A strategy for prevention of fungal infections in lung transplantation: Role of bronchoalveolar lavage fluid galactomannan and fungal culture

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.

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.

Multi-Locus Microsatellite Typing of Colonising and Invasive Aspergillus fumigatus Isolates from Patients Post Lung Transplantation and with Chronic Lung Disease

Aspergillus fumigatus can cause different clinical manifestations/phenotypes in lung transplant (LTx) recipients and patients with chronic respiratory diseases. It can also precipitate chronic lung allograft dysfunction (CLAD) in LTx recipients. Many host factors have been linked with the severity of A. fumigatus infection, but little is known about the contribution of different A. fumigatus strains to the development of different phenotypes and CLAD. We used multi-locus microsatellite typing (MLMT) to determine if there is a relationship between strain (i.e., genotype) and phenotype in 60 patients post LTx or with chronic respiratory disease across two time periods (1 November 2006-31 March 2009 and 1 November 2015-30 June 2017). The MLMT (STRAf) assay was highly discriminatory (Simpson's diversity index of 0.9819-0.9942) with no dominant strain detected. No specific genotype-phenotype link was detected, but several clusters and related strains were associated with invasive aspergillosis (IA) and colonisation in the absence of CLAD. Host factors were linked to clinical phenotypes, with prior lymphopenia significantly more common in IA cases as compared with A. fumigatus-colonised patients (12/16 [75%] vs. 13/36 [36.1%]; p = 0.01), and prior Staphylococcus aureus infection was a significant risk factor for the development of IA (odds ratio 13.8; 95% confidence interval [2.01-279.23]). A trend toward a greater incidence of CMV reactivation post-A. fumigatus isolation was observed (0 vs. 5; p = 0.06) in LTx recipients. Further research is required to determine the pathogenicity and immunogenicity of specific A. fumigatus strains.

Update on therapeutic approaches for invasive fungal infections in adults

Invasive fungal infections are increasingly encountered with the expansion of iatrogenic immunosuppression, including not only solid organ and hematopoietic stem cell transplant recipients but also patients with malignancies or autoimmune diseases receiving immunomodulatory therapies, such as Bruton Tyrosine Kinase (BTK) inhibitor. Their attributable mortality remains elevated, part of which is a contribution from globally emerging resistance in both molds and yeasts. Because antifungal susceptibility test results are often unavailable or delayed, empiric and tailored antifungal approaches including choice of agent(s) and use of combination therapy are heterogeneous and often based on clinician experience with knowledge of host's net state of immunosuppression, prior antifungal exposure, antifungal side effects and interaction profile, clinical severity of disease including site(s) of infection and local resistance data. In this review, we aim to summarize previous recommendations and most recent literature on treatment of invasive mold and yeast infections in adults to guide optimal evidence-based therapeutic approaches. We review the recent data that support use of available antifungal agents, including the different triazoles that have now been studied in comparison to previously preferred agents. We discuss management of complex infections with specific emerging fungi such as Scedosporium spp., Fusarium spp., Trichosporon asahii, and Candida auris. We briefly explore newer antifungal agents or formulations that are now being investigated to overcome therapeutic pitfalls, including but not limited to olorofim, rezafungin, fosmanogepix, and encochleated Amphotericin B. We discuss the role of surgical resection or debridement, duration of treatment, follow-up modalities, and need for secondary prophylaxis, all of which remain challenging, especially in patients chronically immunocompromised or awaiting more immunosuppressive therapies.

Antimicrobial Stewardship in Immunocompromised Patients: Current State and Future Opportunities

Immunocompromised (IC) patients are high risk for complications due to a high rate of antibiotic exposure. Antimicrobial stewardship interventions targeted to IC patients can be challenging due to limited data in this population and a high risk of severe infection-related outcomes. Here, the authors review immunocompromised antimicrobial stewardship barriers, metrics, and opportunities for antimicrobial use and testing optimization. Last, the authors highlight future steps in the field.

Systematic fungal biomarker or polymerase chain reaction testing in lung transplant recipients: Retrospective analysis to optimize their use

BACKGROUND

Among lung transplant recipients, serial bronchoscopies are performed frequently. Often, serial galactomannan (GM), 1,3-β-d-glucan (BDG), and Pneumocystis jirovecii (PJ) testing is performed with these broncho-alveolar lavages (BALs) as standard of care with limited data to support their routine use.

METHODS

After Institutional Review Board approval, we retrospectively collected all blood and BAL GM, BDG, and PJ test results from January 2015 to July 20, 2022. Primary data collection from the Northwestern Medicine EDW was supplemented by manual chart review.

RESULTS

During the study period, 236 lung transplant recipients were cared for by our center. Of these patients, 217 (91.9%) had 1418 GM tests performed; 61 (4.3%) were positive (index ≥1). Fungal cultures were requested for most BAL-GM (90.7%). Out of duplicates in same BAL, results discrepancy was minimal (3.4%). 172 (72.9%) had BDG tests were performed; 25.6% were positive. Thirteen patients had multiple BDG during one hospitalization (mean 2.3 tests); none of the negative test repeated became positive. Eleven negative BDG were seen in patients with invasive aspergillosis (IA). Note that, 577 PJ testing were performed (direct fluorescent antibody [n = 494] or polymerase chain reaction [PCR] [n = 80], or both [n = 3]) in 174 different patients. None were positive.

CONCLUSION

Despite supplemental GM, BDG, and Pneumocystis jirovecii pneumonia PCR being performed routinely on lung transplant recipients undergoing BAL at our center, the data suggests a more tailored approach may be appropriate. There is no role for routine serial testing with these assays during a single hospitalization. BDG confers no added-value over GM with cultures for IA diagnosis.

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.

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.

Invasive Pulmonary Aspergillosis

Invasive pulmonary aspergillosis is growing in incidence, as patients at risk are growing in diversity. Outside the classical context of neutropenia, new risk factors are emerging or newly identified, such as new anticancer drugs, viral pneumonias and hepatic dysfunctions. Clinical signs remain unspecific in these populations and the diagnostic work-up has considerably expanded. Computed tomography is key to assess the pulmonary lesions of aspergillosis, whose various features must be acknowledged. Positron-emission tomography can bring additional information for diagnosis and follow-up. The mycological argument for diagnosis is rarely fully conclusive, as biopsy from a sterile site is challenging in most clinical contexts. In patients with a risk and suggestive radiological findings, probable invasive aspergillosis is diagnosed through blood and bronchoalveolar lavage fluid samples by detecting galactomannan or DNA, or by direct microscopy and culture for the latter. Diagnosis is considered possible with mold infection in lack of mycological criterion. Nevertheless, the therapeutic decision should not be hindered by these research-oriented categories, that have been completed by better adapted ones in specific settings. Survival has been improved over the past decades with the development of relevant antifungals, including lipid formulations of amphotericin B and new azoles. New antifungals, including first-in-class molecules, are awaited.

Antimicrobial stewardship in solid organ transplant recipients: Current challenges and proposed metrics

BACKGROUND

Solid organ transplant (SOT) recipients are challenging populations for antimicrobial stewardship interventions due to a variety of reasons, including immunosuppression, consequent risk of opportunistic and donor-derived infections, high rates of infection with multi-drug resistant organisms (MDROs), Clostridioides difficile, and need for prolonged antimicrobial prophylaxis. Despite this, data on stewardship interventions and metrics that address the distinct needs of these patients are limited.

METHODS

We performed a narrative review of the current state of antimicrobial stewardship in SOT recipients, existing interventions and metrics in this population, and considerations for implementation of transplant-specific stewardship programs.

RESULTS

Antimicrobial stewardship metrics are evolving even in the general patient population. Data on metrics applicable to the SOT population are even more limited. Standard process, outcomes, and balancing metrics may not always apply to the SOT population. A successful stewardship program for SOT recipients requires reviewing existing data, applying general stewardship principles, and understanding the nuances of SOT patients.

CONCLUSION

As antimicrobial stewardship interventions are being implemented in SOT recipients; new metrics are needed to assess their impact. In conclusion, SOT patients present a challenging but important opportunity for antimicrobial stewards.

ABBREVIATIONS

SOT, antimicrobial stewardship program, MDRO, Clostridioides difficile infection, Centers for Disease Control and Prevention, Infectious Diseases Society of America, prospective audit and feedback, hematopoietic cell transplant, cytomegalovirus, trimethoprim-sulfamethoxazole, surgical site infections, nucleic acid amplification testing, days of therapy, defined daily dose, and length of stay.

Antifungal prophylactic effectiveness and intrapulmonary concentrations of voriconazole versus posaconazole in lung transplant recipients

Invasive fungal diseases (IFDs) are one of the leading causes of death in lung transplant recipients. This study aimed to compare the antifungal prophylactic effectiveness, intrapulmonary and plasma levels of voriconazole with posaconazole in lung transplant recipients. This retrospective cohort study analyzed adult recipients who underwent lung transplantation between June 2017 and December 2020. Voriconazole oral tablets or posaconazole oral suspension were used for prophylaxis against posttransplant IFD. Drug concentrations in bronchoalveolar lavage fluid (BALF) and plasma were measured by using liquid chromatography-mass spectrometry. The 182 recipients included 142 in the voriconazole group and 40 in the posaconazole group. The trough plasma levels were comparable between voriconazole and posaconazole (1.65 ± 0.09 vs. 1.69 ± 0.03 μg/ml, p = 0.55). However, the BALF levels were significantly higher for posaconazole than voriconazole (17.47 ± 11.51 vs. 0.56 ± 0.49 μg/ml, p < 0.001). There was no significant difference in the total incidence of breakthrough IFDs between the voriconazole and posaconazole groups (10.6% vs. 7.5%, p = 0.77). The intrapulmonary concentrations of posaconazole were significantly higher than voriconazole. The two agents had comparable antifungal prophylactic effectiveness.

Antifungal prophylaxis in adult lung transplant recipients: Uncertainty despite 30 years of experience. A systematic review of the literature and network meta-analysis

BACKGROUND

Invasive fungal infections (IFI), particularly invasive aspergillosis (IA), cause significant morbidity and mortality in lung transplant (LTx) recipients. The optimum strategy and antifungal agents for prevention are unclear.

METHODS

We performed a comprehensive literature search, systematic review, and network meta-analysis using a frequentist framework to compare the efficacy of various antifungal drugs on the incidence of IA/IFI in the setting of universal prophylaxis or no prophylaxis following lung transplantation.

RESULTS

We included 13 eligible studies comprising of 1515 LTx recipients and 12 different prophylaxis strategies/antifungal combinations. The greatest number of direct comparisons were between the inhaled amphotericin formulations. The top three ranked treatments were inhaled liposomal amphotericin B (L-AmB), inhaled amphotericin deoxycholate (AmBd), and itraconazole plus inhaled amphotericin B (AmB). Among the azoles, isavuconazole ranked highest. The certainty of the evidence, assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework, was very low.

CONCLUSION

Although universal antifungal prophylaxis post lung transplantation is commonly used, robust data from randomized controlled trials (RCTs) to inform the choice of antifungal agent and prophylaxis strategy are lacking. This exploratory network meta-analysis provides insight into the probable relative effectiveness of various antifungal agents in preventing IA, and this analysis should serve as a guide when selecting antifungals to be assessed in a RCT.

Epidemiology of Candidemia in Lung Transplant Recipients and Risk Factors for Candidemia in the Early Post-Transplant Period in the Absence of Universal Antifungal Prophylaxis

BACKGROUND

Lung transplant recipients are at increased risk of candidemia, especially in the early post-transplant period. However, the specific predisposing factors have not been established. The natural history of candidemia post-lung transplantation, in the absence of universal antifungal prophylaxis, is not known.

METHODS

We retrospectively examined the epidemiology of candidemia at any time post-transplant in patients who underwent lung transplantation at our centre between 2016 and 2019. We undertook a case-control study and used logistic regression to evaluate the risk factors for candidemia during the first 30 days post transplantation.

RESULTS

During the study period 712 lung transplants were performed on 705 patients. Twenty-five lung transplant recipients (LTRs) (3.5%) experienced 31 episodes of candidemia. The median time to candidemia was 19.5 days (IQR 10.5-70.5), with 61.2% (n = 19) episodes of candidemia occurring within the first 30 days post-transplantation. Pre-transplant hospitalization, post-transplant ECMO and post-transplant renal replacement therapy were associated with an increased risk of candidemia in the first 30 days post-transplant. Of those with candidemia in the first 30 days, 31.2% died within 30 days of the index positive blood culture. Candidemia was associated with decreased survival within 30 days post-transplant.

CONCLUSION

This study highlights the greatest risk period of lung transplant recipients for development of candidemia and identifies several factors associated with increased risk of candidemia. These findings will help guide future studies on antifungal prophylaxis. This article is protected by copyright. All rights reserved.

Phase IV clinical trial with a single treatment arm to evaluate bronchopulmonary penetration of isavuconazole in pulmonary transplant recipients (PBISA01): Study protocol clinical trial. (Preprint)

Background

Aspergillosis is the most frequently observed invasive fungal disease (IFD) in lung transplant recipients. Isavuconazole (ISA) has shown a better safety profile and noninferiority to voriconazole in the treatment of patients with IFD.

Objective

The aim of this study is to describe the bronchopulmonary pharmacokinetic profile of oral ISA by analyzing the degree of penetration in the epithelial lining fluid and alveolar macrophages in patients receiving lung transplantation with a diagnosis of IFD.

Methods

A total of 12 patients aged ≥18 years receiving a lung transplant with an IFD diagnosis and indication for ISA treatment and follow-up bronchoscopy will be included in the study. After 5 days of treatment with ISA and before the treatment is discontinued, the patients will be randomized (1:1:1:1) to perform the scheduled bronchoscopy at various times after the administration of ISA (2, 4, 8, and 12 hours). In total, 4 blood samples will be obtained per patient: at 72 hours after treatment initiation, on the day of the bronchoscopy, at the time of the bronchoalveolar lavage (simultaneously), and at 7 days after treatment initiation, to analyze tacrolimus and ISA plasma levels. ISA concentrations will be measured in plasma, epithelial lining fluid, and alveolar macrophages by a high-performance liquid chromatography/UV coupled to fluorescence method.

Results

Enrollment for the PBISA01 trial began in October 2020 and was completed in October 2021. All samples will be analyzed once recruitment is complete, and the results are expected to be published in October 2022.

Conclusions

There are no clinical studies that analyze the bronchopulmonary penetration of ISA. Bronchoalveolar lavage performed routinely in the follow-up of lung transplant recipients constitutes an opportunity to analyze the bronchopulmonary penetration of ISA.

Trial Registration

European Clinical Trials Register 2019-004240-30; www.clinicaltrialsregister.eu/ctr-search/trial/2019-004240-30/ES

International Registered Report Identifier (IRRID)

DERR1-10.2196/37275

Fungal infections in lung transplantation

Lung transplant is a potential life-saving procedure for chronic lung diseases. Lung transplant recipients (LTRs) are at the greatest risk for invasive fungal infections (IFIs) among solid organ transplant (SOT) recipients because the allograft is directly exposed to fungi in the environment, airway and lung host defenses are impaired, and immunosuppressive regimens are particularly intense. IFIs occur within a year of transplant in 3-19% of LTRs, and they are associated with high mortality, prolonged hospital stays, and excess healthcare costs. The most common causes of post-LT IFIs are Aspergillus and Candida spp.; less common pathogens are Mucorales, other non-Aspergillus moulds, Cryptococcus neoformans, Pneumocystis jirovecii, and endemic mycoses. The majority of IFIs occur in the first year following transplant, although later onset is observed with prolonged antifungal prophylaxis. The most common manifestations of invasive mould infections (IMIs) include tracheobronchial (particularly at anastomotic sites), pulmonary and disseminated infections. The mortality rate of tracheobronchitis is typically low, but local complications such as bronchomalacia, stenosis and dehiscence may occur. Mortality rates associated with lung and disseminated infections can exceed 40% and 80%, respectively. IMI risk factors include mould colonization, single lung transplant and augmented immunosuppression. Candidiasis is less common than mould infections, and manifests as bloodstream or other non-pulmonary invasive candidiasis; tracheobronchial infections are encountered uncommonly. Risk factors for and outcomes of candidiasis are similar to those of non lung transplant recipients. There is evidence that IFIs and fungal colonization are risk factors for allograft failure due to chronic rejection. Mould-active azoles are frontline agents for treatment of IMIs, with local debridement as needed for tracheobronchial disease. Echinocandins and azoles are treatments for invasive candidiasis, in keeping with guidelines in other patient populations. Antifungal prophylaxis is commonly administered, but benefits and optimal regimens are not defined. Universal mould-active azole prophylaxis is used most often. Other approaches include targeted prophylaxis of high-risk LTRs or pre-emptive therapy based on culture or galactomannan (GM) (or other biomarker) results. Prophylaxis trials are needed, but difficult to perform due to heterogeneity in local epidemiology of IFIs and standard LT practices. The key to devising rational strategies for preventing IFIs is to understand local epidemiology in context of institutional clinical practices.

Management of Multidrug Resistant Infections in Lung Transplant Recipients with Cystic Fibrosis

Cystic fibrosis (CF) is an inherited multisystem disease characterised by bronchiectasis and chronic respiratory infections which eventually cause end stage lung disease. Lung transplantation (LTx) is a well-established treatment option for patients with CF-associated lung disease, improving survival and quality of life. Navigating recurrent infections in the setting of LTx is often difficult, where immune suppression must be balanced against the constant threat of infection. Sepsis/infections are one of the major contributors to post-LTx mortality and multiresistant organisms (eg, Burkholderia cepacia complex, Mycobacterium abscessus complex, Scedosporium spp. and Lomentospora spp.) pose a significant threat to survival. This review will summarize current and novel therapies to assist with the management of multiresistant bacterial, mycobacterial, viral and fungal infections which threaten the CF LTx cohort.

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

BACKGROUND

Invasive fungal infection (IFI) remains a common complication after lung transplantation, causing significant morbidity and mortality. We have attempted to quantify systematically risk factors of IFI in lung transplant recipients.

METHODS

Studies were retrieved from Ovid MEDLINE, Ovid Embase, Cochrane database of systematic reviews and Cochrane central register of controlled trials. All case-control and cohort studies evaluating the risk factors of IFI in adult lung transplant recipients were screened. Two researchers reviewed and assessed all studies independently. We pooled the estimated effect of each factor associated with IFI by using a random effect model.

RESULTS

Eight studies were included in the systematic review and 5 studies were eligible for the meta-analysis. Rates of IFI range from 8% to 33% in lung transplant recipients. Independent risk factors for invasive aspergillosis (IA) in lung transplantation include previous fungal colonization (odds ratio [OR] 2.44; 95% confidence interval [CI] 0.08-0.47), cytomegalovirus infection (OR 1.96; 95% CI 1.08-3.56), and single lung transplantation (OR 1.77; 95% CI 1.08-2.91). Pre-emptive antifungal therapy is a protective factor for IA in lung transplant (OR 0.2; 95% CI 0.08-0.47).

CONCLUSION

Cytomegalovirus infection, previous fungal colonization and single lung transplantation independently increase the risk of IA in lung transplant recipients. Pre-emptive antifungal therapy is a protective factor for IA in the lung transplant population.

The time is now: antimicrobial stewardship in solid organ transplantation

PURPOSE OF REVIEW

To provide a summary of complications of antimicrobials and opportunities for antimicrobial stewardship (AS) in solid organ transplant (SOT) patient care.

RECENT FINDINGS

Personalized, precision antimicrobial prescribing in SOT aiming to avoid negative consequences of antimicrobials is essential to improving patient outcomes. The positive impact AS efforts in transplant care has been recognized and bespoke activities tailored to special interests of transplant patients and providers are evolving. Strategies to optimize stewardship interventions targeting antibacterial, antiviral, and antifungal drug selection and dosing in the transplant population have been recently published though clinical integration using a 'handshake' stewardship model is an optimal starting point in transplant care. Other recent studies involving transplant recipients have identified opportunities to shorten duration or avoid antimicrobials for certain commonly encountered clinical syndromes. This literature, informing recent consensus clinical practice guidelines, may help support institutional practice guidelines and protocols. Proposals to track and report stewardship process and outcome measures as a routine facet of programmatic transplant quality reporting have been published. However, developing novel metrics accounting for nuances of transplant patients and programs is critical. Important studies are needed to evaluate organizational transplant prescribing cultures and optimal behavioral science-based interventions relevant to antimicrobial use in this population.

SUMMARY

Consequences of antimicrobial use, such as drug toxicities, and Clostridiodes difficile (CDI) and multidrug-resistant organisms colonization and infection disproportionately affect SOT recipients and are associated with poor allograft and patient outcomes. Stewardship programs encompassing transplant patients aim to personalize antimicrobial prescribing and optimize outcomes. Further studies are needed to better understand optimal intervention strategies in SOT.

Lung transplantation for late-onset non-infectious chronic pulmonary complications of allogenic hematopoietic stem cell transplant

Background

Late onset non-infectious pulmonary complications (LONIPCs) following allogenic hematopoietic stem cell transplantation (allo-HSCT) confer a significant mortality risk. Lung transplantation (LTx) has the potential to provide survival benefit but the impact of prior allo-HSCT on post-LTx outcomes is not well studied.

Methods

This retrospective, single-centre cohort study assessed the post-LTx outcomes of adults with LONIPCs of allo-HSCT. Outcomes of LTx for LONIPCs were compared to propensity-score matched LTx controls (n = 38, non-HSCT) and recipients of re-LTx (n = 70) for chronic lung allograft dysfunction (CLAD).

Results

Nineteen patients underwent DLTx for LONIPCs of allo-HSCT between 2003 and 2019. Post-LTx survival was 50% at 5-years. Survival to 1-year post-LTx was similar to matched controls (p = 0.473). Survival, conditional on 1-year survival, was lower in the allo-HSCT cohort (p = 0.034). An increased risk of death due to infection was identified in the allo-HSCT cohort compared to matched controls (p = 0.003). Compared to re-LTx recipients, the allo-HSCT cohort had superior survival to 1-year post-LTx (p = 0.034) but conditional 1-year survival was similar (p = 0.145).

Conclusion

This study identifies an increased risk of post-LTx mortality in recipients with previous allo-HSCT, associated with infection. It supports the hypothesis that allo-HSCT LTx recipients are relatively more immunosuppressed than patients undergoing LTx for other indications. Optimisation of post-LTx immunosuppressive and antimicrobial strategies to account for this finding should be considered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01699-8.

Late Onset Invasive Pulmonary Aspergillosis in Lung Transplant Recipients in the Setting of a Targeted Prophylaxis/Preemptive Antifungal Therapy Strategy

BACKGROUND

Invasive pulmonary aspergillosis (IPA) is a significant cause of morbidity and mortality in lung transplant recipients (LTRs). It is unclear how a targeted prophylaxis/ preemptive antifungal therapy strategy impacts the incidence of IPA beyond the first-year posttransplant.

METHODS

This is a retrospective cohort of LTRs from January 2010 to December 2014. We included all LTRs who survived beyond the first year and followed them until death or 4 years postoperatively. Incidence of probable/proven IPA and Aspergillus colonization were assessed as per International Society for Heart and Lung Transplantation (ISHLT) criteria. Patients with risk factors, positive Aspergillus cultures, or galactomannan (GM) received targeted prophylaxis/preemptive therapy within the first-year posttransplant.

RESULTS

During the study period, 350 consecutive LTRs underwent 1078 bronchoscopies. Positive bronchoalveolar lavage for GM or Aspergillus cultures was reported for 15% (52/350) of LTRs between 2 and 4 years after transplantation. Among them, the median time to positive Aspergillus culture or GM positivity was 703 days (interquartile range, 529-754 d). The incidence rate of IPA and Aspergillus colonization was 30 of 1000 patient-y, and 63 of 1000 patient-y, respectively. The mortality rate was significantly higher in patients with IPA than without IPA (107/1000 patient-years versus 18/1000 patient-years; P < 0.0001). Rate of first-year colonization and IPA was 33% and 9%, respectively. Among the 201 patients who had a negative bronchoscopy during the first year posttransplant, only 6 (3%) developed IPA during the follow-up.

CONCLUSIONS

A targeted prophylaxis/preemptive therapy strategy within the first-year posttransplant resulted in 4% incidence of IPA at 4-years after transplantation. However, IPA was associated with higher mortality.

Nebulized Amphotericin B Dosing Regimen for Aspergillus Prevention After Lung Transplant

OBJECTIVES

Lung transplant guidelines recommend nebulized amphotericin B with or without systemic antifungal agents for fungal prophylaxis. However, amphotericin formulation, dosing, and frequency vary between studies. We assessed the safety and effectiveness of nebulized amphotericin B to prevent Aspergillus infection in 2 regimens, ie, twice daily compared with 3 times daily.

MATERIALS AND METHODS

This was a single-center retrospective cohort study. We included patients at least 14 years old who underwent lung transplant and received nebulized amphotericin B alone or in combination with another antifungal agent either twice daily or 3 times daily. The primary endpoint was the incidence of lung Aspergillus infection, and the secondary endpoints were nebulized amphotericin B side effects and breakthrough Aspergillus infection.

RESULTS

A total of 84 patients were included. The group given nebulized amphotericin twice daily had a higher rate of Aspergillus infection at 17% compared with 4% in the group treated 3 times daily (P = .24). No serious side effects were reported, but coughing and diarrhea were more common in patients who received amphotericin B 3 times daily.

CONCLUSIONS

A systemic antifungal agent combined with nebulized amphotericin either twice or 3 times daily has been effective to prevent Aspergillus infection. Nebulized amphotericin twice daily may be a more viable option to increase a patient's adherence and decrease medication cost and side effects. However, a larger randomized controlled trial is needed to determine the best dosing regimen for nebulized amphotericin B as a fungal prophylaxis after lung transplant.

Bronchoalveolar lavage: role in the evaluation of pulmonary interstitial disease

INTRODUCTION

Bronchoalveolar lavage (BAL), a noninvasive, well-tolerated procedure is an important diagnostic tool that can facilitate the diagnosis of various lung diseases. This procedure allows the assessment of large alveolar compartments, by providing cells as well as non-cellular constituents from the lower respiratory tract. Alterations in BAL fluid and cells ratio reflects pathological changes in the lung parenchyma. In some cases, clinicians use BAL as a differential diagnosis guide for interstitial lung disease.

AREAS COVERED

In this review, we summarized the diagnostic criteria for BAL in interstitial lung diseases, pulmonary infections, lung cancer and other pathologies such as fat embolism, gastroesophageal reflux and collagen vascular disease. For this review, we have selected scientific papers published in the PubMed database in our area of interest. We aimed to highlight the usefulness of BAL in respiratory pathology.

EXPERT OPINION

Although BAL fluid analyzes has an essential role in the diagnostic work-up of many lung pathologies, it should be performed in selected patients. For accurate results, the BAL technique is very important to be standardized.

Antimicrobial stewardship in transplant patients

PURPOSE OF REVIEW

To provide an update on the current landscape of antimicrobial stewardship in solid organ transplant (SOT) recipients.

RECENT FINDINGS

Constructing personalized antimicrobial prescribing approaches to avoid untoward consequences of antimicrobials while improving outcomes is an emerging and critical aspect of transplant medicine. Stewardship activities encompassing the specialized interests of transplant patients and programs are evolving. New literature evaluating strategies to optimize antimicrobial agent selection, dosing, and duration have been published. Additionally, consensus guidance for certain infectious clinical syndromes is available and should inform institutional clinical practice guidelines. Novel metrics for stewardship-related outcomes in transplantation are desperately needed. Though exciting new molecular diagnostic technologies will likely be pivotal in the care of immunocompromised patients, optimal clinical adaptation and appropriate integration remains unclear. Important studies understanding the behaviors influencing antimicrobial prescribing in organizational transplant cultures are needed to optimize interventions.

SUMMARY

Consequences of antimicrobial use, such as Clostridiodes difficile and infections with multidrug-resistant organisms disproportionately affect SOT recipients and are associated with poor allograft and patient outcomes. Application of ASP interventions tailored to SOT recipients is recommended though further studies are needed to provide guidance for best practice.

Infection prophylaxis and management of fungal infections in lung transplant

Lung transplantation has emerged as a lifesaving treatment for a wide range of advanced lung diseases. While the survival of lung transplant recipients continues to improve, infectious complications contribute substantially to morbidity and mortality following lung transplantation. The incidence of invasive fungal infections is variable, with a mean occurrence of 8.6%. The majority of fungal infections in lung transplant recipients are caused Aspergillus and Candida species. This review provides an update in the current approaches for the diagnosis, management and prevention of fungal infections and the late complications that are associated.

Diagnostic Value of Galactomannan in Bronchoalveolar Lavage Fluid for Chronic Respiratory Disease with Pulmonary Aspergillosis

The objective of this study was to explore the diagnostic value of the bronchoalveolar lavage fluid galactomannan (BALF GM) test for chronic respiratory disease with pulmonary aspergillosis and to establish the optimal cutoff value. Samples from a total of 309 chronic respiratory disease patients seen at the respiratory medicine department of Peking University Shenzhen Hospital from September 2016 to September 2019 were analyzed. According to the diagnostic criteria, we divided the patients into a case group (n = 79, comprising 25 proven cases and 54 probable cases) and a control group (n = 230). Bronchoalveolar lavage fluid was collected, and the BALF GM test results were analyzed. A nonparametric rank sum test showed that the mean rank of the case group was 255.30, which was higher than that of the control group (120.55). The Z-value was -11.567 (P = 0.000), indicating that the general distributions of BALF GM differed between the two groups. A BALF GM cutoff value of 0.88 showed the highest diagnostic efficacy for pulmonary aspergillosis. The sensitivity, specificity, positive predictive value, and negative predictive value were 77.2%, 93%, 79.2%, and 92.2%, respectively. As the cutoff value increased, the specificity and sensitivity of the BALF GM test increased and decreased, respectively. The BALF GM test can be used confirm the diagnosis of patients with pulmonary aspergillosis and chronic respiratory disease. The optimum BALF GM cutoff value is 0.88.

Incidence and outcomes of invasive fungal infection among solid organ transplant recipients: A population-based cohort study

BACKGROUND

Invasive fungal infection (IFI) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. The long-term probability of post-transplant IFI is poorly understood.

METHODS

We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada, to determine the incidence rate; 1-, 5-, and 10-year cumulative probabilities of IFI; and post-IFI all-cause mortality in SOT recipients from 2002 to 2016. We also determined post-IFI, death-censored renal allograft failure.

RESULTS

We included 9326 SOT recipients (median follow-up: 5.35 years). Overall, the incidence of IFI was 8.3 per 1000 person-years. The 1-year cumulative probability of IFI was 7.4% for lung, 5.4% for heart, 1.8% for liver, 1.2% for kidney-pancreas, and 1.1% for kidney-only allograft recipients. Lung transplant recipients had the highest incidence rate and 10-year probability of IFI: 43.0 per 1000 person-years and 26.4%, respectively. The 1-year all-cause mortality rate after IFI was 34.3%. IFI significantly increased the risk of mortality in SOT recipients over the entire follow-up period (hazard ratio: 6.50, 95% CI: 5.69-7.42). The 1-year probability of death-censored renal allograft failure after IFI was 9.8%.

CONCLUSION

Long-term cumulative probability of IFI varies widely among SOT recipients. Lung transplantation was associated with the highest incidence of IFI with considerable 1-year all-cause mortality.

Invasive Aspergillosis in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines provide information on epidemiology, diagnosis, and management of Aspergillus after organ transplantation. Aspergillus is the most common invasive mold infection in solid-organ transplant (SOT) recipients, and it is the most common invasive fungal infection among lung transplant recipients. Time from transplant to diagnosis of invasive aspergillosis (IA) is variable, but most cases present within the first year post-transplant, with shortest time to onset among liver and heart transplant recipients. The overall 12-week mortality of IA in SOT exceeds 20%; prognosis is worse among those with central nervous system involvement or disseminated disease. Bronchoalveolar lavage galactomannan is preferred for the diagnosis of IA in lung and non-lung transplant recipients, in combination with other diagnostic modalities (eg, chest CT scan, culture). Voriconazole remains the drug of choice to treat IA, with isavuconazole and lipid formulations of amphotericin B regarded as alternative agents. The role of combination antifungals for primary therapy of IA remains controversial. Either universal prophylaxis or preemptive therapy is recommended in lung transplant recipients, whereas targeted prophylaxis is favored in liver and heart transplant recipients. In these guidelines, we also discuss newer antifungals and diagnostic tests, antifungal susceptibility testing, and special patient populations.

Cytokine profile in lung transplant recipients with Aspergillus spp colonization

We studied cytokine profiles in BAL of LTRs with Aspergillus spp colonization who did not progress to IPA in the absence of antifungal prophylaxis. This was a retrospective, single center case-control study. BAL samples were analyzed for cytokines. Patients with Aspergillus spp in BAL who did not receive prophylaxis and did not develop IPA were compared to LTRs with Aspergillus spp that received prophylaxis, LTRs with IPA and controls. Twenty-one patients with Aspergillus colonization who did not develop IPA, seven patients with suspected IPA who received prophylaxis, 4 IPA and 19 controls were included. IPA group had significantly higher levels (median [IQR]) of MIP-1 beta compared to the Suspected IPA group (5 vs 5 P: 0.03). The Suspected IPA group had significantly higher levels of IL-12 (11.38 vs 1 P: 0.0001), IL-1 RA (86.11 vs 23.98 P: 0.0118), IP-10 (22.47 vs 0.86 P: 0.0151), HGF (40.92 vs 16.82 P: 0.0055), and MIG (169.62 vs 5 P: 0.0005) than Colonization group. We have identified a unique cytokine signature in patients with Aspergillus colonization that do not develop IPA. Our study forms basis for a larger study to use these cytokines profile to identify patients at a lower risk of developing IPA.

Controversies and emerging topics in lung transplantation

Lung transplantation provides a realistic hope of improved survival and enhanced quality of life. However, outcomes can be disappointing, meaning many decisions are highly controversial. Practice is largely based on expert opinion and there is a dearth of high-level evidence. Not surprisingly, this leads to centre-specific practices that may vary considerably in controversial areas. The aim of this review, therefore, is to explore some of those domains and present the available evidence. As the science of lung transplantation approaches its fifth decade, we are only now reaching a critical mass of clinicians and scientific researchers to enable adequately powered studies to assist in informing our approach to some of these controversies.

Lung transplantation provides a realistic hope of improved survival and enhanced quality of life. However, outcomes can be disappointing, meaning many decisions are highly controversial. Better evidence is desperately needed.http://ow.ly/Dl4N30maYV9