Use Of Antifungal Treatment Research Articles

Galleria mellonella as a Model for the Study of Fungal Pathogens: Advantages and Disadvantages.

The study of pathogenicity and virulence of fungal strains, in vivo in the preclinical phase, is carried out through the use of animal models belonging to various classes of mammals (rodents, leproids, etc.). Although animals are functionally more similar to humans, these studies have some limitations in terms of ethics (animal suffering), user-friendliness, cost-effectiveness, timing (physiological response time) and logistics (need for adequately equipped laboratories). A good in vivo model must possess some optimal characteristics to be used, such as rapid growth, small size and short life cycle. For this reason, insects, such as Galleria mellonella (Lepidoptera), Drosophila melanogaster (Diptera) and Bombyx mori (Lepidoptera), have been widely used as alternative non-mammalian models. Due to their simplicity of use and low cost, the larvae of G. mellonella represent an optimal model above all to evaluate the virulence of fungal pathogens and the use of antifungal treatments (either single or in combination with biologically active compounds). A further advantage is also represented by their simple neuronal system limiting the suffering of the animal itself, their ability to survive at near-body ambient temperatures as well as the expression of proteins able to recognise combined pathogens following the three R principles (replacement, refinement and reduction). This review aims to assess the validity as well as the advantages and disadvantages of replacing mammalian classes with G. mellonella as an in vivo study model for preclinical experimentation.

Treatments and Outcomes of Critically Ill Patients with Candida spp. Colonization of the Lower Respiratory Tract in Regina, Saskatchewan.

Among critically ill patients receiving mechanical ventilation, Candida spp. are commonly detected in the lower respiratory tract (LRT). This is generally considered to represent colonization. To evaluate the use of antifungal treatments and the clinical outcomes of patients with Candida colonization of the LRT. This retrospective analysis involved consecutive patients admitted to the intensive care unit between April 2016 and May 2021with positive results on Candida spp. testing of LRT samples. Data related to antifungal treatment and clinical outcomes were analyzed descriptively, and multivariable logistic regression was performed. Of 200 patients initially identified, 160 (80%) died in hospital. Antifungal therapy was given to 103 (51.5%) of the patients, with treatment being more likely among those with shock and those who received parenteral nutrition. Mortality was high among patients with positive Candida results on LRT culture, regardless of treatment. Multivariable logistic regression, with adjustment for age, sex, comorbidities, and sequential organ failure assessment (SOFA) score, showed that antifungal treatment was associated with lower odds of death (odds ratio 0.39, 95% confidence interval 0.17-0.87) compared with no treatment (p = 0.021). This study showed higher mortality rates than have been reported previously. Further investigation into the role of antifungal therapy among critically ill patients with Candida spp. colonization is required.

Increased prevalence of fungemia in Medina, Saudi Arabia.

The prevalence of fungal infection is increasing globally due to an increase in the immunocompromised and aging population. We investigated epidemiological changes in fungemia in one of the major centers in Medina over seven years period with 87,447 admissions. Retrospective search of records for causative agents of fungemia in inpatients at King Fahad Hospital (KFH) in 2013-2019. Fungal-positive blood cultures, demographic, and treatment data were extracted. A total of 331 fungemia episodes proven by blood culture were identified in 46 patients. The annual prevalence of fungemia increased from 0.072 in 2013 to 1.546 patients per 1,000 in 2019. The mean age of fungemia episodes was 56 years, and 62% of episodes occurred in females. Samples from central blood incubated aerobically yielded the highest fungemia rate, accounting for 55% (n = 182). Among yeast species, Candida parapsilosis was responsible for the highest number of episodes 37% (n = 122), followed by Candida glabrata (32%; n = 107), Candid albicans (29%; n = 94), and Cryptococcus neoformans (1%; n = 4). Among molds, Lichtheimia (Absidia) species was the most common (1%; n = 3). Yeast-like fungi Trichosporion mucoides accounted for (0.003% n = 1). The use of antifungal treatment has increased (96%) over the years (2013-2019). An increase in resistance rate of 2% was found in C. albicans and C. glabrata. The most prevalent comorbidity was renal disease (24.2%). C. parapsilosis was the leading cause of fungemia. The association of renal disease with increased candidemia was alarming. This study is a fundamental resource to establish management policies for fungal infection in the region.

375: ANTIFUNGAL USE IN CRITICALLY ILL PATIENTS WITH INTRA-ABDOMINAL INFECTION

Introduction: Intra-abdominal infections arise from microorganisms which translocate from their normal location and result in peritoneal inflammation. Initiation of antifungal treatment for complicated intra-abdominal infections has limited clinical evidence and remains unclear. In 2010, the IDSA and SIS released a joint guideline regarding diagnosis and management of complicated intra-abdominal infections (IAIs). However in the following years, the two entities released their own individual guidelines. The goal of this study is to further delineate if there is a potential benefit for use of empiric antifungal therapy in critically ill patients with an IAI. Methods: This is a retrospective chart review study that screened hospitalized adult patients admitted to the intensive care units (ICU) with proven or suspected intra-abdominal infection and associated ICD-10 code between January 2020 to December 2021. Medical charts were reviewed for relevant demographic, clinical, and laboratory data. The primary endpoint is hospital length of stay (LOS). Secondary outcomes include ICU LOS, source of infection, surgical intervention, and mortality. A sub-group analysis comparing azole and echinocandin treatment was conducted; endpoints include hospital LOS, ICU LOS, source of infection, surgical intervention, antifungal duration, mortality, and rate of discharge on antifungal therapy. Results: From January 2020 – December 2021, 1086 patients were screened for eligibility and 166 patients were enrolled. The sample size was primarily male (53.4%) and Hispanic (36.1%) or Asian (28.9%). In this study, statistical significance was found for LOS (p< 0.0001), ICU LOS (p< 0.0001), surgical intervention (p< 0.0001) and peritoneum as source of infection (p=0.0006). In the sub-group analysis, statistical significance was found with surgical intervention (p< 0.0001), hospital LOS (p< 0.0001) and ICU LOS (p< 0.0001) in the micafungin treatment arm. Conclusions: In this study, use of antifungal treatment in critically ill patients decreased hospital LOS, ICU LOS, and surgical intervention. Patients on antifungal treatment may have had a higher severity of IAIs. There is an ongoing need for better characterization of patients at risk for poor prognosis.

Survival in rhino-orbito-cerebral mucormycosis: An international, multicenter ID-IRI study

BackgroundMucormycosis is an emerging aggressive mold infection. This study aimed to assess the outcome of hospitalized adults with rhino-orbito-cerebral mucormycosis (ROCM). The secondary objective was to identify prognostic factors in this setting. MethodsThis study was an international, retrospective, multicenter study. Patients’ data were collected from 29 referral centers in 6 countries. All qualified as “proven cases” according to the EORTC/MSGERC criteria. ResultsWe included 74 consecutive adult patients hospitalized with ROCM. Rhino-orbito-cerebral type infection was the most common presentation (n = 43; 58.1%) followed by rhino-orbital type (n = 31; 41.9%). Twenty (27%) had acquired nosocomial bacterial infections. A total of 59 (79.7%) patients (16 in combination) received appropriate antifungal treatment with high-doses of liposomal amphotericin B. Fifty-six patients (75.7%) underwent curative surgery. Thirty-five (47.3%) required intensive care unit admission (27; 36.5% under mechanical ventilation). Hospital survival was 56.8%, being reduced to 7.4% in patients with invasive mechanical ventilation. A multivariate binary backward logistic regression model identified confusion at admission (OR 11.48), overlapping hospital-acquired infection (OR 10.27), use of antifungal treatment before diagnosis (OR 10.20), no surgical debridement (OR 5.92), and the absence of prior sinusitis (OR 6.32) were independently associated with increased risk for death. ConclusionToday, ROCM still has high mortality rate. Improving source control, rational therpy, and preventing nosocomial infections may improve survival in this severe infection.

Intensive Care Antifungal Stewardship Programme Based on T2Candida PCR and Candida Mannan Antigen: A Prospective Study.

Non-culture-based biomarkers may improve diagnosis and antifungal treatment (AFT) of invasive candidiasis (IC). We evaluated an antifungal stewardship programme (AFSP) in a prospective intensive care unit (ICU) study, which included T2Candida and Candida mannan antigen (MAg) screening of patients with sepsis and a high risk of IC. Patients with non-neutropenic sepsis and a high risk of IC from two large tertiary ICUs were prospectively included, during a one-year period. IC was classified as proven, likely, possible or unlikely. The AFSP, diagnostic values of T2Candida and MAg, and the consumption of antifungals were evaluated. An amount of 219 patients with 504 T2Candida/MAg samples were included. IC was classified as proven in 29 (13.2%), likely in 7 (3.2%) and possible in 10 (5.5%) patients. Sensitivity/specificity/PPV/NPV values, comparing proven/likely versus unlikely IC, were 47%/100%/94%/90% for BC alone, 50%/97%/75%/90% for T2Candida alone, and 39%/96%/67%/88% for MAg alone. For the combination of T2Candida/MAg taken ≤3 days after AFT initiation, sensitivity/specificity/PPV/NPV was 70%/90%/63%/93%. T2Candida/MAg contributed to early (<3 days) AFT initiation in 13%, early AFT discontinuation in 25% and abstaining from AFT in 24% of patients. No reduction in overall use of AFT during the study period compared with the previous year was observed. An AFSP based on T2Candida and MAg screening contributed to a reduction of unnecessary treatment, but not overall AFT use. The diagnostic performance of T2Candida was lower than previously reported, but increased if T2Candida was combined with MAg.

Identification and Characterization of Mediators of Fluconazole Tolerance in Candida albicans.

Candida albicans is an important human pathogen and a major concern in intensive care units around the world. C. albicans infections are associated with a high mortality despite the use of antifungal treatments. One of the causes of therapeutic failures is the acquisition of antifungal resistance by mutations in the C. albicans genome. Fluconazole (FLC) is one of the most widely used antifungal and mechanisms of FLC resistance occurring by mutations have been extensively investigated. However, some clinical isolates are known to be able to survive at high FLC concentrations without acquiring resistance mutations, a phenotype known as tolerance. Mechanisms behind FLC tolerance are not well studied, mainly due to the lack of a proper way to identify and quantify tolerance in clinical isolates. We proposed here culture conditions to investigate FLC tolerance as well as an easy and efficient method to identity and quantify tolerance to FLC. The screening of C. albicans strain collections revealed that FLC tolerance is pH- and strain-dependent, suggesting the involvement of multiple mechanisms. Here, we addressed the identification of FLC tolerance mediators in C. albicans by an overexpression strategy focusing on 572 C. albicans genes. This strategy led to the identification of two transcription factors, CRZ1 and GZF3. CRZ1 is a C2H2-type transcription factor that is part of the calcineurin-dependent pathway in C. albicans, while GZF3 is a GATA-type transcription factor of unknown function in C. albicans. Overexpression of each gene resulted in an increase of FLC tolerance, however, only the deletion of CRZ1 in clinical FLC-tolerant strains consistently decreased their FLC tolerance. Transcription profiling of clinical isolates with variable levels of FLC tolerance confirmed a calcineurin-dependent signature in these isolates when exposed to FLC.

Diagnosis of Progressive Disseminated Histoplasmosis in Advanced HIV: A Meta-Analysis of Assay Analytical Performance.

Histoplasmosis is an important cause of mortality in people with advanced HIV, especially in countries with limited access to diagnostic assays. Histoplasmosis can be diagnosed using culture, histopathology, and antibody, antigen, and molecular assays. Several factors may affect the analytical performance of these laboratory assays, including sample type, clinical stage of the disease, and previous use of antifungal treatment, among others. Here we describe the results of a systematic literature review, followed by a meta-analysis of the analytical performances of the diagnostic laboratory assays employed. Our initial search identified 1631 references, of which 1559 references were excluded after title and abstract screening, leaving 72 references identified as studies relevant to the validation of histoplasmosis diagnostic assays. After evaluating the full text, 30 studies were selected for final review, including one paper not identified in the initial search. The meta-analysis for assay analytical performance shows the following results for the overall sensitivity (Sen) and specificity (Spe) of the various methods evaluated: Culture, Sen 77% (no data for specificity calculation); antibody detection assays, Sen 58%/Spe 100%; antigen detection assays, Sen 95%/Spe 97%; and DNA detection assays (molecular), Sen 95%/Spe 99%. Of the 30 studies reviewed, nearly half (n = 13) evaluated Histoplasma antigen assays, which were determined to be the most accurate methodology for diagnosis of progressive disseminated histoplasmosis in advanced HIV (inverse of the negative likelihood ratio was 13.2). Molecular assays appear promising for accurate diagnosis of histoplasmosis, but consensus on exact techniques is needed. Cultures showed variable sensitivity related to sample type and laboratory handling. Finally, antibody assays presented high specificity but low sensitivity. This poor sensitivity is most likely due the highly immunosuppressed state of this patient population. Diagnostic assays are crucial for accurate diagnosis of progressive disseminated histoplasmosis (PDH) with advanced HIV disease.

Epidemiology and treatment approaches in management of invasive fungal infections in hematological malignancies: Results from a single-centre study.

Invasive fungal infections (IFIs) are a leading cause of morbidity and attributable mortality in oncohematologic patients. Timely diagnosis is essential but challenging. Herein we retrospectively describe 221 cases of antifungal treatments (AFT) administered in a monocentric real-life cohort of hematological malignancies. Between January 2010 and July 2017, 196 oncohematologic patients were treated with AFT at our Hematology Department. Diagnosis of IFIs was carried out according to EORTC/MSG-2008 guidelines.The most represented disease was acute myeloid leukemia (104 patients). Median age was 61 years; at fever onset 177 (80%) patients had a neutrophil count<0.5x109/L. Twenty-nine (13%) patients were receiving antifungal prophylaxis (26 posaconazole, 2 fluconazole, 1 itraconazole). The incidence of AFT was 13%. Serum galactomannan antigen (GM) was positive in 20% of the tested cases, while 85% of the patients had a CT scan suggestive for IFI. Twenty-one percent of these cases had a GM positive. Sixty-five out of 196 patients (33%) showed positive culture results, in particular Candida spp. were identified in 45 isolates, while Aspergillus spp. in 16 cases. Fourteen patients presented multiple positivity. Twenty-two (10%) cases were classified as proven IFIs, 61 (28%) as probable and 81 (37%) as possible, but 57 (26%) cases could not be classified. Fifty-nine percent of the patients received single agent AFT, 37% sequential AFT, 8% a combination regimen. Liposomal-amphotericin-B was the most used AFT. IFIs attributable mortality was 20%. This epidemiologic survey underlined a persistent significant use of AFT and a high mortality rate of IFIs. We suggest that further powerful diagnostic approaches should be investigated to improve the diagnostic accuracy and potential therapeutic implication.

Approach of clinicians to candiduria and related outcome in the elderly

Candiduria is increasingly frequent in hospitalized debilitated patients. We aimed to evaluate the approach of clinicians to candiduria in the oldest old, and its effect on clearance and mortality. An observational study without intervention was carried out during 2012 and 2013 in three Spanish hospitals over patients with nosocomial candiduria aged 80 and over. Following a diagnostic algorithm, we assessed the appropriateness of antifungal therapy and analyzed the impact of the clinical approach (antifungal therapy, antibiotics discontinuation and catheter removal or replacement) on the outcome (mortality at 60 days and resolution, persistence or recurrence of candiduria). Hundred and forty eight patients were included. Symptomatology was attributable to candiduria in 31 instances and 19 asymptomatic patients were found at risk of developing candidemia. In response to culture-results, 77 (52%) of patients were treated with antifungals, mainly fluconazole (97.4%). The use of pharmacological therapy was appropriate (P<0.05) but subtherapeutical doses of fluconazole were widely used and follow-up samples were scarcely submitted. At 60 days of diagnosis the mortality was high (29.7%). The replacement or removal of the catheter resulted in a decrease in mortality and the use of antifungal treatment was associated with recurrence (P<0.05). In the absence of clinical practice guidelines with enough evidence, our study suggests that catheter removal should always be tried in the elderly with candiduria, since it reduces the mortality. The repetition of culture should help to better characterize the asymptomatic episodes, which are predominant, and to reduce the use of antifungals.

Low and constant micafungin concentrations may be sufficient to lead to resistance mutations in FKS2 gene of Candida glabrata.

We studied the ability of five echinocandin-susceptible C. glabrata isolates to acquire in vitro resistance to anidulafungin and micafungin. All isolates became phenotypically resistant after 2-4 days of exposure to low and constant micafungin concentrations (P < .05). Mutations in the HS1 region of the FKS2 gene were found in all isolates. The acquisition of resistance was not related to the previous use of antifungal treatment in the patients or the presence of mutations at MSH2 gene. We found differences (P < .0001) in the median survival of Galleria mellonella larvae infected with FKS2 mutant isolates (5 days) and wild-type isolates (3 days).

Galactomannan and PCR versus culture and histology for directing use of antifungal treatment for invasive aspergillosis in high-risk haematology patients: a randomised controlled trial

Empirical treatment with antifungal drugs is often used in haematology patients at high risk of invasive aspergillosis. We compared a standard diagnostic strategy (culture and histology) with a rapid biomarker-based diagnostic strategy (aspergillus galactomannan and PCR) for directing the use of antifungal treatment in this group of patients. In this open-label, parallel-group, randomised controlled trial, eligible patients were adults undergoing allogeneic stem-cell transplantation or chemotherapy for acute leukaemia, with no history of invasive fungal disease. Enrolled patients were randomly assigned (1:1) by a computer-generated schedule to follow either a standard diagnostic strategy (based on culture and histology) or a biomarker-based diagnostic strategy (aspergillus galactomannan and PCR) to direct treatment with antifungal drugs. Patients, were followed up for 26 weeks or until death. Masking of the use of different diagnostic tests was not possible for patients, treating physicians, or investigators. The primary endpoint was empirical treatment with antifungal drugs in the 26 weeks after enrolment (for the biomarker-based diagnostic strategy, a single postive galactomannan or PCR result was deemed insufficient to confirm invasive aspergillosis, so treatment in this context was classified as empirical). This outcome was assessed by an independent data review committee from which the study allocations were masked. Analyses were by intention to treat and included all enrolled patients. This study is registered with ClinicalTrial.gov, number NCT00163722. 240 eligible patients were recruited from six Australian centres between Sept 30, 2005, and Nov 19, 2009. 122 were assigned the standard diagnostic strategy and 118 the biomarker-based diagnostic strategy. 39 patients (32%) in the standard diagnosis group and 18 (15%) in the biomarker diagnosis group received empirical antifungal treatment (difference 17%, 95% CI 4-26; p=0·002). The numbers of patients who had hepatotoxic and nephrotoxic effects did not differ significantly between the standard diagnosis and biomarker diagnosis groups (hepatotoxic effects: 21 [17%] vs 12 [10%], p=0·11; nephrotoxic effects: 52 [43%] vs 60 [51%], p=0·20). Use of aspergillus galactomannan and PCR to direct treatment reduced use of empirical antifungal treatment. This approach is an effective strategy for the management of invasive aspergillosis in high-risk haematology patients. Australian National Health and Medical Research Council, Cancer Council New South Wales, Pfizer, Merck, Gilead Sciences.

Factors effecting impact of Aspergillus fumigatus sensitization in cystic fibrosis

The clinical impact of Aspergillus fumigatus (Af) sensitization in cystic fibrosis (CF) is controversial. We examined the effect of Af sensitization (Afs) on pulmonary function and growth using a retrospective cohort analysis over two 5-year study periods: 1996-2000 (19 Afs cases and 19 controls) and 2001-2005 (24 Afs cases and 23 controls). Sensitization was defined as Af specific radioallergosorbent test (RAST) >or= 17.5 iu/ml and total serum IgE level >or=150 iu/ml. We examined the impact of changing treatment schedules over these periods. Afs cases had lower median FEV(1) %predicted (%PR) compared to matched controls 1996: 67 versus 80, P < 0.01; 2001: 78 versus 93, P < 0.01. Afs cases in the 2001 cohort had a higher FEV(1) %PR compared to Afs cases in the 1996 cohort: 78 versus 67, P < 0.01. For the 1996 Afs cohort FEV(1) %PR fell significantly over 5 years but not for the 2001 Afs cohort. Af RAST and total IgE reflected the changes in pulmonary function. Children in the 2001 Afs cohort were prescribed significantly more oral antifungal treatment (odds ratio 4.3, 95%CI 1.2-15.7, P = 0.03). Afs children continue to have poorer lung function compared to controls but this observational, hypothesis generating study, suggests that the use of antifungal treatment is associated with better lung function.

Fungal colonization of haematological patients receiving cytotoxic chemotherapy: emergence of azole-resistantSaccharomyces cerevisiae

Fungal colonization during cytotoxic chemotherapy was studied in 42 patients with a recent diagnosis of a haematological malignancy. In total, 2759 surveillance cultures were taken from the nostrils, throat, urine, stool and perineal region. Seven hundred and ninety-six positive surveillance cultures (28.9%) yielded 968 fungal isolates. The rate of fungal colonization did not differ between patients with acute leukaemia, patients with other haematological malignancies and control patients in the same ward at admission (71% vs. 67% vs. 80%). Patients with acute leukaemia were colonized at a significantly lower rate in samples from the throat (32%), urine (10%), stool (45%) and perineum (29%) taken during hospitalization when compared with other haematological patients (respective values 58%, 21%, 67% and 45%;P -values 0.001). This could be attributed to differences in the use of antifungal drugs. Although 21/42 (50%) of our patients had multiple-site fungal colonization at the end of follow-up, only one systemic Candida infection was diagnosed. Extensive use of antifungal treatment may have influenced the low incidence of systemic fungal infections during the follow-up. In addition to Candida species, Malassezia furfur, Geotrichum candidum and Saccharomyces cerevisiae were frequently isolated. The rate of S. cerevisiae isolation increased significantly over time after admission (1% vs. 18% of isolates, P<0.001), suggesting hospital-acquired transmission. These isolates were highly resistant to azole antifungals (MIC90128μg/mL for fluconazole and 16μg/mL for itraconazole), and caused persistent multiple site colonization in 12 patients. Extensive use of antifungal agents in a haematological ward may keep the incidence of invasive fungal infections low in spite of heavy fungal colonization. However, there may be a risk of emergence of resistant fungal strains.

Systemic fungal infections in neonates

Systemic fungal infections, previously considered to be a rare complication, are now frequently diagnosed in VLBW infants receiving intensive care. Confirming the diagnosis by laboratory tests is difficult and a high index of suspicion is required. Prompt and aggressive use of antifungal treatment is justified in a clinically septic neonate, especially those with a raised serum concentration of C reactive protein, who do not show a satisfactory response to antibiotics. The newer generation of liposomal amphotericin and azole antifungal drugs appear to be safe, effective, and well tolerated. With increasing awareness, prompt treatment, and better neonatal intensive care, the outcome of systemic fungal infection in preterm infants should improve.