Epidemiology of mucormycosis: review of 18 cases in a tertiary care hospital

COVID-19 associated rhino-orbital-cerebral mucormycosis: An observational study from Eastern India, with special emphasis on neurological spectrum

AIMS

1: Describe the epidemiology and determine risk factors for COVID-19 associated mucormycosis. 2: Elaborate the clinical spectrum of Rhino-Orbital-Cerebral Mucormycosis (ROCM), pattern of neuroaxis involvement and it's radiological correlates.

METHODS

Observational study. Consecutive, confirmed cases of mucormycosis (N = 55) were included. A case of mucormycosis was defined as one who had clinical and radiological features consistent with mucormycosis along with demonstration of the fungus in tissue via KOH mount/culture/histopathological examination (HPE). Data pertaining to epidemiology, risk factors, clinico-radiological features were analysed using percentage of total cases.

RESULTS

Middle aged, diabetic males with recent COVID-19 infection were most affected. New onset upper jaw toothache was a striking observation in several cases. Among neurological manifestations headache, proptosis, vision loss, extraocular movement restriction; cavernous sinus, meningeal and parenchymal involvement were common. Stroke in ROCM followed a definitive pattern with watershed infarction.

CONCLUSIONS

New onset upper jaw toothache and loosening of teeth should prompt an immediate search for mucormycosis in backdrop of diabetic patients with recent COVID-19 disease, aiding earlier diagnosis and treatment initiation. Neuroaxis involvement was characterized by a multitude of features pertaining to involvement of optic nerve, extraocular muscles, meninges, brain parenchyma and internal carotid artery.

Mucormycosis: The Scathing Invader

Mucormycosis is an invasive fungal infection that has been increasing in incidence over the years. Increase in the number of diabetics, malignancy patients, and use of immunosuppressants has mainly led to this gradual upward surge. Mucormycosis has various clinical forms, including rhino-orbito-cerebral, pulmonary, gastrointestinal, and cutaneous. Fungi belonging to Mucorales are thermotolerant and ubiquitous, found growing on organic substrates such as bread, decaying fruits and vegetables, crop debris in soil, compost, and animal excreta. During this second wave of the COVID-19 pandemic, the number of cases of mucormycosis has increased manifold in a short span of time. Associated comorbidity of diabetes mellitus, increased use of higher doses and prolonged duration of systemic corticosteroids, the glucogenic and prothrombotic propensity of the virus, hypoxic environment, COVID pneumonia, increased hospitalization, ICU admissions, and mechanical ventilation have all contributed toward this high rise in numbers. The rhin-orbito-cerebral form is the commonest manifestation of mucormycosis in COVID. Rhizopus oryzae, the main species causing mucormycosis, is identified by hyaline, sparsely-septate, broad, ribbon-like hyphae with irregular right-angle branching ribbon-like hyphae with rhizoids. For the early diagnosis of this infection, 10% KOH mount is very important. These fungi are very rapidly growing and thus can be differentiated from their main ally, Aspergillus. Treatment is mainly in the form of extensive surgical debridement along with liposomal amphotericin B. Posaconazole and isavuconazole are second-line agents, which can also be used for maintenance. Control of diabetes and COVID-19, along with judicious use of antibiotics and systemic corticosteroids, are equally important as management strategies in these pandemic times.

Neutropenic Enterocolitis due to Mucormycosis in a Patient with Myelodysplastic Syndrome

Neutropenic enterocolitis is a fatal enterocolitis occurring in neutropenic patients with immunocompromised diseases including hematologic malignancies. Gastrointestinal (GI) mucormycosis in hematologic malignancies has been rarely reported. Especially, in myelodysplastic syndrome (MDS), GI mucormycosis has never been reported. We report a case of GI mucormocysis manifesting as neutropenic enterocolitis in a patient with MDS.

Pulmonary mucormycosis: clinical features and outcomes

PURPOSE

Mucormycosis encompasses a group of opportunistic fungal infections caused by Zygomycetes, order Mucorales. Mucormycosis can manifest as rhino-orbito-cerebral, pulmonary, gastrointestinal, cutaneous, and disseminated infections. Pulmonary mucormycosis is the second most common presentation. This manuscript characterizes the demographics, clinical presentation, diagnostic procedures, radiologic findings, therapeutic interventions, and outcome in pulmonary mucormycosis.

METHODS

We retrospectively reviewed clinical data of 35 patients with pulmonary mucormycosis from 2000 to 2015. Microbiologic diagnosis was based on positive culture from a sterile site or findings on histopathology consistent with mucormycosis. Independent predictors of 28-day mortality were assessed using logistic regression. Survival curves were estimated using Kaplan-Meier method.

RESULTS

There was male predominance with a mean age of 55 ± 15 years. Analysis of predisposing conditions revealed the prevailing presence of malignancy. Sixty-six percent of patients were receiving immunosuppressive agents. Common presenting clinical findings were fever, neutropenia, dyspnea, and cough. Radiologic findings included pleural effusion and nodules. All patients received medical therapy and 43% underwent additional surgical intervention. Twenty eight day mortality was 29% with concurrent bacteremia found as the sole independent predictor. Similar survival from pulmonary mucormycosis was noted over time.

CONCLUSIONS

Pulmonary mucormycosis is an opportunistic angioinvasive fungal infection. Physicians must have a high level of suspicion in immunocompromised patients with fever and respiratory symptoms refractory to antibiotics. A low threshold should be had for performing an invasive procedure to gain reliable diagnosis, as early, aggressive medical and surgical interventions are needed for successful treatment.

Wound infection caused by Lichtheimia ramosa due to a car accident

A 32-year-old immunocompetent man sustained severe traumas contaminated with organic material due to a car accident. An infection caused by Lichtheimia ramosa at the site of contamination was early diagnosed and cured by multiple surgical debridement and daily cleansing with antiseptic solution only.

A significant number of reported Absidia corymbifera (Lichtheimia corymbifera) infections are caused by Lichtheimia ramosa (syn. Lichtheimia hongkongensis): an emerging cause of mucormycosis

Recently, we and others reported the discovery of Lichtheimia ramosa (syn. Lichtheimia hongkongensis). We also hypothesized that a proportion of ‘Absidia corymbifera (Lichtheimia corymbifera)' reported in the literature could be L. ramosa. In this study, we characterized 13 strains that had been reported as ‘A. corymbifera (L. corymbifera)' in the literature over an 11-year period. Microscopic examination of agar block smear preparations of all 13 strains showed abundant circinate side branches and pleomorphic giant cells with finger-like projections of L. ramosa. ITS1–5.8S–ITS2 rRNA gene cluster (internal transcribed spacer (ITS)) and partial elongation factor-1alpha (EF1α) gene sequencing showed that all 13 strains were clustered with L. ramosa; partial β-actin gene sequencing showed that most of the 13 strains were clustered with L. ramosa; and partial 28S rRNA gene sequencing showed that all 13 strains were clustered with L. ramosa, but one strain of L. corymbifera (HKU25) was also clustered with other strains of L. ramosa. A significant number of reported A. corymbifera (L. corymbifera) infections are L. ramosa infections which are of global distribution. In clinical microbiology laboratories, L. ramosa should be suspected if an Absidia-like mold that possesses abundant circinate side branches on the sporangiophores and pleomorphic giant cells with finger-like projections is observed. ITS and partial EF1α gene sequencing are more reliable than partial β-actin and 28S rRNA gene sequencing for identification of the Lichtheimia species.

Coinfection by Aspergillus and zygomycetes species in a case of acute rhinosinusitis

Invasive mycotic infections can be effectively treated if rapid identification of fungus is obtained. We reported a case of coinfection by Aspergillus and Rhizopus sp. involving nose, paranasal sinuses, orbit, and brain in a 68-year-old known hypertensive male. He was presented to ENT OPD with history of fever and intermittent headache since fifteen days along with history of right-sided nasal obstruction and proptosis since seven days. CT scan of brain and paranasal sinuses showed findings of pansinusitis with cellulitic changes in right orbit. MRI confirmed the same along with features of intracranial extension with focal meningitis in right frontotemporal region. Laboratory parameters did not conclude much except for leucocytosis and hyponatremia. Patient was taken for endoscopic debridement from nose and paranasal sinuses, and tissue was sent for microbiological and histopathological examination. Minced tissue was processed, and after 48 hrs of incubation two types of growth were identified, one was yellowish, granular, and powdery consistent with Aspergillus sp., and another was cottony and woolly consistent with Rhizopus sp. LCB mount confirmed presence of Aspergillus flavus and Rhizopus arrhizus. Patient responded to therapy with IV amphotericin B and surgical debridement. On discharge patient's condition was good.

Recent advances in the treatment of mucormycosis

In recent years, substantial advances have been achieved in the treatment of mucormycosis. It is now clear that early initiation of therapy results in substantially better outcomes, underscoring the need to maintain a high index of suspicion and aggressively biopsy potential lesions. Increasing data support the need for surgical excision of infected and/or necrosed tissue whenever feasible. Based on their superior safety and efficacy, lipid formulations of amphotericin B have become the standard treatment for mucormycosis. Posaconazole may be useful as salvage therapy, but cannot be recommended as primary therapy for mucormycosis based on available data. Pre-clinical and limited retrospective clinical data suggest that combination therapy with lipid formulations of amphotericin and an echinocandin improves survival during mucormycosis. A definitive trial is needed to confirm these results. The use of the iron chelator, deferasirox, as adjunctive therapy also improved outcomes in animal models of mucormycosis. However, its efficacy was not confirmed in a recent, phase 2 clinical trial. Additional study is required of the potential for abrogation of iron acquisition as adjunctive treatment of mucormycosis. Combination polyene-posaconazole therapy was of no benefit in pre-clinical studies. Adjunctive therapy with recombinant cytokines, hyperbaric oxygen, and/or granulocyte transfusions can be considered in selected patients. Large-scale, prospective, randomized clinical trials are needed to define optimal management strategies for mucormycosis.

Lichtheimia hongkongensis sp. nov., a novel Lichtheimia spp. associated with rhinocerebral, gastrointestinal, and cutaneous mucormycosis

Three thermotolerant "Absidia-like" isolates with unique morphologic characteristics, recovered from nasopharyngeal swab of a liver transplant recipient, gastric biopsy of a renal transplant recipient, and skin biopsy of a man with burn, respectively, were characterized. Microscopic examination showed nonseptate hyphae with highly branched sporangiophores. Uniquely, most side branches were circinate, and abundant pleomorphic giant cells with fingerlike projections were observed, characteristics absent from other Absidia/Lichtheimia spp. ITS1-5.8S-ITS2 rRNA gene cluster, partial EF1alpha gene, and partial beta-actin gene sequencing showed that the 3 strains formed a distinct cluster, most closely related to, but distinct from, Lichtheimia corymbifera, Lichtheimia blakesleeana, and Lichtheimia hyalospora. Based on the morphologic and genotypic characteristics, we propose a new species, Lichtheimia hongkongensis sp. nov., to describe this fungus, which caused rhinocerebral, gastrointestinal, and cutaneous mucormycosis, respectively, in 3 patients. A significant proportion of L. corymbifera associated with mucormycosis reported may be L. hongkongensis.

The rise of an opportunistic infection called "Invasive Zygomycosis"

Invasive zygomycosis is a devastating fungal infection seen mostly in immune-compromised patients. We present a case of a 48-year old diabetic man, with aplastic anemia, who developed severe pulmonary mucormycosis that led to his rapid demise despite early diagnosis and treatment with liposomal amphotericin B. We also conducted an extensive review of the pathogenesis of invasive zygomycosis, its history, predisposing factors, clinical aspects, diagnostic modalities, treatment options, morbidity and mortality.