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

Biliary diffusion and antifungal activity of caspofungin and fluconazole in liver transplant recipients: A pilot study

Invasive candidiasis, including intra-abdominal candidiasis (IAC), is a common complication after liver transplantation. Antifungal drugs such as echinocandins and fluconazole (FCZ) are frequently used to prevent or treat such fungal infections. The diffusion of these antifungals within abdominal body sites has been rarely reported, in particular, in liver transplant recipients. This study aimed to evaluate the biliary diffusion of caspofungin (CAS) and FCZ. CAS and FCZ concentrations were determined in plasma and bile using a validated liquid chromatography-mass spectrometry method. Biliary concentrations of CAS (n = 5) and FCZ (n = 12) ranged from 1.6 to 4.4 and 6.4 to 33.4 mg/L, respectively, with respective medians of 1.9 and 17.7 mg/L. These values are higher than the MICs for yeast species frequently involved in IAC, suggesting that such antifungal exposure is sufficient to prevent/cure these infections. However, yeast was found in bile collected during CAS treatment from 3/5 patients, raising questions about the effective antifungal activity of this echinocandin at this anatomical site. Our pilot study shows that CAS and FCZ diffuse to the bile of liver transplant recipients. However, whether the observed antifungal concentrations are sufficiently high to prevent/cure IAC remains an unanswered question.

Clinical characteristics and outcomes of colonization and infection by yeast species in solid organ transplant recipients: Molecular identification and antifungal susceptibility patterns of isolates

Fungal infections are serious complications after solid organ transplantation, with high mortality and morbidity. Given the importance of the local epidemiological data and also extensive prophylactic regimens in solid organ transplant (SOT) recipients, this study aimed to investigate the clinical characteristics and resistance patterns of yeast isolates in SOT recipients at a main referral transplant center in Iran. Of the 275 recipients enrolled, 22 (8%) had at least one positive yeast culture at a median of 5 days after transplantation. Bacterial infection and reoperation were significantly associated with colonization or infection caused by yeast species (P = .001). Moreover, mortality and length of ICU/hospital stay were significantly higher in patients with positive yeast cultures (P < .05). The most frequent species isolated was Candida albicans (50%), followed by C. glabrata (22.7%). Of species with definite breakpoints, the fluconazole-resistant rate was 23%. Caspofungin and amphotericin B showed potent activity against all isolates. Regarding the high risk of fungal infections, awareness of local epidemiological trends and resistance patterns can help improve outcomes in SOT recipients.

Microbiome composition recovery after liver transplantation correlates with initial liver disease severity and antibiotics treatment

Liver transplantation (LT) is crucial for end-stage liver disease, but it is linked to infection risks. Pathobionts, microorganisms potentially harmful under specific conditions, can cause complications posttransplant. Monitoring such pathogens in fecal samples can be challenging and therefore remains underexplored post-LT. This study aimed to analyze the gut microbiome before and after LT, tracking pathobionts and correlating clinical data. The study involved 17 liver transplant recipients, 17 healthy relatives (spouses), and 13 donors. Gut samples collected pretranplantation and posttransplantation underwent bacterial and fungal profiling through DNA sequencing. Quantitative polymerase chain reaction was used to assess microbial load. Statistical analyses included alpha and beta diversity measures, differential abundance analysis, and correlation tests between microbiome and clinical parameters. Microbiome analysis revealed dynamic changes in diversity posttransplant. Notably, high-severity patients showed persistent and greater dysbiosis during the first months post-LT compared with low-severity patients, partly due to an antibiotic treatment pre-LT. The analysis identified a higher proportion of pathogens such as Escherichia coli/Shigella flexneri in high-severity cases posttransplant. Furthermore, butyrate producers including Roseburia intestinalis, Anaerostipes hadrus, and Eubacterium coprostanoligenes were positively correlated with levels of albumin. This study offers valuable insights into post-LT microbiome changes, shedding light on the need for tailored prophylactic treatment post-LT.

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.

Universal antifungal prophylaxis effectively prevents fungal bloodstream infection in pediatric liver transplant recipients: a retrospective real-world study

OBJECTIVES

Fungal bloodstream infection (fBSI) following pediatric liver transplantation presents a significant challenge; however, there remains a paucity of guidance regarding antifungal prophylaxis in this population. This study aimed to evaluate the effectiveness of universal antifungal prophylaxis and propose a desirable strategy.

METHODS

We enrolled 604 pediatric patients who underwent liver transplantation between 2020 and 2023, including 242 patients with empirical prophylaxis and 362 patients with universal prophylaxis. Univariate and multivariate logistic regression analyses were performed to identify independent factors for fBSI.

RESULTS

Eight (2.2%) pediatric recipients in the universal prophylaxis group and 13 (5.4%) in the empirical group developed fBSI (P = 0.038). Universal prophylaxis was a protective factor (P = 0.044), while high-volume intraoperative plasma transfusion and deceased donor liver transplantation were independent risk factors for fBSI (P = 0.035 and 0.008, respectively). Universal antifungal strategy showed an increased overall survival trend after liver transplantation although without significant statistical difference (P = 0.217). Patients with fBSI had poorer survival than those without fBSI (P <0.001).

CONCLUSIONS

Universal prophylaxis strategy for fBSI in pediatrics after liver transplantation is desirable as it could markedly decrease the occurrence of fBSI. Pediatric patients with deceased donors and high-volume intraoperative transfusion should be paid more attention to preventing fBSI.

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.

Risk factors for COVID-19-associated pulmonary aspergillosis: a systematic review and meta-analysis

BACKGROUND

COVID-19-associated pulmonary aspergillosis (CAPA) has been reported to be an emerging and potentially fatal complication of severe COVID-19. However, risk factors for CAPA have not been systematically addressed to date.

METHODS

In this systematic review and meta-analysis to identify factors associated with CAPA, we comprehensively searched five medical databases: Ovid MEDLINE; Ovid Embase; the Cochrane Database of Systematic Reviews; the Cochrane Central Register of Controlled Trials; and the WHO COVID-19 Database. All case-control and cohort studies in adults (aged >18 years) that described at least six cases of CAPA and evaluated any risk factors for CAPA, published from Dec 1, 2019, to July 27, 2023, were screened and assessed for inclusion. Only studies with a control population of COVID-19-positive individuals without aspergillosis were included. Two reviewers independently screened search results and extracted outcome data as summary estimates from eligible studies. The primary outcome was to identify the factors associated with CAPA. Meta-analysis was done with random-effects models, with use of the Mantel-Haenszel method to assess dichotomous outcomes as potential risk factors, or the inverse variance method to assess continuous variables for potential association with CAPA. Publication bias was assessed with funnel plots for factors associated with CAPA. The study is registered with PROSPERO, CRD42022334405.

FINDINGS

Of 3561 records identified, 27 articles were included in the meta-analysis. 6848 patients with COVID-19 were included, of whom 1324 (19·3%) were diagnosed with CAPA. Diagnosis rates of CAPA ranged from 2·5% (14 of 566 patients) to 47·2% (58 of 123). We identified eight risk factors for CAPA. These factors included pre-existing comorbidities of chronic liver disease (odds ratio [OR] 2·70 [95% CI 1·21-6·04], p=0·02; I2=53%), haematological malignancies (OR 2·47 [1·27-4·83], p=0·008; I2=50%), chronic obstructive pulmonary disease (OR 2·00 [1·42-2·83], p<0·0001; I2=26%), and cerebrovascular disease (OR 1·31 [1·01-1·71], p=0·05; I2=46%). Use of invasive mechanical ventilation (OR 2·83; 95% CI 1·88-4·24; p<0·0001; I2=69%), use of renal replacement therapy (OR 2·26 [1·76-2·90], p<0·0001; I2=14%), treatment of COVID-19 with interleukin-6 inhibitors (OR 2·88 [1·52-5·43], p=0·001; I2=89%), and treatment of COVID-19 with corticosteroids (OR 1·88 [1·28-2·77], p=0·001; I2=66%) were also associated with CAPA. Patients with CAPA were typically older than those without CAPA (mean age 66·6 years [SD 3·6] vs 63·5 years [5·3]; mean difference 2·90 [1·48-4·33], p<0·0001; I2=86%). The duration of mechanical ventilation in patients with CAPA was longer than in those without CAPA (n=7 studies; mean duration 19·3 days [8·9] vs 13·5 days [6·8]; mean difference 5·53 days [1·30-9·77], p=0·01; I2=88%). In post-hoc analysis, patients with CAPA had higher all-cause mortality than those without CAPA (n=20 studies; OR 2·65 [2·04-3·45], p<0·0001; I2=51%).

INTERPRETATION

The identified risk factors for CAPA could eventually be addressed with targeted antifungal prophylaxis in patients with severe COVID-19.

FUNDING

None.

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.

Long-term follow-up of temporary abdominal closure in complex abdomens during liver transplant

BACKGROUND

Temporary abdominal closure is commonly employed in liver transplantation when patient factors make primary fascial closure challenging. However, there is minimal data evaluating long-term survival and patient outcomes after temporary abdominal closure.

METHODS

A single-center, retrospective review of patients undergoing liver transplantation from January 2013 through December 2017 was performed with a 5-year follow-up. Patients were characterized as either requiring temporary abdominal closure or immediate primary fascial closure at the time of liver transplantation.

RESULTS

Of 422 patients who underwent 436 liver transplantations, 17.2% (n = 75) required temporary abdominal closure, whereas 82.8% (n = 361) underwent primary fascial closure. Patients requiring temporary abdominal closure had higher Model for End-Stage Liver Disease scores preoperatively (27 [22-36] vs 23 [20-28], P = .0002), had higher rates of dialysis preoperatively (28.0% vs 12.5%, P = .0007), and were more likely to be hospitalized within 90 days of liver transplantation (64.0% vs 47.5%, P = .0093). On univariable analysis, survival at 1 year was different between the groups (90.9% surviving at 1 year for primary fascial closure versus 82.7% for temporary abdominal closure, P = .0356); however, there was no significant difference in survival at 5 years (83.7% vs 76.0%, P = .11). On multivariable analysis, there was no difference in survival after adjusting for multiple factors. Patients requiring temporary abdominal closure were more likely to have longer hospital stays (median 16 days [9.75-29.5] vs 8 days [6-14], P < .0001), more likely to be readmitted within 30 days (45.3% vs 32.2%, P = .03), and less likely to be discharged home (36.5% vs 74.2%, P < .0001).

CONCLUSIONS

Temporary abdominal closure after liver transplantation appears safe and has similar outcomes to primary fascial closure, though it is used more commonly in complex patients.

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.

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.

Invasive Fungal Breakthrough Infections under Targeted Echinocandin Prophylaxis in High-Risk Liver Transplant Recipients

Invasive fungal infections (IFIs) are frequent and outcome-relevant complications in the early postoperative period after orthotopic liver transplantation (OLT). Recent guidelines recommend targeted antimycotic prophylaxis (TAP) for high-risk liver transplant recipients (HR-LTRs). However, the choice of antimycotic agent is still a subject of discussion. Echinocandins are increasingly being used due to their advantageous safety profile and the increasing number of non-albicans Candida infections. However, the evidence justifying their use remains rather sparse. Recently published data on breakthrough IFI (b-IFI) raise concerns about echinocandin efficacy, especially in the case of intra-abdominal candidiasis (IAC), which is the most common infection site after OLT. In this retrospective study, we analyzed 100 adult HR-LTRs undergoing first-time OLT and receiving echinocandin prophylaxis between 2017 and 2020 in a tertiary university hospital. We found a breakthrough incidence of 16%, having a significant impact on postoperative complications, graft survival, and mortality. The reasons for this may be multifactorial. Among the pathogen-related factors, we identified the breakthrough of Candida parapsilosis in 11% of patients and one case of persistent IFI due to the development of a secondary echinocandin resistance of an IAC caused by Candida glabrata. Consequently, the efficacy of echinocandin prophylaxis in liver transplantation should be questioned. Further studies are necessary to clarify the matter of breakthrough infections under echinocandin prophylaxis.

Risk Factors for Nontuberculous Mycobacteria Infections in Solid Organ Transplant Recipients: A Multinational Case-Control Study

BACKGROUND

Risk factors for nontuberculous mycobacteria (NTM) infections after solid organ transplant (SOT) are not well characterized. Here we aimed to describe these factors.

METHODS

Retrospective, multinational, 1:2 matched case-control study that included SOT recipients ≥12 years old diagnosed with NTM infection from 1 January 2008 to 31 December 2018. Controls were matched on transplanted organ, NTM treatment center, and post-transplant survival greater than or equal to the time to NTM diagnosis. Logistic regression on matched pairs was used to assess associations between risk factors and NTM infections.

RESULTS

Analyses included 85 cases and 169 controls (59% male, 88% White, median age at time of SOT of 54 years [interquartile range {IQR} 40-62]). NTM infection occurred in kidney (42%), lung (35%), heart and liver (11% each), and pancreas transplant recipients (1%). Median time from transplant to infection was 21.6 months (IQR 5.3-55.2). Most underlying comorbidities were evenly distributed between groups; however, cases were older at the time of NTM diagnosis, more frequently on systemic corticosteroids and had a lower lymphocyte count (all P < .05). In the multivariable model, older age at transplant (adjusted odds ratio [aOR] 1.04; 95 confidence interval [CI], 1.01-1.07), hospital admission within 90 days (aOR, 3.14; 95% CI, 1.41-6.98), receipt of antifungals (aOR, 5.35; 95% CI, 1.7-16.91), and lymphocyte-specific antibodies (aOR, 7.73; 95% CI, 1.07-56.14), were associated with NTM infection.

CONCLUSIONS

Risk of NTM infection in SOT recipients was associated with older age at SOT, prior hospital admission, receipt of antifungals or lymphocyte-specific antibodies. NTM infection should be considered in SOT patients with these risk factors.