Invasive fungal infection in liver transplant recipients in a prophylactic era: A multicenter retrospective cohort study in Korea

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.

Invasive Fungal Infections after Liver Transplantation

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

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

Invasive fungal infections (IFIs) remain one of the most common infectious complications after organ transplantation, and liver transplant recipients (LTRs) have the highest mortality rate. However, risk factors associated with IFIs have only been evaluated in small single-center studies. We performed a meta-analysis by conducting a comprehensive search using Ovid MEDLINE, Ovid Embase, Cochrane database of systematic reviews, and Cochrane central register of controlled trials. All case-control and cohort studies evaluating risk factors for IFIs in adult LTRs were screened. Utilizing a random-effects model, a multivariate analysis was completed, and 28 studies were eligible for meta-analysis. Rates of IFIs ranged from 1.4% to 32.7%. Previous antibiotic use (OR 9.3; 95% CI 3.2-27.0) and bacterial infection (OR 4.3; 95% CI 2.1-8.6) were risk factors of invasive candidiasis. Yet for invasive aspergillosis, posttransplant renal replacement therapy (OR 9.2; 95% CI 4.2-20.4), reoperation (OR 8.0; 95% CI 2.9-21.7), and cytomegalovirus infection (OR 6.2; 95% CI 2.0-19.3) were risk factors. The top independent risk factors for IFIs during studies from 2010 to 2019 were previous fungal colonization (OR 9.19; 95% CI 4.92-17.16), reoperation (OR 5.45; 95% CI 2.93-10.15), and previous bacterial infections (OR 3.81; 95% CI 2.13-6.83). These risk factors may be targeted by antifungal prophylaxis in LTRs.

Risk Factors of Invasive Fungal Infection in Recipients After Liver Transplantation: A Systematic Review and Meta-Analysis

Objectives: Invasive fungal infection (IFI) remains an important cause of mortality in liver transplantation (LT). The objective of this meta-analysis was to identify the risk factors for IFI after LT.

Methods: We searched for relevant studies published up to June 2020 from PubMed, Web of Science, Embase, and the Cochrane Library. Odds ratios (ORs) and their corresponding 95% CIs were used to identify significant differences in the risk factors. Heterogeneity between studies was evaluated by the I² test, and potential publication bias was assessed with Egger's test. The quality of included studies was evaluated with the Newcastle-Ottawa Scale (NOS).

Results: A total of 14 studies enrolling 4,284 recipients were included in the meta-analysis. Reoperation (OR = 2.18, 95% CI: 1.61–2.94), posttransplantation dialysis (OR = 2.03, 95% CI: 1.52–2.72), bacterial infection (OR = 1.81, 95% CI: 1.33–2.46), live donor (OR = 1.78, 95% CI: 1.20–2.63), retransplantation (OR = 2.45, 95% CI: 1.54–3.89), and fungal colonization (OR = 2.60, 95% CI: 1.99–3.42) were associated with the risk factors of IFI after LT.

Conclusions: Despite some risk factors that have been identified as significant factors for IFI post-LT, which may inform prevention recommendations, rigorous and well-designed studies with adequate sample sizes should be conducted to solve the limitations of this study.

Candida glabrata Antifungal Resistance and Virulence Factors, a Perfect Pathogenic Combination

In recent years, a progressive increase in the incidence of invasive fungal infections (IFIs) caused by Candida glabrata has been observed. The objective of this literature review was to study the epidemiology, drug resistance, and virulence factors associated with the C. glabrata complex. For this purpose, a systematic review (January 2001-February 2021) was conducted on the PubMed, Scielo, and Cochrane search engines with the following terms: "C. glabrata complex (C. glabrata sensu stricto, C. nivariensis, C. bracarensis)" associated with "pathogenicity" or "epidemiology" or "antibiotics resistance" or "virulence factors" with language restrictions of English and Spanish. One hundred and ninety-nine articles were found during the search. Various mechanisms of drug resistance to azoles, polyenes, and echinocandins were found for the C. glabrata complex, depending on the geographical region. Among the mechanisms found are the overexpression of drug transporters, gene mutations that alter thermotolerance, the generation of hypervirulence due to increased adhesion factors, and modifications in vital enzymes that produce cell wall proteins that prevent the activity of drugs designed for its inhibition. In addition, it was observed that the C. glabrata complex has virulence factors such as the production of proteases, phospholipases, and hemolysins, and the formation of biofilms that allows the complex to evade the host immune response and generate fungal resistance. Because of this, the C. glabrata complex possesses a perfect pathogenetic combination for the invasion of the immunocompromised host.

Epidemiology, risk factors, and association of antifungal prophylaxis on early invasive fungal infection in heart transplant recipients

BACKGROUND

Invasive fungal infection (IFI) in heart transplant recipients is associated with poor outcomes. Estimated risk of 1-year IFI in heart transplant recipients is 3.4-8.6% with risk factors inconsistently identified in previous studies. The role of antifungal prophylaxis is unclear. The transplant program at Mayo Clinic provides 6 months of universal azole prophylaxis for those heart transplant recipients in Arizona. We sought to define risk factors for 1-year IFI and determine the effect of antifungal prophylaxis.

METHODS

We conducted a retrospective cohort study of patients undergoing heart transplantation at Mayo Clinic from January 2000 to March 2019. We analyzed demographics, details of transplant hospitalization, antifungal prophylaxis, and fungal infection. Multivariable Cox analyses were performed to identify risk factors of 1-year IFI and impact of IFI on posttransplant mortality.

RESULTS

A total of 966 heart transplant recipients were identified with a median age of 56 years (IQR 47, 62). A total of 444 patients received antifungal prophylaxis. Over 1-year follow-up, 62 patients developed IFI with a cumulative incidence of 6.4%. In multivariable analysis, factors associated with IFI were renal replacement therapy (RRT) (HR 3.24, 95% CI 1.65-6.39), allograft rejection (HR 2.33, 95% CI 1.25-4.34), and antifungal prophylaxis (HR 0.32, 95% CI 0.11-0.96). RRT was also associated with invasive mold infection (HR 3.00, 95% CI 1.29-6.97).

CONCLUSIONS

RRT and allograft rejection after transplantation are associated with 1-year IFI, and RRT is also associated with invasive mold infection. Antifungal prophylaxis appears to be protective and further study is needed in the heart transplant population.

Detection of antifungal drug-resistant and ERG11 gene mutations among clinical isolates of Candida species isolated from Khartoum, Sudan

Background:  Candida species are one of the most important opportunistic fungal pathogens that cause both superficial and systemic infections, especially in immunocompromised individuals. Considering the sharp increase in the rate of  Candida infections, and resistance to commonly used antifungal agents in the last decades; this study was conducted to determine the rate of resistance among clinical isolates of  Candida species, and to characterize some of the resistant genes among resistant isolates collected in Khartoum. 

Methods: This is a cross-sectional laboratory-based study included 100 pre-screened  Candida species isolates from Khartoum state hospitals. Chromogenic media was used for  Candida isolation and/or identification. The standard disc diffusion method was performed to investigate the susceptibility to fluconazole, itraconazole, and amphotericin. Following genomic DNA extraction, the entire  ERG11 gene was amplified from some C. albicans resistant isolates, sequenced, and further analyzed.

Results: Out of 100 clinical isolates collected, 51% were  C. albicans, followed by  C. glabrata (31%),  C. krusie (8%),  C. tropicals (5%), and C. dupliniens (5%). Resistance rate was 23% for fluconazole, 4% for itraconazole, while there were no amphotericin resistant isolates detected. C. albicans  ERG11 gene sequence reveals 15 different mutations. Among these, three (D116E, E266D, and V488I) were missense mutations; however, these substitutions do not contribute to fluconazole resistance.

Conclusion:  C. albicans was found to be the most common species. Resistance against fluconazole was observed most frequently; however, mutations in ERG11 are unlikely to be the reason behind fluconazole resistance among these isolates.

Molecular characterization of fungi causing colonization and infection in organ transplant recipients: A one-year prospective study

Background and Purpose:

Organ transplant recipients are vulnerable to fungal infections. The aim of this study was to determine the prevalence of fungal colonization and infections among patients who underwent various transplantations and molecularly characterize the etiological agents.

Materials and Methods:

This study was conducted on candidates for transplantation in Imam Khomeini Hospital, Tehran, Iran, from April 2017 to April 2018. All patients were monitored for fungal colonization or infections before and after transplantation. Isolated fungi were identified using molecular methods.

Results:

A total of 125 patients, including 86 males and 39 females, with the mean age of 52.2 years participated in the study (age range: 15-75 years). Out of 125 patients, 84 (67.2%) cases had fungal colonization that appeared pre- and post-transplantation in 21 and 63 cases, respectively (alone or concurrent with another infection in 55 and 29 cases, respectively). In addition, a total of 39 episodes of fungal infections were diagnosed in 36 (28.8%) recipients (alone or concurrent with colonization in 7 and 29 cases, respectively). Out of the 39 fungal infections, 9 cases appeared pre-transplantation, while the other 30 cases occurred post-transplantation. However, no fungal colonization or infection was observed in 34 (27.2%) patients. Oral candidiasis (n=20) was the most common type of infection, followed by funguria (n=7), onychomycosis (n=5), candidemia (n=3), rhinocerebral mucormycosis (n=1), cutaneous mucormycosis (n=1), cutaneous aspergillosis (n=1), and peritonitis (n=1). Six yeast species were recovered from colonization cases with the dominance of Candida albicans both before and after transplantation. The observed fungal infections were caused by 11 distinct species, including the members of Candida (i.e., C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei), Aspergillus (i.e., A. oryzae and A. candidus), Rhizopus (i.e., R. oryzae and R. microsporus), Trichosporon asahii, and Trichophyton interdigitale. The results also indicated that the development of a fungal infection post-transplantation was associated with fungal colonization (r=0.0184; P=0.043).

Conclusion:

Based on the results, fungal colonization was a common finding in transplant recipients at Imam Khomeini Hospital. However, the incidence of fungal infections was comparable with those of other centers. As the oral cavity was the most common site of colonization and infection, it might be beneficial to take further care about the oral health of patients using effective mouthwash.

Candidemia in solid organ transplant recipients in Spain: Epidemiological trends and determinants of outcome

BACKGROUND

Despite being considered a high-risk population for invasive fungal disease, specific features of candidemia among solid organ transplant (SOT) recipients remain poorly characterized.

METHODS

We compiled prospective data from two multicenter studies on candidemia performed over two consecutive periods in Spain: the CANDIPOP Study (2010-2011) and the CANDI-Bundle Study (2016-2018). Episodes diagnosed in adult SOT recipients in 10 participating centers were included. Risk factors for clinical failure (all-cause 7-day mortality and/or persistent candidemia for ≥72 hours) and 30-day mortality were investigated by univariate analysis.

RESULTS

We included 55 episodes of post-transplant candidemia (32 and 23 of which occurred during the first and second periods). Kidney (38.2%) and liver recipients (30.9%) were the most common populations. Candida albicans accounted for 27.3% of episodes. The proportion of C glabrata increased over time (18.8% vs 30.4% for the first and second periods). There were no differences in the rate of fluconazole non-susceptible isolates (50.0% vs 60.0%, respectively). Clinical failure and 30-day mortality occurred in 25.5% and 27.3% of episodes and were associated with the severity of candidemia (Pitt score and severe sepsis/septic shock). Kidney transplantation (unadjusted odds ratio [uOR]: 0.17; 95% confidence interval [CI]: 0.03-0.85; P-value = .020), early catheter removal (uOR: 0.15; 95% CI: 0.03-0.76; P-value = .013), and appropriate early antifungal therapy (uOR: 0.14; 95% CI: 0.02-0.89; P-value = .041) were protective for 30-day mortality.

CONCLUSIONS

High rates of non-albicans species and fluconazole non-susceptibility must be taken into account to optimize therapeutic management and outcomes in SOT recipients with candidemia.