Risk factors of invasive fungal infections in lung transplant recipients: A systematic review and meta-analysis

Antifungal prophylaxis against invasive Candida and Aspergillus infection in adult heart transplant recipients: protocol for a systematic review and meta-analysis

INTRODUCTION

Invasive fungal infections (IFI) can contribute to increased mortality and morbidity rates after heart transplant in adults. The most common causes are Aspergillus and Candida species. There is uncertainty on how effective antifungal prophylaxis is against Candida spp infections and limited guidance on the prevention of Aspergillus spp infections. This systematic review and meta-analysis will assess the literature to see if antifungal prophylaxis reduces the incidence of IFI after heart transplant in adults.

METHODS AND ANALYSIS

This systematic review protocol follows the Preferred Reporting Items for Systematic reviews and Meta Analysis guidelines. A systematic search of the Cochrane Library, Web of Science, Scopus, Embase, MEDLINE, and Proquest databases will be undertaken. Reference lists of retrieved publications and conference abstracts will also be searched. Title, abstract and full-text screening will be undertaken by two reviewers. Discrepancies will be resolved by a third reviewer. Studies with paediatric patients, multi-organ transplants, or patients with a second heart transplant will be excluded, along with those who do not have clear definitions and diagnostic criteria for IFI. Risk of bias will be assessed using the Cochrane Risk of Bias 2 tool and the Risk of Bias in Non-randomised Studies of Interventions tool. A meta-analysis will be carried out, but if studies are not deemed to be sufficiently similar, only a narrative synthesis will be undertaken.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review as primary data will not be collected. The results of the review will be disseminated through publication in an academic journal and scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42024516588.

The epidemiology of invasive fungal infections in transplant recipients

Transplant patients, including solid-organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, are exposed to various types of complications, particularly rejection. To prevent these outcomes, transplant recipients commonly receive long-term immunosuppressive regimens that in turn make them more susceptible to a wide array of infectious diseases, notably those caused by opportunistic pathogens. Among these, invasive fungal infections (IFIs) remain a major cause of mortality and morbidity in both SOT and HSCT recipients. Despite the continuing improvement in early diagnostics and treatments of IFIs, the management of these infections in transplant patients is still complicated. Here, we provide an overview concerning the most recent trends in the epidemiology of IFIs in SOT and HSCT recipients by describing the prominent yeast and mold species involved, the timing of post-transplant IFIs and the risk factors associated with their occurrence in these particularly weak populations. We also give special emphasis into basic research advances in the field that recently suggested a role of the global and long-term prophylactic regimen in orchestrating various biological disturbances in the organism and conditioning the emergence of the most adapted fungal strains to the particular physiological profiles of transplant patients.

A novel approach to reducing hepatotoxicity related to fungal prophylaxis in pediatric lung transplant recipients

BACKGROUND

Pediatric lung transplant patients are at risk for developing invasive fungal infections post-transplant. No consensus exists on optimal antifungal regimens and voriconazole, a common first-line agent, has been shown to cause hepatotoxicity. We describe a single-center experience utilizing a novel antifungal regimen of intravenous micafungin and nebulized amphotericin B immediately post-transplant with conversion to an azole at the time of hospital discharge and compare it to a historical cohort of patients who received voriconazole monotherapy throughout their immediate post-operative course.

METHODS

This is a retrospective review of patients in the age 0-18 who received a lung transplant from June 2016-May 2021. Data points collected included: demographic data, transplant date and discharge date, Aspergillus colonization, type of lung transplant, hospitalization and level of care information, induction and antifungal medication regimen; AST, ALT, GGT, bilirubin, and direct bilirubin at various timepoints; and respiratory and blood culture results. The two patient groups were compared by assessment of changes in LFTs and culture results.

RESULTS

Forty-two patients were included in the analysis, with 24 patients receiving micafungin and nebulized amphotericin and 18 patients receiving voriconazole. All patients in both groups experienced a post-operative elevation in at least one transaminase or bilirubin. More patients in the micafungin/amphotericin group had resolution of all abnormal LFTs by 1 month post-transplant (p = .036). Additionally, patients in the micafungin/amphotericin group experienced faster normalization of their LFTs compared with the voriconazole group (p < .001). Ten patients in the micafungin/amphotericin group and five patients in the voriconazole group were found to have fungal growth on culture post-transplant, but this difference was not found to be statistically significant (p = .507).

CONCLUSIONS

An antifungal regimen of micafungin and nebulized amphotericin B liposomal may be useful at decreasing the duration of elevated liver enzymes in pediatric patients in the immediate post-lung transplant period when compared with voriconazole monotherapy. Larger prospective studies looking at antifungal regimens in pediatric patients post-lung transplant are warranted.

Risk Factors for Early Fungal Disease in Solid Organ Transplant Recipients: A Systematic Review and Meta-analysis

BACKGROUND

Invasive fungal infections are associated with high morbidity in solid organ transplant recipients. Risk factor modification may help with preventative efforts. The objective of this study was to identify risk factors for the development of fungal infections within the first year following solid organ transplant.

METHODS

We searched for eligible articles through February 3, 2023. Studies published after January 1, 2001, that pertained to risk factors for development of invasive fungal infections in solid organ transplant were reviewed for inclusion. Of 3087 articles screened, 58 were included. Meta-analysis was conducted using a random-effects model to evaluate individual risk factors for the primary outcome of any invasive fungal infections and invasive candidiasis or invasive aspergillosis (when possible) within 1 y posttransplant.

RESULTS

We found 3 variables with a high certainty of evidence and strong associations (relative effect estimate ≥ 2) to any early invasive fungal infections across all solid organ transplant groups: reoperation (odds ratio [OR], 2.92; confidence interval [CI], 1.79-4.75), posttransplant renal replacement therapy (OR, 2.91; CI, 1.87-4.51), and cytomegalovirus disease (OR, 2.97; CI, 1.78-4.94). Both posttransplant renal replacement therapy (OR, 3.36; CI, 1.78-6.34) and posttransplant cytomegalovirus disease (OR, 2.81; CI, 1.47-5.36) increased the odds of early posttransplant invasive aspergillosis. No individual variables could be pooled across groups for invasive candidiasis.

CONCLUSIONS

Several common risk factors exist for the development of any invasive fungal infections in solid organ transplant recipients. Additional risk factors for invasive candidiasis and aspergillosis may be unique to the pathogen, transplanted organ, or both.

ERS International Congress 2023: highlights from the Thoracic Surgery and Lung Transplantation Assembly

Five sessions presented at the European Respiratory Society Congress 2023 were selected by Assembly 8, consisting of thoracic surgeons and lung transplant professionals. Highlights covering management of adult spontaneous pneumothorax, malignant pleural effusion, infectious and immune-mediated complications after lung transplantation, as well as the pro and con debate on age limit in lung transplantation and results of the ScanCLAD study were summarised by early career members, supervised by the assembly faculty.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Risk Factors for Invasive Fungal Infection in Lung Transplant Recipients on Universal Antifungal Prophylaxis

Background

Many centers use universal antifungal prophylaxis after lung transplant, but risk factors for invasive fungal infection (IFI) in this setting are poorly described.

Methods

This retrospective, single-center cohort study including 603 lung transplant recipients assessed risk factors for early (within 90 days of transplant) invasive candidiasis (IC) and invasive mold infection (IMI) and late (90-365 days after transplant) IMI using Cox proportional hazard regression.

Results

In this cohort, 159 (26.4%) patients had 182 IFIs. Growth of yeast on donor culture (hazard ratio [HR], 3.30; 95% CI, 1.89-5.75) and prolonged length of stay (HR, 1.02; 95% CI, 1.01-1.03) were associated with early IC risk, whereas transplantation in 2016 or 2017 (HR, 0.21; 95% CI, 0.06-0.70; HR, 0.25; 95% CI, 0.08-0.80, respectively) and female recipient sex (HR, 0.53; 95% CI, 0.30-0.93) were associated with reduced risk. Antimold therapy (HR, 0.21; 95% CI, 0.06-0.78) was associated with lower early IMI risk, and female donor sex (HR, 0.40; 95% CI, 0.22-0.72) was associated with lower late IMI risk. Recent rejection was a risk factor for late IMI (HR, 1.73; 95% CI, 1.02-2.95), and renal replacement therapy predisposed to early IC, early IMI, and late IMI (HR, 5.67; 95% CI, 3.01-10.67; HR, 7.54; 95% CI, 1.93-29.45; HR, 5.33; 95% CI, 1.46-19.49, respectively).

Conclusions

In lung transplant recipients receiving universal antifungal prophylaxis, risk factors for early IC, early IMI, and late IMI differ.

Population pharmacokinetics and covariate-based dosing individualization of voriconazole in lung transplant recipients

This study aimed to explore pharmacokinetics of voriconazole and its covariates in lung transplant recipients using population approach in order to propose dosing individualization. Data from routine therapeutic drug monitoring in adult lung transplant recipients treated with oral voriconazole were analysed with a three-stage population pharmacokinetic model using nonlinear mixed-effects modelling. Monte Carlo simulations based on final voriconazole pharmacokinetic model were used to generate the theoretical distribution of pharmacokinetic profiles at various dosing regimens. A total of 78 voriconazole serum concentrations collected from 40 patients were included in pharmacokinetic analysis. The only significant covariate was age for voriconazole clearance. Population voriconazole apparent clearance started at 32.26 L/h and decreased by 0.021 L/h with each year of patient's age, while population apparent volume of distribution was 964.46 L. Based on this model, we have proposed an easy-to-use dosing regimen consisting of a loading dose of 400 mg every 12 h for the first 48 h of treatment followed by maintenance dose of 300 mg every 12 h in patients aged up to 59 years, or by maintenance dose of 200 mg every 12 h in patients aged above 59 years.

Prevention and Management of Infections in Lung Transplant Recipients

Anti-rejection medications are essential in preventing organ rejection amongst solid organ transplant recipients; however, these agents also cause profound immunosuppression, predisposing lung transplant recipients (LTRs) to infectious complications. The timely management including prevention, diagnosis, and treatment of such infectious complications is vital to prevent significant morbidity and mortality in solid organ transplant recipients and allograft dysfunction. LTRs are inundated with microbes that may be recognized as commensals in hosts with intact immune systems. Bacterial infections are the most common ones, followed by viral pathogens. Indications of a brewing infectious process may be subtle. Hence, the importance of adapting vigilance around isolated hints through symptomatology and signs is pivotal. Signals to suggest an infectious process, such as fever and leukocytosis, may be dampened by immunosuppressive agents. One must also be vigilant about drug interactions of antibiotics and immunosuppressive agents. Treatment of infections can become challenging, as antimicrobials can interact with immunosuppressive agents, and antimicrobial resistance can surge under antimicrobial pressure. Transplant infectious disease physicians work in concert with transplant teams to obtain specimens for diagnostic testing and follow through with source control when possible. This heavily impacts medical decisions and fosters a multidisciplinary approach in management. Furthermore, the reduction of immunosuppression, although it augments the risk of allograft rejection, is as crucial as the initiation of appropriate antimicrobials when it comes to the management of infections.

Associations between invasive aspergillosis and cytomegalovirus in lung transplant recipients: a nationwide cohort study

Cytomegalovirus (CMV) and invasive aspergillosis (IA) cause morbidity among lung transplant recipients (LTXr). Early diagnosis and treatment could improve outcomes. We examined rates of CMV after IA and vice versa to assess whether screening for one infection is warranted after detecting the other. All Danish LTXr, 2010-2019, were followed for IA and CMV for 2 years after transplantation. IA was defined using ISHLT criteria. Adjusted incidence rate ratios (aIRR) were estimated by Poisson regression adjusted for time after transplantation. We included 295 LTXr, among whom CMV and IA were diagnosed in 128 (43%) and 48 (16%). The risk of CMV was high the first 3 months after IA, IR 98/100 person-years of follow-up (95% CI 47-206). The risk of IA was significantly increased in the first 3 months after CMV, aIRR 2.91 (95% CI 1.32-6.44). Numbers needed to screen to diagnose one case of CMV after IA, and one case of IA after CMV was approximately seven and eight, respectively. Systematic screening for CMV following diagnosis of IA, and vice versa, may improve timeliness of diagnosis and outcomes for LTXr.

Necrotising pneumonia caused by Curvularia hawaiiensis (syn. Bipolaris hawaiiensis) and Mycobacterium tuberculosis coinfection in a patient with ascariasis: a case report and review

INTRODUCTION

Curvularia hawaiiensis (formerly Bipolaris hawaiiensis) is a plant pathogen often isolated from soil and vegetative material. However, only a few cases of opportunistic invasive infections in humans have been described.

CASE

A 16-year-old female patient without comorbidities was admitted to the emergency department because of fever and chest pain. We described the first coinfection of Curvularia hawaiiensis and Mycobacterium tuberculosis necrotising pneumonia.

DISCUSSION

Multiple infections can alter immune responses. However, immunosuppression is the most critical risk factor for infection with species of the genus Curvularia. Therefore, it is crucial to carefully examine patients with tuberculosis, as they may rarely be coinfected with unusual fungi.

Diagnosis and Treatment of Fungal Infections in Lung Transplant Recipients

Fungal infections are a significant source of morbidity in the lung transplant population via direct allograft damage and predisposing patients to the development of chronic lung allograft dysfunction. Prompt diagnosis and treatment are imperative to limit allograft damage. This review article discusses incidence, risk factors, and symptoms with a specific focus on diagnostic and treatment strategies in the lung transplant population for fungal infections caused by Aspergillus, Candida, Coccidioides, Histoplasma, Blastomyces, Scedosporium/Lomentospora, Fusarium, and Pneumocystis jirovecii. Evidence for the use of newer triazole and inhaled antifungals to treat isolated pulmonary fungal infections in lung transplant recipients is also discussed.

Approach to the diagnosis of invasive fungal infections of the respiratory tract in the immunocompromised host

PURPOSE OF REVIEW

The burden of invasive fungal infection is increasing worldwide, largely due to a growing population at-risk. Most serious human fungal pathogens enter the host via the respiratory tract. Early identification and treatment of invasive fungal respiratory infections (IFRIs) in the immunocompromised host saves lives. However, their accurate diagnosis is a difficult challenge for clinicians and mortality remains high.

RECENT FINDINGS

This article reviews IFRIs, focussing on host susceptibility factors, clinical presentation, and mycological diagnosis. Several new diagnostic tools are coming of age including molecular diagnostics and point-of-care antigen tests. As diagnosis of IFRI relies heavily on invasive procedures like bronchoalveolar lavage and lung biopsy, several novel noninvasive diagnostic techniques are in development, such as metagenomics, 'volatilomics' and advanced imaging technologies.

SUMMARY

Where IFRI cannot be proven, clinicians must employ a 'weights-of-evidence' approach to evaluate host factors, clinical and mycological data. Implementation studies are needed to understand how new diagnostic tools can be best applied within clinical pathways. Differentiating invasive infection from colonization and identifying antifungal resistance remain key challenges. As our diagnostic arsenal expands, centralized clinical mycology laboratories and efforts to ensure access to new diagnostics in low-resource settings will become increasingly important.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Adverse Events Associated with Universal versus Targeted Antifungal Prophylaxis among Lung Transplant Recipients-A Nationwide Cohort Study 2010-2019

Background: Invasive fungal infections in lung transplant (LTX) recipients cause substantial morbidity, but the best strategy for prevention has not yet been determined. We evaluated adherence to and rates of adverse events of universal versus targeted prophylaxis. Methods: All LTX recipients in the Danish National LTX Centre (2010−2019) were included. Before July 2016, universal voriconazole prophylaxis was used. After July 2016, only high-risk patients received targeted prophylaxis with posaconazole and inhaled amphotericin B. Proportions of triazole discontinuation, side-effects, off-target calcineurin-inhibitor (CNI) levels, and acute rejection were compared between the two periods. Results: Universal and targeted prophylaxis was initiated in 183/193 and 6/102 patients, respectively. Only 37% completed > 9 of the intended 12 weeks of voriconazole; 72% of discontinuations were due to hepatotoxicity. In the universal vs. targeted prophylaxis period, 89% vs. 72% (p < 0.001) patients had low CNI episodes, and 37% vs. 1% (p < 0.001) of these were associated with discontinuation of triazole; 40% vs. 14% (p < 0.001) had acute rejection; and 23% vs. 3% (p < 0.001) had acute rejection associated with low CNI episodes. Conclusions: Universal voriconazole prophylaxis was associated with high rates of discontinuation, mainly caused by hepatotoxicity. In comparison to the targeted posaconazole period, more patients had low CNI levels and acute rejection in the universal voriconazole period.

Japonamides A and B, Two New Cyclohexadepsipeptides from the Marine-Sponge-Derived Fungus Aspergillus japonicus and Their Synergistic Antifungal Activities

Two new cyclohexadepsipeptides japonamides A (1) and B (2) were isolated from the ethyl acetate extract of a marine-sponge-derived fungus Aspergillus japonicus based on molecular networking. Their structures were elucidated by comprehensive spectral analysis and their absolute configurations were confirmed by Marfey's method. Compounds 1 and 2 showed no antifungal activities against Candida albicans SC5314 measured by the broth microdilution method but exhibited prominent synergistic antifungal activities in combination with fluconazole, ketoconazole, or rapamycin. The Minimum inhibitory concentrations (MICs) of rapamycin, fluconazole, and ketoconazole were significantly decreased from 0.5 to 0.002 μM, from 0.25 to 0.063 μM, and from 0.016 to 0.002 μM, in the presence of compounds 1 or 2 at 3.125 μM, 12.5 μM, and 6.25 μM, respectively. Surprisingly, the combination of compounds 1 or 2 with rapamycin showed a strong synergistic effect, with fractional inhibitory concentration index (FICI) values of 0.03.

Multiresistant organisms: bacteria and beyond

PURPOSE OF REVIEW

Infections with multiresistant organisms are an emerging problem, cause early mortality post lung transplantation and are sometimes associated with graft dysfunction. Frequently they raise questions about the selection of lung transplant candidates and therapeutic management post lung transplantation. There are no guidelines and management must be individualized. This review summarizes the available therapeutic options in cases of multidrug-resistant (MDR) organisms and outcomes after lung transplant.

RECENT FINDINGS

Improvements in diagnosis, new and more effective drugs and the experience gained in the management of these infections in lung transplantation, lead to a more optimistic horizon than that found a decade ago.

SUMMARY

Update on the management of Burkholderia cepacia complex, Mycobacterium abscessus complex, Aspergillus spp., Scedosporium spp. and Lomentospora prolificans infections. This review clarifies current posttransplant outcomes and adds a little hope in these scenarios.