Posaconazole as rescue therapy in African histoplasmosis

Epidemiological, clinical, diagnostic, and therapeutic features of histoplasmosis: A systematic review

Histoplasmosis is a mycosis due to a dimorphic fungus Histoplasma capsulatum. This study aimed at providing an overview of histoplasmosis epidemiological, clinical, diagnostic, and therapeutic aspects from the last 30 years. This review was carried out using a systematic literature search on histoplasmosis from 1992 to 2021. We describe the clinical features, diagnostic methods and treatment. Empirical searches were conducted via the databases PubMed, Google Scholar and Science Direct. Between 1992 and 2021, 190 manuscripts were published and reported 212 cases of histoplasmosis. These publications included 115 and 97 cases of American and African histoplasmosis respectively. The number of publications increased over the last ten years with a maximum in 2020 (12.34 % of the cases reported). The disseminated forms of histoplasmosis were the most frequently reported cases as compared to the localized forms. This was the case with the American histoplasmosis (75.65 %) as well as with the African histoplasmosis (55.67 %). Itraconazole (31.17 %) and Amphotericin B (26.62 %) were the most used drugs in the management of these cases. American histoplasmosis is distributed worldwide whereas African histoplasmosis is mainly present in intertropical Africa. There is a critical need for setting up a global surveillance system, towards a better understanding of the disease.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Histoplasmosis in Africa: Current perspectives, knowledge gaps, and research priorities

Background

Histoplasmosis is a chronic granulomatous disease caused by the thermally dimorphic fungus Histoplasma capsulatum. The 2 variants Histoplasma capsulatum var. capsulatum (Hcc) and Histoplasma capsulatum var. duboisii (Hcd) causes infection in humans and commonly termed classical or American histoplasmosis and African histoplasmosis, respectively. Histoplasma capsulatum var. farciminosum (Hcf) affects equines. In recent times, there have been heightened sensitization on fungal infections such as histoplasmosis in Africa, aimed at improving awareness among relevant stakeholders, particularly healthcare workers. This effort is expected to be paralleled with increased detection of both classical and African histoplasmosis, which has remained underdiagnosed over the years. In this narrative review, we describe the current perspectives of histoplasmosis in Africa, identify knowledge gaps, and suggest research priorities.

Methods

A PubMed, Google Scholar, and Africa Journal Online (AJOL) literature search was conducted for studies on histoplasmosis in Africa between 2000 and 2020. Histoplasmosis essays in medical mycology textbooks were also consulted. This narrative review was prepared from the data gathered.

Findings

In the past 2 decades, histoplasmosis in general has seen a relative increase in case detection in some Africa countries, probably attributable to the gradually increasing medical mycology advocacy efforts in Africa. Histoplasmosis cases are dominated by African histoplasmosis mostly in Western and Central Africa, while classical histoplasmosis is more common in Southern and Northern Africa. Although both classical and African histoplasmosis are common in Africa, the latter is more restricted to Africa, and cases outside the continent usually have a travel history to the continent. Despite the clinical and laboratory difference between African histoplasmosis and classical histoplasmosis, it is not straightforward to distinguish them. The typical manifestation of African histoplasmosis is the appearance of lesions affecting the skin, bones, and lymph nodes and unusually linked to human immunodeficiency virus (HIV)/AIDS. By contrast, classical histoplasmosis mostly affects the lungs and is often associated with immunosuppression, mainly HIV/AIDS. The present perspectives of histoplasmosis in Africa highlight unclear details on the true burden, strain diversity, infection route and genetic basis of African histoplasmosis, availability of specie-specific diagnostic tools, and compliance with recommended antifungal therapy. These knowledge gaps represent research questions that require scientific exploration.

Conclusions

Despite a subtle increase in identifying histoplasmosis cases in Africa, it remains underdiagnosed and neglected in some parts of the continent. Increasing awareness and training among healthcare workers, bridging diagnostic and therapeutic gaps, and encouraging more research in Africa are crucial to improve the current perspectives of histoplasmosis in Africa.

Histoplasmosis in African children: clinical features, diagnosis and treatment

Most of the reviews on histoplasmosis documented in literature have been in the adult population. Very few studies highlight the peculiarities associated with histoplasmosis in Africa especially in the pediatric population. This review addresses the above concerns with clinical summaries and diagnosis of some case reports of histoplasmosis in African children. We highlighted 44 case reports of histoplasmosis in African children (1950–2021) distributed across Western Africa (38.6%, n = 17), Eastern Africa (9.1%, n = 4), Southern Africa (9.1%, n = 4), and Central Africa (43.2%, n = 19). No case report was found from Northern Africa. The age range was 1–17 years, with a mean of 9.2. Of the 44 case reports, 8 cases (18.2%, 8/44) were caused by Histoplasma capsulatum var capsulatum, 33 cases (75%, 33/44) were caused by Histoplasma capsulatum var duboisii, and specie identification was not found in 3 cases. Only three (6.8%) cases were HIV positive; 56.8% (25/44) were disseminated histoplasmosis, pulmonary histoplasmosis accounted for just one case (2.3%, 1/44). Extrapulmonary presentation included skin lesions (ulcers, fistulas, nodules, patches, pigmentations, papules, and abscesses), bone lesions, osteoarthritis, and fractures. The commonest sites affected were skin ( n = 29, 65.9%), bones ( n = 20, 45.5%), and lymph nodes ( n = 15, 34.1%). Histopathology was the commonest diagnostic method ( n = 33, 75%). Amphotericin B was first-line therapy in 45.5% of the cases ( n = 20) followed by ketoconazole (20.5%, n = 9); 27 cases (61.4%) had favorable outcomes, 8 cases (18.2%) had fatal outcomes, while in 9 cases, the outcome was not revealed. This review revealed several cases of histoplasmosis misdiagnosed as other conditions including tuberculosis ( n = 3, 6.8%), pneumonia ( n = 1, 2.3%), cancers ( n = 4, 9.1%), nephritic syndrome ( n = 1, 2.3%), leishmaniasis ( n = 1, 2.3%), and hyperreactive malarial splenomegaly syndrome ( n = 1, 2.3%). In addition, histoplasmosis was not considered in some case reports even when symptoms were suggestive. Diagnosis of histoplasmosis was made at autopsy with postmortem findings suggestive of histoplasmosis ( n = 3, 6.8%). This report highlights the need for a paradigm shift on the part of pediatricians in Africa. They need to look beyond clinical conditions considered common in our environment for this age group and evaluate for other diseases including histoplasmosis.

Histoplasmosis in Children; HIV/AIDS Not a Major Driver

The classification of histoplasmosis as an AIDS-defining illness has largely attributed its occurrence in people to the presence of HIV/AIDS especially in Africa. Prior to the advent of the HIV/AIDS epidemic, several cases of histoplasmosis were documented both in the pediatric and adult populations. Our review revealed 1461 reported cases of pediatric histoplasmosis globally in the last eight decades (1939-2021). North America (n = 1231) had the highest number of cases, followed by South America (n = 135), Africa (n = 65), Asia (n = 26) and Europe (n = 4). Histoplasmosis was much more common in the non-HIV pediatric population (n = 1418, 97.1%) compared to the HIV population. The non-HIV factors implicated were, childhood malignancies (n = 207), such as leukemias and lymphomas as well as their treatment, lung diseases (n = 7), environmental exposures and toxins (n = 224), autoimmune diseases (n = 12), organ transplants (n = 12), long-term steroid therapy (n = 3), the use of immunosuppressive drugs such as TNF-alpha inhibitors (n = 7) malnutrition (n = 12), histiocytosis (n = 3), Hyper immunoglobulin M and E syndromes (n = 15, 1.2%), pancytopenia (n = 26), diabetes mellitus (n = 1) and T-cell deficiency (n = 21). Paediatricians should always consider or rule out a diagnosis of histoplasmosis in children presenting with symptoms suggestive of the above clinical conditions.

Histoplasmosis Diagnosed in Europe and Israel: A Case Report and Systematic Review of the Literature from 2005 to 2020

Human histoplasmosis is a mycosis caused by two distinct varieties of a dimorphic fungus: Histoplasma capsulatum var. capsulatum and H. capsulatum var. duboisii. In Europe, it is usually imported by migrants and travellers, although there have been some autochthonous cases, especially in Italy; however, most European physicians are unfamiliar with its clinical and pathological picture, particularly among immunocompromised patients without HIV infection. This systematic review of all the cases of histoplasmosis reported in Europe and Israel between 2005 and 2020 identified 728 cases diagnosed in 17 European countries and Israel described in 133 articles. The vast majority were imported (mainly from Central and South America), but there were also seven autochthonous cases (six in Europe and one in Israel). The patients were prevalently males (60.4%), and their ages ranged from 2 to 86 years. The time between leaving an endemic region and the diagnosis of histoplasmosis varied from a few weeks to more than 40 years. Progressive disseminated histoplasmosis was the most frequent clinical picture among people living with HIV infection (89.5%) or a different immunocompromising condition (57.1%), but it was also recorded in 6.2% of immunocompetent patients. Twenty-eight cases were caused by Histoplasma duboisii. Immunocompromised patients without HIV infection had the worst outcomes, with a mortality rate of 32%.

Paediatric Histoplasmosis 2000-2019: A Review of 83 Cases

Histoplasmosis is an endemic fungal infection that is confined to specific geographical regions. Histoplasma spp. are primary pathogens that cause disease in both immunocompetent and immunocompromised patients, ranging from a single-organ (mostly affecting the lungs) infection to life-threatening disseminated disease. Knowledge about the clinical epidemiology relies on data from adult populations; little is known about the patient and disease characteristics in the paediatric population. Therefore, a structured review of published cases of paediatric histoplasmosis between 2000 and 2019 was performed. A literature search of PubMed was conducted and the epidemiological and clinical data from 83 cases were analysed. The mean age at presentation was 9.5 ± 5.5 years, and 51% were girls. Two-thirds of the children were immunocompromised. The majority of children presented with disseminated disease. The most frequently observed clinical symptoms were respiratory symptoms, alongside non-specific systemic features, including fever, myalgia, fatigue and weight loss. The mortality rate was 11%. Histoplasmosis affects children of any age. Being immunocompromised is a risk factor for severe and disseminated disease. The lack of specific presenting features leads to underreporting and delay in diagnosis. To improve the recognition and outcome of histoplasmosis in childhood, increased awareness and surveillance systems are warranted.

Successful Use of Multidisciplinary Palliative Care in the Outpatient Treatment of Disseminated Histoplasmosis in an HIV Positive Child

Histoplasmosis is an uncommon opportunistic infection in human immunodeficiency virus (HIV) positive children. The most common form is primary disseminated histoplasmosis, characterized by persistent fever and failure to thrive. A 10-year-old HIV positive girl presented to the Baylor College of Medicine Children’s Foundation—Tanzania Mbeya Center of Excellence (COE) with ulcerated skin lesions and a violaceous facial rash. She also had persistent fevers, severe acute malnutrition, and severe anemia. At diagnosis, the patient was failing first line antiretroviral therapy (ART) with a cluster of differentiation 4 immune cells (CD4) of 24 cells/µL and an HIV viral load (VL) of 196,658 cp/mL. The patient was changed to a second line ART regimen (abacavir, lamivudine, and ritonavir-boosted lopinavir) and received nutritional support, blood transfusions, multiple antibiotics, and meticulous wound care. She also received comprehensive symptom management, psychosocial support, and emergency housing through the COE’s palliative care program. Biopsy of a lesion showed intracytoplasmic organisms consistent with Histoplasmosis capsulatum var capsulatum. The patient was treated with conventional amphotericin B and oral itraconazole and she achieved wound healing as well as immune reconstitution and HIV viral suppression. Amphotericin infusions were given as an outpatient despite the resource constraints of the setting in southwestern Tanzania. Histoplasmosis should be considered in the differential diagnosis of the immunocompromised host with unusual skin manifestations and persistent fever.

Histoplasmosis overlapping with HIV and tuberculosis in sub-Saharan Africa: challenges and research priorities

Histoplasmosis, tuberculosis and HIV are all highly prevalent in sub-Saharan Africa (SSA). Co-occurrence of two or more of these infections has been reported in several populations of patients, especially those with advanced HIV infection where these opportunistic infections contribute to a significant morbidity and mortality. With a high burden of pulmonary tuberculosis (PTB) secondary to HIV in SSA, histoplasmosis is commonly misdiagnosed as smear-negative PTB in HIV patients due to similar clinical and radiological presentations. This is also partly the result of the lack of trained clinical and laboratory personnel to make a definite diagnosis of histoplasmosis. There is a low index of clinical suspicion for histoplasmosis, and cases are mostly discovered accidently and documented through case reports and case series. Similarly, the high cost and lack of fungal diagnostics in most SSA countries makes it difficult to make a diagnosis. There is a need to build local capacity for mycology so that patients are managed to improve on the index of clinical suspicion and diagnostic capabilities. Moreover, simple accurate point-of-care diagnostic tests and first-line antifungal treatment for histoplasmosis are not available in many SSA countries. This review describes the existence of co-infections of histoplasmosis, tuberculosis and HIV in SSA, highlighting the challenges and research priorities.

Management of osteoarticular fungal infections in the setting of immunodeficiency

Introduction: Osteoarticular fungal infections (OAFIs) complicate the clinical course of high-risk patients, including immunosuppressed individuals. Their management, however, despite being intricate, is governed by evidence arising from sub-optimal quality research, such as case series. Guidelines are scarce and when present result in recommendations based on low quality evidence. Furthermore, the differences between the management of immunocompromised and immunocompetent patients are not distinct. This is a narrative review after a literature search in PubMed, up to November 2019.Areas covered: The major fungal groups causing osteomyelitis and/or arthritis are Candida spp., Aspergillus spp., non-Aspergillus filamentous fungi, non-Candida yeasts and endemic dimorphic fungi. Their epidemiology is briefly analyzed with emphasis on immunodeficiency and other risk factors. Management of OAFIs includes appropriate antifungal drug therapy (liposomal amphotericin B, triazoles or echinocandins), local surgery and immunotherapy for primary immunodeficiencies. Cessation of immunosuppressive drugs is also mandated.Expert opinion: Management of OAFIs includes affordable and available options and approaches. However, research on therapeutic practices is urgently required to be further improved, due to the rarity of affected patients. Evolution is expected to translate into novel antifungal drugs, less invasive and precise surgical approaches and targeted enhancement of immunoregulatory pathways in defense of challenging fungal pathogens.

Diagnosis and treatment of histoplasmosis in solid organ transplant patients

PURPOSE OF REVIEW

Unlike immunocompetent hosts, solid organ transplant (SOT) recipients with posttransplant histoplasmosis (PTH) often present with disseminated disease and have an attributable mortality of approximately 10%. In this review, we discuss currently available diagnostic tests and treatment strategies in PTH.

RECENT FINDINGS

None of the available tests have a 100% diagnostic accuracy. Histoplasma antigen assays are the most sensitive commercially available tests. However, crossreactivity of histoplasma antigen with aspergillus galactomannan and false positive histoplasma antigen tests because of rabbit antithymocyte globulin may cause difficulty in interpreting positive test results in transplant recipients. Molecular assays such as amplification and sequencing of 'panfungal' portions of the 28S ribosomal RNA from clinical specimens appear to be promising.Lipid formulations of amphotericin B and itraconazole are the drugs of choice in the treatment of PTH. Other extended spectrum azoles also appear to be effective, but, like itraconazole, problems with drug interactions and prolongation of the QTc interval (except for isavuconazole, which shortens the QTc interval) remain. Mycophenolate therapy is associated with severe disease and should be stopped during active disease and, if feasible, calcineurin inhibitors and steroids should be reduced.

SUMMARY

A combination of various tests (culture, antigen tests, nucleic amplification tests, etc.) should be used to optimize diagnostic yield. The role of unbiased next generation sequencing for early diagnosis and newer azoles in the treatment needs to be further explored.

Posaconazole salvage therapy: The Posifi study

BACKGROUND

Posaconazole (PCZ) is used mainly for the prevention of invasive fungal infection (IFI).

METHODS

A multicentre retrospective, investigational study using a non-randomized, single-arm design carried out in six tertiary hospitals in Spain to evaluate the use of PCZ in different forms of administration in the (non-prophylactic) treatment of IFI.

RESULTS

Over an eight-year-period, 67 patients were included in this study. PCZ was administered as salvage therapy (intolerant or refractory to a previous antifungal agent) in 65/67 (97%); of these, it was used against Aspergillosis (68.6%), Zygomycosis (13.4%), other moulds (8.9%) and yeast (10.5%). The median duration of PCZ therapy was 75 days. The oral solution was associated with low serum levels (<0.7 mg/L) in 63% of available patients. Clinical response at 3 and 12 months of PCZ therapy were for aspergillosis: 47.8% and 41.3%; for zygomycosis: 55.5% and 55.5%; and for other mycoses: 69.2% and 69.2%, respectively. Suspension by toxicity was only observed in 6% and 7.5% of patients at 3 and 12 months, respectively, mainly with grade III/IV elevations of liver function test (LFTs).

CONCLUSIONS

Posaconazole salvage therapy, especially oral tablets, can be an effective alternative option for patients with IFI who cannot tolerate or do not respond to other antifungal therapies.

Susceptibility profile of echinocandins, azoles and amphotericin B against yeast phase of Talaromyces marneffei isolated from HIV-infected patients in Guangdong, China

Talaromyces marneffei (T. marneffei) can cause talaromycosis, a fatal systemic mycosis, in patients with AIDS. With the increasing number of talaromycosis cases in Guangdong, China, we aimed to investigate the susceptibility of 189 T. marneffei clinical strains to eight antifungal agents, including three echinocandins (anidulafungin, micafungin, and caspofungin), four azoles (posaconazole, itraconazole, voriconazole, and fluconazole), and amphotericin B, with determining minimal inhibition concentrations (MIC) by Sensititre YeastOne™ YO10 assay in the yeast phase. The MICs of anidulafungin, micafungin, caspofungin, posaconazole, itraconazole, voriconazole, fluconazole, and amphotericin B were 2 to > 8 μg/ml, >8 μg/ml, 2 to > 8 μg/ml, ≤ 0.008 to 0.06 μg/ml, ≤ 0.015 to 0.03 μg/ml, ≤ 0.008 to 0.06 μg/ml, 1 to 32 μg/ml, and ≤ 0.12 to 1 μg/ml, respectively. The MICs of all echinocandins were very high, while the MICs of posaconazole, itraconazole, and voriconazole, as well as amphotericin B were comparatively low. Notably, fluconazole was found to have a higher MIC than other azoles, and exhibited particularly weak activity against some isolates with MICs over 8 μg/ml. Our data in vitro support the use of amphotericin B, itraconazole, voriconazole, and posaconazole in management of talaromycosis and suggest potential resistance to fluconazole.

Histoplasmosis in transplant recipients

Histoplasma capsulatum is a dimorphic fungus that most often causes asymptomatic infection in the immunocompetent population. In immunocompromised patients, including solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, however, it is likely to cause severe life-threatening infection. Post-transplant histoplasmosis (PTH) in SOT is uncommon with an incidence of ≤1% and is even rarer in HCT patients. The majority of PTH in SOT is diagnosed in the first 2 years following transplantation. Histoplasmosis may result from endogenous reactivation of latent infection, de novo post-transplant acquisition, and donor-derived infection. Disseminated infection is common. Fever is the most common symptom and clinical features are often nonspecific, but patients with disseminated infection may present with a septic picture. Other features, including pancytopenia and hepatosplenomegaly, may not be prominent early in the course of illness. Contemporary histoplasma antigen assays are the most sensitive tests but cross-reactivity with antigens of other fungi, including with Aspergillus galactomannan, is not uncommon. Treatment should be continued for at least a year. Histoplasma antigen levels have prognostic value and can be used to monitor the response to therapy. The attributable mortality is approximately 10%. Routine screening of donors and recipients is not currently recommended.