Invasive fungal infections among organ transplant recipients: results of the Transplant-Associated Infection Surveillance Network (TRANSNET)

Multi-arm ε-polylysines exhibit broad-spectrum antifungal activities against Candida species

Invasive fungal infections pose a crucial threat to public health and are an under-recognized component of antimicrobial resistance, which is an emerging crisis worldwide. Here we designed and synthesized a panel of multi-arm ε-polylysines (ε-mPLs, nR-Km) with a precise number of n = 3-6 arms of ε-oligo(L-lysine)s and a precise arm length of m = 3-7 ε-lysine residues. ε-mPLs have good biocompatibility and exhibited broad-spectrum antifungal activities towards Aspergillus, Mucorales and Candida species, and their antifungal activities increased with residue arm length. Among these ε-mPLs, 3R-K7 showed high antifungal activity against C. albicans with a MIC value of as low as 24 μg mL-1 (only 1/16th that of ε-PL) and also exhibited similar antifungal activity towards the clinically isolated multi-drug resistant (MDR) C. albicans strain. Furthermore, 3R-K7 could inhibit the formation of C. albicans biofilms and kill the cells within mature C. albicans biofilms. Mechanistic studies proved that 3R-K7 killed fungal cells by entering the cells to generate reactive oxygen species (ROS) and induce cell apoptosis. An in vivo study showed that 3R-K7 significantly increased the survival rate of mice in a systemic murine candidiasis model, demonstrating that ε-mPL has great potential as a new antifungal agent.

Occurrence of Aspergillus fumigatus azole resistance in soils from Switzerland

Aspergillus fumigatus is a fungal species causing diverse diseases in humans. The use of azoles for treatments of A. fumigatus diseases has resulted in azole resistance. Azoles are also widely used in the environment for crop protection, which resulted in azole resistance. Resistance is primarily due to mutations in cyp51A, which encodes the target protein for azoles. Here we addressed the occurrence of azole resistance in soils from a vast part of Switzerland. We aimed to associate the use of azoles in the environment with the occurrence of azole resistance. We targeted sample sites from different agricultural environments as well as sites with no agricultural practice (natural sites and urban sites). Starting from 327 sites, 113 A. fumigatus isolates were recovered (2019-2021), among which 19 were azole-resistant (15 with TR34/L98H and four with TR46/Y121F/T289A resistance mutations in cyp51A). Our results show that azole resistance was not associated with a specific agricultural practice. Azoles could be chemically detected in investigated soils, however, their presence was not associated with the occurrence of azole-resistant isolates. Interestingly, genetic markers of resistance to other fungicides were detected but only in azole-resistant isolates, thus reinforcing the notion that A. fumigatus cross-resistance to fungicides has an environmental origin. In conclusion, this study reveals the spreading of azole resistance in A. fumigatus from the environment in Switzerland. The proximity of agricultural areas to urban centers may facilitate the transmission of resistant strains to at-risk populations. Thus, vigilant surveillance is required to maintain effective treatment options for aspergillosis.

Invasive Aspergillosis among Lung Transplant Recipients during Time Periods with Universal and Targeted Antifungal Prophylaxis-A Nationwide Cohort Study

The optimal prevention strategy for invasive aspergillosis (IA) in lung transplant recipients (LTXr) is unknown. In 2016, the Danish guidelines were changed from universal to targeted IA prophylaxis. Previously, we found higher rates of adverse events in the universal prophylaxis period. In a Danish nationwide study including LTXr, for 2010-2019, we compared IA rates in time periods with universal vs. targeted prophylaxis and during person-time with vs. person-time without antifungal prophylaxis. IA hazard rates were analyzed in multivariable Cox models with adjustment for time after LTX. Among 295 LTXr, antifungal prophylaxis was initiated in 183/193 and 6/102 during the universal and targeted period, respectively. During the universal period, 62% discontinued prophylaxis prematurely. The median time on prophylaxis was 37 days (IQR 11-84). IA was diagnosed in 27/193 (14%) vs. 15/102 (15%) LTXr in the universal vs. targeted period, with an adjusted hazard ratio (aHR) of 0.94 (95% CI 0.49-1.82). The aHR of IA during person-time with vs. person-time without antifungal prophylaxis was 0.36 (95% CI 0.12-1.02). No difference in IA was found during periods with universal vs. targeted prophylaxis. Prophylaxis was protective of IA when taken. Targeted prophylaxis may be preferred over universal due to comparable IA rates and lower rates of adverse events.

Epidemiology and Risk Factors for Invasive Fungal Infections in Pancreas Transplant in the Absence of Postoperative Antifungal Prophylaxis

Background

Invasive fungal infections (IFIs) remain a rare yet dreaded complication following pancreas transplantation. Current guidelines recommend antifungal prophylaxis in patients with 1 or more risk factors. At our center, single-dose antifungal prophylaxis is administered in the operating room but none subsequently, regardless of risk factors. Here we evaluate the 1-year incidence, outcome, and risk factors associated with IFI following pancreas transplantation.

Methods

A retrospective, single-center cohort study was conducted in patients who underwent pancreas transplantation between 1 January 2009 and 31 December 2019. Records were manually reviewed, and cases were adjudicated using consensus definitions. The 1-year cumulative incidence, mortality, and risk factors were analyzed by Kaplan-Meier method and differences between populations were assessed with Fisher test and Mann-Whitney U test.

Results

Three hundred sixty-nine recipients were included. Twelve IFIs were identified: candidiasis (8), aspergillosis (2), histoplasmosis (1), and cryptococcosis (1). Intra-abdominal infections were the most common presentation (5), followed by bloodstream infections (3), disseminated disease (2), pulmonary disease (1), and invasive fungal sinusitis (1). Median time to IFI was 64 days (interquartile range, 30-234 days). One-year cumulative incidence was 3.25% (95% confidence interval, 1.86%-5.65%). There were no significant differences between patients with or without IFI regarding type of transplant (P = .17), posttransplant dialysis (P = .3), rejection (P = .5), cytomegalovirus serostatus (P = .45), or reoperation (P = .19). For patients with IFI, the 1-year graft and patient survival rates were 58% versus 95% (P < .0001) and 75% versus 98.6% (P < .001), respectively.

Conclusions

Our study suggests that the use of a single-dose antifungal prophylaxis administered in the operating room but none subsequently does not result in an increased incidence of IFI following pancreas transplantation.

Invasive pulmonary aspergillosis in the intensive care unit: current challenges and best practices

The prevalence of invasive pulmonary aspergillosis (IPA) is growing in critically ill patients in the intensive care unit (ICU). It is increasingly recognized in immunocompetent hosts and immunocompromised ones. IPA frequently complicates both severe influenza and severe coronavirus disease 2019 (COVID-19) infection. It continues to represent both a diagnostic and therapeutic challenge and can be associated with significant morbidity and mortality. In this narrative review, we describe the epidemiology, risk factors and disease manifestations of IPA. We discuss the latest evidence and current published guidelines for the diagnosis and management of IPA in the context of the critically ill within the ICU. Finally, we review influenza-associated pulmonary aspergillosis (IAPA), COVID-19-associated pulmonary aspergillosis (CAPA) as well as ongoing and future areas of research.

Ultrasound of pancreatic transplant complications: a primer for radiologists

Pancreatic transplantation is an established treatment for patients with type 1 diabetes patients and select type 2 diabetes patients, with excellent survival rates as graft health is evaluated through regular imaging and early detection of complications. Amongst the various imaging methods that may aid in diagnosis of pancreatic transplant complications, ultrasound is a widely available, quick, portable, and cost-effective technique, often used as the sole method to assess for pancreatic transplant complications. When assessing a patient with a pancreatic transplant, the radiologist should be methodical in assessing the vasculature, the pancreatic parenchyma, and the peripancreatic regions. Complications can be categorised based on time from transplant and type of complications, and include vascular, parenchymal, and enteric/anastomotic complications. Doppler has a major role in the diagnosis of vascular complications including arterial and venous thrombosis, arterial stenosis, pseudoaneurysms, and haematomas. Pancreatic complications include rejections and pancreatitis, and are often diagnosed through a combination of clinical, laboratory, and imaging findings, such as pancreatic heterogeneity or the presence of pancreatic pseudocysts. Enteric/anastomotic complications include leaks and bowel obstructions, and may require cross-sectional imaging in addition to ultrasound. This review covers the most common and high-impact vascular, parenchymal, and enteric/anastomotic complications that should be considered in every radiologist's search pattern when assessing a pancreatic graft, as well as their respective postoperative timeframes.

Submandibular gland abscess in a kidney transplant recipient: a diagnostic and therapeutic enigma

A renal allograft transplant recipient presented to our emergency department with pus discharging right-sided cheek swelling. She had the same presentation 1 year after kidney transplant surgery. The abscess was incised and drained, and a sample was sent for culture and sensitivity. The culture initially grew Aspergillus fumigatus for which she was started on itraconazole. While the patient was on antifungal therapy, immunohistochemistry revealed diffuse large B-cell lymphoma to be the primary disease, and rituximab chemotherapy was initiated. The patient is being followed up and is currently in remission.We are reporting this rare case to raise awareness so that clinicians consider the possibility of post-transplant lymphoproliferative disorder when they see a similar presentation.

Investigating infectious outcomes in adult patients undergoing solid organ transplantation: A retrospective single-center experience, Paris, France

OBJECTIVES

This study described the demographic characteristics, clinical presentation, treatment, and outcomes of solid organ transplant recipients who were admitted to our center for infection. It also determined factors associated with a poor outcome, and compares early and late period infections.

METHODS

In this retrospective observational study, conducted at a tertiary care center in France between October 2017 and March 2019, infectious outcomes of patients with solid organ transplant where studied.

RESULTS

A total of 104 patients were included with 158 hospitalizations for infection. Among these 104 patients, 71 (68%) were men. The median age was 59 years old. The most common symptoms on admission were fever (66%) and chills (31%). Lower respiratory tract infections were the most common diagnosis (71/158 hospitalizations). Urinary tract infections were frequently seen in kidney transplant recipients (25/60 hospitalizations). One or more infectious agents were isolated for 113 hospitalizations (72%): 70 bacteria, 36 viruses and 10 fungi, with predominance of gram-negative bacilli (53 cases) of which 13 were multidrug-resistant. The most frequently used antibiotics were third generation cephalosporins (40 cases), followed by piperacillin-tazobactam (26 cases). We note that 25 infections (16%) occurred during the first 6 months (early post-transplant period). Patients admitted during the early post-transplant period were more often on immunosuppressive treatment with prednisone (25/25 VS 106/133) (p = 0.01), mycophenolic acid (22/25 VS 86/133) (p = 0.03), presented for an urinary tract infection (10/25 VS 25/133) (p = 0.04) or a bacterial infection (17/25 VS 53/133) (p = 0.01). Patients with later infection had more comorbidities (57/83 VS 9/21) (p = 0.03), cancer (19/83 VS 0/21) (p = 0.04) or were on treatment with everolimus (46/133 VS 0/25) (p = 0.001). During 31 hospitalizations (20%), patients presented with a serious infection requiring intensive care (n = 26; 16%) or leading to death (n = 7; 4%). Bacteremia, pulmonary and cardiac complications were the main risk factors associated with poor outcome.

CONCLUSION

Infections pose a significant challenge in the care of solid organ transplant patients, particularly those with comorbidities and intensive immunosuppression. This underscores the crucial importance of continuous surveillance and epidemiologic monitoring within this patient population.

Current Epidemiology and Clinical Features of Cryptococcus Infection in Patients Without Human Immunodeficiency Virus: A Multicenter Study in 46 Hospitals in Australia and New Zealand

BACKGROUND

Patients without human immunodeficiency virus (HIV) are increasingly recognized as being at risk for cryptococcosis. Knowledge of characteristics of cryptococcosis in these patients remains incomplete.

METHODS

We conducted a retrospective study of cryptococcosis in 46 Australian and New Zealand hospitals to compare its frequency in patients with and without HIV and describe its characteristics in patients without HIV. Patients with cryptococcosis between January 2015 and December 2019 were included.

RESULTS

Of 475 patients with cryptococcosis, 90% were without HIV (426 of 475) with marked predominance in both Cryptococcus neoformans (88.7%) and Cryptococcus gattii cases (94.3%). Most patients without HIV (60.8%) had a known immunocompromising condition: cancer (n = 91), organ transplantation (n = 81), or other immunocompromising condition (n = 97). Cryptococcosis presented as incidental imaging findings in 16.4% of patients (70 of 426). The serum cryptococcal antigen test was positive in 85.1% of tested patients (319 of 375); high titers independently predicted risk of central nervous system involvement. Lumbar puncture was performed in 167 patients to screen for asymptomatic meningitis, with a positivity rate of 13.2% where meningitis could have been predicted by a high serum cryptococcal antigen titer and/or fungemia in 95% of evaluable cases. One-year all-cause mortality was 20.9% in patients without HIV and 21.7% in patients with HIV (P = .89).

CONCLUSIONS

Ninety percent of cryptococcosis cases occurred in patients without HIV (89% and 94% for C. neoformans and C. gattii, respectively). Emerging patient risk groups were evident. A high level of awareness is warranted to diagnose cryptococcosis in patients without HIV.

Aspergillus spp. renal arteritis after kidney transplantation: A reappraisal

BACKGROUND

Aspergillus spp. is an uncommon and life-threatening cause of transplantrenal artery pseudoaneurysm after kidney transplantation.

CASE

We report the case of a 62-year-old woman who underwent kidney transplantation 10 months before and presented a 7-cm asymptomatic transplant renal artery pseudoaneurysm. Transplanted kidney and pseudoaneurysm were surgically removed in emergency. Renal graft, urine, and pseudoaneurysm cultures grew Aspergillus flavus. She recovered after 12 months of antifungal therapy.

LITERATURE REVIEW

To date 14 cases of Aspergillus spp. renal arteritis after kidney transplantation have been published, including 50% Aspergillus flavus arteritis. Vast majority were diagnosed within 90 days after transplantation (73%). Despite allograft nephrectomy and antifungal therapy, mortality rate was high (33%).

Treatment of Invasive Aspergillosis: How It's Going, Where It's Heading

Despite improvements in treatment and diagnostics over the last two decades, invasive aspergillosis (IA) remains a devastating fungal disease. The number of immunocompromised patients and hence vulnerable hosts increases, which is paralleled by the emergence of a rise in IA cases. Increased frequencies of azole-resistant strains are reported from six continents, presenting a new challenge for the therapeutic management. Treatment options for IA currently consist of three classes of antifungals (azoles, polyenes, echinocandins) with distinctive advantages and shortcomings. Especially in settings of difficult to treat IA, comprising drug tolerance/resistance, limiting drug-drug interactions, and/or severe underlying organ dysfunction, novel approaches are urgently needed. Promising new drugs for the treatment of IA are in late-stage clinical development, including olorofim (a dihydroorotate dehydrogenase inhibitor), fosmanogepix (a Gwt1 enzyme inhibitor), ibrexafungerp (a triterpenoid), opelconazole (an azole optimized for inhalation) and rezafungin (an echinocandin with long half-life time). Further, new insights in the pathophysiology of IA yielding immunotherapy as a potential add-on therapy. Current investigations show encouraging results, so far mostly in preclinical settings. In this review we discuss current treatment strategies, give an outlook on possible new pharmaceutical therapeutic options, and, lastly, provide an overview of the ongoing research in immunotherapy for IA.

Etiologic characteristics revealed by mNGS-mediated ultra-early and early microbiological identification in airway secretions from lung transplant recipients

Background

Post-operative etiological studies are critical for infection prevention in lung transplant recipients within the first year. In this study, mNGS combined with microbial culture was applied to reveal the etiological characteristics within one week (ultra-early) and one month (early) in lung transplant recipients, and the epidemiology of infection occurred within one month.

Methods

In 38 lung transplant recipients, deep airway secretions were collected through bronchofiberscope within two hours after the operation and were subjected to microbial identification by mNGS and microbial culture. The etiologic characteristics of lung transplant recipients were explored. Within one month, the infection status of recipients was monitored. The microbial species detected by mNGS were compared with the etiological agents causing infection within one month.

Results

The detection rate of mNGS in the 38 airway secretions specimens was significantly higher than that of the microbial culture (P<0.0001). MNGS identified 143 kinds of pathogenic microorganisms; bacterial pathogens account for more than half (72.73%), with gram-positive and -negative bacteria occupying large proportions. Fungi such as Candida are also frequently detected. 5 (50%) microbial species identified by microbial culture had multiple drug resistance (MDR). Within one month, 26 (68.42%) recipients got infected (with a median time of 9 days), among which 10 (38.46%) cases were infected within one week. In the infected recipients, causative agents were detected in advance by mNGS in 9 (34.62%) cases, and most of them (6, 66.67%) were infected within one week (ultra-early). In the infection that occurred after one week, the consistency between mNGS results and the etiological agents was decreased.

Conclusion

Based on the mNGS-reported pathogens in airway secretions samples collected within two hours, the initial empirical anti-infection regimes covering the bacteria and fungi are reasonable. The existence of bacteria with MDR forecasts the high risk of infection within 48 hours after transplant, reminding us of the necessity to adjust the antimicrobial strategy. The predictive role of mNGS performed within two hours in etiological agents is time-limited, suggesting continuous pathogenic identification is needed after lung transplant.

Invasive aspergillosis in liver transplant recipients, an infectious complication with low incidence but significant mortality

BACKGROUND

Infections, including invasive fungal infections (IFIs), are among the leading causes of mortality in liver transplant recipients during the first year post-transplantation.

AIM

To investigate the epidemiology, clinical manifestations, risk factors, treatment outcomes, and mortality rate of post-liver transplantation invasive aspergillosis (IA).

METHODS

In this case-control study, 22 patients with IA were identified by reviewing the archived and electronic medical records of 850 patients who received liver transplants at the Imam Khomeini Hospital complex in Tehran, Iran, between 2014 and 2019. The control group comprised 38 patients without IA infection matched for age and sex. The information obtained included the baseline characteristics of liver transplant patients, operative reports, post-transplantation characteristics of both groups and information about the fungal infection of the patient group.

RESULTS

The prevalence rate of IA among liver transplant recipients at Imam Khomeini Hospital was 2.7%. The risk factors of IA among studied patients included high serum creatinine levels before and post-transplant, renal replacement therapy, antithymocyte globulin induction therapy, post-transplant bile leakage, post-transplant hepatic artery thrombosis, repeated surgery within 30 d after the transplant, bacterial pneumonia before the aspergillosis diagnosis, receiving systemic antibiotics before the aspergillus infection, cytomegalovirus infection, and duration of post-transplant hospitalization in the intensive care unit. The most prevalent form of infection was invasive pulmonary aspergillosis, and the most common chest computed tomography scan findings were nodules, pleural effusion, and the halo sign. In the case group, prophylactic antifungal therapy was administered more frequently than in the control group. The antifungal therapy response rate at 12 wk was 63.7%. The 3- and 12- mo mortality rates of the patients with IA were 36.4% and 45.4%, respectively (compared with the mortality rate of the control group in 12 mo, which was zero).

CONCLUSION

In this study, the prevalence of IA among liver transplant recipients was relatively low. However, it was one of the leading causes of mortality following liver transplantation. Targeted antifungal therapy may be a factor in the low incidence of infections at our facility. Identifying the risk factors of IFIs, maintaining an elevated level of clinical suspicion, and initiating early antifungal treatment may significantly improve the prognosis and reduce the mortality rate of liver transplant recipients.

Fungal mechanisms of intracellular survival: what can we learn from bacterial pathogens?

Fungal infections represent a major, albeit neglected, public health threat with serious medical and economic burdens globally. With unacceptably high mortality rates, invasive fungal pathogens are responsible for millions of deaths each year, with a steadily increasing incidence primarily in immunocompromised individuals. The poor therapeutic options and rise of antifungal drug resistance pose further challenges in controlling these infections. These fungal pathogens have adapted to survive within mammalian hosts and can establish intracellular niches to promote survival within host immune cells. To do that, they have developed diverse methods to circumvent the innate immune system attack. This includes strategies such as altering their morphology, counteracting macrophage antimicrobial action, and metabolic adaptation. This is reminiscent of how bacterial pathogens have adapted to survive within host cells and cause disease. However, relative to the great deal of information available concerning intracellular bacterial pathogenesis, less is known about the mechanisms fungal pathogens employ. Therefore, here we review our current knowledge and recent advances in our understanding of how fungi can evade and persist within host immune cells. This review will focus on the major fungal pathogens, including Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus, among others. As we discover and understand the strategies used by these fungi, similarities with their bacterial counterparts are becoming apparent, hence we can use the abundant information from bacteria to guide our studies in fungi. By understanding these strategies, new lines of research will open that can improve the treatments of these devastating fungal diseases.

Update on Epidemiology and Outcomes of Infection in Pediatric Organ Transplant Recipients

Pediatric solid organ transplant (SOT) recipients are at risk for infection following transplantation. Data from adult SOT recipients are often used to guide prevention and treatment of infections associated with organ transplantation in children. This article highlights key recent pediatric SOT-specific publications for an array of infectious complications of organ transplantation. Attention is given to areas of need for future study.

Invasive fungal infections in liver diseases

Patients with liver diseases, including decompensated cirrhosis, alcohol-associated hepatitis, and liver transplant recipients are at increased risk of acquiring invasive fungal infections (IFIs). These infections carry high morbidity and mortality. Multiple factors, including host immune dysfunction, barrier failures, malnutrition, and microbiome alterations, increase the risk of developing IFI. Candida remains the most common fungal pathogen causing IFI. However, other pathogens, including Aspergillus, Cryptococcus, Pneumocystis, and endemic mycoses, are being increasingly recognized. The diagnosis of IFIs can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by detecting antigens, antibodies, or nucleic acid. Here, we provide an update on the epidemiology, pathogenesis, diagnosis, and management of IFI in patients with liver disease and liver transplantation.

Candidemia in thoracic solid organ transplant recipients: Characteristics and outcomes relative to matched uninfected and bacteremic thoracic organ transplant recipients

BACKGROUND

Little is understood about the risk factors and outcomes from candidemia in thoracic solid organ transplant recipients.

METHODS

This is a single-center retrospective cohort study of patients undergoing heart or lung transplant between January 1, 2013 and December 31, 2022. We performed two comparisons among heart and lung transplant recipients: (1) recipients with candidemia versus matched, uninfected recipients, and (2) recipients with candidemia versus recipients with bacteremia.

RESULTS

During the study 384 heart and 194 lung transplants were performed. Twenty-one (5.5%) heart and six (3.1%) lung recipients developed candidemia. Heart recipients with candidemia were more likely to have had delayed chest closure (38.1% vs. 0%, p < .0001), temporary mechanical circulatory support (57.1% vs. 11.9%, p = .0003), and repeat surgical chest exploration 76.2% vs. 16.7%, p < .0001) than uninfected controls. Heart and lung recipients who developed candidemia were more likely to have been on renal replacement therapy prior to infection relative to uninfected controls (57.1% vs. 11.9%, p = .0003 and 66.7% vs. 0%, p = .0041, respectively). Heart recipients with candidemia had significantly lower post-transplant survival and lower post-infection survival relative to matched uninfected controls and heart recipients with bacteremia, respectively (p < .0001 and p = .0002, respectively).

CONCLUSIONS

Candidemia following heart and lung transplantation is associated with significant morbidity and mortality. Further research is needed to understand if heart recipients with delayed chest closure, temporary mechanical circulatory support, renal replacement therapy, and repeat surgical chest exploration may benefit from targeted antifungal prophylaxis.

Diagnosis, Prevention, and Treatment of Infections in Kidney Transplantation

Kidney transplant often is complicated by infections in the recipient from therapy-related and patient-related risk factors. Infections in kidney transplant recipients are associated with increased morbidity, mortality, and allograft dysfunction. There is a predictable timeline after kidney transplant regarding the types of pathogens causing infections, reflecting the net state of immunosuppression. In the early post-transplant period, bacterial infections comprise two thirds of all infections, followed by viral and fungal infections. Infections occurring early after kidney transplantation are generally the result of postoperative complications. In most cases, opportunistic infections occur within 6 months after kidney transplantation. They may be caused by a new infection, a donor-derived infection, or reactivation of a latent infection. Community-acquired pneumonia, upper respiratory tract infections, urinary tract infections, and gastrointestinal infections are the most common infections in the late period after transplantation when the net immunosuppression is minimal. It is crucial to seek information on the time after transplant, reflecting the net state of immunosuppression, previous history of exposure/infections, geography, and seasonal outbreaks. It is imperative that we develop regionally specific guidelines on screening, prevention, and management of infections after kidney transplantation.

Dosing Optimization of Posaconazole in Lung-Transplant Recipients Based on Population Pharmacokinetic Model

Although posaconazole tablets show relatively low variability in pharmacokinetics (PK), the proportion of patients achieving the PK/PD target at the approved uniform dose for both prophylaxis and therapy is not satisfactory. The aim of this study was to develop a posaconazole population PK model in lung-transplant recipients and to propose a covariate-based dosing optimization for both prophylaxis and therapy. In this prospective study, 80 posaconazole concentrations obtained from 32 lung-transplant patients during therapeutic drug monitoring were analyzed using nonlinear mixed-effects modelling, and a Monte Carlo simulation was used to describe the theoretical distribution of posaconazole PK profiles at various dosing regimens. A one-compartment model with both linear absorption and elimination best fit the concentration-time data. The population apparent volume of distribution was 386.4 L, while an apparent clearance of 8.8 L/h decreased by 0.009 L/h with each year of the patient's age. Based on the covariate model, a dosing regimen of 200 mg/day for prophylaxis in patients ˃60 years, 300 mg/day for prophylaxis in patients ˂60 years and for therapy in patients ˃60 years, and 400 mg/day for therapy in patients ˂60 years has been proposed. At this dosing regimen, the PK/PD target for prophylaxis and therapy is reached in 95% and 90% of population, respectively, representing significantly improved outcomes in comparison with the uniform dose.

Cryptococcemia in pancreas-kidney transplant patient

Solid organ transplant recipients have a higher risk of developing invasive fungal infections (IFIs) due to immunosuppressive therapy. Cryptococcosis is the third most commonly occurring invasive fungal infection in solid organ transplant (SOT) recipients. Cryptococcemia is associated with high mortality rate. We present a case of cryptococcemia in a 31-year-old female with a pancreas-kidney transplant who was admitted to hospital for the management of a suspected Hemodialysis catheter-related bloodstream infection (CRBSI).

Antifungal prophylaxis and pre-emptive therapy: When and how?

The growing pool of critically ill or immunocompromised patients leads to a constant increase of life-threatening invasive infections by fungi such as Aspergillus spp., Candida spp. and Pneumocystis jirovecii. In response to this, prophylactic and pre-emptive antifungal treatment strategies have been developed and implemented for high-risk patient populations. The benefit by risk reduction needs to be carefully weighed against potential harm caused by prolonged exposure against antifungal agents. This includes adverse effects and development of resistance as well as costs for the healthcare system. In this review, we summarise evidence and discuss advantages and downsides of antifungal prophylaxis and pre-emptive treatment in the setting of malignancies such as acute leukaemia, haematopoietic stem cell transplantation, CAR-T cell therapy, and solid organ transplant. We also address preventive strategies in patients after abdominal surgery and with viral pneumonia as well as individuals with inherited immunodeficiencies. Notable progress has been made in haematology research, where strong recommendations regarding antifungal prophylaxis and pre-emptive treatment are backed by data from randomized controlled trials, whereas other critical areas still lack high-quality evidence. In these areas, paucity of definitive data translates into centre-specific strategies that are based on interpretation of available data, local expertise, and epidemiology. The development of novel immunomodulating anticancer drugs, high-end intensive care treatment and the development of new antifungals with new modes of action, adverse effects and routes of administration will have implications on future prophylactic and pre-emptive approaches.

Comparison of different therapeutic approaches for pulmonary cryptococcosis in kidney transplant recipients: a 15-year retrospective analysis

Introduction

Organ transplant recipients are at increased risk of developing pulmonary cryptococcosis (PC) due to weakened cell-mediated immunity caused by immunosuppressors. However, the nonspecific symptoms associated with PC can often lead to misdiagnosis and inappropriate treatment.

Methods

We conducted a retrospective analysis of data from 23 kidney transplant recipients with PC between April 2006 to January 2021.

Results

The median time from transplantation to the diagnosis of pathology-proven PC 4.09  years. Seventeen patients presented respiratory symptoms, including sputum-producing cough and dyspnea. Additionally, three patients also developed central nervous system (CNS) infections. Chest CT scans frequently revealed nodule-shaped lesions, which can mimic lung carcinoma. Serological tests did not demonstrate any specific changes. Nine patients received surgical resection as treatment. Fourteen patients were treated with antifungal medication only. No recurrence was observed in all 23 patients.

Conclusion

Our study suggests that fever and sputum-producing cough are common symptoms of PC, and cryptococcal meningitis should not be excluded if corresponding symptoms occur. Fluconazole is a common and effective antifungal agent. Surgical resection should be considered for patients who do not respond well to antifungal therapy. Clinicians should be aware of these findings when evaluating transplant recipients with respiratory symptoms.

Oral candidiasis in patients with kidney transplantation in Iran: prevalence and antifungal susceptibility pattern

Aim: This study aimed to identify Candida species recovered from the oral cavity of patients with kidney transplantation. Materials & methods: Two swabs were taken from the oral cavities of 40 patients before and after transplantation, cultured on Sabouraud dextrose agar, and yeasts identified. Antifungal drug susceptibility testing was performed with fluconazole and itraconazole. Results: Candida glabrata was the most frequently isolated species in patients, followed by Candida albicans and Rhodotorula. C. glabrata isolates from patients before transplantation were resistant to fluconazole, whereas C. albicans was fluconazole-resistant both before and after transplantation. Conclusion: The importance of non-albicans Candida species in the oral cavity of patients sheds light on performing antifungal tests for achieving the best outcome to prevent therapeutic failure.

An update on current and novel molecular diagnostics for the diagnosis of invasive fungal infections

BACKGROUND

Invasive fungal infections cause millions of infections annually, but diagnosis remains challenging. There is an increased need for low-cost, easy to use, highly sensitive and specific molecular assays that can differentiate between colonized and pathogenic organisms from different clinical specimens.

AREAS COVERED

We reviewed the literature evaluating the current state of molecular diagnostics for invasive fungal infections, focusing on current and novel molecular tests such as polymerase chain reaction (PCR), digital PCR, high-resolution melt (HRM), and metagenomics/next generation sequencing (mNGS).

EXPERT OPINION

PCR is highly sensitive and specific, although performance can be impacted by prior/concurrent antifungal use. PCR assays can identify mutations associated with antifungal resistance, non-Aspergillus mold infections, and infections from endemic fungi. HRM is a rapid and highly sensitive diagnostic modality that can identify a wide range of fungal pathogens, including down to the species level, but multiplex assays are limited and HRM is currently unavailable in most healthcare settings, although universal HRM is working to overcome this limitation. mNGS offers a promising approach for rapid and hypothesis-free diagnosis of a wide range of fungal pathogens, although some drawbacks include limited access, variable performance across platforms, the expertise and costs associated with this method, and long turnaround times in real-world settings.

Invasive Fungal Infections: The Early Killer after Liver Transplantation

BACKGROUND

Liver transplantation is a standard of care and a life-saving procedure for end-stage liver diseases and certain malignancies. The evidence on predictors and risk factors for poor outcomes is lacking. Therefore, we aimed to identify potential risk factors for mortality and to report on overall 90-day mortality after orthotopic liver transplantation (OLT), especially focusing on the role of fungal infections.

METHODS

We retrospectively reviewed medical charts of all patients undergoing OLT at a tertiary university center in Europe.

RESULTS

From 299 patients, 214 adult patients who received a first-time OLT were included. The OLT indication was mainly due to tumors (42%, 89/214) and cirrhosis (32%, 68/214), including acute liver failure in 4.7% (10/214) of patients. In total, 8% (17/214) of patients died within the first three months, with a median time to death of 15 (1-80) days. Despite a targeted antimycotic prophylaxis using echinocandins, invasive fungal infections occurred in 12% (26/214) of the patients. In the multivariate analysis, patients with invasive fungal infections had an almost five times higher chance of death (HR 4.6, 95% CI 1.1-18.8; p = 0.032).

CONCLUSIONS

Short-term mortality after OLT is mainly determined by infectious and procedural complications. Fungal breakthrough infections are becoming a growing concern. Procedural, host, and fungal factors can contribute to a failure of prophylaxis. Finally, invasive fungal infections may be a potentially modifiable risk factor, but the ideal perioperative antimycotic prophylaxis has yet to be determined.

COVID-19-associated pulmonary aspergillosis in immunocompetent patients: a virtual patient cohort study

The opportunistic fungus Aspergillus fumigatus infects the lungs of immunocompromised hosts, including patients undergoing chemotherapy or organ transplantation. More recently however, immunocompetent patients with severe SARS-CoV2 have been reported to be affected by COVID-19 Associated Pulmonary Aspergillosis (CAPA), in the absence of the conventional risk factors for invasive aspergillosis. This paper explores the hypothesis that contributing causes are the destruction of the lung epithelium permitting colonization by opportunistic pathogens. At the same time, the exhaustion of the immune system, characterized by cytokine storms, apoptosis, and depletion of leukocytes may hinder the response to A. fumigatus infection. The combination of these factors may explain the onset of invasive aspergillosis in immunocompetent patients. We used a previously published computational model of the innate immune response to infection with Aspergillus fumigatus. Variation of model parameters was used to create a virtual patient population. A simulation study of this virtual patient population to test potential causes for co-infection in immunocompetent patients. The two most important factors determining the likelihood of CAPA were the inherent virulence of the fungus and the effectiveness of the neutrophil population, as measured by granule half-life and ability to kill fungal cells. Varying these parameters across the virtual patient population generated a realistic distribution of CAPA phenotypes observed in the literature. Computational models are an effective tool for hypothesis generation. Varying model parameters can be used to create a virtual patient population for identifying candidate mechanisms for phenomena observed in actual patient populations.

Minimizing the Risk of Donor-Derived Events and Maximizing Organ Utilization Through Education and Policy Development

Herein, we review the current knowledge of donor-derived disease and current US Organ Procurement and Transplantation Network policies to minimize the risk. During the process, we also consider actions to further mitigate the risk of donor-derived disease. The overarching goal is to provide an infectious disease perspective on the complex decision of organ acceptance for transplant programs and candidates.

Amide- and bis-amide-linked highly potent and broadly active antifungal agents for the treatment of invasive fungal infections- towards the discovery of pre-clinical development candidate FC12406

Most fungal infections are common, localized to skin or mucosal surfaces and can be treated effectively with topical antifungal agents. However, while invasive fungal infections (IFIs) are uncommon, they are very difficult to control medically, and are associated with high mortality rates. We have previously described highly potent bis-guanidine-containing heteroaryl-linked antifungal agents, and were interested in expanding the range of agents to novel series so as to reduce the degree of aromaticity (with a view to making the compounds more drug-like), and provide broadly active high potency derivatives. We have investigated the replacement of the central aryl ring from our original series by both amide and a bis-amide moieties, and have found particular structure-activity relationships (SAR) for both series', resulting in highly active antifungal agents against both mold and yeast pathogens. In particular, we describe the in vitro antifungal activity, absorption, distribution, metabolism and elimination (ADME) properties, and off-target properties of FC12406 (34), which was selected as a pre-clinical development candidate.

The Novel Monoclonal IgG1-Antibody AB90-E8 as a Diagnostic Tool to Rapidly Distinguish Aspergillus fumigatus from Other Human Pathogenic Aspergillus Species

In most cases, invasive aspergillosis (IA) is caused by A. fumigatus, though infections with other Aspergillus spp. with lower susceptibilities to amphotericin B (AmB) gain ground. A. terreus, for instance, is the second leading cause of IA in humans and of serious concern because of its high propensity to disseminate and its in vitro and in vivo resistance to AmB. An early differentiation between A. fumigatus and non-A. fumigatus infections could swiftly recognize a potentially ineffective treatment with AmB and lead to the lifesaving change to a more appropriate drug regime in high-risk patients. In this study, we present the characteristics of the monoclonal IgG₁-antibody AB90-E8 that specifically recognizes a surface antigen of A. fumigatus and the closely related, but not human pathogenic A. fischeri. We show immunostainings on fresh frozen sections as well as on incipient mycelium picked from agar plates with tweezers or by using the expeditious tape mount technique. All three methods have a time advantage over the common procedures currently used in the routine diagnosis of IA and outline the potential of AB90-E8 as a rapid diagnostic tool.

Entrapment Syndrome in a Kidney Transplant Recipient with Cryptococcal Meningitis

Cryptococcus neoformans primarily affects immunocompromised individuals and the central nervous system (CNS) is the most common site of dissemination. Entrapped temporal horn syndrome (ETH) remains a rare CNS manifestation and has not previously been described in solid organ transplant recipients. Here, we present a case of ETH in a 55-year-old woman with history of renal transplant and prior treated Cryptococcal meningitis.

Novel Approaches in the Management of Mucormycosis

Purpose of Review

Invasive mucormycosis (IM), caused by fungi of the order Mucorales, is one of the deadliest fungal infection among hematologic cancer patients. Its incidence is also increasingly reported in immunocompetent individuals, notably with the COVID-19 pandemic. Therefore, there is an urgent need for novel diagnostic and therapeutic approaches of IM. This review discusses the current advances in this field.

Recent Findings

Early diagnosis of IM is crucial and can be improved by Mucorales-specific PCR and development of lateral-flow immunoassays for specific antigen detection. The spore coat proteins (CotH) are essential for virulence of the Mucorales and may represent a target for novel antifungal therapies. Adjuvant therapies boosting the immune response, such as interferon-γ, anti-PDR1 or fungal-specific chimeric antigen receptor (CAR) T-cells, are also considered.

Summary

The most promising perspectives for improved management of IM consist of a multilayered approach targeting both the pathogen and the host immune system.

Invasive Pulmonary Aspergillosis in Coronavirus Disease 2019 Patients Lights and Shadows in the Current Landscape

Invasive pulmonary aspergillosis (IPA) presents a known risk to critically ill patients with SARS-CoV-2; quantifying the global burden of IPA in SARS-CoV-2 is extremely challenging. The true incidence of COVID-19-associated pulmonary aspergillosis (CAPA) and the impact on mortality is difficult to define because of indiscriminate clinical signs, low culture sensitivity and specificity and variability in clinical practice between centers. While positive cultures of upper airway samples are considered indicative for the diagnosis of probable CAPA, conventional microscopic examination and qualitative culture of respiratory tract samples have quite low sensitivity and specificity. Thus, the diagnosis should be confirmed with serum and BAL GM test or positive BAL culture to mitigate the risk of overdiagnosis and over-treatment. Bronchoscopy has a limited role in these patients and should only be considered when diagnosis confirmation would significantly change clinical management. Varying diagnostic performance, availability, and time-to-results turnaround time are important limitations of currently approved biomarkers and molecular assays for the diagnosis of IA. The use of CT scans for diagnostic purposes is controversial due to practical concerns and the complex character of lesions presented in SARS-CoV-2 patients. The key objective of management is to improve survival by avoiding misdiagnosis and by initiating early, targeted antifungal treatment. The main factors that should be considered upon selection of treatment options include the severity of the infection, concomitant renal or hepatic injury, possible drug interactions, requirement for therapeutic drug monitoring, and cost of therapy. The optimal duration of antifungal therapy for CAPA is still under debate.

Invasive Fungal Infections after Liver Transplantation

Invasive fungal infections represent a major challenge in patients who underwent organ transplantation. Overall, the most common fungal infections in these patients are candidiasis, followed by aspergillosis and cryptococcosis, except in lung transplant recipients, where aspergillosis is most common. Several risk factors have been identified, which increase the likelihood of an invasive fungal infection developing after transplantation. Liver transplant recipients constitute a high-risk category for invasive candidiasis and aspergillosis, and therefore targeted prophylaxis is favored in this patient population. Furthermore, a timely implemented therapy is crucial for achieving optimal outcomes in transplanted patients. In this article, we describe the epidemiology, risk factors, prophylaxis, and treatment strategies of the most common fungal infections in organ transplantation, with a focus on liver transplantation.

Aspergillus Galactomannan Titer as a Diagnostic Marker of Invasive Pulmonary Aspergillosis in Lung Transplant Recipients: A Single-Center Retrospective Cohort Study

Invasive pulmonary aspergillosis (IPA) can occur in immunocompromised patients, and an early detection and intensive treatment are crucial. We sought to determine the potential of Aspergillus galactomannan antigen titer (AGT) in serum and bronchoalveolar lavage fluid (BALF) and serum titers of beta-D-glucan (BDG) to predict IPA in lung transplantation recipients, as opposed to pneumonia unrelated to IPA. We retrospectively reviewed the medical records of 192 lung transplant recipients. Overall, 26 recipients had been diagnosed with proven IPA, 40 recipients with probable IPA, and 75 recipients with pneumonia unrelated to IPA. We analyzed AGT levels in IPA and non-IPA pneumonia patients and used ROC curves to determine the diagnostic cutoff value. The Serum AGT cutoff value was 0.560 (index level), with a sensitivity of 50%, specificity of 91%, and AUC of 0.724, and the BALF AGT cutoff value was 0.600, with a sensitivity of 85%, specificity of 85%, and AUC of 0.895. Revised EORTC suggests a diagnostic cutoff value of 1.0 in both serum and BALF AGT when IPA is highly suspicious. In our group, serum AGT of 1.0 showed a sensitivity of 27% and a specificity of 97%, and BALF AGT of 1.0 showed a sensitivity of 60% and a specificity of 95%. The result suggested that a lower cutoff could be beneficial in the lung transplant group. In multivariable analysis, serum and BALF AGT, with a minimal correlation between the two, showed a correlation with a history of diabetes mellitus.

Diagnosis and Treatment of Invasive Aspergillosis Caused by Non-fumigatus Aspergillus spp

With increasing frequency, clinical and laboratory-based mycologists are consulted on invasive fungal diseases caused by rare fungal species. This review aims to give an overview of the management of invasive aspergillosis (IA) caused by non-fumigatus Aspergillus spp.-namely A. flavus, A. terreus, A. niger and A. nidulans-including diagnostic and therapeutic differences and similarities to A. fumigatus. A. flavus is the second most common Aspergillus spp. isolated in patients with IA and the predominant species in subtropical regions. Treatment is complicated by its intrinsic resistance against amphotericin B (AmB) and high minimum inhibitory concentrations (MIC) for voriconazole. A. nidulans has been frequently isolated in patients with long-term immunosuppression, mostly in patients with primary immunodeficiencies such as chronic granulomatous disease. It has been reported to disseminate more often than other Aspergillus spp. Innate resistance against AmB has been suggested but not yet proven, while MICs seem to be elevated. A. niger is more frequently reported in less severe infections such as otomycosis. Triazoles exhibit varying MICs and are therefore not strictly recommended as first-line treatment for IA caused by A. niger, while patient outcome seems to be more favorable when compared to IA due to other Aspergillus species. A. terreus-related infections have been reported increasingly as the cause of acute and chronic aspergillosis. A recent prospective international multicenter surveillance study showed Spain, Austria, and Israel to be the countries with the highest density of A. terreus species complex isolates collected. This species complex seems to cause dissemination more often and is intrinsically resistant to AmB. Non-fumigatus aspergillosis is difficult to manage due to complex patient histories, varying infection sites and potential intrinsic resistances to antifungals. Future investigational efforts should aim at amplifying the knowledge on specific diagnostic measures and their on-site availability, as well as defining optimal treatment strategies and outcomes of non-fumigatus aspergillosis.

Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature

BACKGROUND

Cryptococcosis is an increasingly common infection given the growing immunocompromised population worldwide. Cryptococcal antigen (CrAg) testing demonstrates excellent sensitivity and specificity and is the mainstay of diagnosis. However, there may be rare instances in which false-negative CrAg results can delay diagnosis and early treatment, which are critical to ensure positive outcomes.

CASE PRESENTATION

A 31-year-old man living with HIV/AIDS who was not taking antiretroviral therapy was hospitalized with fever, diarrhea, and headaches. CD4 count on presentation was 71 cells/uL, and HIV viral load was 3,194,949 copies/mL. Serum CrAg testing was initially negative, however CSF CrAg performed several days later was positive at 1:40 and blood and CSF cultures grew Cryptococcus neoformans. Colonoscopy revealed mucosal papules throughout the sigmoid colon, and tissue biopsy showed yeast within the lamina propria consistent with GI cryptococcosis. Given the high burden of disease, the original serum CrAg specimen was serially diluted and subsequently found to be positive at 1:2,560, confirming the postzone phenomenon.

CONCLUSION

Cryptococcosis has a wide array of presentations including intraluminal GI disease, as seen in this patient. While serum CrAg testing displays excellent test characteristics, it is important for clinicians to be aware of the rare instances in which false-negative results may occur in the presence of excess antigen, as in this case.

Intestinal Mucormycosis in a Child With Maple Syrup Urine Disease After Orthotopic Liver Transplant

Mucormycosis can result in serious morbidity and mortality, especially in transplant recipients. In this case report, we present a 3-year-old female patient with maple syrup urine disease who developed mucormycosis infection after deceased donor split liver transplant. Progressive segmental necrosis of the small intestines and new ischemic areas were observed after repeated abdominal surgeries. Microscopic examination of biopsy material revealed mucormycosis. Early recognition is crucial for treatment, and patients with clinical suspicion can be treated empirically with antifungal medicine. However, diagnostic tests with accurate and fast results are needed and more effective therapeutic methods should be developed for better outcomes.

Invasive Aspergillosis and the Impact of Azole-resistance

Purpose of Review

IA (invasive aspergillosis) caused by azole-resistant strains has been associated with higher clinical burden and mortality rates. We review the current epidemiology, diagnostic, and therapeutic strategies of this clinical entity, with a special focus on patients with hematologic malignancies.

Recent Findings

There is an increase of azole resistance in Aspergillus spp. worldwide, probably due to environmental pressure and the increase of long-term azole prophylaxis and treatment in immunocompromised patients (e.g., in hematopoietic stem cell transplant recipients). The therapeutic approaches are challenging, due to multidrug-resistant strains, drug interactions, side effects, and patient-related conditions.

Summary

Rapid recognition of resistant Aspergillus spp. strains is fundamental to initiate an appropriate antifungal regimen, above all for allogeneic hematopoietic cell transplantation recipients. Clearly, more studies are needed in order to better understand the resistance mechanisms and optimize the diagnostic methods to identify Aspergillus spp. resistance to the existing antifungal agents/classes. More data on the susceptibility profile of Aspergillus spp. against the new classes of antifungal agents may allow for better treatment options and improved clinical outcomes in the coming years. In the meantime, continuous surveillance studies to monitor the prevalence of environmental and patient prevalence of azole resistance among Aspergillus spp. is absolutely crucial.

Invasive aspergillosis in liver transplant recipients

BACKGROUND

Liver transplantation is increasing worldwide with underlying pathologies dominated by metabolic and alcoholic diseases in developed countries.

METHODS

We provide a narrative review of invasive aspergillosis (IA) in liver transplant (LT) recipients. We searched PubMed and Google Scholar for references without language and time restrictions.

RESULTS

The incidence of IA in LT recipients is low (1.8%), while mortality is high (∼50%). It occurs mainly early (<3 months) after LT. Some risk factors have been identified before (corticosteroid, renal, and liver failure), during (massive transfusion and duration of surgical procedure), and after transplantation (intensive care unit stay, re-transplantation, re-operation). Diagnosis can be difficult and therefore requires full radiological and clinicobiological collaboration. Accurate identification of Aspergillus species is recommended due to the cryptic species, and susceptibility testing is crucial given the increasing resistance of Aspergillus fumigatus to azoles. It is recommended to reduce the dose of tacrolimus (50%) and to closely monitor the trough level when introducing voriconazole, isavuconazole, and posaconazole. Surgery should be discussed on a case-by-case basis. Antifungal prophylaxis is recommended in high-risk patients. Environmental preventative measures should be implemented to prevent outbreaks of nosocomial aspergillosis in LT recipient units.

CONCLUSION

IA remains a very serious disease in LT patients and should be promptly sought and, if possible, prevented by clinicians when risk factors are identified.

Dihydroorotate dehydrogenase inhibitor olorofim has potent in vitro activity against Microascus/Scopulariopsis, Rasamsonia, Penicillium and Talaromyces species

BACKGROUND

Treatment options against infections caused by rare but emerging moulds may be limited by their reduced susceptibility or resistance to clinically available antifungals. The investigational antifungal olorofim, which targets the biosynthesis of pyrimidines within fungi, has activity against different species of filamentous fungi, including Aspergillus and Scedosporium/Lomentospora prolificans isolates that are resistant to available antifungals.

OBJECTIVE

We evaluated the in vitro activity of olorofim against 160 isolates within the genera Microascus/Scopulariopsis, Penicillium, Talaromyces and the Rasamsonia argillacea species complex.

METHODS

One hundred sixty clinical isolates that had previously been identified to the species level by DNA sequence analysis were included. Antifungal susceptibility testing was performed by CLSI M38 broth microdilution for olorofim, amphotericin B, caspofungin, posaconazole and voriconazole.

RESULTS

Olorofim demonstrated in vitro activity against each of the genera tested. Overall, olorofim MICs ranged from ≤0.008 to 0.5 mg/L against all isolates tested, with MIC₉₀ and modal MIC values ranging from ≤0.008 to 0.25 mg/L and ≤0.008 to 0.03 mg/L, respectively. This activity was also maintained against individual isolates that had reduced susceptibility to or in vitro resistance against amphotericin B, posaconazole and/or voriconazole.

CONCLUSIONS

The investigational agent olorofim demonstrated good in vitro activity against clinical isolates of emerging mould pathogens, including those with reduced susceptibility or resistance to clinically available antifungals. Further studies are warranted to determine how well this in vitro activity translates into in vivo efficacy against infections caused by these fungi.

Isavuconazole for the Treatment of Invasive Mold Disease in Solid Organ Transplant Recipients: A Multicenter Study on Efficacy and Safety in Real-life Clinical Practice

BACKGROUND

Isavuconazole has theoretical advantages over other mold-active triazoles for the treatment of invasive aspergillosis and mucormycosis after solid organ transplantation (SOT). The available clinical experience, nevertheless, is scarce.

METHODS

We performed a retrospective study including all adult SOT recipients with proven or probable invasive mold disease (IMD) that received isavuconazole for ≥24 h as first-line or salvage therapy at 10 Spanish centers between September 2017 and November 2021. The primary efficacy outcome was clinical response (complete or partial resolution of attributable symptoms and findings) by weeks 6 and 12. Safety outcomes included the rates of treatment-emergent adverse events and premature isavuconazole discontinuation.

RESULTS

We included 81 SOT recipients that received isavuconazole for a median of 58.0 days because of invasive aspergillosis (n = 71) or mucormycosis (n = 10). Isavuconazole was used as first-line (72.8%) or salvage therapy due because of previous treatment-emergent toxicity (11.1%) or refractory IMD (7.4%). Combination therapy was common (37.0%), mainly with an echinocandin or liposomal amphotericin B. Clinical response by weeks 6 and 12 was achieved in 53.1% and 54.3% of patients, respectively, and was more likely when isavuconazole was administered as first-line single-agent therapy. At least 1 treatment-emergent adverse event occurred in 17.3% of patients, and 6.2% required premature discontinuation. Daily tacrolimus dose was reduced in two-thirds of patients by a median of 50.0%, although tacrolimus levels remained stable throughout the first month of therapy.

CONCLUSIONS

Isavuconazole is a safe therapeutic option for IMD in SOT recipients, with efficacy comparable to other patient groups.

Aspergillus Section Terrei and Antifungals: From Broth to Agar-Based Susceptibility Testing Methods

Providing timely antifungal treatment to patients suffering from life-threatening invasive fungal infections (IFIs) is essential. Due to the changing epidemiology and the emergence of antifungal resistance in Aspergillus, the most commonly responsible mold of IFIs, antifungal susceptibility testing (AFST) has become increasingly important to guide clinical decisions. This study assessed the essential agreement (EA) between broth microdilution methods (the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST)) and the Etest of amphotericin B (AmB), liposomal amphotericin B (L-AmB), and isavuconazole (ISA) against 112 Aspergillus section Terrei. An EA within ±2 dilutions of ≥90% between the two methods was considered acceptable. Excellent EA was found between EUCAST and CLSI of AmB and ISA (98.2% and 95.5%, respectively). The correlation of Etest results and EUCAST/CLSI was not acceptable (<90%) for any tested antifungal; however, Etest and CLSI for AmB (79.6%) and ISA (77.6%) showed a higher EA than Etest and EUCAST for AmB (49.5%) and ISA (46.4%). It was concluded that the Etest method requires its own clinical breakpoints (CBPs) and epidemiological cutoff values (ECVs), and interpreting Etest results using EUCAST and CLSI-adapted CBPs and ECVs could result in misinterpretation as Etest shows lower minimum inhibitory concentrations (MICs).

Incidence of Invasive Fungal Infections in Liver Transplant Recipients under Targeted Echinocandin Prophylaxis

Invasive fungal infections (IFIs) are one of the most important infectious complications after liver transplantation, determining morbidity and mortality. Antimycotic prophylaxis may impede IFI, but a consensus on indication, agent, or duration is still missing. Therefore, this study aimed to investigate the incidence of IFIs under targeted echinocandin antimycotic prophylaxis in adult high-risk liver transplant recipients. We retrospectively reviewed all patients undergoing a deceased donor liver transplantation at the Medical University of Innsbruck in the period from 2017 to 2020. Of 299 patients, 224 met the inclusion criteria. We defined patients as being at high risk for IFI if they had two or more prespecified risk factors and these patients received prophylaxis. In total, 85% (190/224) of the patients were correctly classified according to the developed algorithm, being able to predict an IFI with a sensitivity of 89%. Although 83% (90/109) so defined high-risk recipients received echinocandin prophylaxis, 21% (23/109) still developed an IFI. The multivariate analysis identified the age of the recipient (hazard ratio-HR = 0.97, p = 0.027), split liver transplantation (HR = 5.18, p = 0.014), massive intraoperative blood transfusion (HR = 24.08, p = 0.004), donor-derived infection (HR = 9.70, p < 0.001), and relaparotomy (HR = 4.62, p = 0.003) as variables with increased hazard ratios for an IFI within 90 days. The fungal colonization at baseline, high-urgency transplantation, posttransplant dialysis, bile leak, and early transplantation showed significance only in a univariate model. Notably, 57% (12/21) of the invasive Candida infections were caused by a non-albicans species, entailing a markedly reduced one-year survival. The attributable 90-day mortality rate of an IFI after a liver transplant was 53% (9/17). None of the patients with invasive aspergillosis survived. Despite targeted echinocandin prophylaxis, there is still a notable risk for IFI. Consequently, the prophylactic use of echinocandins must be critically questioned regarding the high rate of breakthrough infections, the increased occurrence of fluconazole-resistant pathogens, and the higher mortality rate in non-albicans Candida species. Adherence to the internal prophylaxis algorithms is of immense importance, bearing in mind the high IFI rates in case algorithms are not followed.

Pulmonary Histoplasmosis: A Clinical Update

Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. The areas of highest endemicity lie within the Mississippi and Ohio River Valleys of North America and parts of Central and South America. The most common clinical presentations include pulmonary histoplasmosis, which can resemble community-acquired pneumonia, tuberculosis, sarcoidosis, or malignancy; however, certain patients can develop mediastinal involvement or progression to disseminated disease. Understanding the epidemiology, pathology, clinical presentation, and diagnostic testing performance is pivotal for a successful diagnosis. While most immunocompetent patients with mild acute or subacute pulmonary histoplasmosis should receive therapy, all immunocompromised patients and those with chronic pulmonary disease or progressive disseminated disease should also receive therapy. Liposomal amphotericin B is the agent of choice for severe or disseminated disease, and itraconazole is recommended in milder cases or as "step-down" therapy after initial improvement with amphotericin B. In this review, we discuss the current epidemiology, pathology, diagnosis, clinical presentations, and management of pulmonary histoplasmosis.

Statin Use May Be Associated With a Lower Risk of Invasive Aspergillosis in Lung Transplant Recipients

BACKGROUND

Statins are competitive inhibitors of 3-hydroxy-3methylglutaryl coenzyme A reductase (HMG-CoA reductase) that catalyses HMG-CoA conversion to mevalonate, a process involved in synthesizing cholesterol in humans and ergosterol in fungi. The effect of statin use on the risk of development of invasive aspergillosis (IA) in lung transplant recipients (LTRs) is not well documented.

METHODS

This retrospective study included LTRs from 2010 to 2017 who were followed for one-year post-transplant. Proven or probable IA was diagnosed as per ISHLT criteria. We performed a multivariable Cox proportional hazards model of the association between IA and statin use (minimum of 2 weeks duration prior to IA), adjusting for other known IA risk factors.

RESULTS

We identified 785 LTRs, 44% female, mean age 53 years old, the most common underlying disease being pulmonary fibrosis (23.8%). In total, 451 LTRs (57%) received statins post-transplant, atorvastatin was the most commonly used statin (68%). The mean duration of statins post-transplant was 347 days (interquartile range [IQR]: 305 to 346). And 55 (7%) LTRs developed IA in the first-year post-transplant. Out of these 55 LTRs, 9 (16.3%) had received statin before developing IA. In multivariable analysis, statin use was independently associated with a lower risk of IA (P = .002, SHR 0.30, 95% confidence interval [CI] 95% .14-.64). Statin use was also associated with a lower incidence of post-transplant Aspergillus colonization, 114 (34%) in the no statin group vs 123 (27%) in the statin group (P = .038).

CONCLUSIONS

The use of statin for a minimum of two weeks during the first-year post-transplant was associated with a 70% risk reduction of IA in LTRs.

Antimicrobial stewardship in solid organ transplant-Opportunities in the National Health Service

BACKGROUND

Antimicrobial stewardship (AMS) is an intervention, which ensures the appropriateness of antimicrobial use to avoid in part the rising problem of antimicrobial resistance and negative effects of inappropriate antimicrobial use. In the solid organ transplant (SOT) population, which is prone to a particularly high risk of infection resulting from immunosuppression and anatomical issues with each type of SOT, the need for good stewardship has never been more important. This article looks at current AMS practice in SOT units in the United Kingdom and how things could be improved in the future.

METHODS

The current practice of AMS alongside national antimicrobial resistance rates were reviewed using national mandatory reporting data. The background to the current practice and policies in place in the National Health Service (NHS) were also reviewed and possibilities for future approaches explored.

RESULTS

AMS is a requirement within all NHS hospitals in the United Kingdom as per government policy. Mandatory reporting of specific bloodstream infections (BSIs) and antimicrobial consumption alongside financial incentives has been the approach nationwide. Gram-negative resistance rates in BSIs have been increasing prior to the COVID-19 pandemic. Little SOT-specific data on antimicrobial resistance exists, and the general approach to AMS in SOT units has generally modeled the national approach.

CONCLUSION

Although there is a good, standardized approach to AMS in the NHS, there is a need for SOT-specific AMS approaches to be developed in the United Kingdom. More data is required on antimicrobial resistance rates, and studies are needed to investigate optimal antimicrobial prophylaxis regimens for each solid organ group. Tools to aid AMS efforts and novel treatment options for complex multiresistant infection must also be explored amongst transplant centers.

Five-year surveillance study of clinical and environmental Triazole-Resistant Aspergillus fumigatus isolates in Iran

BACKGROUND

Invasive aspergillosis is one of the most common fungal infections and azole resistance in Aspergillus fumigatus (ARAf) is a growing medical concern in high-risk patients. To our knowledge, there is no comprehensive epidemiological surveillance study on the prevalence and incidence of ARAf isolates available in Iran.

OBJECTIVES

The study aimed to report a five-year survey of triazole phenotypes and genotype patterns concerning the resistance in clinical and environmental A. fumigatus in Iran.

METHODS

During the study time frame (2016-2021), a total of 1208 clinical and environmental Aspergillus species were collected. Isolates were examined and characterised by in vitro antifungal susceptibility testing (CLSI M38 broth microdilution) and cyp51A sequencing.

RESULTS

In total, 485 Aspergillus section Fumigati strains were recovered (clinical, n = 23; 4.74% and environment, n = 462; 95.26%). Of which A. fumigatus isolates were the most prevalent species (n = 483; 99.59%). Amphotericin B and the echinocandins demonstrated good in vitro activity against the majority of isolates in comparison to triazole. Overall, 16.15% (n = 78) of isolates were phenotypically resistant to at least one of the azoles. However, 9.73% of A. fumigatus isolates for voriconazole were classified as resistant, 89.03% were susceptible, and 1.24% were intermediate. While, for itraconazole and posaconazole, using the epidemiological cut-off value 16.15% and 6.83% of isolates were non-wild types, respectively. Remarkably, in 21.79% (n = 17) phenotypically resistant isolates, no mutations were detected within the cyp51A gene.

CONCLUSION

Although the incidence of ARAf varies from country to country, in Iran the rate has ranged from 3.3% to 18%, significantly increasing from 2013 to 2021. Strikingly, a quarter of the phenotypically resistant isolates harboured no mutations in the cyp51A gene. It seems that other mechanisms of resistance are importantly increasing. To fill a gap in our understanding of the mechanism for azole resistance in the non-cyp51A strains, we highly recommend further and more extensive monitoring of the soil with or without exposure to fungicides in agricultural and hospital areas.