Burden of Serious Fungal Infections in Argentina

Clinical insights into invasive aspergillosis among immunosuppressed patients: A single-centre experience from Argentina

BACKGROUND

Invasive aspergillosis poses a significant threat to immunocompromised individuals. Diagnostic criteria incorporating biomarkers and imaging have improved diagnosis, and treatment options have expanded. However, in Argentina, diverse patient demographics and environmental factors add complexity to managing this infection.

AIMS

This study aims to explore the epidemiology, diagnostic methods, and treatment of invasive aspergillosis in an Argentine hospital setting.

METHODS

We collected data from patients with suspected invasive aspergillosis at a tertiary care hospital in Central-Northern Argentina. Variables included demographics, underlying conditions, diagnostic criteria, treatment, and outcomes.

RESULTS

With a median age of 44.5 years and a 51% of male patients, our institution conducted invasive aspergillosis screenings on 192 patients, many of whom were battling malignancies (90%). One third of them had the infection set as probable or possible. Imaging (31%) and positive microbiological results (16%) were examples of diagnostic evidence. With an overall mortality rate of 15%, half of the patients got antifungal treatment for a median of seven days. Mortality among the diagnosed patients was 22%. Patients without stem-cell transplantation had a high death rate (31%), although this difference was not statistically significant; in patients having pulmonary nodules (15%) the death rate was not statistically significant either. There were no discernible variations in mortality according to the type of treatment received.

CONCLUSIONS

Our study reveals that invasive aspergillosis remains a significant issue in high-risk patients, and has a notable mortality rate, particularly among those patients with pulmonary nodules. Computed tomography provides a high diagnostic yield.

Evolving Epidemiology, Improving Diagnostic Tests and Their Importance for the Correct Diagnosis of Histoplasmosis

Histoplasmosis has traditionally been described as having discrete geographic areas of endemicity. Over the last few decades, it has become more and more clear that these areas are not accurate depictions of where histoplasmosis can occur. Our understanding of where histoplasmosis occurs has improved in recent years due to improving access to diagnostic testing and increased reporting as well as larger at-risk populations (HIV and non-HIV immune suppression) resulting in more cases. Although areas of relatively higher risk and case numbers certainly still exist, histoplasmosis has been observed in much of the world at this point. Our knowledge of the geographic distribution of histoplasmosis, though improving, remains incomplete. While diagnostic testing has traditionally been confined to visualization and/or culture in much of the world, antigen testing has emerged as an excellent tool. Unfortunately access to antigen testing has been inadequate for much of the world, but this has started to change in recent years and will likely change more dramatically in the near future, assuming ongoing positive developments in the area of lateral flow tests for antigen testing. In this review, we describe the current understanding of the geographic distribution of histoplasmosis, the current landscape of diagnostic testing, and the evolution of both areas with an eye towards the future.

Global burden of reported lower respiratory system fungal infection

Background

The epidemiological trend of lower respiratory tract fungal infections remains unclear. This study aims to quantify the global burden of these infections from 1990 to 2021 using data from the Global Burden of Disease Study 2021.

Methods

Data were analyzed at global, regional, and national levels, considering factors such as age, gender, region, and socio-demographic index (SDI). Key indicators included age-standardized disability-adjusted life-year (ASDR) and age-standardized mortality rates (ASMR).

Results

On a global scale, the burden of lower respiratory fungal infections decreased significantly from 1990 to 2021, with a decline in mortality rates. Regionally, substantial disparities were observed among the 21 geographic super-regions. Nationally, Argentina experienced the greatest increase in ASDR and ASMR, while Finland showed the largest decrease, with average annual percentage changes (AAPC) below -5 for both indicators. Sex-based analysis revealed a notably higher burden in males compared to females. ASDR and ASMR were negatively correlated with SDI in most regions.

Conclusion

Although the global burden of lower respiratory tract fungal infections has decreased, it remains a substantial public health issue, particularly in low-SDI regions. There is an urgent need to implement targeted preventive measures to address this ongoing challenge.

Evidence-based clinical standard for the diagnosis and treatment of candidemia in critically ill patients in the intensive care unit

Candidemia is the predominant form of invasive candidiasis and the most frequently occurring serious fungal infection in critically ill patients in Intensive Care Units (ICU). Studies carried out in Latin America reveal a higher incidence of candidemia and higher mortality rates when compared to North America or Europe. This highlights the need to develop guidelines for correctly diagnosing and treating candidemia in critically ill patients in the ICU. These guidelines are part of the efforts to implement antifungal optimization programs in the region to obtain better clinical outcomes and promote rational antifungal use. This evidence-based clinical standard, established through expert consensus for the Latin American context, contains recommendations and algorithms for diagnosing and treating candidemia in critically ill ICU patients.

Fungal Disease Response Centre: Pioneering Diagnostic Approach for Regions With Dispersed Hospital Centres

BACKGROUND

Access to fungal disease diagnosis is crucial for reducing mortality, yet it varies widely across Argentina, especially outside Buenos Aires. In regions like Santa Fe and Paraná, where most healthcare facilities are under 150 beds, maintaining specialised mycology labs is challenging.

OBJECTIVES

This work describes the establishment and first-year results of a centralised Fungal Disease Response Centre (FDRC) and referral network serving this region, covering approximately 1 million inhabitants.

METHODS

The FDRC provided tests from the WHO's Essential Diagnostic List, along with antifungal susceptibility testing and molecular diagnostics. Additionally, we offered continuous training, a courier service and digital tools for service requests and result reporting.

METHODS

In 2023, the FDRC handled samples from 878 patients from 22 institutions, performing 1151 tests on 897 samples. Common tests included Aspergillus galactomannan quantification and molecular diagnostics, diagnosing 101 fungal infections including fungaemias, histoplasmosis, aspergillosis and deep-seated candidiasis. Average turnaround times were 6.2 h for antigen-based tests and 21.5 h for molecular tests.

CONCLUSIONS

This centralised service improved diagnosis speed and quality, overcoming limitations of smaller labs. It also enabled population-based studies, revealing higher-than-expected histoplasmosis prevalence. The FDRC's first-year results demonstrate that regional centralisation can enhance diagnostic quality, improve patient outcomes and advance epidemiological knowledge.

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.

Sero-Epidemiology of Pneumocystis Infection among Infants, Children, and Adults in Chile

Previous serologic surveys show >80% of infants in Chile have anti-Pneumocystis antibodies by 2 years of age, but the seroepidemiology of Pneumocystis infection beyond infancy is unknown. We describe the sero-epidemiology in infants, children, and adults at different locations in Chile. Serum samples were prospectively obtained from 681 healthy adults (age ≥ 17 years) and 690 non-immunocompromised infants/children attending eight blood banks or outpatient clinics (2 in Santiago) in Chile. ELISA was used to measure serum IgM and IgG antibodies to Pneumocystis jirovecii major surface antigen (Msg) constructs MsgA and MsgC1. Serologic responses to Pneumocystis Msg showed a high frequency of reactivity, inferring infection. Among infants/children increasing age and the proportion with detectable IgM responses to MsgA, and IgG responses to MsgA, and MsgC1 were positively associated. Among adults there was almost universal seropositivity to one or more Pneumocystis Msg constructs. In infants and children rates of detectable IgM responses to MsgC1 and MsgA were greater than IgG responses. In Santiago, rates of seropositivity among infants/children were greater in clinics located in a more socio-economically deprived part of the city. In Chile, a serological response to Pneumocystis Msg constructs was common across ages regardless of geographical location and climatic conditions. Observed higher rates of IgM responses than IgG responses is consistent with concept of recent/ongoing exposure to Pneumocystis in children and adults. Higher rates of seropositivity in infants/children residing in more densely populated areas of Santiago infers crowding poses an increased risk of transmission.

Candida albicans Modulates Murine and Human Beta Defensin-1 during Vaginitis

Vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC) are two forms of a disease caused by Candida spp. β-defensin (BD) is one of the most important families of antimicrobial peptides in the female genital tract and includes molecules that exert essential local functions as antimicrobial and PMN chemoattractant peptides. However, the information on their role during murine and human VVC and RVVC is limited. Thus, we analyzed the behavior and contribution of BD1 to the local response in a VVC mice model and the local cytokine profile and human BD1 and BD3 expression in cervicovaginal lavage from patients with VVC and RVVC. We demonstrated that, in patients with RVVC BD1, mRNA and protein expression were severely diminished and that the aspartate proteinase and lipase secreted by C. albicans are involved in that decrease. This study provides novel information about the pathogenesis of VVC and describes a highly efficient C. albicans escape strategy for perpetuating the infection; these results may contribute to the development of new or combined treatment approaches.

COVID-19 associated with disseminated histoplasmosis in a kidney transplant patient

We report a case of disseminated histoplasmosis and COVID-19 infection in a renal transplant recipient in Argentina. The patient exhibited respiratory symptoms, and a chest computed tomography scan (CT) showed multiple bilateral centrilobular opacities with a tree-in-bud pattern in both lobes. The patient was initially treated as having bacterial community-acquired pneumonia, and then tuberculosis. A month later, histoplasmosis was diagnosed, and Histoplasma capsulatum LAmB clade was isolated from sputum, skin and oral lesions. The patient was hospitalized and treatment was started with intravenous liposomal amphotericin B. During the course of the antifungal therapy the respiratory symptoms worsened, a new chest CT showed a unilateral lesion with a ground glass appearance and SARS-CoV-2 was detected in a new nasopharyngeal sample. In addition, plasma therapy was administered, and the immunosuppressive regimen was adjusted (everolimus was interrupted, mycophenolate mofetil reduced, and meprednisone increased). Finally, the patient's progress was favorable and was discharged after five days on oral itraconazole treatment for histoplasmosis.

Emergence of Triazole Resistance in Aspergillus spp. in Latin America

Purpose of Review

Azole resistance in Aspergillus spp. is becoming a public health problem worldwide. However, data about this subject is lacking in Latin American countries. This review focuses in the epidemiology and molecular mechanisms of azole resistance in Aspergillus spp. emphasizing in Latin America. Data on Aspergillus fumigatus stands out because it is the most prevalent Aspergillus spp. pathogen.

Recent Findings

Azole resistance in Aspergillus spp. emergence was linked with intensive use of these antifungals both in the clinical setting and in the environment (as pesticides). Reports on azole-resistant A. fumigatus strains are being constantly published in different countries. Molecular mechanisms of resistance mainly involve substitution in the azole target (CYP51A) and/or overexpression of this gene. However, several other non-CYP51A-related mechanisms were described. Moreover, intrinsically resistant cryptic Aspergillus species are starting to be reported as human pathogens.

Summary

After a comprehensive literature review, it is clear that azole resistance in Aspergillus spp. is emerging in Latin America and perhaps it is underestimated. All the main molecular mechanisms of azole resistance were described in patients and/or environmental samples. Moreover, one of the molecular mechanisms was described only in South America. Cryptic intrinsic azole-resistant species are also described.

The global impact of Aspergillus infection on COPD

Background

Advanced chronic obstructive pulmonary disease (COPD) often leads to hospitalisation and invasive aspergillosis (IA) is a serious complication. Aspergillus sensitisation may worsen symptoms in COPD.

Methods

We identified published papers between January 2000 and May 2019 with > 50 subjects and GOLD criteria for grade II, III or IV (FEV1/FVC < 70% and FEV1 < 80%) using standardised criteria in multiple countries, to re-estimate the prevalence of COPD. Hospitalised COPD patients develop IA in 1.3–3.9%, based on positive cultures of Aspergillus spp. and radiological findings. Given limited data on per-patient annual hospitalisation rates, we assumed a conservative 10.5% estimate. Annual IA mortality in COPD was estimated using the literature rates of 43–72%. A separate literature search assessed the impact of Aspergillus sensitisation on severity of COPD (by FEV1).

Results

We re-estimated the global prevalence of COPD GOLD stages II-IV at 552,300,599 people (7.39% of the population) with 339,206,893 (8.58%) in Asia, 85,278,783 (8.52%) in the Americas, 64,298,051 (5.37%) in Africa, 59,484,329 (7.77%) in Europe and 4,032,543 (10.86%) in Oceania. An estimated 57,991,563 (10.5%) people with COPD are admitted to hospital annually and of these 753,073 (1.3%) – 2,272,322 (3.9%) develop IA and 540,451–977,082 deaths are predicted annually. Aspergillus sensitisation prevalence in COPD was 13.6% (7.0–18.3%) and not related to lower predicted FEV1% (P > 0.05).

Conclusions

The prevalence of COPD is much higher than previously estimated. Overall COPD mortality may be higher than estimated and IA probably contributes to many deaths. Improved rapid diagnosis of IA using culture and non-culture based techniques is required in COPD hospital admissions to reduce mortality.

[Invasive candidiasis: A view to central nervous system infection]

Candidemia is the most frequent invasive mycosis in hospitalized patients worldwide. Fungal infection in central nervous system is a life-threatening complication which aggravates patients' prognosis. This article summarizes relevant aspects on the clinical characteristics of this pathology, mechanisms of fungus invasion, local immune response to Candida albicans and the impact of genetic defects on innate immune receptors that increase susceptibility to the acquisition of this form of mycosis.

Re-drawing the Maps for Endemic Mycoses

Endemic mycoses such as histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, and talaromycosis are well-known causes of focal and systemic disease within specific geographic areas of known endemicity. However, over the past few decades, there have been increasingly frequent reports of infections due to endemic fungi in areas previously thought to be “non-endemic.” There are numerous potential reasons for this shift such as increased use of immune suppressive medications, improved diagnostic tests, increased disease recognition, and global factors such as migration, increased travel, and climate change. Regardless of the causes, it has become evident that our previous understanding of endemic regions for these fungal diseases needs to evolve. The epidemiology of the newly described Emergomyces is incomplete; our understanding of it continues to evolve. This review will focus on the evidence underlying the established areas of endemicity for these mycoses as well as new data and reports from medical literature that support the re-thinking these geographic boundaries. Updating the endemic fungi maps would inform clinical practice and global surveillance of these diseases.

Use of an Argentinean Wildlife Tissue Collection for Epidemiological Studies of Histoplasmosis

Histoplasmosis is a worldwide systemic endemic mycosis caused by several cryptic species included within the Histoplasma capsulatum complex. Domestic and wild mammals are susceptible to infection by this fungus and could be used as indicators of its presence in the environment. The aim of the study was to identify the natural reservoirs of H. capsulatum in the Argentinean Humid Pampas eco-region analyzing a wildlife frozen-tissue collection and trace its distribution patterns over time and space. Tissue samples from 34 small wild mammals caught in the Humid Pampas were analyzed using two molecular markers: 100 kDa protein coding gene (Hcp100) and ITS1 rDNA. Results showed that 32.4% of them were infected with H. capsulatum and its DNA was detected in 5/17 Calomys laucha; 3/6 Calomys musculinus; 1/5 Akodon azarae, 1/3 Monodelphis dimidiata; and 1/2 Didelphis albiventris. In the single specimen studied of Cavia aperea, no H. capsulatum DNA was detected. This is the first H. capsulatum infection report in C. laucha and C. musculinus rodents and M. dimidiate opossum which proves that tissue collections are an important source of material for epidemiological studies of endemic disease over time.

Global Epidemiology of Mucormycosis

Mucormycosis is an angio-invasive fungal infection, associated with high morbidity and mortality. A change in the epidemiology of mucormycosis has been observed in recent years with the rise in incidence, new causative agents and susceptible population. The rise has been perceived globally, but it is very high in the Asian continent. Though diabetes mellitus overshadow all other risk factors in Asia, post-tuberculosis and chronic renal failure have emerged as new risk groups. The rhino-cerebral form of mucormycosis is most commonly seen in patients with diabetes mellitus, whereas, pulmonary mucormycosis in patients with haematological malignancy and transplant recipients. In immunocompetent hosts, cutaneous mucormycosis is commonly seen following trauma. The intriguing clinical entity, isolated renal mucormycosis in immunocompetent patients is only reported from China and India. A new clinical entity, indolent mucormycosis in nasal sinuses, is recently recognized. The causative agents of mucormycosis vary across different geographic locations. Though Rhizopusarrhizus is the most common agent isolated worldwide, Apophysomycesvariabilis is predominant in Asia and Lichtheimia species in Europe. The new causative agents, Rhizopus homothallicus, Mucor irregularis, and Thamnostylum lucknowense are reported from Asia. In conclusion, with the change in epidemiology of mucormycosis country-wise studies are warranted to estimate disease burden in different risk groups, analyse the clinical disease pattern and identify the new etiological agents.