Healthcare-associated mucormycosis

Mucor irregularis-associated cutaneous mucormycosis: Case report and review

Solid organ transplant recipients are at risk for invasive fungal diseases, and are also exposed to healthcare-associated mucormycosis. Mainly causing localized cutaneous mucormycosis, Mucor irregularis infection is reported for the first time in a kidney-transplant recipient. A healthcare-associated origin was highly suspected in this case. We performed a literature review and highlight the characteristics of this very rare fungus.

[PCR-based diagnosis of mucormycosis in tissue samples]

Mucormycosis is characterized by a rapid, often fatal progression. Early diagnosis of invasive mucormycosis is the key for timely therapeutic intervention and improved survival. Contrary to the more prevalent aspergillosis, effective antifungal therapy of mucormycosis is mainly limited to amphotericin B. Given the importance to guide the timely initiation of amphotericin B and possible surgical intervention, rapid and specific identification of fungal hyphae is essential. Conventional histopathology depends on abundance and morphology of the fungi as well as on the skills of the personnel, and usually shows an accuracy of 80 %. PCR assays targeting fungal ribosomal genes to identify Mucorales at least at genus level increase sensitivity, allow a rapid identification as well as detection of double mold infections. Thus, PCR assays are beneficial to complement existing approaches. They are recommended to rapidly specify tissue diagnosis and accurate identification of fungi. This will help to guide effective therapy and thereby, survival will increase. Retrospective analyses of mucormycosis by PCR help to evaluate therapeutic interventions and will optimize treatment options.

Hospital days, hospitalization costs, and inpatient mortality among patients with mucormycosis: a retrospective analysis of US hospital discharge data

Background

Mucormycosis is a rare and potentially fatal fungal infection occurring primarily in severely immunosuppressed patients. Because it is so rare, reports in the literature are mainly limited to case reports or small case series. The aim of this study was to evaluate inpatient mortality, length of stay (LOS), and costs among a matched sample of high-risk patients with and without mucormycosis in a large nationally representative database.

Methods

We conducted a retrospective analysis using the 2003–2010 Healthcare Cost and Utilization Project – Nationwide Inpatient Sample (HCUP-NIS). The NIS is a nationally representative 20% sample of hospitalizations from acute care United States (US) hospitals, with survey weights available to compute national estimates. We classified hospitalizations into four mutually exclusive risk categories for mucormycosis: A- severely immunocompromised, B- critically ill, C- mildly/moderately immunocompromised, D- major surgery or pneumonia. Mucormycosis hospitalizations (“cases”) were identified by ICD-9-CM code 117.7. Non-mucormycosis hospitalizations (“non-cases”) were propensity-score matched to cases 3:1. We examined demographics, clinical characteristics, and hospital outcomes (mortality, LOS, costs). Weighted results were reported.

Results

From 319,366,817 total hospitalizations, 5,346 cases were matched to 15,999 non-cases. Cases and non-cases did not differ significantly in age (49.6 vs. 49.7 years), female sex (40.5% vs. 41.0%), White race (53.3% vs. 55.9%) or high-risk group (A-49.1% vs. 49.0%, B-20.0% vs. 21.8%, C-25.5% vs. 23.8%, D-5.5% vs. 5.4%). Cases experienced significantly higher mortality (22.1% vs. 4.4%, P < 0.001), with mean LOS and total costs more than 3-fold higher (24.5 vs. 8.0 days and $90,272 vs. $25,746; both P < 0.001).

Conclusions

In a national hospital database, hospitalizations with mucormycosis had significantly higher inpatient mortality, LOS, and hospital costs than matched hospitalizations without mucormycosis. Findings suggest that interventions to prevent or more effectively treat mucormycosis are needed.

A 29-year-old man with hospital-acquired cavitary pneumonia

Cavitary lung processes pose a formidable diagnostic challenge. Causes vary widely and include cavitary pneumonia, vasculitis and malignancy. In some cases, patient history and basic work-up may yield a diagnosis, but in others, an extensive work-up, including tissue biopsy, may be necessary to establish the cause. The authors present a case of cavitary pneumonia that complicated an open lung biopsy. It developed in the hospital and was caused by mucormycosis, a potential emerging infection causing health care-associated infections.

Biology, systematics, and clinical manifestations of Zygomycota infections

Fungi cause opportunistic, nosocomial, and community-acquired infections. Among fungal infections (mycoses) zygomycoses are exceptionally severe, with a mortality rate exceeding 50%. Immunocompromised hosts, transplant recipients, and diabetic patients with uncontrolled keto-acidosis and high iron serum levels are at risk. Zygomycota are capable of infecting hosts immune to other filamentous fungi. The infection often follows a progressive pattern, with angioinvasion and metastases. Moreover, current antifungal therapy frequently has an unfavorable outcome. Zygomycota are resistant to some of the routinely used antifungals, among them azoles (except posaconazole) and echinocandins. The typical treatment consists of surgical debridement of the infected tissues accompanied by amphotericin B administration. The latter has strong nephrotoxic side effects, which make it unsuitable for prophylaxis. Delayed administration of amphotericin and excision of mycelium-containing tissues worsens survival prognoses. More than 30 species of Zygomycota are involved in human infections, among them Mucorales is the most abundant. Prognosis and treatment suggestions differ for each species, which makes fast and reliable diagnosis essential. Serum sample PCR-based identification often gives false-negative results; culture-based identification is time-consuming and not always feasible. With the dawn of Zygomycota sequencing projects significant advancement is expected, as in the case of treatment of Ascomycota infections.

Mucormycosis in a renal transplant recipient: case report and comprehensive review of literature

Mucormycosis is a rare but devastating infection. We present a case of fatal disseminated mucormycosis infection in a renal transplant patient. Uncontrolled diabetes mellitus and immunosuppression are the major predisposing factors to infection with Mucorales. Mucorales are angioinvasive and can infect any organ system. Lungs are the predominant site of infection in solid organ transplant recipients. Prompt diagnosis is challenging and influences outcome. Treatment involves a combination of surgical and medical therapies. Amphotericin B remains the cornerstone in the medical management of mucormycosis, although other agents have been used. Newer agents are promising.

Isavuconazole therapy protects immunosuppressed mice from mucormycosis

We studied the in vitro and in vivo efficacies of the investigational drug isavuconazole against mucormycosis due to Rhizopus delemar. Isavuconazole was effective, with MIC and minimal fungicidal concentration (MFC) values ranging between 0.125 and 1.00 μg/ml. A high dose of isavuconazole prolonged the survival time and lowered the tissue fungal burden of cyclophosphamide/cortisone acetate-treated mice infected with R. delemar and was as effective as a high-dose liposomal amphotericin B treatment. These results support the further development of this azole against mucormycosis.

Our recommendations for avoiding exposure to fungi outside the hospital for patients with haematological cancers

Despite several chemotherapeutic and preventative advances, opportunistic fungal infections remain common unintended consequences of cancer treatment. Currently, cancer patients spend most of their time between treatments at home, where they can inadvertently come across potential hazards from environmental and food sources. Therefore, infection prevention measures are of the utmost importance for these patients. Although clinicians closely observe patients throughout their treatment courses in the hospital, the focus of clinical visits is predominantly on cancer care, and clinicians seldom provide recommendations for prevention of such infections. Herein, we provide practical recommendations for busy clinicians to help them educate patients regarding potential sources of fungal infections outside the hospital.

Neurologic infections in diabetes mellitus

Even at a time when HIV/AIDS and immunosuppressive therapy have increased the number of individuals living with significant immunocompromise, diabetes mellitus (DM) remains a major comorbid disorder for several rare but potentially lethal infections, including rhino-orbital-cerebral mucormycosis and malignant external otitis. DM is also a commonly associated condition in patients with nontropical pyomyositis, pyogenic spinal infections, Listeria meningitis, and blastomycosis. As West Nile virus spread to and across North America over a decade ago, DM appeared in many series as a risk factor for death or neuroinvasive disease. More recently, in several large international population-based studies, DM was identified as a risk factor for herpes zoster. The relationships among infection, DM, and the nervous system are multidirectional. Viral infections have been implicated in the pathogenesis of type 1 and type 2 DM, while parasitic infections have been hypothesized to protect against autoimmune disorders, including type 1 DM. DM-related neurologic disease can predispose to systemic infection - polyneuropathy is the predominant risk factor for diabetic foot infection. Because prognosis for many neurologic infections depends on timely institution of antimicrobial and sometimes surgical therapy, neurologists caring for diabetic patients should be familiar with the clinical features of the neuroinfectious syndromes associated with DM.

Invasive mold infections in solid organ transplant recipients

Invasive mold infections represent an increasing source of morbidity and mortality in solid organ transplant recipients. Whereas there is a large literature regarding invasive molds infections in hematopoietic stem cell transplants, data in solid organ transplants are scarcer. In this comprehensive review, we focused on invasive mold infection in the specific population of solid organ transplant. We highlighted epidemiology and specific risk factors for these infections and we assessed the main clinical and imaging findings by fungi and by type of solid organ transplant. Finally, we attempted to summarize the diagnostic strategy for detection of these fungi and tried to give an overview of the current prophylaxis treatments and outcomes of these infections in solid organ transplant recipients.

Disseminated infection due to Saksenaea vasiformis secondary to cutaneous mucormycosis

Mucormycosis is an uncommon opportunistic fungal infection caused by Zygomycetes. It usually affects immunocompromised, diabetic and trauma patients with infected wounds. We report a case of disseminated infection secondary to facial cutaneous mucormycosis caused by Saksenaea vasiformis in a diabetic patient who had a farming accident causing him severe head injury. The patient was treated with a combination of surgical debridement and antifungal therapy with liposomal amphotericin B, but he had a slow and fatal outcome. In cases of tissue necrosis following trauma involving wound contact with soil (i.e., potential fungal contamination), testing for the presence of Zygomycetes fungi such as S. vasiformis in both immunocompetent and immunocompromised patients is crucial. The reason is that this infection usually has a rapid progression and may be fatal if appropriate treatment is not administered.

Efficacy of liposomal amphotericin B and posaconazole in intratracheal models of murine mucormycosis

Mucormycosis is a life-threatening fungal infection almost uniformly affecting diabetics in ketoacidosis or other forms of acidosis and/or immunocompromised patients. Inhalation of Mucorales spores provides the most common natural route of entry into the host. In this study, we developed an intratracheal instillation model of pulmonary mucormycosis that hematogenously disseminates into other organs using diabetic ketoacidotic (DKA) or cyclophosphamide-cortisone acetate-treated mice. Various degrees of lethality were achieved for the DKA or cyclophosphamide-cortisone acetate-treated mice when infected with different clinical isolates of Mucorales. In both DKA and cyclophosphamide-cortisone acetate models, liposomal amphotericin B (LAmB) or posaconazole (POS) treatments were effective in improving survival, reducing lungs and brain fungal burdens, and histologically resolving the infection compared with placebo. These models can be used to study mechanisms of infection, develop immunotherapeutic strategies, and evaluate drug efficacies against life-threatening Mucorales infections.

Emerging fungal infections in solid organ transplant recipients

The most important emerging and rare fungal pathogens in solid organ transplant recipients are the Zygomycetes, Scedosporium, Fusarium, and the dark molds. Factors affecting the emergence of these fungi include the combination of intensive immunosuppressive regimens with increasingly widespread use of long-term azole antifungal therapy; employment of aggressive diagnostic approaches (eg, sampling of bronchoalveolar lavage fluid); and changes in patients' interactions with the environment. This article reviews the epidemiology, microbiology, and clinical impact of emerging fungal infections in solid organ transplant recipients, and provides up-to-date recommendations on their treatment.

[Clinical and radiological aspects of mucormycosis]

Mucormycosis is an infection caused by filamentous fungi of the Mucorales order. The predisposing factors are mostly diabetic ketoacidosis and severe immunosuppressive conditions such as prolonged neutropenia, steroid or T-cell suppressor therapy, solid organ transplantation or allogeneic hematopoietic stem cell transplantation. Mucormycosis can also occur in immunocompetent patients, especially after trauma, burns or direct inoculation of the fungi (e.g. intravenous drug abuse). The most frequently targeted primary sites of infection are sinuses with a rapid spread to the adjacent tissues including the brain, the lower respiratory tract, the digestive tract and the skin. Mucorales are able to invade the vessels causing hematogenous dissemination, vascular thrombosis and, ultimately, necrosis of the lesions. Clinical and radiological aspects are similar to those observed in other invasive filamentous fungi infections such as invasive aspergillosis, fusariosis or scedosporiosis. CT-scan or MRI are mandatory to assess the extension of the lesions. The diagnosis remains difficult and is often delayed resulting in a poor outcome.

Pulmonary mucormycosis: an emerging infection

Mucormycosis is a rare, but emerging, life-threatening, rapidly progressive, angioinvasive fungal infection that usually occurs in immunocompromised patients. We present a case of pulmonary mucormycosis in a diabetic patient who was on chronic steroid therapy for ulcerative colitis. Early recognition of this diagnosis, along with aggressive management, is critical to effective therapy and patient survival. The delay in diagnosis of this rapidly progressive infection can result in mortality.

Emerging invasive fungal diseases in transplantation

Invasive fungal infections continue to be a major cause of morbidity and mortality in severely immunocompromised transplant patients. Although Candida spp. and Aspergillus spp. represent the majority of identified pathogens, other fungi have become increasingly prevalent among this patient population. Diagnosis and treatment of invasive fungal infections remain a challenge in transplant medicine despite recent major advances. In this review, we will emphasize emerging topics in invasive fungal infections in transplantations that occurred in 2011-2012. The current literature was reviewed to synthesize new trends in epidemiology, recent outbreaks, clinical findings, and advances in diagnostic and therapeutic resources.

Donor-derived fungal infections in organ transplant recipients: guidelines of the American Society of Transplantation, infectious diseases community of practice

Donor-derived fungal infections can be associated with serious complications in transplant recipients. Most cases of donor-derived candidiasis have occurred in kidney transplant recipients in whom contaminated preservation fluid is a commonly proposed source. Donors with cryptococcal disease, including those with unrecognized cryptococcal meningoencephalitis may transmit the infection with the allograft. Active histoplasmosis or undiagnosed and presumably asymptomatic infection in the donor that had not resolved by the time of death can result in donor-derived histoplasmosis in the recipient. Potential donors from an endemic area with either active or occult infection can also transmit coccidioidomycosis. Rare instances of aspergillosis and other mycoses, including agents of mucormycosis may also be transmitted from infected donors. Appropriate diagnostic evaluation and prompt initiation of appropriate antifungal therapy are warranted if donor-derived fungal infections are a consideration. This document discusses the characteristics, evaluation and approach to the management of donor-derived fungal infections in organ transplant recipients.