Pre- and post-transplant bacterial infections in liver transplant recipients

Recipient donor sex combinations in solid organ transplantation and impact on clinical outcome: A scoping review

INTRODUCTION

Solid organ transplantation (SOT) is a lifesaving treatment for end-stage organ failure. Although many factors affect the success of organ transplantation, recipient and donor sex are important biological factors influencing transplant outcome. However, the impact of the four possible recipient and donor sex combinations (RDSC) on transplant outcome remains largely unclear.

METHODS

A scoping review was carried out focusing on studies examining the association between RDSC and outcomes (mortality, graft rejection, and infection) after heart, lung, liver, and kidney transplantation. All studies up to February 2023 were included.

RESULTS

Multiple studies published between 1998 and 2022 show that RDSC is an important factor affecting the outcome after organ transplantation. Male recipients of SOT have a higher risk of mortality and graft failure than female recipients. Differences regarding the causes of death are observed. Female recipients on the other hand are more susceptible to infections after SOT.

CONCLUSION

Differences in underlying illnesses as well as age, immunosuppressive therapy and underlying biological mechanisms among male and female SOT recipients affect the post-transplant outcome. However, the precise mechanisms influencing the interaction between RDSC and post-transplant outcome remain largely unclear. A better understanding of how to identify and modulate these factors may improve outcome, which is particularly important in light of the worldwide organ shortage. An analysis for differences of etiology and causes of graft loss or mortality, respectively, is warranted across the RDSC groups.

PRACTITIONER POINTS

Recipient and donor sex combinations affect outcome after solid organ transplantation. While female recipients are more susceptible to infections after solid organ transplantation, they have higher overall survival following SOT, with causes of death differing from male recipients. Sex-differences should be taken into account in the post-transplant management.

Infections After Liver Transplant -Timeline, Management and Prevention

Liver transplantation (LT) is the standard treatment for end- stage liver disease. Patient and graft survival have improved significantly in the last three decades owing to improvement in surgical technique, better perioperative management and better immunosuppressive regimens. However, LT recipients are at increased risk of infections, particularly in the first year after transplantation. The risk of infection is directly proportional to immunosuppressive regimen and graft function. In this review, we will briefly discuss the timeline of infections after liver transplant, preventive strategies and management of infectious complications.

Pre-transplant multidrug-resistant infections in liver transplant recipients-epidemiology and impact on transplantation outcome

BACKGROUND

Cirrhotic patients are highly exposed to healthcare services and antibiotics. Although pre-liver transplantation (LT) infections are directly related to the worsening of liver function, the impact of these infections on LT outcomes is still unclear. This study aimed to identify the effect of multidrug-resistant microorganism (MDRO) infections before LT on survival after LT.

METHODS

Retrospective study that included patients who underwent LT between 2010 and 2019. Variables analyzed were related to patients' comorbidities, underlying diseases, time on the waiting list, antibiotic use, LT surgery, and occurrences post-LT. Multivariate analyses were performed using logistic regression, and Cox regression for survival analysis.

RESULTS

A total of 865 patients were included; 351 infections were identified in 259 (30%) patients, of whom 75 (29%) had ≥1 pre-LT MDRO infection. The most common infection was spontaneous bacterial peritonitis (34%). The agent was identified in 249(71%), 53(15%) were polymicrobial. The most common microorganism was Klebsiella pneumoniae (18%); the most common MDRO was ESBL-producing Enterobacterales (16%), and carbapenem-resistant (CR) Enterobacterales (10%). Factors associated with MDRO infections before LT were previous use of therapeutic cephalosporin (p = .001) and fluoroquinolone (p = .001), SBP prophylaxis (p = .03), ACLF before LT (p = .03), and days of hospital stay pre-LT (p < .001); HCC diagnosis was protective (p = .01). Factors associated with 90-day mortality after LT were higher MELD on inclusion to the waiting list (p = .02), pre-LT MDRO infection (p = .04), dialysis after LT (p < .001), prolonged duration of LT surgery (p < .001), post-LT CR-Gram-negative bacteria infection (p < .001), and early retransplantation (p = .004).

CONCLUSION

MDRO infections before LT have an important impact on survival after LT.

The Role of Pretransplant Infections in Pediatric Receiving LDLT in Indonesia: A 7-y Retrospective Study

Liver transplantation is the definitive treatment for pediatric end-stage liver disease. Infections posttransplantation might significantly affect the outcome of the surgery. This study aimed to identify the role of pretransplant infection among children who underwent living donor liver transplantation (LDLT) in Indonesia.

Methods

This is an observational, retrospective cohort study. A total of 56 children were recruited between April 2015 and May 2022. Patients were categorized into 2 according to the presence of pretransplantation infections requiring hospitalization before the surgery. Diagnosis of posttransplantation infection was observed for up to 1 y based on the clinical features and laboratory parameters.

Results

The most common indication for LDLT was biliary atresia (82.1%). Fifteen of 56 patients (26.7%) had a pretransplant infection, whereas 73.2% of patients were diagnosed with a posttransplant infection. There was no significant association between pretransplant and posttransplant infection in all 3-time points (≤1 mo, 2-6 mo, and 6-12 mo). The most common organ involvement posttransplantation was respiratory infections (50%). The pretransplant infection did not significantly affect posttransplant bacteremia, length of stay, duration of mechanical ventilation, initiation of enteral feeding, hospitalization cost, and graft rejection.

Conclusions

Our data showed that pretransplant infections did not significantly affect clinical outcomes in post-LDLT procedures. A prompt and sufficient diagnosis and treatment before and after the LDLT procedure is the best way to obtain an optimal outcome.

Fibrinolysis resistance after liver transplant as a predictor of early infection

BACKGROUND

Infection is a leading cause of morbidity in liver transplant (LT). Considering that the fibrinolytic system is altered in sepsis, we investigated the relationship between fibrinolysis resistance (FR) and post-transplant infection.

METHODS

Fibrinolysis was quantified using thrombelastography (TEG) with the addition of tPA to quantify FR. FR was defined as LY30 = 0% and stratified as transient if present on POD1 or POD5 (tFR), persistent (pFR) if present on both, or no FR (nFR) if absent.

RESULTS

180 LT recipients were prospectively enrolled. 52 (29%) recipients developed infection. 72 had tFR; 37 had pFR; and 71 had nFR. Recipients with pFR had significantly greater incidence of infections (51% vs. 26% tFR vs. 20% nFR, p = 0.002). pFR was independently associated with increased odds of post-transplant infection (adjusted OR 3.39, p = 0.009).

CONCLUSIONS

Persistent fibrinolysis resistance is associated with increased risk of post-transplant infection.

Metagenomic Next-Generation Sequencing Versus Traditional Laboratory Methods for the Diagnosis and Treatment of Infection in Liver Transplantation

Background

Metagenomic next-generation sequencing (mNGS) has emerged as an effective method for the noninvasive and precise detection of infectious pathogens. However, data are lacking on whether mNGS analyses could be used for the diagnosis and treatment of infection during the perioperative period in patients undergoing liver transplantation (LT).

Methods

From February 2018 to October 2018, we conducted an exploratory study using mNGS and traditional laboratory methods (TMs), including culture, serologic assays, and nucleic acid testing, for pathogen detection in 42 pairs of cadaveric liver donors and their corresponding recipients. Method performance in determining the presence of perioperative infection and guiding subsequent clinical decisions was compared between mNGS and TMs.

Results

The percentage of liver donors with mNGS-positive pathogen results (64.3%, 27/42) was significantly higher than that using TMs (28.6%, 12/42; P&lt;0.05). The percentage of co-infection detected by mNGS in liver donors was 23.8% (10/42) significantly higher than 0.0% (0/42) by TMs (P&lt;0.01). Forty-three pathogens were detected using mNGS, while only 12 pathogens were identified using TMs. The results of the mNGS analyses were consistent with results of the TM analyses in 91.7% (11/12) of donor samples at the species level, while mNGS could be used to detect pathogens in 66.7% (20/30) of donors deemed pathogen-negative using TMs. Identical pathogens were detected in 6 cases of donors and recipients by mNGS, among which 4 cases were finally confirmed as donor-derived infections (DDIs). For TMs, identical pathogens were detected in only 2 cases. Furthermore, 8 recipients developed early symptoms of infection (&lt;7 days) after LT; we adjusted the type of antibiotics and/or discontinued immunosuppressants according to the mNGS results. Of the 8 patients with infections, 7 recipients recovered, and 1 patient died of severe sepsis.

Conclusions

Our preliminary results show that mNGS analyses can provide rapid and precise pathogen detection compared with TMs in a variety of clinical samples from patients undergoing LT. Combined with symptoms of clinical infection, mNGS showed superior advantages over TMs for the early identification and assistance in clinical decision-making for DDIs. mNGS results were critical for the management of perioperative infection in patients undergoing LT.

C-Reactive Protein Is an Independent Predictor of 30-Day Bacterial Infection Post-Liver Transplantation

The relationship between aseptic systemic inflammation and postoperative bacterial infection is unclear. We investigated the correlation of systemic inflammation biomarkers with 30-day clinically significant bacterial infections (CSI) after liver transplantation (LT). This retrospective study enrolled 940 patients who received LT and were followed for 30 days. The primary end point was 30-day CSI events. The cohort was divided into exploratory (n = 508) and validation (n = 432) sets according to different centers. Area under the receiver operated characteristic (AUROC) and Cox regression models were fitted to study the association between baseline systemic inflammation levels and CSI after LT. A total of 255 bacterial infectious events in 209 recipients occurred. Among systemic inflammation parameters, baseline C-reactive protein (CRP) was independently associated with 30-day CSI in the exploratory group. The combination of CRP and organ failure number showed a good discrimination for 30-day CSI (AUROC = 0.80, 95% CI, 0.76–0.84) and the results were confirmed in an external verification group. Additionally, CRP levels were correlated with bacterial product lipopolysaccharide. In conclusion, our study suggests that pre-transplantation CRP is independent of other prognostic factors for 30-day CSI post-LT, and can be integrated into tools for assessing the risk of bacterial infection post-LT or as a component of prognostic models.

Early post-liver transplantation infections and their effect on long-term survival

BACKGROUND

Infections post-liver transplantation are major drivers for morbidity and mortality. However, the impact of infections within 180 days post-liver transplantation on long-term survival is not clear.

METHODS

We present a retrospective cohort of 317 liver transplant patients for whom all infectious episodes were prospectively collected during a mean follow-up of 4.4 years.

RESULTS

A total of 143/317 (45%) of patients suffered from any infectious episode during the first 6 months following liver transplantation. Patients with surgical site infections have a reduced survival compared to those with no infection (HR 0.33, 95% CI 0.172-0.636, P = .001), whereas infections from other sources, including pneumonia, UTI, and line-related infections, were not associated with increased mortality. Furthermore, even though the presence of any infection within 30 days or 6 months post-transplantation did not affect survival, more than a single infectious episode per patient was significantly associated with increased mortality (HR 1.70, CI 1.12-2.60, P = .013). In a multivariate analysis, the number of infectious episodes remained statistically significant (HR 1.58, 95% CI 1.03-2.43, P = .035) upon adjustment for other major variables associated with comorbidities and infection risk.

CONCLUSIONS

Surgical site infections and the number of infectious episodes within 180 days post-liver transplantation are major determinants of long-term survival among these patients.

Outcomes of Liver Transplant for Adults With Wilson's Disease

Wilson's disease (WD) is a rare genetic disorder with protean manifestations. Even if liver transplantation (LT) could represent an effective therapeutic option for patients with end-stage liver disease, it has remained controversial in the presence of neuropsychiatric involvement. This study aimed to examine the frequency of adult LT for WD in Italy, focusing on the disease phenotype at the time of LT. A retrospective, observational, multicenter study was conducted across Italy exploring the frequency and characteristics of adults transplanted for WD between 2006 and 2016. A total of 29 adult WD patients underwent LT during the study period at 11 Italian LT centers (accounting for 0.4% of all LTs performed), and 27 of them were considered in this analysis (male/female, n = 9/18; age at LT, 29 years [19-60 years]; median Model for End-Stage Liver Disease score at LT, 27 [6-49]). Isolated hepatic phenotype was the indication for LT in 17 (63%) patients, whereas 2 (7%) patients underwent LT for neurological impairment on compensated liver disease. Overall 1- and 5-year patient survival was excellent (88% and 83%, respectively). Neuropsychiatric symptoms early after LT completely recovered in only a few patients. In conclusion, WD remains an uncommon, unusual indication for LT in Italy, displaying good post-LT graft and patient survival. Because isolated neuropsychiatric involvement represents a rare indication to LT, more data are needed to properly assess the value of LT for WD in this subset of patients.