Fungal Isolation in Respiratory Tract After Lung Transplantation: Epidemiology, Clinical Consequences, and Associated Factors

Fungal colonization before or after lung transplantation has no negative impact on survival or the development of chronic lung allograft dysfunction

Introduction

Long-term survival following lung transplantation (LTx) faces impediments due to chronic lung allograft dysfunction (CLAD), while infections hinder short-term survival. Fungal colonization and invasive fungal infections (IFI) are common within the first year after LTx. There is ongoing debate regarding the impact of such events on CLAD development and mortality. This study aims to investigate this matter further.

Methods

A total of 134 LTx recipients transplanted between 2011 and 2020 were included. The median follow-up time was 3.9 years. Fungal colonization and IFI were defined according to international consensus guidelines and were noted if present within the first 12 months after LTx.

Results

Postoperative fungal colonization was found in 101 patients, and 14 patients had an IFI within twelve months of transplantation. Nineteen patients were neither colonized nor infected. Out of the 115 patients with colonization or IFI, 61 patients had growth of a yeast such as Candida species (spp.). Fifty-six patients were colonized prior to LTx. Being colonized with fungus before or within the first 12 months post-LTx did not significantly affect survival or CLAD development.

Conclusions

The results of the current study indicate that fungal colonization either pre-transplantation or within the first 12 months after does not correlate with increased risks of mortality or CLAD development. These findings show that while fungal colonization is a common occurrence in LTx recipients, it does not predispose the patients of the cohort to adverse outcomes.

Fungal Tracheobronchitis in Lung Transplant Recipients: Incidence and Utility of Diagnostic Markers

Fungal tracheobronchitis caused by Aspergillus and Candida spp. is a recognized complication after lung transplantation, but knowledge of the incidence of Candida tracheobronchitis is lacking. The diagnosis relies on fungal cultures in bronchoalveolar lavage fluid (BALF), but cultures have low specificity. We aimed to evaluate the one-year incidence of fungal tracheobronchitis after lung transplantation and to assess the utility of diagnostic markers in serum and BALF to discriminate fungal tracheobronchitis from colonization. Ninety-seven consecutively included adult lung-transplant recipients were prospectively followed. BALF and serum samples were collected at 1, 3 and 12 months after transplantation and analyzed for betaglucan (serum and BALF), neutrophils (BALF) and galactomannan (BALF). Fungal tracheobronchitis was defined according to consensus criteria, modified to include Candida as a mycologic criterion. The cumulative one-year incidence of Candida and Aspergillus tracheobronchitis was 23% and 16%, respectively. Neutrophils of >75% of total leukocytes in BALF had 92% specificity for Candida tracheobronchitis. The area under the ROC curves for betaglucan and galactomannan in BALF to discriminate Aspergillus tracheobronchitis from colonization or no fungal infection were high (0.86 (p < 0.0001) and 0.93 (p < 0.0001), respectively). To conclude, the one-year incidence of fungal tracheobronchitis after lung transplantation was high and dominated by Candida spp. Diagnostic markers in BALF could be useful to discriminate fungal colonization from tracheobronchitis.

Intensive care readmissions in the first year after lung transplantation: Incidence, early risk factors and outcome

BACKGROUND

Predictive factors of intensive care readmissions after lung transplantation (LT) have not been established. The main objective of this study was to assess early risk factors for ICU readmission during the first year after LT.

METHODS

This retrospective, observational, single-centre study included all consecutive patients who underwent LT in our institution between January 2016 and November 2019. Patients who died during the initial hospitalisation in the ICU were excluded. Surgical and medical ICU readmissions were collected during the first year. The results are expressed as medians, interquartile ranges, absolute numbers and percentages. Statistical analyses were performed using the chi-square test, Fisher's exact test and Mann-Whitney U test as appropriate (p < 0.05 as significance). Multivariate analysis was performed to identify independent risk factors for readmission. The Paris-North-Hospitals Institutional Review Board reviewed and approved the study.

RESULTS

A total of 156 patients were analysed. Eighteen of them (12%) died during the initial ICU hospitalisation. During the first year after LT, ICU readmission was observed for 49/138 (36%) patients. Among these patients, 14/49 (29%) died during the study period. Readmission was mainly related to respiratory failure (35 (71%) patients), infectious diseases (28 (57%) patients), airway complications (11 (22%) patients), and immunologic complications (4 (8%) patients). In the multivariate analysis, ICU readmission was associated with the use of high doses of catecholamines during surgery, and the increased duration of initial ICU stay.

CONCLUSION

The initial severity of haemodynamic failure and a prolonged postoperative course seem to be key determinants of ICU readmissions after LT.

The Prediction and Prognosis of Fungal Infection in Lung Transplant Recipients-A Retrospective Cohort Study in South Korea

(1) Background: Lung transplant recipients (LTRs) are at substantial risk of invasive fungal disease (IFD), although no consensus has been reached on the use of antifungal agents (AFAs) after lung transplantation (LTx). This study aimed to assess the risk factors and prognosis of fungal infection after LTx in a single tertiary center in South Korea. (2) Methods: The study population included all patients who underwent LTx between January 2012 and July 2019 at a tertiary hospital. It was a retrospective cohort study. Culture, bronchoscopy, and laboratory findings were reviewed during episodes of infection. (3) Results: Fungus-positive respiratory samples were predominant in the first 90 days and the overall cumulative incidence of Candida spp. was approximately three times higher than that of Aspergillus spp. In the setting of itraconazole administration for 6 months post-LTx, C. glabrata accounted for 36.5% of all Candida-positive respiratory samples. Underlying connective tissue disease-associated interstitial lung disease, use of AFAs before LTx, a longer length of hospital stay after LTx, and old age were associated with developing a fungal infection after LTx. IFD and fungal infection treatment failure significantly increased overall mortality. Host factors, antifungal drug resistance, and misdiagnosis of non-Aspergillus molds could attribute to the breakthrough fungal infections. (4) Conclusions: Careful bronchoscopy, prompt fungus culture, and appropriate use of antifungal therapies are recommended during the first year after LTx.

Genotyping and In Vitro Antifungal Susceptibility Profile of Neoscytalidium Species Isolates from Respiratory Tract

The fungus genus Neoscytalidium is mainly distributed in (sub) tropical regions of the world and has been essentially considered as a phytopathogen. There are however several reports of human infection caused by Neoscytalidium spp. through direct or indirect contact with contaminated plants or soil. Reliable and accurate identification to species level is critical for implementing proper therapeutic strategies. In the present study we investigated the genotypes and in vitro antifungal susceptibility patterns of Neoscytalidium species identified from respiratory tracts of patients with various underlying diseases. The identity and diversity of the isolates were done using PCR and sequencing of five different loci (the ITS region, D1/D2 domains of 28S rRNA gene, and part of the beta tubulin, elongation factor 1α and chitin synthase genes). The in-vitro antifungal susceptibility was also performed using the Clinical and Laboratory Standards Institute (CLSI) M38-Ed3-2017 guidelines. Overall, 13 isolates were identified as Neoscytalidium species (eight N. dimidiatum and five N. novaehollandiae). Two sequence types (STs) were identified by the alignment of 1846 combined base pairs among 13 clinical isolates. All isolates classified as N. dimidiatum were clustered in ST6 (61.5%) and those of N. novaehollandiae were in ST7 (38.5%). Luliconazole was the most active antifungal in vitro against species. This is the first report of N. novaehollandiae isolation from respiratory tracts samples. Further study from other regions of the world with a larger set of clinical specimens is required to provide additional insight into diversity of Neoscytalidium species.

Blood transfusion of the donor is associated with stage 3 primary graft dysfunction after lung transplantation

BACKGROUND

The first aim of this study was to assess the association between stage 3 PGD and pre-donation blood transfusion of the donor. The secondary objectives were to assess the epidemiology of donor transfusion and the outcome of LT recipients according to donor transfusion status and massive donor transfusion status.

METHODS

This was an observational, prospective, single-center study. The results are expressed as absolute numbers, percentages, medians, and interquartile ranges. Statistical analyses were performed using Chi squared, Fischer's exact tests, and Mann-Whitney U tests (P < .05 was considered significant). A multivariate analysis was performed.

RESULTS

Between January 2016 and February 2019, 147 patients were included in the analysis. PGD was observed in 79 (54%) patients, 45 (31%) of whom had stage 3 PGD. Pre-donation blood transfusion was administered in 48 (33%) donors (median of 3[1-9] packed red cells (PRCs)). On multivariate analysis, stage 3 PGD was significantly associated with donor blood transfusion (OR 2.69, IC (1.14-6.38), P = .024). Mortality at days 28 and 90 was not significantly different according to the pre-donation transfusion status of the donor.

CONCLUSION

Pre-donation blood transfusion is associated with stage 3 PGD occurrence after LT. Transfusion data of the donor should be included in donor lung assessment.

Microbiome-mediated regulation of anti-fungal immunity

Anti-fungal immunity is characterized by the continuous interplay between immune activation and immune regulation processes. These processes have now been clearly shown not only in animal pre-clinical models but also in humans. To create and maintain this immune homeostasis, reciprocal interactions among the host immune system, fungal pathogens, and the microbiome are crucial. Notably, the microbiome exerts multiple direct and indirect antifungal effects that are particularly aimed at minimizing host tissue damage. Thus, in this microbiome era, the architecture of 3D culture system or 'tissue organoids' might finally represent a simple but effective in vitro 'holobiont' to unravel the diverse interactions and adaptations that evolve to overcome fungal infections.