Hidden Killers: Human Fungal Infections

A176 Aims: Invasive fungal infection is potentially fatal complication in patients with liver transplantation, but the treatment is hampered by the non-specific nature of clinical and radiological signs and the insensitivity of current laboratory diagnostic methods. The aim of this study was to review the single-center experience with invasive fungal infections in LDLT and to report the impact of b-D glucan on invasive fungal and pneumocystis carinii infection as a diagnostic and therapeutic marker. Methods: From 1991 to 2003, 75 cases of LDLT were performed in our institution and since case no. 22 we measured the serum level of b-D glucan. Fungal colonization was defined as the presence of a fungus in one or more surveillance superficial cultures in the absence of any clinical symptoms or signs of infection. Invasive fungal infections were divided into definite and probable infections according to the following criteria : definite invasive fungal infection was diagnosed by one of these criteria as follows: 1) presence of fungus in the blood, cerebrospinal fluid, ascites and biopsy specimens; 2) ophthalmologic evidence; 3) more than 11pg/ml serum level of b-D glucan and isolation of fungus from at least two superficial sites with febrile condition; 4) isolation of fungus from bronchoalveolar lavage with radiological evidence of pneumonitis. Probable invasive fungal infection was defined as more than 11pg/ml serum level of b-D glucan together with febrile symptom above 38? which was not responded by antibiotics for more than one week or radiological evidence of pneumonitis or esophagitis. For the prophylaxis of the fungal infection (includes more than 11pg/ml serum level of b-D glucan), fluconazole and micafungin were administered. Active fungal infection was treated by fluconazole, amphotericin B, flucytosine and micafungin. Results: We experienced one definite and 5 probable invasive fungal infections (group A). The level of b-D glucan between group A and 20 recipients more than 11pg/ml of b-D glucan without clinical symptoms were significantly different (85.2 vs. 26.4 pg/ml, p<0.001). Six recipients were diagnosed as pneumonia by chest X-ray or CT. One definite invasive fungal infection had quite high serum level of b-D glucan (122 pg/ml) and isolation of fungus from three superficial sites with febrile condition. Two out of 5 probable fungal infections had high serum level of b-D glucan (39, 37 pg/ml) without isolation of fungal organisms from sputa with febrile symptom above 38? and radiological evidence of pneumonia. Only two out of 5 recipients with invasive fungal infections were alive. One recipient who was diagnosed as pneumocystis carinii pneumonia had quite high serum level of b-D glucan (169 pg/ml) and his clinical symptoms were correlated with the level of b-D glucan. Conclusion: In some cases b-D glucan was temporarily elevated within 2 weeks after LDLT. But it was very useful for the diagnostic and therapeutic marker for the invasive fungal and pneumocystis carinii infection.

Most fungal infections in humans occur in the setting of iatrogenic immunosuppression or HIV infection. In the absence of these factors, fungi cause mild, self-limited infections that typically involve mucocutaneous surfaces. Hence, when persistent or recurrent mucocutaneous infections (chronic mucocutaneous candidiasis [CMC]) or invasive fungal infections (IFIs) develop in a "normal" host, they are indicative of genetic defects causing innate or adaptive immune dysfunction. In this review, recent developments concerning genetic and immunologic factors that affect the risk for IFIs and CMC are critically discussed.

Invasive fungal infection caused by Blastobotrys mokoenaii in an immunocompromised patient with acute myeloid leukemia: A case report

Fungi are a versatile group of saprophytic microorganisms that have evolved a mechanism to survive in their hosts. Infections caused by fungi are called opportunistic, as they cause no disease or mild symptoms in infected healthy individuals, but which can be fatal, life–threatening, and invasive in nature in immunocompromised individuals. In invasive fungal infections, fungi invade the deep tissues and establish themselves, where they cause prolonged illness. They pose an important health problem worldwide and are the main reason for the high rates of morbidity and mortality among immunocompromised individuals and other individuals at high risk of invasive fungal infections. Candida spp., Aspergillus spp., Cryptococcus spp., and Pneumocystis spp. are the most common species responsible for invasive fungal infections. An invasive fungal infection kills about one and half million people every year. The use of antineoplastic, immunosuppressive agents, broad-spectrum antibiotics, and antifungal agents increases the chance of invasive fungal infections. Irrespective of the large amount of recent effort being made, the treatment of invasive fungal infections is very challenging, and due to limited research in this field, the diagnosis of invasive fungal infections is also a hurdle. The objective and focus of this chapter are the invasive fungal infections in humans, diagnostic methods, and future implications of treatment of these infections, which need more research in the field to facilitate the development of better diagnostic tests, therapies, and preventive vaccines as well.

Objective To evaluate the diagnostic value of serum (1-3)-β-D-glucan detection for invasive fungal infection (IFI) in neonates. Methods Eighty-seven neonates who were suspected to be IFI cases in neonatal intensive care unit from May 2008 to January 2010 were enrolled into this study. All subjects had infection symptoms, while did no react to the antibiotics treatment. The diagnosis of IFI was made according to Invasive pulmonary fungal infection diagnostic criteria of children set by Subspecialty Group of Respiratory Diseases, the Society of Pediatrics, Chinese Medical Association and Invasive fungal infection diagnostic criteria for critical patients set by the Society of Critical Care Medicine, Chinese Medical Association. Circulating (1-3)-β-D-glucan levels were determined with GKT-5M set kinetic fungus detection kit. Levels of (1-3)-Β-D-glucan in IFI group and that in the control group were compared; optimal cut-off value was established with receiver operating characteristic (ROC) curve; and the sensitivity and specificity at the cut-off value of 20.0 pg/ml and optimal cut-off value were calculated and compared. Results Among the 87 suspected cases, 59 cases were not diagnosed as IFI and 28 cases were diagnosed as IFI finally. Five patients were confirmed to be IFI; seven cases were clinically diagnosed and 16 cases were still suspected IFI. Among the five confirmed cases, four cases were blood culture positive for Candida parapsilosis, one case Candida albicans positive and two cases both cerebrospinal fluid culture and blood culture positive for Candida albicans. The median levels of (1-3)-β-D-glucan of patients diagnosed as IFI (n=28) was 131.6 pg/ml(18.6-9999.0 pg/ml), which was higher than that of the patients without IFI (8.5 pg/ml, 5.0-34.6 pg/ml)(Z=-5.064, P<0.05). Area under ROC curve was 0.806 (95% CI: 0.725-0.886, P<0.05). The sensitivity (96.43% vs 69.49%) and specificity (72.22% vs 84.21%) for (1-3)-β-D-glucan were different as 20.0 pg/ml and 53.7 pg/ml were used as the cut-off values for diagnosing IFI. Conclusions (1-3)-β-D-glucan level could be used to diagnose IFI of neonates, but further studies are needed to evaluate false-positive rates and its cut-off value in IFI diagnosis. Key words: Mycoses; Infant, newborn; beta-Glucan

Fungal infections

Risk Factors and Rates of Fungal Infection in Lung Transplant Recipients Who Receive Posaconazole and Inhaled Amphotericin Combination Prophylaxis Therapy

Fungi are ubiquitous and nearly 1.5 million fungal species exist in the universe, but only few fungi were known to be pathogenic to humans. The temperature of 37 °C, low redox potential in tissues and immune barrier prevent majority of fungi from invading human hosts. However with the change of host environment due to co-morbidities, several saprophytic fungi get the opportunity to adapt to human tissue. The impact of modern medical interventions and fungi adapting to this environment are reasons why many fungi are now known to cause invasive human disease. Fungal infection in humans varies from superficial colonization to invasive diseases and allergic manifestations; each group associated with unique risk factors. Impact of the global burden of fungal infections is often overlooked and estimates are often extrapolations of limited available data. There is also wide variation in the geographical niches occupied by fungi across the world for reasons largely unknown. Natural disasters also contribute to the upsurge of invasive fungal infections. The severity of infection closely parallels a suppression of immunity. Invasive fungal infections are important causes of morbidity and mortality of hospitalized patients. Diagnosis of these fungal infections is often a challenge due to poor sensitivity, specificity and long turnaround times of conventional diagnostic methods. Availability of advanced, rapid technologies is sparse in the majority of laboratories in developing countries. Several biomarkers and molecular techniques are being studied to reduce these turnaround times. In spite of availability of new antifungals, therapy is often empirical due to rapid progression of disease and non-availability of early diagnosis. There is no ideal antifungal agent. Limited spectrum, drug-interaction, toxicity and cost of antifungals are limiting factors. A brief description of these challenges is presented in this introductory chapter.

Invasive fungal infections in humans caused by several Candida species, increased considerably in immunocompromised or critically ill patients, resulting in substantial morbidity and mortality. Candida albicans is the most prevalent species, although the frequency of these organisms varies greatly according to geographic region. Infections with C. albicans and non-albicans Candida species have become more common, especially in the past 20 years, as a result of aging, immunosuppressive medication use, endocrine disorders, malnourishment, extended use of medical equipment, and an increase in immunogenic diseases. Despite C. albicans being the species most frequently associated with human infections, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei also have been identified. Several antifungal drugs with different modes of action are approved for use in clinical settings to treat fungal infections. However, due to the common eukaryotic structure of humans and fungi, only a limited number of antifungal drugs are available for therapeutic use. Furthermore, drug resistance in Candida species has emerged as a result of the growing use of currently available antifungal drugs against fungal infections. Amphotericin B (AmB), a polyene class of antifungal drugs, is mainly used for the treatment of serious systemic fungal infections. AmB interacts with fungal plasma membrane ergosterol, triggering cellular ion leakage via pore formation, or extracting the ergosterol from the plasma membrane inducing cellular death. AmB resistance is primarily caused by changes in the content or structure of ergosterol. This review summarizes the antifungal drug resistance exhibited by Candida species, with a special focus on AmB.

Objective To investigate the clinical practicability of the (1, 3)-β-D glucan in bronchoalveolar lavage fluid in diagnosis of invasive pulmonary fungal infection(IPFI). Methods A total of 134 patients with lung disease were selected, of which 32 cases were confirmed or clinically diagnosed with pulmonary fungal infection, 48 patients were suspected cases, 54 cases were non IPFI. All patients were given normal bronchoalveolar lavage clysis, the contents of the (1, 3)-β-D glucan and galactomannan of the bronchoalveolar lavage fluid and serum were detected, the clinical practicability of the two methods for detection in diagnosis of invasive pulmonary fungal infection were compared. Results Thirty-two patients suffered invasive fungal infection, of which 10 cases of the patients were diagnosed with pneumocystis carinii pneumpnia with G test of the bronchoalveolar lavage positive, the sensitivity was 100%, while bronchoalveolar lavage G test and GM test which were used for the diagnosis of invasive fungal infection had similar sensitivity, but specificity of broncho-alveolar lavage G test was lower. The specificity of dextran in serum was higher. Conclusions The (1, 3)-β-D glucan test in the bronchoalveolar lavage fluid shows a low specificity, so identifying the special factors which will interfere the experimental performance may improve the clinical practicability of the (1, 3)-β-D glucan in bronchoalveolar lavage fluid in fungal glucan monitoring. Key words: Invasive fungal infection; Aspergillus; Bronchoalveolar lavage fluid

Measurement of (1-->3)-beta-D-Glucan (BG) has emerged as an adjunct diagnostic strategy for invasive fungal infections (IFI). Subjects at 6 clinical sites in the United States were enrolled as either fungal infection-negative subjects (n = 170) or subjects with proven or probable IFI according to European Organization for the Research and Treatment of Cancer/Mycoses Study Group criteria (n = 163). A central laboratory and 4 sites performed assays. A single sample was obtained per patient and was evaluated using an assay to detect serum BG derived from fungal cell walls (range, 0 to > 7000 pg/mL). At a cutoff of 60 pg/mL, the sensitivity and specificity of the assay were 69.9% and 87.1%, respectively, with a positive predictive value (PPV) of 83.8% and a negative predictive value (NPV) of 75.1%. At a cutoff value of 80 pg/mL, the sensitivity and specificity were 64.4% and 92.4%, respectively, with a PPV of 89% and an NPV of 73%. Of the 107 patients with proven candidiasis, 81.3% had positive results at a cutoff value of 60 pg/mL, and 77.6% had positive results at a cutoff value of 80 pg/mL. Of the 10 patients with aspergillosis, 80% had positive results at cutoff values of 60 and 80 pg/mL. The 3 subjects diagnosed with Fusarium species had positive results at a cutoff value of 60 pg/mL. Patients infected with Mucor or Rhizopus species (both of which lack BG) had negative results at both cutoff values, and of the 12 patients with Cryptococcus infection, 3 had positive results at a cutoff value of 60 pg/mL, and 2 had positive results at a cutoff value of 80 pg/mL. Of the subjects with proven positive results who were receiving antifungal therapy (n = 118), 72.9% had results positive for BG at a cutoff value of 60 pg/mL, and 69.5% had results positive for BG at a cutoff value of 80 pg/mL. The interlaboratory sample test r2 was 0.93. Reproducible assay results with high specificity and high PPV in a multicenter setting demonstrate that use of an assay to detect serum BG derived from fungal cell walls is a useful diagnostic adjunct for IFI.

Invasive fungal infections (IFI) have significantly increased over the past years due to advances in medical care for the at-risk immunocompromised population. IFI are often difficult to diagnose and manage, and can be associated with substantial morbidity and mortality. This study aims to contribute to understanding the etiology of invasive and subcutaneous fungal infections, their associated risk factors, and to perceive the outcome of patients who developed invasive disease, raising awareness of these infections at a local level but also in a global context. A laboratory surveillance approach was conducted over a seven-year period and included: (i) cases of invasive and subcutaneous fungal infections caused by filamentous/dimorphic fungi, confirmed by either microscopy or positive culture from sterile samples, (ii) cases diagnosed as probable IFI according to the criteria established by EORTC/MSG when duly substantiated. Fourteen Portuguese laboratories were enrolled. Cases included in this study were classified according to the new consensus definitions of invasive fungal diseases (IFD) published in 2020 as follows: proven IFI (N = 31), subcutaneous fungal infection (N = 23). Those proven deep fungal infections (N = 54) totalized 71.1% of the total cases, whereas 28.9% were classified as probable IFI (N = 22). It was possible to identify the etiological fungal agent in 73 cases (96%). Aspergillus was the most frequent genera detected, but endemic dimorphic fungi represented 14.47% (N = 11) of the total cases. Despite the small number of cases, a high diversity of species were involved in deep fungal infections. This fact has implications for clinical and laboratory diagnosis, and on the therapeutic management of these infections, since different species, even within the same genus, can present diverse patterns of susceptibility to antifungals.

Fungal infections in humans are responsible for mild to severe infections resulting in systemic effects that cause a large amount of mortality. Invasive fungal infections are having similar symptomatic effects to those of COVID-19. The COVID-19 patients are immunocompromised in nature and have a high probability of developing severe fungal infections, resulting in the development of further complications. The existing antifungal therapy has associated problems related to the development of drug resistance, being sub-potent in nature, and the presence of undesirable toxic effects. The fungal dihydrofolate reductase is an essential enzyme involved in the absorption of dietary folic acid and its conversion into tetrahydrofolate, which is a coenzyme required for the biosynthesis of the fungal nucleotides. Thus, in the current study, an attempt has been made to identify potential folate inhibitors of Candida albicans by a computational drug repurposing approach. Based upon the molecular docking simulation-based virtual screening followed by the molecular dynamic simulation of the macromolecular complex, benzbromarone has been identified as a potential anti-folate agent for the development of a novel therapy for the treatment of candidiasis.Supplementary informationThe online version contains supplementary material available at 10.1007/s00894-022-05185-w.

Simultaneous increase in 1,3-β-d-glucan and procalcitonin levels in Pseudomonas aeruginosa infection

Background Belatacept is a selective co-stimulation blocker associated with improved long-term outcomes in kidney transplant recipients (KTR). The impact of belatacept on risk of invasive fungal infection (IFI) in KTR remains unclear, with existing data limited to small case series and case reports.TableClinical Characteristics of the Study CohortFigureInvasive Fungal Infections in Kidney Transplant Recipients Methods We conducted a retrospective propensity-matched study of adult HIV-negative KTR transplanted at our center between 2016-2020 who received de-novo belatacept- or tacrolimus-based immunosuppression. Matching variables included sex, donor type, age at transplant, HLA mismatch, and diabetes as cause of kidney failure. Data was extracted from the clinical data warehouse. IFI was identified via ICD codes and confirmed by chart review using EORTC/MSGERC definitions. Clinical characteristics were compared using Wilcoxon Rank and Fisher Exact tests. Time to IFI was evaluated with Kaplan Meier curves log-rank testing. Results A total of 293 belatacept- and 293 tacrolimus-treated KTR were compared. Proven IFI occurred in 14 (4.8%) belatacept- and 17 (5.8%) tacrolimus-treated KTR (p=0.713, Table). Median time to IFI was 370 days (IQR 122, 555) vs 359-days (IQR 225,979), respectively (p=0.48). Event rates were 1.09 per 100-person years in both groups. IFI in belatacept patients included invasive candidiasis (N=6), cryptococcosis (N=4), invasive aspergillosis (N=2), Pneumocystis pneumonia (N=1), and non-speciated mold causing invasive fungal sinusitis (N=1). IFI in the tacrolimus group included invasive candidiasis (N=5), invasive aspergillosis (N=5, including 1 with Paecilomyces coinfection), cryptococcosis (N=5), Acrophilaophora brain abscess (N=1), and non-speciated mold causing invasive sinopulmonary fungal infection (N=1) (Figure). Death occurred in 3/14 (21%) belatacept vs 8/17 (47.1%) tacrolimus patients with IFI (p=0.258). Conclusion De-novo belatacept-based immunosuppression was not associated with increased risk of IFI compared to tacrolimus. These findings suggest routine antifungal prophylaxis is not indicated in KTR receiving de-novo belatacept-based immunosuppression. Disclosures Christian P. Larsen, MD, PhD, Bristol-Myers Squibb: Advisor/Consultant|CareDx: Advisor/Consultant|Eledon: Advisor/Consultant