Epidemiology and clinical manifestations of mucormycosis

Animal Models to Study Mucormycosis

Mucormycosis is a rare but often fatal or debilitating infection caused by a diverse group of fungi. Animal models have been crucial in advancing our knowledge of mechanisms influencing the pathogenesis of mucormycoses, and to evaluate therapeutic strategies. This review describes the animal models established for mucormycosis, summarizes how they have been applied to study mucormycoses, and discusses the advantages and limitations of the different model systems.

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.

Polysaccharides Cell Wall Architecture of Mucorales

Invasive fungal infections are some of the most life-threatening infectious diseases in the hospital setting. In industrialized countries, the most common fungal species isolated from immunocompromised patients are Candida and Aspergillus spp. However, the number of infections due to Mucorales spp. is constantly increasing and little is known about the virulence factors of these fungi. The fungal cell wall is an important structure protecting fungi from the environment. A better knowledge of its composition should improve our understanding of host-pathogen interactions. Cell wall molecules are involved in tissue adherence, immune escape strategies, and stimulation of host defenses including phagocytosis and mediators of humoral immunity. The fungal cell wall is also a target of choice for the development of diagnostic or therapeutic tools. The present review discusses our current knowledge on the cell wall structure of Mucorales in terms of the polysaccharides and glyco-enzymes involved in its biosynthesis and degradation, with an emphasis on the missing gaps in our knowledge.

Disease Entities in Mucormycosis

Mucormycosis is an emerging life-threatening fungal infection caused by Mucorales. This infection occurs mainly in immunocompromised patients, especially with hematological malignancy, transplantation, or diabetes mellitus. Rhino-orbito-cerebral and pulmonary mucormycosis are the predominant forms. Interestingly, location is associated with the underlying disease as pulmonary mucormycosis is more frequent in hematological malignancy patients whereas rhino-orbito-cerebral mucormycosis is associated with diabetes. Cutaneous mucormycosis results from direct inoculation, mainly after trauma or surgery. Gastro-intestinal mucormycosis occurs after ingestion of contaminated food or with contaminated device and involves the stomach or colon. Disseminated disease is the most severe form and is associated with profound immunosuppression. Uncommon presentations with endocarditis, osteoarticluar or isolated cerebral infections are also described. Finally, health-care associated mucormycosis is a matter of concern in premature newborns and burn units. Clinical symptoms and CT scan findings are not specific, only the early reversed halo sign is associated with pulmonary mucormycosis. Circulating Mucorales DNA detection is a recent promising diagnostic tool that may lead to improving the diagnosis and prompting therapeutic initiation that should include antifungal treatment, correction of the underlying disease and surgery when feasible.

Extracorporeal Membrane Oxygenation for Diffuse Alveolar Hemorrhage Caused by Idiopathic Pulmonary Hemosiderosis: A Case Report and a Review of the Literature

Diffuse alveolar hemorrhage (DAH) is a life-threatening condition presenting with hemoptysis, anemia, and diffuse radiographic pulmonary infiltrates; it causes acute respiratory failure. Idiopathic pulmonary hemosiderosis (IPH) is a rare cause of DAH occurring predominantly in children. Bleeding is often considered to be a contraindication for extracorporeal membrane oxygenation (ECMO) due to systemic anticoagulation. We present an 8-year-old girl with DAH caused by IPH. Unfractionated heparin was administered to maintain an activated clotting time of 150 to 180 seconds. The DAH resolved with immunosuppressive therapy, and the patient survived to decannulation. ECMO may be applied as a rescue therapy for DAH even with systemic anticoagulation.

Severe facial necrosis in a type 1 diabetic patient secondary to mucormycosis masquerading as an internal maxillary artery occlusion: a case report

BACKGROUND

Mucormycosis is a group of rare but life threatening angioinvasive infections caused by fungi of the order Mucorales that often occurs in immunocompromised patients and individuals with poorly controlled diabetes. Rhinocerebral mucormycosis can mimic sinusitis but can rapidly progress to deeper disease and cause facial necrosis. Facial vascular thrombosis is a rare complication of mucormycosis and can confound diagnosis of the disease.

CASE PRESENTATION

We report the case of a 25-year-old female with poorly controlled type 1 diabetes mellitus who initially presented with symptoms of sinusitis but rapidly progressed with signs of left-sided facial necrosis due to occlusion of the left internal maxillary artery. Early surgical debridement did not yield a microbiological diagnosis. Deeper surgical debridements ultimately revealed angioinvasive fungal disease consistent with mucormycosis. The patient recovered after repeated surgical intervention and aggressive parenteral antifungal therapy.

CONCLUSION

This case illustrates an atypical complication of mucormycosis, and emphasizes that a high index of suspicion in vulnerable patient populations aids in the diagnosis of this life-threatening infection.

Broad antifungal resistance mediated by RNAi-dependent epimutation in the basal human fungal pathogen Mucor circinelloides

Mucormycosis—an emergent, deadly fungal infection—is difficult to treat, in part because the causative species demonstrate broad clinical antifungal resistance. However, the mechanisms underlying drug resistance in these infections remain poorly understood. Our previous work demonstrated that one major agent of mucormycosis, Mucor circinelloides, can develop resistance to the antifungal agents FK506 and rapamycin through a novel, transient RNA interference-dependent mechanism known as epimutation. Epimutations silence the drug target gene and are selected by drug exposure; the target gene is re-expressed and sensitivity is restored following passage without drug. This silencing process involves generation of small RNA (sRNA) against the target gene via core RNAi pathway proteins. To further elucidate the role of epimutation in the broad antifungal resistance of Mucor, epimutants were isolated that confer resistance to another antifungal agent, 5-fluoroorotic acid (5-FOA). We identified epimutant strains that exhibit resistance to 5-FOA without mutations in PyrF or PyrG, enzymes which convert 5-FOA into the active toxic form. Using sRNA hybridization as well as sRNA library analysis, we demonstrate that these epimutants harbor sRNA against either pyrF or pyrG, and further show that this sRNA is lost after reversion to drug sensitivity. We conclude that epimutation is a mechanism capable of targeting multiple genes, enabling Mucor to develop resistance to a variety of antifungal agents. Elucidation of the role of RNAi in epimutation affords a fuller understanding of mucormycosis. Furthermore, it improves our understanding of fungal pathogenesis and adaptation to stresses, including the evolution of drug resistance.

The emerging infection mucormycosis causes high mortality in part because the major causative fungi, including Mucor circinelloides, are resistant to most clinically available antifungal drugs. We previously discovered an RNA interference-based resistance mechanism, epimutation, through which M. circinelloides develops transient resistance to the antifungal agent FK506 by altering endogenous RNA expression. We further characterize this novel mechanism by isolating epimutations in two genes that confer resistance to another antifungal agent, 5-fluoroorotic acid. Thus, we demonstrate epimutation can induce resistance to multiple antifungals by targeting a variety of genes. These results reveal epimutation plays a broad role enabling rapid and reversible fungal responses to environmental stresses, including drug exposure, and controlling antifungal drug resistance and RNA expression. As resistance to antifungals emerges, a deeper understanding of the causative mechanisms is crucial for improving treatment.

Mucor circinelloides Thrives inside the Phagosome through an Atf-Mediated Germination Pathway

Mucormycosis is an emerging fungal infection that is often lethal due to the ineffectiveness of current therapies. Here, we have studied the first stage of this infection-the germination of Mucor circinelloides spores inside phagocytic cells-from an integrated transcriptomic and functional perspective. A relevant fungal gene network is remodeled in response to phagocytosis, being enriched in crucial functions to survive and germinate inside the phagosome, such as nutritional adaptation and response to oxidative stress. Correspondingly, the phagocytic cells induced a specific proinflammatory and apoptotic response to the pathogenic strain. Deletion of fungal genes encoding putative transcription factors (atf1, atf2, and gcn4), extracellular proteins (chi1 and pps1), and an aquaporin (aqp1) revealed that these genes perform important roles in survival following phagocytosis, germination inside the phagosome, and virulence in mice. atf1 and atf2 play a major role in these pathogenic processes, since their mutants showed the strongest phenotypes and both genes control a complex gene network of secondarily regulated genes, including chi1 and aqp1 These new insights into the initial phase of mucormycosis define genetic regulators and molecular processes that could serve as pharmacological targets.IMPORTANCE Mucorales are a group of ancient saprophytic fungi that cause neglected infectious diseases collectively known as mucormycoses. The molecular processes underlying the establishment and progression of this disease are largely unknown. Our work presents a transcriptomic study to unveil the Mucor circinelloides genetic network triggered in fungal spores in response to phagocytosis by macrophages and the transcriptional response of the host cells. Functional characterization of differentially expressed fungal genes revealed three transcription factors and three extracellular proteins essential for the fungus to survive and germinate inside the phagosome and to cause disease in mice. Two of the transcription factors, highly similar to activating transcription factors (ATFs), coordinate a complex secondary gene response involved in pathogenesis. The significance of our research is in characterizing the initial stages that lead to evasion of the host innate immune response and, in consequence, the dissemination of the infection. This genetic study offers possible targets for novel antifungal drugs against these opportunistic human pathogens.

Preexposure to Isavuconazole Increases the Virulence of Mucorales but Not Aspergillus fumigatus in a Drosophila melanogaster Infection Model

Breakthrough mucormycosis in patients receiving isavuconazole prophylaxis or therapy has been reported. We compared the impact of isavuconazole and voriconazole exposure on the virulence of clinical isolates of Aspergillus fumigatus and different Mucorales species in a Drosophila melanogaster infection model. In contrast to A. fumigatus, a hypervirulent phenotype was found in all tested Mucorales upon preexposure to either voriconazole or isavuconazole. These findings may contribute to the explanation of breakthrough mucormycosis in isavuconazole-treated patients.

[Uncommon mycoses]

BACKGROUND

Fungal infections should be suspected in severe wounds that have been contaminated with organic material or soil, even when the patient is immunocompetent. The aim of this article is to contribute to a better understanding and knowledge of the antifungal sensitivity and epidemiology of some rare pathogens that may trigger severe infections.

CASE REPORT

Four different moulds were isolated from the wounds of an immunocompetent woman who was involved in a road accident: Lichtheimia corymbifera, Scedosporium boydii, Fusarium solani and Purpureocillium lilacinum. Some of them were isolated from different sites. A profile of in vitro resistance was performed with an Epsilometer (Etest™) using five antifungal agents: voriconazole, posaconazole, itraconazole, anidulafungin an amphotericin B. The results obtained were consistent with those from other cases reported in the literature.

CONCLUSIONS

Early aggressive surgery, antifungal therapy and, above all, frequent debridement of necrotic tissue, are the tools against filamentous fungi infections. Antifungal sensitivity of any mould involved in an infection has to be determined, in order to a better understanding of these rare pathogens whose incidence is increasing.

Managing mucormycosis in a resource-limited setting: challenges and possible solutions

Mucormycosis is a potentially fatal fungal infection with high prevalence in poor-resource settings. Besides being an extremely expensive disease to treat, the challenges range from lack of experienced mycologists or mycology department to knowledge and availability of treatment regimes.

Mucormycotic Osteomyelitis Involving the Maxilla: A Rare Case Report and Review of the Literature

Osteomyelitis is an inflammatory process of bone and marrow contents. These changes in bone are primarily seen in soft tissue followed by calcified tissue. It is an opportunistic infection due to the complication of some other conditions rendering the host susceptible to disease. Consequences of this infection range from draining tract to malignant transformation. Various etiological factors are involved in origin of the disease; among them, fungal origin is rare. Specific feature in fungal osteomyelitis is the involvement of maxillary sinus with a complaint of sinusitis associated with diabetes mellitus. Here, we discuss a case of osteomyelitis with fungal infection involving the maxilla. The patient is under medication for the past five years due to diabetes.

Severe Gastric Mycormycosis Infection Followed by Cytomegalovirus Pneumonia in a Renal Transplant Recipient: A Case Report and Concise Review of the Literature

Mucormycosis is an uncommonly encountered fungal infection in solid-organ transplantation, occurring most often gastrointestinally. The most common and fatal infectious disease is cytomegalovirus (CMV) pneumonia, which may result in acute respiratory distress syndrome (ARDS), with rapid onset. Early diagnosis, active treatment, and rational reduction of immunosuppressants are crucial for successful kidney transplantation. We performed successful treatment for both mucormycosis and CMV pneumonia and adjusted the tacrolimus dose accordingly. The case we describe was that of a 47-year-old woman with history of renal transplantation 1 month earlier. She presented with chest pain and gastrointestinal bleeding and was diagnosed with gastric mucormycosis and a secondary episode of hospital-acquired pneumonia. Preemptive therapy, which included liposomal amphotericin B and posaconazole, was adminstered when voriconazole proved to be unhelpful and before histologic reports of gastric mucormycosis. Moreover, CMV re-activation was confirmed by CMV antibody detection, and we administered gancyclovir and thymosin α1 but reduced the strength of the immunosuppressive drugs. Fourteen days after the aforementioned therapy, the patient began to recover and she was discharged on day 81 postoperatively. We conclude that preemptive treatment is critical for severe infection in renal transplant recipients, especially with the rarely seen gastric mucormycosis and with ARDS. In addition, immunoregulated agents, such as asthymosin α1, are also of great value in renal transplant recipients in the setting of opportunistic pathogen infections.

Skin Infections

Cutaneous infections are common in immunocompromised patients. Neutropenia predisposes patients to fungal, bacterial and viral infections. Antibacterial antifungal and antiviral prophylaxis have caused a significant reduction in some of these infections.

There are two main types of cutaneous infections : primary cutaneous infections and cutaneous manifestations of a disseminated infection. In the latter, skin lesions may be the window to disseminated bloodstream infection and the first and only evidence of a disseminated life threatening infection.

The diagnosis may be at your fingertips; therefore a thorough skin exam is the clue. However, it’s also important to know the characteristic lesions associated with different infections. It will help expedite diagnosis so appropriate treatment is initiated promptly in neutropenic patients, which can be lifesaving.

In a retrospective study of 43 neutropenic febrile patients with cutaneous lesions, fungal infections were the most frequent, and nodular lesions on the lower extremities were the most prevalent (Naorungroj and Aiempanakit, J Am Acad Dermatol 74:AB166, 2016).

Skin biopsy for pathological study and culture remains the gold standard and should be obtained early to confirm the suspected diagnosis. In these immunocompromised patients the inflammatory response is altered by either the primary disease or its treatment. Therefore, routine pathogens may present in an atypical fashion, with diminished or absent induration, erythema, or pustulation in response to bacterial resulting cutaneous infection without typical cellulitis (Urabe, Clin Infect Dis 39:S53–S55, 2004). Skin lesions are evaluated not only by morphology, but also in the context of the clinical setting and biopsy result. The skin biopsy is inexpensive, relatively noninvasive and without contraindication, and may avoid the need for more invasive procedures such an open lung biopsy (Grossman, et al., Cutaneous manifestations of infection in the immunocompromised host. Springer Science+Business Media, LLC, New York, 2012).

In addition to antimicrobial therapy, surgery should not be postponed in the face of progressive skin and soft tissue infection in this population (Brzozowski and Ross, J Hand Surg Br 22:679–680, 1997).

Challenges in the diagnosis and treatment of mucormycosis

The diagnosis and treatment of mucormycosis are challenging. The incidence of the disease seems to be increasing. Hematological malignancies are the most common underlying disease in countries with high income and uncontrolled diabetes in developing countries. Clinical approach to diagnosis lacks sensitivity and specificity. Radiologically, multiple (≥10) nodules and pleural effusion are reportedly associated with pulmonary mucormycosis. Another finding on computerized tomography (CT) scan, which seems to indicate the presence of mucormycosis, is the reverse halo sign. Microscopy (direct and on histopathology) and culture are the cornerstones of diagnosis. Molecular assays can be used either for detection or identification of mucormycetes, and they can be recommended as valuable add-on tools that complement conventional diagnostic procedures. Successful management of mucormycosis is based on a multimodal approach, including reversal or discontinuation of underlying predisposing factors, early administration of active antifungal agents at optimal doses, complete removal of all infected tissues, and use of various adjunctive therapies. Our armamentarium of antifungals is slightly enriched by the addition of two newer azoles (posaconazole and isavuconazole) to liposomal amphotericin B, which remains the drug of choice for the initial antifungal treatment, according to the recently published guidelines by ECIL-6, as well as those published by ECMM/ESCMID. Despite the efforts for better understanding of the pathogenesis, early diagnosis and aggressive treatment of mucormycosis, the mortality rate of the disease remains high.

Zygomycosis due to Mucor racemosus Associated with a Circovirus Infection in a Blue Tit (Cyanistes caeruleus)

In spring 2014, several wild passeriform garden birds were found severely ill or dead, all with severe periocular swellings. A blue tit (Cyanistes caeruleus) showing severe depression was humanely destroyed and sent for necropsy examination. In this bird, the lower eyelids were sagging, red and oedematous. Microscopical examination revealed marked infiltration of the eyelid tissue with fungal hyphae (stained by periodic acid-Schiff) without any inflammatory reaction. Polymerase chain reaction followed by sequencing identified Mucor racemosus and a so far unknown circovirus. The circovirus infection in this bird might have induced immunosuppression and thus facilitated the fungal infection. To our knowledge this is the first report of ocular M. racemosus infection associated with circovirus infection in a bird.

Isolated bilateral renal mucormycosis in apparently immunocompetent patients-a case series from India and review of the literature

BACKGROUND

Isolated renal mucormycosis (IRM) is a potentially fatal disease affecting immunocompromised hosts. IRM affecting apparently immunocompetent patients is rare, with few previous reports, mostly from India. We describe 10 cases of bilateral IRM with no underlying risk factors.

METHODS

We performed a retrospective analysis of cases of IRM from our hospital information system admitted between 2009 and 2016. We analyzed the data of this cohort of IRM, including epidemiological characteristics, clinical presentation, diagnostic procedures, treatment details and outcome.

RESULTS

In all, 10 cases of bilateral IRM were identified. All of them were males with a mean age of 24.7 years (range 10-42). Most patients were initially managed as acute bacterial pyelonephritis with acute kidney injury. A total of eight patients were diagnosed antemortem. Diagnostic clues include sepsis not controlled with broad-spectrum antibiotics and enlarged kidneys with or without hypodensities on ultrasound/computed tomography imaging. Three patients also gave a specific history of passing white flakes in their urine. Eight patients received specific antifungal therapy with amphotericin B with or without posaconazole. Three patients in whom the disease was apparently confined to the pelvicalyceal system underwent local irrigation with Amp-B. One patient underwent bilateral nephrectomy. Four patients succumbed to the disease while five patients were successfully treated. One patient was discharged against medical advice.

CONCLUSIONS

IRM is a rare, life-threatening disease associated with high mortality even in immunocompetent individuals. Typical clinical and radiological findings and a high index of suspicion may help in early diagnosis, but definitive diagnosis requires histopathological and/or microbiological confirmation. Early and rapid diagnosis along with aggressive multidisciplinary management including initiation of specific antifungal therapy with or without surgical debridement is vital for a successful outcome.

Pulmonary mucormycosis in an adolescent female with type 1 diabetes mellitus

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Diabetes is present in 15% of pediatric patients with mucormycosis [1–2].

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Treatment includes amphotericin B, as well as surgical debridement for invasive disease.

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High index of suspicion is required as delay of treatment leads to disseminated disease.

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The mortality rate is near 50%, while for disseminated disease is almost 100%.

Mucormycosis is a relatively rare, life-threatening and opportunistic infection that affects immunocompromised patients. We present the unusual case of pulmonary mucormycosis in a 13-year-old Caucasian female that had recently been diagnosed with type 1 diabetes. Our case serves as an example to healthcare providers treating immunosuppressed patients with pneumonia to have a high clinical suspicion for fungal infections, as delay in diagnosis and treatment can result in disseminated disease and higher patient mortality risk.

Liquid-Based Cytopathology Test: A Novel Method for Diagnosing Pulmonary Mucormycosis in Bronchial Brushing Samples

Background: Pulmonary mucormycosis, a relatively rare but severe pulmonary fungal disease with a high mortality rate, is difficult to diagnose in immunocompromised patients. Conventional cytopathology (CCP) examination of respiratory samples can help detect Mucorales, but its diagnostic sensitivity is poor. The aim of this study was to assess the first application of liquid-based cytopathology test (LCT) to detect Mucorales.

Methods: A total of 33 pairs of bronchial brushing samples from 27 patients diagnosed as pulmonary mucormycosis by fiberoptic bronchoscopy biopsy were prepared as slides using both CCP and LCT. LCT and CCP used the same cytology brush to obtain samples at the same site during the same time as the fiberoptic bronchoscopy biopsy. All samples were stained with Papanicolaou, GMS and PAS. CCP and LCT slides were evaluated from the rate of positive detection, 8 cytomorphological features and 7 background features.

Results: LCT-prepared slides showed a higher positive rate of Mucorales detection than CCP-prepared slides for Papanicolaou’s staining [28/33 (84.85%) vs. 15/33 (45.45%), p = 0.001] and for “special staining” with GMS and PAS [29/33 (87.88%) vs. 18/33 (54.55%), p = 0.003]. Clearer smear background and more distinct stereoscopic cytopathological features were observed in LCT. Messy yarn-like necrosis observed in conventionally prepared 75.76% (25/33) samples was cytomorphological suggestive for the diagnosis of mucormycosis.

Conclusion: This retrospective study suggests that LCT may be better than CCP to detect Mucorales in bronchial brushing samples from patients with pulmonary mucormycosis.

Diagnosis and Treatment of Isolated Cerebral Mucormycosis: Patient-Level Data Meta-Analysis and Mayo Clinic Experience

BACKGROUND

Isolated cerebral mucormycosis is a rare and serious infection associated with intravenous drug abuse.

METHODS

We performed a comprehensive meta-analysis of cases reported in studies and have included an unreported case from our institution. We searched PubMed/Medline, EMBASE, Scopus, Cochrane Databases, and our institution's electronic medical health records from inception through March 31, 2018. The cases were considered isolated (only affecting the cerebrum, cerebellum, or brainstem) if the absence of other primary sources of infection had been documented. Continuous variables were summarized using the median and interquartile range and categorical variables using frequencies and proportions. The relationships between variables were tested using the Wilcoxon rank sum and Pearson χ² tests.

RESULTS

A total of 130 studies (141 patients) met the eligibility requirements and were screened; 68 patients were included. The median age was 28 years (interquartile range, 24-38); 57% were men. Most patients had a history of intravenous drug abuse (82%), and 20% had positive human immunodeficiency virus findings. The lesion location was mostly supratentorial (91%), especially in the basal ganglia (71.2%). The cultures were positive in 38%, with Rhizopus the most common organism (59%). The mortality rate was 65%. The survivors were significantly more likely to have received amphotericin B (92% vs. 43%; P < 0.001) or to have undergone stereotactic aspiration (58% vs. 25%; P < 0.01).

CONCLUSIONS

Isolated cerebral mucormycosis has a pooled mortality rate of 65%. The presence of lesions in the basal ganglia, rapidly progressive symptoms, and a history of intravenous drug abuse should raise suspicion for the early initiation of amphotericin B and stereotactic aspiration.

Urgent Infections of the Head and Neck

Infections of the head and neck are common and appropriately managed by primary care providers in most cases. However, some infections are associated with significant morbidity and require urgent recognition and management by specialty services. These include deep neck space infections originating in the oral cavity, pharynx, and salivary glands, as well as complicated otologic and sinonasal infection. This article provides a review of these conditions, including the pathophysiology, presenting features, and initial management strategy.

Successful treatment of invasive mucormycosis with isavuconazole in pediatric patients

BACKGROUND

Invasive mold infections (IMIs) are a leading cause of mortality among immunocompromised patients. Isavuconazole is a new drug that shows promise in the adult population for the treatment of IMIs. No data regarding the use of isavuconazole in pediatric patients have been published.

METHODS

Patients with a diagnosis of IMI from our pediatric hemato-oncology division, treated with isavuconazole between 2010 and 2016, were identified using the hospital's computerized database. Data including demographics, clinical course, and outcome were collected. Pharmacokinetic samples were obtained from two younger patients to guide dosing.

RESULTS

In total, three patients (4.5, 5, and 19 years of age) with invasive mucormycosis who were treated with isavuconazole were identified. All patients were treated with isavuconazole as a second line therapy and experienced improvement following the initiation of this treatment.

CONCLUSIONS

Based on our limited clinical experience, isavuconazole may be a safe and effective treatment option for children and adolescents afflicted by IMI. Prospective clinical trials should be performed in order to evaluate the pharmakokinetics and safety of isavuconazole in the pediatric population.

Invasive Gastrointestinal Mucormycosis: A Master Masquerader

We report 3 previously healthy children of postneonatal age who developed fatal form of gastrointestinal mucormycosis after systemic inflammatory response syndrome, shock and metabolic acidosis. Abdominal distension and peritonitis were secondary complications. The study highlights the importance of clinical suspicion of gastrointestinal mucormycosis when the triad of shock requiring vasoactive drugs, metabolic acidosis and abdominal distension is present.

Rhinocerebral Mucormycosis With Temporal Artery Thrombosis in an Adolescent Following HLA-haploidentical Stem Cell Transplantation

Rhinocerebral mucormycosis (RCM) can lead to internal carotid artery thrombosis. Here, we report the first case of RCM with temporal artery thrombosis following HLA-haploidentical stem cell transplantation in an adolescent presenting with low-grade fever, right mandibular pain, and right jaw claudication. This case suggests that RCM can cause temporal artery thrombosis and should be considered as a differential diagnosis in severely immunocompromised patients with maxillary sinusitis presenting with jaw claudication.

Clinical Outcomes of Oral Suspension versus Delayed-Release Tablet Formulations of Posaconazole for Prophylaxis of Invasive Fungal Infections

Posaconazole is used for prophylaxis for invasive fungal infections (IFIs) among patients with hematologic malignancies. We compared the incidence of breakthrough IFIs and early discontinuation between patients receiving delayed-release tablet and oral suspension formulations of posaconazole.

Posaconazole is used for prophylaxis for invasive fungal infections (IFIs) among patients with hematologic malignancies. We compared the incidence of breakthrough IFIs and early discontinuation between patients receiving delayed-release tablet and oral suspension formulations of posaconazole. This was a retrospective cohort study of patients receiving posaconazole between 1 January 2010 and 30 June 2016. We defined probable or proven breakthrough IFIs using the European Organization for Research and Treatment of Cancer (EORTC) criteria. Overall, 547 patients received 860 courses of posaconazole (53% received the oral suspension and 48% received the tablet); primary indications for prophylaxis were acute myeloid leukemia (69%), graft-versus-host disease (18%), and myelodysplastic syndrome (3%). There were no significant differences in demographics or indications between patients receiving the different formulations. The incidence and incidence rate of probable or proven IFIs were 1.6% and 3.2 per 10,000 posaconazole days, respectively. There was no significant difference in the rate of IFIs between suspension courses (2.8 per 10,000 posaconazole days) and tablet courses (3.7 per 10,000 posaconazole days) (rate ratio = 0.8, 95% confidence interval [CI] = 0.3 to 2.3). Of the 14 proven or probable cases of IFI, 8/14 had posaconazole serum concentrations measured, and the concentrations in 7/8 were above 0.7 μg/ml. Posaconazole was discontinued early in 15.5% of courses; however, the frequency of discontinuation was also not significantly different between the tablet (16.5%) and oral suspension (14.6%) formulations (95% CI for difference = −0.13 to 0.06). In conclusion, the incidence of breakthrough IFIs was low among patients receiving posaconazole prophylaxis and not significantly different between patients receiving the tablet formulation and those receiving the oral suspension formulation.

Tongue necrosis secondary to mucormycosis in a diabetic patient: A first case report in Malaysia

Mucormycosis is a rare fungal infection and high mortality that commonly affects patients with the weakened immune system. We present an unusual case of tongue necrosis probably due to the healthcare-associated mucormycosis (HCM) in a diabetic patient. Although cannot be proved with certainty, we surmise that intubation as a risk factor in our case. The diagnosis was confirmed by histopathological examination (HPE) of the necrotic tissue specimen. The patient was responded well to lipid complex amphotericin B (250mg) regime after surgery. Subsequent follow up revealed that no signs of recurrence. Early, recognition, diagnosis, prompt treatment and awareness among clinician are representing the most effective way of managing the disease.

Identification of Mucorales in patients with proven invasive mucormycosis by polymerase chain reaction in tissue samples

BACKGROUND

Accurate diagnosis of mucormycosis, a life-threatening fungal infection, remains a challenge for physicians.

OBJECTIVES

To identify the causative Mucorales in fresh clinical samples and formalin-fixed paraffin-embedded (FFPE) samples of patients with proven mucormycosis by molecular method.

PATIENTS/METHODS

Fresh clinical samples of patients with proven mucormycosis according to the EORTC/MSG criteria admitted between 2015 and 2017 and histopathologically proven FFPE archives collected during 2004-2007 and 2015-2017 from Mazandaran University-affiliated hospitals of northern Iran were included. Seminested PCR targeting the 18S rDNA of Mucorales and ITS region was performed, and PCR products were then sequenced.

RESULTS

While culture was positive only in 5 of 9 (56%) of fresh specimen cases, PCR was positive in all 9 (100%) histologically proven mucormycosis. Ten of 18 (56%) FFPE samples were PCR-positive. Overall, Mucorales PCR was positive in 19 of 27 (70%) samples. Mucorales species were Rhizopus arrhizus in 16 (84%) cases, R. arrhizus/Amylomyces rouxii in 2 (10.5%) cases and Rhizopus stolonifer in one case (5.5%). Among 27 mucormycosis cases, 25 (93%) cases were rhinocerebral, and 2 (7%) cases were disseminated. Diabetes mellitus (74%) and neutropaenia (63%) were the main risk factors.

CONCLUSIONS

Seminested PCR targeting 18S rDNA region of Mucorales is useful for identification of the causative agents of mucormycosis.

An Adult Zebrafish Model Reveals that Mucormycosis Induces Apoptosis of Infected Macrophages

Mucormycosis is a life-threatening fungal infection caused by various ubiquitous filamentous fungi of the Mucorales order, although Rhizopus spp. and Mucor spp. are the most prevalent causal agents. The limited therapeutic options available together with a rapid progression of the infection and a difficult early diagnosis produce high mortality. Here, we developed an adult zebrafish model of Mucor circinelloides infection which allowed us to confirm the link between sporangiospore size and virulence. Transcriptomic studies revealed a local, strong inflammatory response of the host elicited after sporangiospore germination and mycelial tissue invasion, while avirulent and UV-killed sporangiospores failed to induce inflammation and were rapidly cleared. Of the 857 genes modulated by the infection, those encoding cytokines, complement factors, peptidoglycan recognition proteins, and iron acquisition are particularly interesting. Furthermore, neutrophils and macrophages were similarly recruited independently of sporangiospore virulence and viability, which results in a robust depletion of both cell types in the hematopoietic compartment. Strikingly, our model also reveals for the first time the ability of mucormycosis to induce the apoptosis of recruited macrophages but not neutrophils. The induction of macrophage apoptosis, therefore, might represent a key virulence mechanism of these fungal pathogens, providing novel targets for therapeutic intervention in this lethal infection.

Mucormycosis in hospitalized patients at a tertiary care center in Lebanon: a case series

PURPOSE

Mucormycosis (MCM) is a rare fungal infection affecting people with impaired immunity. Data related to MCM from Lebanon are scarce. The aim of this study is to shed light on the epidemiology, incidence, and outcome of patients with MCM hospitalized at a tertiary care center in Lebanon.

METHODS

We conducted a retrospective chart review between Jan 1, 2008 and Jan 10, 2018. All patients with proven or probable MCM were included.

RESULTS

A total of 20 patients were included. Their median age was 49 years and the majority were males. Comorbidities included mainly hematologic malignancy and diabetes mellitus. Most common sites of involvement were rhino-orbital and pulmonary, respectively. The number of MCM cases/10.000 hospital admissions increased significantly between 2008 and 2017 (0.47 vs. 1.18; P < 0.05). A liposomal amphotericin B formulation alone or in combination with other antifungals was used as a first line agent in all patients. All-cause mortality was 60%; however, death was attributed to MCM in 20% of cases.

CONCLUSION

The incidence of MCM has significantly increased over the past 10 years at our institution, most likely due to the increasing patient population at risk. Understanding the epidemiology of MCM in our setting would help guide antifungal therapy.

Angioinvasive fungal infections impacting the skin: Diagnosis, management, and complications

As discussed in the first article in this continuing medical education series, angioinvasive fungal infections pose a significant risk to immunocompromised and immunocompetent patients alike, with a potential for severe morbidity and high mortality. The first article in this series focused on the epidemiology and clinical presentation of these infections; this article discusses the diagnosis, management, and potential complications of these infections. The mainstay diagnostic tests (positive tissue culture with histologic confirmation) are often supplemented with serum biomarker assays and molecular testing (eg, quantitative polymerase chain reaction analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry) to ensure proper speciation. When an angioinvasive fungal infection is suspected or diagnosed, further workup for visceral involvement also is essential and may partially depend on the organism. Different fungal organisms have varied susceptibilities to antifungal agents, and knowledge on optimal treatment regimens is important to avoid the potential complications associated with undertreated or untreated fungal infections.

Opportunistic fungal infection in children and management

PURPOSE OF REVIEW

An opportunistic mycosis is a fungal agent of low pathogenicity that specifically infects immunocompromised hosts. Advances in transplantation, preterm care, immunosuppressive therapies and intensive care, have lead to the emergence of pediatric patients with serious immunodeficiency who are vulnerable to nonpathogenic fungi.

RECENT FINDINGS

The advent of the use of biologic agents in pediatric disease as well as the advances in care of preterm and immunosuppressed patients opens up a new cohort of patients at risk of opportunistic mycotic infections. Recent cases of cutaneous histioplasmosis as the presenting sign of hyper-IgM syndrome and the case of cutaneous blastomycosis in a patient treated with infliximab underscore the need to have a high clinical suspicion for deep fungal infections in immunosuppressed patients.

SUMMARY

The current review will focus on the cutaneous manifestations of cutaneous infections by Aspergillus, Blastomyces, histoplasmosis, and mucormycosis. Greater understanding of these diseases and high-quality research in identification and treatment can enhance care of patients in the coming future.

Molecular Confirmation of the Linkage between the Rhizopus oryzae CYP51A Gene Coding Region and Its Intrinsic Voriconazole and Fluconazole Resistance

Rhizopus oryzae is the most prevalent causative agent of mucormycosis, an increasingly reported opportunistic fungal infection. These Mucorales are intrinsically resistant to Candida- and Aspergillus-active antifungal azole drugs, such as fluconazole (FLC) and voriconazole, respectively. Despite its importance, the molecular mechanisms of its intrinsic azole resistance have not been elucidated yet. The aim of this work was to establish if the Rhizopus oryzaeCYP51 genes are uniquely responsible for intrinsic voriconazole and fluconazole resistance in these fungal pathogens. Two CYP51 genes were identified in the R. oryzae genome. We classified them as CYP51A and CYP51B based on their sequence similarity with other known fungal CYP51 genes. Later, we obtained a chimeric Aspergillus fumigatus strain harboring a functional R. oryzae CYP51A gene expressed under the regulation of the wild-type A. fumigatusCYP51A promoter and terminator. The mutant was selected after transformation by using a novel procedure taking advantage of the FLC hypersusceptibility of the A. fumigatusCYP51A deletion mutant used as the recipient strain. The azole susceptibility patterns of the A. fumigatus transformants harboring R. oryzae CYP51A mimicked exactly the azole susceptibility patterns of this mucormycete. The data presented in this work demonstrate that the R. oryzae CYP51A coding sequence is uniquely responsible for the R. oryzae azole susceptibility patterns.

An Interesting Case of a 57-Year-Old Male with an Upper Gastrointestinal Bleeding and Obstructive Uropathy with Bilateral Hydronephrosis Diagnosed with Systemic Mucormycosis

Mucormycosis is a rare and invasive fungal disease with high mortality rate caused by members of the order Mucorales. Mucorales species are vasotrophic organisms that may cause angioinvasive disease in immunosuppressed hosts. Risk factors include diabetic ketoacidosis, chronic kidney disease, organ or bone marrow transplantation, neutropenia, burns, malignancies, and steroid therapy. There are six different clinical presentations of mucormycosis, which includes rhino-orbital cerebral, pulmonary, gastrointestinal, cutaneous, disseminated, and miscellaneous infection. Here, we report a case of a 57-year-old male with stage-IV sarcoidosis on long-term steroids presenting with upper gastrointestinal bleeding and obstructive uropathy who was diagnosed with systemic mucormycosis. Biopsy obtained by endoscopy revealed necrotic debris with acute leukocytic exudate and numerous variably sized, 90-degree angulated fungal hyphae favoring mucormycosis-causing species. Imaging studies showed hydronephrosis, and cystoscopy findings were consistent with fungal infection of the bladder. Isavuconazonium sulfate was used as systemic salvage therapy along with continuous bladder irrigation with amphotericin-B for localized bladder infection after a trial with first-line systemic treatment with intravenous liposomal amphotericin-B failed. A repeat endoscopy showed inflammatory changes with a pathology report in which mucormycosis was no longer appreciated. The patient was discharged home to complete 6 months of antifungal therapy with monthly follow-ups. The patient has been asymptomatic after 12-month completion of therapy.

Orbitocerebral mucormycosis and intracranial haemorrhage: a role for caution with steroids in suspected giant cell arteritis

A 75-year-old man with type 2 diabetes mellitus presented with complete loss of vision in his right eye and severe headaches for the past 24 hours. He had been treated for suspected giant cell arteritis (GCA) with high-dose corticosteroids which were being tapered to stop after an inconclusive right temporal artery biopsy and an erythrocyte sedimentation rate (ESR) value of 8. His current acute presentation, however, raised further concern for partially treated GCA and precipitated treatment with pulsed methylprednisolone. The patient, taking metformin, developed diabetic ketoacidosis and was transferred to the intensive care unit where a swollen, painful right eye with chemosis and complete ophthalmoplegia was subsequently revealed to be secondary to cavernous sinus thrombosis. Rhino-orbital skin necrosis with positive samples for the organism Rhizopus on eventual orbital exenteration revealed angioinvasive fungal infection, mucormycosis, to be the cause. We discuss here the lessons learnt, and how best to treat a susceptible cohort within our ageing western population.

Rhinocerebral mucormycosis, risk factors and the type of oral manifestations in patients referred to a University Hospital in Tabriz, Iran 2007-2017

Inadequate data are available on the global epidemiology of mucormycosis, mainly derived from the evaluation of specific population groups. Rhinocerebral mucormycosis is an invading and fatal mycosis, particularly among diabetic patients. In the present study, patients hospitalised in Imam Reza Hospital in Tabriz, from 2007 to 2017, were evaluated. The hospital information system (HIS) was used to collect the records of the patients. A total of 42 patients with a diagnosis of mucormycosis were included in the study, 40 cases (95%) of which had a diagnosis of the rhinocerebral form. Of these 40 patients, 21 (52.5%) and 19 (47.5%) were male and female, respectively. Seven cases (17.5%) of rhinocerebral mucormycosis were due to dental procedures. The most predisposing factor in the patients was diabetes with 36 (90%) cases. In our study, the role of tooth extraction in patients with uncontrolled diabetes was identified as an important factor. It may show the important role of dentists in preventing of the disease in diabetic patients.

Self-resolving superficial primary cutaneous mucormycosis in a 7-week-old infant

A 7-week-old girl, born at 30 weeks' gestational age, presented to clinic for evaluation of a crop of vesicular lesions that were noted after removal of a bandage that had been in place for 4 days. A punch biopsy of the lesion revealed fungal elements that were later identified as Rhizopus spp. The lesion began to self-resolve, and no further treatment was needed, with full resolution of the lesion by 1 month after presentation. Clinicians should be aware of the variable presentations of mucormycosis and consider fungal infection in the differential diagnosis when evaluating vulnerable patients with skin eruptions.

Surgical Management of Pulmonary Mucormycosis in Third-Trimester Pregnancy

Background  Pulmonary mucormycosis is a rare fungal infection that carries a high mortality. Given the rarity of this disease, its management has not been well established.

Case Description  We report a 36-year-old female presenting with right middle and lower lobe pulmonary mucormycosis during the third trimester of pregnancy. Diagnosis was established using chest computed tomography followed by bronchoalveolar lavage and lung biopsy. Prompt initiation of amphotericin B and right middle and lower lobe lobectomy resulted in maternal survival and fetal viability.

Conclusion  This favorable outcome is attributed to extensive communication between treatment teams in addition to comprehensive surgical planning.