100,000 population /5-year period. Mucormycosis, fungal keratitis and tinea capitis were estimated at 192, 14,431 and 201 episodes each year, respectively.

CONCLUSIONS

The number of patients with mycoses in Vietnam is likely underestimated due to a lack of local data and limited diagnostic capacity, but at least 2.5% of the population might have some form of serious fungal disease.

Addressing Microbial Resistance Worldwide: Challenges over Controlling Life-Threatening Fungal Infections

Fungal infections are a serious global concern because of their ability to spread and colonize host tissues in immunocompromised individuals. Such infections have been frequently reported worldwide and are currently gaining clinical research relevance owing to their resistant character, representing a bottleneck in treating affected people. Resistant fungi are an emergent public health threat. The upsurge of such pathogens has led to new research toward unraveling the destructive potential evoked by these species. Some fungi-grouped into Candida, Aspergillus, and Cryptococcus-are causative agents of severe and systemic infections. They are associated with high mortality rates and have recently been described as sources of coinfection in COVID-hospitalized patients. Despite the efforts to elucidate the challenges of colonization, dissemination, and infection severity, the immunopathogenesis of fungal diseases remains a pivotal characteristic in fungal burden elimination. The struggle between the host immune system and the physiological strategies of the fungi to maintain cellular viability is complex. In this brief review, we highlight the relevance of drug resistance phenotypes in fungi of clinical significance, taking into consideration their physiopathology and how the scientific community could orchestrate their efforts to avoid fungal infection dissemination and deaths.

Comparison of in vitro Susceptibilities of Talaromyces marneffei in Mold and Yeast Forms in Malaysia

Purpose

This study was aimed to determine minimum inhibitory concentration (MIC) differences between yeast and mold forms of T. marneffei in Malaysia.

Patients and Methods

Ninety-seven clinical strains of T. marneffei were received from various Malaysian hospitals from the year 2020 until 2022. Their identities were determined using microscopic, macroscopic and molecular methods. Next, the susceptibility of yeast and mold forms of each isolate against amphotericin B, itraconazole, voriconazole, posaconazole, ketoconazole, isavuconazole, terbinafine, caspofungin and micafungin were tested according to the broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) M38 and M27 guidelines. The geometric means of minimal inhibitory concentration (GM MIC), MIC₅₀, and MIC₉₀ were determined for each antifungal. Additionally, Wilcoxon signed-rank test was used to compare the significant difference of GM MICs for each antifungal, GM MIC, MIC₅₀ and MIC₉₀ for the combined nine antifungals against different growth forms of T. marneffei. The significance was set at p<0.05.

Results

Micafungin had the highest GM MIC, MIC₅₀ and MIC₉₀ for mold form of T. marneffei. For yeast form, amphotericin B achieved the highest GM MIC and MIC₅₀ while micafungin achieved the highest MIC₉₀. However, the GM MIC, MIC₅₀ and MIC₉₀ of terbinafine and azole antifungals on T. marneffei were similar to each other, namely between 0.03 and 0.60µg/mL. The difference of GM MIC of all tested antifungals except caspofungin and micafungin was insignificant. Overall, GM MIC, MIC₅₀ and MIC₉₀ of the combined nine antifungals against two growth forms were insignificant.

Conclusion

The findings suggested either yeast or mold form can be used in the susceptibility testing of T. marneffei against amphotericin B, itraconazole, voriconazole, posaconazole, ketoconazole, isavuconazole and terbinafine.

A Review of Studies on Candida Species in Peninsular Malaysia

Data on the epidemiology and the antifungal susceptibility of Candida species infections in Malaysia is still limited. The study aimed to review and compare studies reporting the prevalence of Candida species and antifungal susceptibility of Candida infections in Peninsular Malaysia. Data from 22 studies published between 2009 and 2018. Data was collected using National Center for Biotechnology Information and Google Scholar using the keywords "Candida and Malaysia." Around 19 Candida species were identified in a total of 35,608 Candida isolates analyzed in these studies. In most studies examined, C. albicans (66.3%) was the predominant species, followed by C. glabrata (11.7%), C. parapsilosis (10.7%), C. tropicalis (9.5%), and C. krusei (1.19%). Vaginal swabs yielded the most isolates, followed by the respiratory system, urine, blood, oral, pus, and other locations. The demographic, racial, and gender data were recorded only in two studies. Totally, eight studies examined 396 isolates for antifungal susceptibility to common antifungal medications. The average antifungal susceptibility of isolates and efficacy of drugs in these studies ranged between 45 and 99% for most common antifungal drugs. Caspofungin had the highest susceptibility at 99%, whereas itraconazole had the lowest at only 45%. Overall, this review provided a comprehensive summary of all the current research on predominant Candida species in Peninsular Malaysia.

In Vitro and In Silico Analysis of Ascorbic Acid Towards Lanosterol 14-α-Demethylase Enzyme of Fluconazole-Resistant Candida albicans

Antibiotic resistance is one of the major concerns and the biggest threats to the world population. The incidents of antibiotic resistance in Candida spp. were frequently recorded. In the present investigation, antifungal potential of ascorbic acid (AA) was evaluated. According to the in vitro analysis, the zone of inhibition of AA (24.75 ± 0.35 mm) against C. albicans was greater as compared to other vitamins tested. AA significantly modulate the growth of C. albicans at 25 mg/ml. The highest percentage (94.67%) of cell viability was observed in untreated cells, and low cell viability (29.36%) was observed in cells treated with 50 mg/ml of AA (2 × MIC). Further, AO/EB (acridine orange/ethidium bromide), propidium iodide staining, and real-time qPCR confirmed the loss of membrane integrity due to membrane lesions that caused cell death. Lanosterol 14-α-demethylase (L-14α-DM) is the product of ERG11 and acted as superior drug target of C. albicans. Molecular docking analysis confirmed that active interaction of ascorbic acid with L-14α-DM. Based on the present investigation, the efficiency of AA was effectively proved through the in vitro and in silico analysis. This finding has evidenced the effectiveness of AA as a potential candidate against C. albicans.

Mapping histoplasmosis in South East Asia - implications for diagnosis in AIDS

Histoplasmosis caused by the fungus Histoplasma capsulatum is often lethal in patients with AIDS. Urine antigen testing is highly sensitive and much quicker for diagnosis than culture. Histoplasmosis has a patchy and incompletely appreciated distribution around the world especially in South East Asia. We conducted a systematic literature review of cases of all disease forms of histoplasmosis in SE Asia, not including the Indian sub-continent. We also reviewed all histoplasmin skin test mapping studies to determine localities of exposure. We found a total of 407 cases contracted or likely to have been contracted in SE Asia. Numbers of cases by country varied: Thailand (233), Malaysia (76), Indonesia (48) and Singapore (21), with few or no cases reported in other countries. Most cases (255 (63%)) were disseminated histoplasmosis and 177 (43%) cases were HIV associated. Areas of high histoplasmin skin test sensitivity prevalence were found in Myanmar, the Philippines, Indonesia, Thailand and Vietnam - 86.4%, 26.0%, 63.6%, 36.0% and 33.7%, respectively. We have drawn maps of these data. Further study is required to ascertain the extent of histoplasmosis within SE Asia. Diagnostic capability for patients with HIV infection is urgently required in SE Asia, to reduce mortality and mis-diagnosis as tuberculosis.

Fungal Diseases in Taiwan-National Insurance Data and Estimation

The burden of fungal diseases based on the real-world national data is limited. This study aimed to estimate the Taiwan incident cases with selected fungal diseases in 2013 using the National Health Insurance Research Database (NHIRD) which covered 99.6% of the 23.4 million population. Over 80,000 incident cases were found and the majority were superficial infections including vulvovaginal candidiasis (477 per 100,000 adult women) and oral candidiasis (90 cases per 100,000 population). Common potentially life-threating fungal diseases were Pneumocystis pneumonia (5.35 cases per 100,000 population), candidemia (3.68), aspergillosis (2.43) and cryptococcal meningitis (1.04). Of the aforementioned cases cancer patients contributed 30.2%, 42.9%, 38.6% and 22.2%, respectively. Of 22,270 HIV-infected persons in NHIRD in 2013, four common diseases were Pneumocystis pneumonia (28.3 cases per 1000 HIV-infected patients), oral candidiasis (17.6), esophageal candidiasis (6.06) and cryptococcal meningitis (2.29). Of pulmonary aspergillosis 32.9% occurred in patients with chronic pulmonary diseases and 26.3% had a prior diagnosis of tuberculosis. There are some notable gaps related to insurance claim data. Cutaneous, urinary tract and eye fungal infections were not captured.

Current Research and New Perspectives in Antifungal Drug Development

In recent times, fungi are becoming more and more active as causal agents of human infections, which is primarily determined by the growing number of people with severe immunosuppression. Thus, the problems of elucidating the mechanisms of action of antifungal preparations, highlighting ways to obtain resistance to their action and research strategies aimed at discovering new compounds with antifungal properties remain the focus of contemporary biomedicine and pharmaceutics. This paper reviews the recent achievements in antifungal drug development and focuses on new natural antifungal remedies with a noticeable effect on pathogens with minimal adverse effects on the host organism.