Microbiological diagnostics of fungal infections

Laboratory tests for the detection of fungal infections are easy to perform. The main obstacle to a correct diagnosis is the correlation between the laboratory findings and the clinical diagnosis. Among pediatric patients, the most common fungal pathogen is Candida. The detection of fungal colonization may be performed through the use of chromogenic culture media, which allows also the identification of Candida subspecies, from which pathogenicity depends. In neonatology, thistest often drives the decision to begin a empiric therapy; in this regard, a close cooperation between microbiologists and clinicians is highly recommended. Blood culture, if positive, is a strong confirmation of fungal infection; however, its low sensitivity results in a high percentage of false negatives, thus decreasing its reliability. Molecular diagnostics is still under evaluation, whereas the detection of some fungal antigens, such as β-D-glucan, galactomannan, mannoprotein, and cryptococcal antigen in the serum is used for adults, but still under evaluations for pediatric patients

Why MIC matters? Microbiologists vs. clinicians

Several mechanisms of resistance may interfere with the patients’ healing from a fungal infection. However, in premature children fungi are generally susceptible to antifungal agents, except in case of vertical transmission from the mother. In vitro sensitivity tests have been recently harmonized between American and European standards, after years of unhomogeneity: to date, the interpretation of epidemiological cut-off of wild-type population and clinical cut-off are common, and are often updated. Sensitivity tests are difficult to perform, but luckily new commercial tests approvedby FDA are available. Sometimes, knowing the intrinsic sensitivities and resistances of every fungal species and subspecies may be enough in the clinical practice, since few resistances are acquired

Diagnosis of invasive fungal infections

A proper diagnostic strategy of invasive fungal infections (IFI) is a very important component in the management of infectious complications in hematological patients. A good diagnostic approach should be adapted to the patient in relation to the underlying disease, stage of disease, localization of infection and immune status. None of the diagnostic markers can be entirely adopted for medical decision making, and sometimes it's useful to use the combination of several microbiological tests.The diagnosis of IFI must therefore have a multidisciplinary approach that includes clinical suspicion, microbiological results and radiological evidence

Invasive Candida Infections in Patients With Haematological Malignancies and Hematopoietic Stem Cell Transplant Recipients: Current Epidemiology and Therapeutic Options.

In the last decades, the global epidemiological impact of invasive candidiasis (IC) in patients with hematologic malignancies (HM) and in hematopoietic stem cell transplant (HSCT) recipients has decreased and the incidence of invasive aspergillosis exceeded that of Candida infections. The use of prevention strategies, first of all antifungal prophylaxis with triazoles, contributed to the reduction of IC in these populations as demonstrated by several epidemiological studies. However, relatively little is known about the current epidemiological patterns of IC in HM and HSCT populations, because recent epidemiological data almost exclusively derive from retrospective experiences and few prospective data are available. Several prospective, controlled studies in the prophylaxis of invasive fungal diseases have been conducted in both the HM and HSCT setting. On the contrary, most of the prospective controlled trials that demonstrated the efficacy of the antifungal drugs echinocandins and voriconazole in the treatment of candidemia and invasive candidiasis mainly involved patients with underlying conditions other than HM or HSCT. For these reasons, international guidelines provided specific indications for the prophylaxis strategies in HM and HSCT patients, whereas the recommendations on therapy of documented Candida infections are based on the results observed in the general population and should be considered with caution

Genetic variability among Blastoschizomyces capitatus isolates from different clinical sources.

Sixteen clinical isolates and nine ATCC reference strains of Blastoschizomyces capitatus were analysed genetically, examined for the cellobiose, arbutin and salicin assimilation and tested for the aspartyl-proteinase secretion. The restriction endonuclease analysis (REA) with HpaII and HinfI enzymes and the electrophoretic karyotype (EK) were investigated. Both the restriction enzymes revealed two groups (I, II) constituted by the same isolates: 17 isolates (68%) in group I and 8 (32%) in group II. The EK analysis revealed sixteen groups. These data prompts for a genetic variability of the isolates of Blastoschizomyces capitatus and their account in two distinct genetic groups as suggested by REA. This grouping was confirmed by examing the utilisation of cellobiose, arbutin and salicin. The tests for secretory aspartyl proteinase (Sap) were positive only for three isolates, suggesting a marginal role of this specific enzyme in pathogenesis for these isolates

Low Incidence Rate of Opportunistic and Viral Infections During Imatinib Treatment in Chronic Myeloid Leukemia Patients in Early and Late Chronic Phase.

<!--StartFragment--> <p class="MsoNormal" style="text-align: justify; line-height: 150%;"><span style="font-family: Arial; mso-ansi-language: EN-GB;" lang="EN-GB">Background: Imatinib has become first line therapy in chronic myeloid leukemia patients. Little is known about the infective consequences during the treatment with this drug in large series of chronic phase patients. </span></p> <p class="MsoNormal" style="text-align: justify; line-height: 150%;"><span style="font-family: Arial; mso-ansi-language: EN-GB;" lang="EN-GB">Material and methods: From January 2001 to September 2006 we treated with imatinib 250 patients in first line (early CP) or after interferon failure (late CP), out of clinical trials and recorded all the bacterial and viral infections occurred.</span></p> <p class="MsoNormal" style="text-align: justify; line-height: 150%;"><span style="font-family: Arial; mso-ansi-language: EN-GB;" lang="EN-GB">Results: We recorded a similar incidence of bacterial and viral infections both in first line and late CP patients (respectively, 16% and 13%) during 3.5 years of follow-up. Analysis of presenting features predisposing to infections revealed differences only in late CP patients, with elevated percentage of high Sokal risk patients and a more longer median time from diagnosis to start of imatinib.</span></p> <p class="MsoNormal" style="text-align: justify; line-height: 150%;"><span style="font-family: Arial; mso-ansi-language: EN-GB;" lang="EN-GB">Conclusions: Opportunistic infections and reactivation of Herpes Zoster are observed during imatinib therapy at very low incidence.</span></p> <!--EndFragment--&gt

Primary Prophylaxis of Invasive Fungal Diseases in Allogeneic Stem Cell Transplantation: Revised Recommendations from a Consensus Process by Gruppo Italiano Trapianto Midollo Osseo (GITMO)

Abstract This document updates and expands the recommendations on primary prophylaxis of invasive fungal diseases (IFD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, published in 2009 by the Gruppo Italiano Trapianto Midollo Osseo (GITMO). A consensus process was undertaken to describe and evaluate current information and practice regarding risk stratification and primary antifungal prophylaxis during the pre-engraftment and postengraftment phases after allo-HSCT. The revised recommendations were based on the evaluation of recent literature including a large, prospective, multicenter epidemiological study of allo-HSCT recipients conducted among the GITMO transplantation centers during the period of 2008 to 2010. It is intended as a guide for the identification of types and phases of transplantation at low, standard, and high risk for IFD, according to the underlying disease, transplantation, and post-transplantation factors. The risk stratification was the critical determinant of the primary antifungal approach for allo-HSCT recipients

Refractory CMV infection in post-transplant phase: epidemiological framing in the Italian context, current patient management and unmet needs

Background: Cytomegalovirus (CMV) infection usually occurs asymptomatically but can represent an important cause of morbidity and mortality in patients with compromised immune system such as transplant patients. Infection may not respond to standard therapies leading to refractoriness (with or without resistance) which jeopardizes transplant successful outcome. Objective: Since refractoriness represents a critical point, a project has been conducted to verify the epidemiology in the Italian context and to convey the current patients’ unmet medical needs. Methods: The project included: literature analysis, expert interviews and results’ validation through expert opinion. Based on literature data, a questionnaire was built and submitted to 8 experts with proven experience in the management of post-transplant CMV infection. Topics included epidemiology, patient management, unmet needs and future perspective. Outcomes were validated by 3 additional national experts in solid organ transplantation, hematopoietic stem cell transplantation and infectious diseases. Results: Epidemiological rates from literature applied to current transplantation numbers in Italy estimate approximately 109 adults and 8 children with refractory post-transplant CMV infection in 2021. If valganciclovir/ganciclovir are ineffective, foscarnet is predominantly used. When foscarnet fails, patients have no therapeutic alternatives. Despite being a minority, this represents a high medical need. Therefore, the introduction of new therapeutic options with a better efficacy/safety profile would lead to a significant improvement in refractory CMV infection management. Conclusion: Although refractory infections represent a minority, they are the most critical issue that can occur in post-transplant patients resulting in a high unmet need due to the lack of specific treatment options and the toxicity of current treatments used

Incidence, Risk Factors and Outcome of Pre-engraftment Gram-Negative Bacteremia after Allogeneic and Autologous Hematopoietic Stem Cell Transplantation: An Italian Prospective Multicenter Survey

Background Gram-negative bacteremia (GNB) is a major cause of illness and death after hematopoietic stem cell transplantation (HSCT), and updated epidemiological investigation is advisable. Methods We prospectively evaluated the epidemiology of pre-engraftment GNB in 1118 allogeneic HSCTs (allo-HSCTs) and 1625 autologous HSCTs (auto-HSCTs) among 54 transplant centers during 2014 (SIGNB-GITMO-AMCLI study). Using logistic regression methods. we identified risk factors for GNB and evaluated the impact of GNB on the 4-month overall-survival after transplant. Results The cumulative incidence of pre-engraftment GNB was 17.3% in allo-HSCT and 9% in auto-HSCT. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most common isolates. By multivariate analysis, variables associated with GNB were a diagnosis of acute leukemia, a transplant from a HLA-mismatched donor and from cord blood, older age, and duration of severe neutropenia in allo-HSCT, and a diagnosis of lymphoma, older age, and no antibacterial prophylaxis in auto-HSCT. A pretransplant infection by a resistant pathogen was significantly associated with an increased risk of posttransplant infection by the same microorganism in allo-HSCT. Colonization by resistant gram-negative bacteria was significantly associated with an increased rate of infection by the same pathogen in both transplant procedures. GNB was independently associated with increased mortality at 4 months both in allo-HSCT (hazard ratio, 2.13; 95% confidence interval, 1.45-3.13; P <.001) and auto-HSCT (2.43; 1.22-4.84; P =.01). Conclusions Pre-engraftment GNB is an independent factor associated with increased mortality rate at 4 months after auto-HSCT and allo-HSCT. Previous infectious history and colonization monitoring represent major indicators of GNB. Clinical Trials registration NCT02088840