Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy.

Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.

Opportunistic Infections, Mortality Risk, and Prevention Strategies in Patients With Vacuoles, E1 Enzyme, X-Linked, Autoinflammatory, Somatic (VEXAS) Syndrome.

Background: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a genetic disorder characterized by bone marrow failure and systemic inflammation, putting patients at risk for infections. This study comprehensively examines the prevalence of opportunistic infections in patients with VEXAS, evaluating their impact on clinical outcomes and potential preventive measures. Methods: Patients with confirmed VEXAS were included. Survival analysis and logistic regression were used to identify associations between opportunistic infections and mortality. Infection rates (IRs) for Pneumocystis jirovecii pneumonia (PJP) and alphaherpesviruses were calculated over a prospective 8-month observation period in relationship to prophylaxis. Results: Of 94 patients with VEXAS, 6% developed PJP; 15% had alphaherpesvirus reactivation, with varicella zoster virus (VZV) being the most common herpesvirus; and 10% contracted a nontuberculous mycobacterial (NTM) infection. Risk of death was significantly increased per month following a diagnosis of PJP (hazard ratio [HR], 72.41 [95% confidence interval {CI}, 13.67-533.70]) or NTM (HR, 29.09 [95% CI, 9.51-88.79]). Increased odds for death were also observed in patients with a history of herpes simplex virus (HSV) reactivation (odds ratio [OR], 12.10 [95% CI, 1.29-114.80]) but not in patients with VZV (OR, 0.89 [95% CI, .30-2.59]). Prophylaxis for PJP (IR, 0.001 vs 0 per person-day, P < .01) and VZV (IR, 0.006 vs 0 per person-day, P = .04) markedly decreased infection rates with a number needed to treat of 4 and 7, respectively. Conclusions: Opportunistic infections are common in patients with VEXAS. Patients who develop PJP, HSV, or NTM are at increased risk for death. Prophylaxis against PJP and VZV is highly effective.

Necrotic skin ulcers in an immunocompromised patient / Úlceras de piel necróticas en un paciente inmunocomprometido

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Treatment strategies and outcome of parvovirus b19 infection in kidney transplant recipients: a case series and literature review of 128 patients.

Abstract Background There is no specific antiviral treatment for parvovirus B19 (PVB19) infection. Objective The objective of this study was to study the treatment and outcome of PVB19 infection in kidney transplant recipients (KTR) at our institution, and cases published in the medical literature. Methods We conducted a retrospective review of PVB19 infection in KTR at an academic medical center over a 16-year period and summarized the data on its treatment and outcome in 120 KTR in the medical literature. Results In our cohort of eight patients, the median time to the onset of PVB19 disease was 7.2 weeks after transplantation. All patients had severe aregenerative anemia (mean hemoglobin (Hb) of 6.2 ± 1.0 g/dl); all were treated with a reduction in their immunosuppressive regimen and the administration of single-dose intravenous immunoglobulin (IVIG) (mean total dosage of 0.87 ± 0.38 g/kg). The median time to anemia improvement (Hb >10 g/dl) was 3-week post-treatment. No recurrences were documented during follow-up (median 25 months). Among 128 patients (including our cohort of 8 and 120 reported in literature), therapeutic strategies included: 43% IVIG alone, 39% IVIG and reduced immunosuppression, 9% reduction of immunosuppression, and 9% conservative therapy. Clinical relapses were observed in 35% of 71 reported cases. Conclusions In KTR, decreasing immunosuppression and the administration of low-dose immunoglobulin seem to be not worse than the standard dose in PVB19 infection.

Infecciones en pacientes sometidos a trasplante de órgano sólido / Infections in solid organ transplant recipients

The main problems in solid organ transplant recipients are rejection and infections. The new immunosuppressive regimens have lowered the risk of rejection, however, infections continue to be one of the most important determinants for morbidity and mortality in these patients. The survival of the transplanted organ is also impacted by the different infectious diseases that occur in the post-transplant period. These infections are of viral, bacterial, fungal and parasitic origin, and their presentation occurs characteristically within well defined risk periods after the transplant. The clinical presentation is commonly atypical; therefore for optimal management, it is necessary to have a through knowledge of the epidemiology and clinical manifestations of these problems, but most importantly, the experience of the clinician in the clinical approach and early detection will result in better outcomes. We review recent information regarding the infectious diseases that affect solid organ recipients according to the type of transplant, the post-transplant, risk factors before the transplant and the type of immunosuppressive therapy used, which are the main determinants for these complications and their prognosis.

Los problemas principales en el paciente sometido a trasplante de órgano sólido (TOS) son el rechazo del órgano y las infecciones. Los nuevos esquemas inmunosupresores han disminuido el riesgo de rechazo, sin embargo, las infecciones siguen siendo uno de los determinantes más importantes de morbilidad y mortalidad en estos pacientes. La sobrevida del órgano trasplantado es impactada también por los diversos procesos infecciosos que ocurren en el periodo postrasplante. Las infecciones que afectan a estos pacientes son de origen viral, bacteriano, fúngico y parasitario y su presentación ocurre característicamente dentro de periodos bien definidos de riesgo posterior al trasplante. La presentación clínica frecuentemente es atípica, por lo que para el manejo óptimo es necesario conocer la epidemiología y las manifestaciones clínicas de estos problemas, pero sobre todo la experiencia del clínico en el abordaje y en la detección temprana resulta en un mejor desenlace. En este artículo se revisa la información reciente sobre las enfermedades infecciosas que afectan a pacientes sometidos a TOS de acuerdo con el tipo de trasplante, al periodo postrasplante, a los factores de riesgo previo al trasplante y al tipo de terapia inmunosupresora utilizada, los cuales son los principales determinantes de estas complicaciones y de su pronóstico.