Revista Iberoamericana De Micologia最新文献

Background

The fungi present in the decaying remains enable a better understanding of the processes of decomposition after death. There are not many studies about fungi on decaying bodies and it is not known which fungal sampling methods are effective.

Aims

The main objective of this study was to find the best method for sampling fungi in carcasses, prove the effectiveness of this method and identify the fungal colonies in animal carcasses from experimental burials.

Methods

Samples from 13 carcasses of Sus scrofa domestica, from the experimental project Taphos-m, were taken with different materials: spatula, sterile swabs and RODAC contact plates.

Results

RODAC contact plates with the RBA culture medium showed higher proliferation of fungal colonies. Thirty genera of fungi were isolated from different substrates (bone, tissue, lime). Most of the fungi genera or groups identified have been described before in the literature, but the substrates they came from were different in some cases.

Conclusions

Sampling with RODAC contact plates was found to be the most effective method, as it provides a nutritional culture medium that may allow growth since the moment of sampling. Fungi colonies grew better in RBA culture medium because bacterial growth is inhibited. Most of the observed fungi are related to the environment but some others have been found related to decomposing bodies for the first time.

Background

Liver abscesses caused by Candida species are mainly found in immunocompromised hosts, associated with conditions (such as neutropenia and mucositis) that facilitate the spreading of microorganisms from the gastrointestinal tract.

Case report

We present the case of a non-immunocompromised 72-year-old woman with a liver abscess caused by Candida haemulonii var. vulnera, in whom potential associated conditions could be polycystic kidney disease and renal replacement therapy. The patient experienced clinical resolution after percutaneous drainage and treatment with caspofungin.

Conclusions

To our knowledge, this is the first case reported in Peru of a liver abscess due to Candida haemulonii var. vulnera, a clinical presentation that has not been described previously. This finding should prompt us to establish active surveillance of causal agents of systemic candidiasis.

The treatment of invasive fungal infections remains a challenge, both for the diagnosis and for the need of providing the appropriate antifungal therapy. Candida auris is a pathogenic yeast that is responsible for hospital outbreaks, especially in intensive care units; it is characterized by a high resistance to the antifungal agents and can become multidrug-resistant. At present, the recommended antifungal agents for the invasive infections with this pathogen are echinocandins, always after carrying out an antifungal susceptibility testing. In case of no clinical response or persistent candidemia, the addition of liposomal amphotericin B or isavuconazole may be considered. Both fungal infection of the central nervous system and that associated with biomedical devices remain rare entities affecting mainly immunocompromised patients. However, an increase in their incidence in recent years, along with high morbidity and mortality, has been shown. The treatment of these infections is conditioned by the limited knowledge of the pharmacokinetic properties of antifungals. A better understanding of the pharmacokinetic and pharmacodynamic parameters of the different antifungals is essential to determine the efficacy of the antifungal agents in the treatment of these infections.

A review on the current evidence of the efficacy and security of liposomal amphotericin B (L-AmB) for the treatment of visceral leishmaniasis (VL) has been performed. In the Indian subcontinent, a single dose of 10 mg/kg has shown effectiveness in the treatment of VL due to Leishmania donovani. In contrast, higher doses of L-AmB (up to 30 mg/kg) are required in Africa to treat a VL of the same etiology. When treating VL by Leishmania infantum acquired in the Americas and Europe the usual dose of L-AmB is 20-21 mg/kg. In HIV co-infected patients the required doses are usually higher, up to 60 mg/kg, and if it is administered in a prophylactic schedule after the treatment of VL relapses are reduced. L-AmB has shown synergism with other antiparasitic drugs, especially with paromomycin in the Indian subcontinent and with miltefosin in patients coinfected with HIV in East Africa. Due to its efficacy and safety profile, L-AmB is the first therapeutic option for VL.

Infections caused by mucorales, with an increasing incidence after candidiasis and aspergillosis, are characterized by the fast angioinvasion of blood vessels and invasion of neighboring organs or structures. Mucorales most commonly cause rhinocerebral, pulmonary, cutaneous, digestive or disseminated infections, and their spread is favored by certain underlying diseases (diabetes, kidney failure) and risk factors (neutropenia, immunosuppression, iron overload). These infections have a high mortality rate, over 40% in many series, and the key to their cure depends on both an early diagnosis and an antifungal treatment, associated in most cases with extensive surgical debridement and other adjunctive therapies. Currently, there are international guidelines, not only local ones, for the management of mucormycosis, in which it is considered by consensus and with a strong recommendation that first-line treatment with high-dose liposomal amphotericin B is the best choice. The combined antifungal treatment of polyene agents with triazoles or candins remains in open debate.

Liposomal amphotericin B is a lipid formulation of the antifungal drug amphotericin B with some distinguishing characteristics in its pharmacological behavior that entail some clinical differences of great interest. The significant improvement in the systemic and renal tolerability is one of them. This fact is related to the great stability of the liposome, promoted by its negative charge, the presence of cholesterol and the remarkable thermo-stability of the remaining lipids that compose it. In this situation, amphotericin B seems to be released from the liposome not spontaneously but when the liposome binds to the ergosterol in the fungal cell membrane. For this reason, there is almost no free amphotericin B in plasma or tissues, although it seems that its availability is greater when there is fungal infection. As a consequence, when the pharmacokinetic behavior is studied, the concentration and availability of liposomal amphotericin B are very high, and its volume of distribution is reduced in comparison with the other formulations.

Liposomal amphotericin B (L-AmB) has been a key cornerstone for the management of invasive fungal infections (IFI) caused by a wide array of molds and yeasts during the last three decades. Multiple studies performed over this period have generated a large body of evidence on its efficacy and safety, becoming the main antifungal agent in the management of IFI in patients with hematologic malignancies in several not mutually exclusive clinical settings. First, L-AmB is the most commonly used antifungal agent in patients undergoing intensive chemotherapy for acute leukemia and high-risk myelodysplastic syndrome, as well as in hematopoietic stem cell transplant recipients. Additionally, due to the administration of newer targeted therapies (such as monoclonal antibodies or small molecule inhibitors), opportunistic mold infections are increasingly being reported in patients with hematologic malignancies usually considered low-risk for IFI. These agents usually have a high drug-drug interaction potential, being triazoles, commonly used for antifungal prophylaxis, included. Finally, patients developing breakthrough IFI because of either subtherapeutic concentrations of antifungal prophylactic drugs in blood or selection of resistant strains, require broad spectrum antifungal therapy, usually with an antifungal of a different class. In both situations, L-AmB remains as the best option for early antifungal therapy.

In recent years, immunodeficiency condition has experienced a rise among children, who are at risk of invasive fungal infections (IFI) due to their health condition. Cancer, non-malignant hematological diseases, as primary immunodeficiencies, hematopoietic stem cell transplantation (HSCT), extreme prematurity, or critically ill condition in Pediatric Intensive Care Unit (PICU) are some immunosuppressive situations in children. The use of oncologic therapies, including immunotherapy and monoclonal antibodies, for the treatment of the aforementioned health conditions has led to an increase in morbidity and mortality rates of IFI in children.

The underlying diseases and their management, comorbidities, the diagnostic tests used (both molecular and imaging), as well as the treatment used can be significantly different between adult patients and children admitted to PICU or with cancer. In pediatrics, the treatment of IFI is based primarily on pharmacokinetic studies performed in adults. In higher risk patients prophylaxis should be considered and, in the case of an IFI diagnosis, an antifungal treatment should be administered as early as possible, supported by the reversion of the immune dysfunction and surgery when appropriate.