Bacterial infection after liver transplantation

Immune response against bacterial infection in organ transplant recipients

This comprehensive review delves into the intricate dynamics between the immune system and bacterial infections in organ transplant recipients. Its primary objective is to fill existing knowledge gaps while critically assessing the strengths and weaknesses of current research. The paper accentuates the delicate balance that must be struck between preventing graft rejection through immunosuppression and maintaining robust immunity against bacterial threats. In this context, personalized medicine emerges as a transformative concept, offering the potential to revolutionize clinical outcomes by tailoring immunosuppressive regimens and vaccination strategies to the unique profiles of transplant recipients. By emphasizing the pivotal role of continuous monitoring, the review underscores the necessity for vigilant surveillance of transplant recipients to detect bacterial infections and associated immune responses early, thereby reducing the risk of severe infections and ultimately improving patient outcomes. Furthermore, the study highlights the significance of the host microbiome in shaping immune responses, suggesting that interventions targeting the microbiome hold promise for enhancing bacterial immunity in transplant recipients, both in research and clinical practice. In terms of future research directions, the review advocates for large-scale, longitudinal studies encompassing diverse patient cohorts to provide more comprehensive insights into post-transplant immune responses. It also advocates integrating multi-omics approaches, including genomics, transcriptomics, proteomics, and microbiome data, to understand immune responses and their underlying mechanisms. In conclusion, this review significantly enriches our understanding of immune responses in transplant recipients. It paves the way for more effective and personalized approaches to managing infections in this complex setting.

Antibiotic Use in the Surgical Intensive Care Unit

Judicious use of antibiotics in the critically ill starts with the evaluation for suspected infection, including close consideration of the patient's history. If infection is present or strongly suspected, empiric antibiotics should be promptly initiated and selected based on the source of infection, patient factors, and local resistance patterns. If the surgeon decides source control is indicated, they must determine the optimal approach and timing. As soon as culture and sensitivity data are available, de-escalation to narrower spectrum agents is essential to decrease the risks of antibiotic toxicity and resistance. Importantly, surgeons should participate in antibiotic stewardship in their patients.

Perioperative Use of IgM-Enriched Immunoglobulins in Liver Transplantation Recipients at High Risk for Infections: A Preliminary Study

Background: Infections frequently occur after orthotopic liver transplantation (OLT) and are associated with increased mortality. In 2018, we introduced perioperative administration of intravenous immunoglobulin enriched in IgM as an optional therapy in recipients at a high risk of infection. This preliminary study evaluated whether this preparation reduced infections in the early post-transplantation period. Methods: Adult patients with a high risk of postoperative infections who underwent OLT between January 2014 and December 2021 in our center were included in the study. The primary outcome was the occurrence of new postoperative bacterial and fungal infections within the first 30 days after OLT. Results: Ninety recipients at a high risk of postoperative infections who underwent OLT were included, of whom 51 (57%) received IgM preparation. Patients treated and not treated with IgM were similar in terms of demographics, model of end-stage liver disease score, and risk factors for postoperative infections. The occurrence of new infections was lower (absolute risk reduction (ARR) 21.2%; p = 0.038) in patients who received IgM than in those who did not. Multivariate analysis adjusted for confounders (OR 0.348; p = 0.033) and propensity score-based matching analysis (ARR 21.2%, p = 0.067) confirmed an association between IgM preparation and lower occurrence of postoperative infections. The 90-day mortality rate was lower (ARR 13.4%, p = 0.018) in patients who received IgM preparation. Conclusions: In OLT recipients at high risk for infections, perioperative administration of an IgM-enriched preparation seems to reduce the development of new infections within the first 30 days after OLT.

High Number of Plasma Exchanges Increases the Risk of Bacterial Infection in ABO-incompatible Living Donor Liver Transplantation

BACKGROUND

Bacterial infections are major complications that cause significant mortality and morbidity in living donor liver transplantation (LDLT). The risk of bacterial infection has not been studied in ABO-incompatible (ABOi) recipients with a desensitization protocol in relation to the number of plasma exchanges (PEs). Therefore, we aimed to analyze the risk of bacterial infection in ABOi LDLT recipients with a high number of PEs compared with recipients with a low number of PEs.

METHODS

A retrospective study was performed with 681 adult LDLT recipients, of whom 171 ABOi LDLT recipients were categorized into the high (n = 52) or low (n = 119) PE groups based on a cutoff value of 6 PE sessions. We compared bacterial infections and postoperative bacteremia within 6 mo after liver transplantation with the ABO-compatible (ABOc) LDLT group (n = 510) as a control group.

RESULTS

The high PE group showed a bacterial infection rate of 49.9% and a postoperative bacteremia rate of 28.8%, which were significantly higher than those of the low PE group (31.1%, 17.8%) and the ABOc group (26.7%, 18.0%). In multivariate analysis, the high PE group was found to have a 2.4-fold higher risk of bacterial infection ( P  = 0.008). This group presented a lower 5-y survival rate of 58.6% compared with the other 2 groups (81.5% and 78.5%; P  = 0.030 and 0.001).

CONCLUSIONS

A high number of preoperative PEs increases bacterial infection rate and postoperative bacteremia in ABOi LDLT.

Graft-to-recipient weight ratio and risk of systemic inflammatory response syndrome early after liver transplantation in children

BACKGROUND

Systemic inflammatory responses soon after liver transplantation in children can lead to complications and poor outcomes, so here we examined potential risk factors of such responses.

METHODS

Data were retrospectively analyzed for 69 children who underwent liver transplantation at a single center between July 2017 and November 2019 through follow-up lasting up to one years. Numerous clinicodemographic factors were compared between those who suffered early systemic inflammatory response syndrome (SIRS) or not.

RESULTS

Of the 69 patients in our analysis, early SIRS occurred in 35 [50.7%, 95% confidence interval (CI), 38.6-62.8%]. Those patients showed significantly higher graft-to-recipient weight ratio (3.69 ± 1.26 vs. 3.12 ± 0.99%, P = 0.042) and lower survival rate at one year (85.7% vs. 100%, P = 0.023). Multivariate analysis found graft-to-recipient weight ratio > 4% to be an independent risk factor for early SIRS [odds ratio (OR) 3.8, 95% CI 1.08-13.371, P = 0.037], and a cut-off value of 4.04% predicted the syndrome in our patients, and area under the receiver operating characteristic curve of 0.656 (95% CI 0.525-0.788, P = 0.026).

CONCLUSIONS

Graft-to-recipient weight ratio > 4% may predict higher risk of SIRS soon after liver transplantation in children.

The predictors of fungal infections after liver transplantation and the influence of fungal infections on outcomes

The primary objective of this study was to assess the incidence, timing, risk factors of fungal infections (FIs) within 3 months after liver transplantation (LT). The secondary objective was to evaluate the impact of FIs on outcomes. Four hundred and ten patients undergoing LT from January 2015 until January 2023 in a tertiary university hospital were included in the present retrospective cohort study to investigate the risk factors of FIs and to assess the impacts of FIs on the prognosis of LT recipients using logistic regression. The incidence of FIs was 12.4% (51/410), and median time from LT to the onset of FIs was 3 days. By univariate analysis, advanced recipient age, prolonged hospital stay prior to LT, high Model for End Stage Liver Disease (MELD) score, use of broad-spectrum antibiotics, and elevated white blood cell (WBC) count, increased operating time, massive blood loss and red blood cell transfusion, elevated alanine aminotransferase on day 1 and creatinine on day 3 after LT, prolonged duration of urethral catheter, prophylactic antifungal therapy, the need for mechanical ventilation and renal replacement therapy were identified as factors of increased post-LT FIs risk. Multivariate logistic regression analysis identified that recipient age ≥ 55 years[OR = 2.669, 95%CI: 1.292-5.513, P = 0.008], MELD score at LT ≥ 22[OR = 2.747, 95%CI: 1.274-5.922, P = 0.010], pre-LT WBC count ≥ 10 × 109/L[OR = 2.522, 95%CI: 1.117-5.692, P = 0.026], intraoperative blood loss ≥ 3000 ml [OR = 2.691, 95%CI: 1.262-5.738, P = 0.010], post-LT duration of urethral catheter > 4 d [OR = 3.202, 95%CI: 1.553-6.602, P = 0.002], and post-LT renal replacement therapy [OR = 5.768, 95%CI: 1.822-18.263, P = 0.003] were independently associated with the development of post-LT FIs. Post-LT prophylactic antifungal therapy ≥ 3 days was associated with a lower risk of the development of FIs [OR = 0.157, 95%CI: 0.073-0.340, P < 0.001]. As for clinical outcomes, FIs had a negative impact on intensive care unit (ICU) length of stay ≥ 7 days than those without FIs [OR = 3.027, 95% CI: 1.558-5.878, P = 0.001] but had no impact on hospital length of stay and 1-month all-cause mortality after LT. FIs are frequent complications after LT and the interval between the onset of FIs and LT was short. Risk factors for post-LT FIs included high MELD score at LT, advanced recipient age, pre-LT WBC count, massive intraoperative blood loss, prolonged post-LT duration of urethral catheter, and the need for post-LT renal replacement therapy. However, post-LT prophylactic antifungal therapy was independently associated with the reduction in the risk of FIs. FIs had a significant negative impact on ICU length of stay.

Risk factors and crucial prognostic indicators of mortality in liver transplant recipients with bloodstream infections: A comprehensives study of 1049 consecutive liver transplants over an 11-year period

BACKGROUND

Liver transplantation (LT) is a pivotal treatment for end-stage liver disease. However, bloodstream infections (BSI) in the post-operative period present a significant threat to patient survival. This study aims to identify risk factors for post-LT BSI and crucial prognostic indicators for mortality among affected patients.

METHODS

We conducted a retrospective study of adults diagnosed with end-stage liver disease who underwent their initial LT between 2010 and 2021. Those who developed BSI post-LT during the same hospital admission were classified into the BSI group.

RESULTS

In this cohort of 1049 patients, 89 (8.4%) developed BSI post-LT, while 960 (91.5%) did not contract any infection. Among the BSI cases, 17 (19.1%) patients died. The average time to BSI onset was 48 days, with 46% occurring within the first month post-LT. Of the 123 isolated microorganisms, 97 (78.8%) were gram-negative bacteria. BSI patients had significantly longer stays in the intensive care unit and hospital compared to non-infected patients. The 90-day and in-hospital mortality rates for recipients with BSI were significantly higher than those without infections. Multivariate analysis indicated heightened BSI risk in patients with blood loss >3000 mL during LT (odds ratio [OR] 2.128), re-operation within 30 days (OR 2.341), post-LT bile leakage (OR 3.536), and graft rejection (OR 2.194). Additionally, chronic kidney disease (OR 6.288), each 1000 mL increase in intraoperative blood loss (OR 1.147) significantly raised mortality risk in BSI patients, whereas each 0.1 mg/dL increase in albumin levels correlated with a lower risk of death from BSI (OR 0.810).

CONCLUSIONS

This study underscores the need for careful monitoring and management in the post-LT period, especially for patients at higher risk of BSI. It also suggests that serum albumin levels could serve as a valuable prognostic indicator for outcomes in LT recipients experiencing BSI.

A 29-mRNA host-response classifier identifies bacterial infections following liver transplantation - a pilot study

PURPOSE

Infections are common complications in patients following liver transplantation (LTX). The early diagnosis and prognosis of these infections is an unmet medical need even when using routine biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT). Therefore, new approaches are necessary.

METHODS

In a prospective, observational pilot study, we monitored 30 consecutive patients daily between days 0 and 13 following LTX using the 29-mRNA host classifier IMX-BVN-3b that determine the likelihood of bacterial infections and viral infections. True infection status was determined using clinical adjudication. Results were compared to the accuracy of CRP and PCT for patients with and without bacterial infection due to clinical adjudication.

RESULTS

Clinical adjudication confirmed bacterial infections in 10 and fungal infections in 2 patients. 20 patients stayed non-infected until day 13 post-LTX. IMX-BVN-3b bacterial scores were increased directly following LTX and decreased until day four in all patients. Bacterial IMX-BVN-3b scores detected bacterial infections in 9 out of 10 patients. PCT concentrations did not differ between patients with or without bacterial, whereas CRP was elevated in all patients with significantly higher levels in patients with bacterial infections.

CONCLUSION

The 29-mRNA host classifier IMX-BVN-3b identified bacterial infections in post-LTX patients and did so earlier than routine biomarkers. While our pilot study holds promise future studies will determine whether these classifiers may help to identify post-LTX infections earlier and improve patient management.

CLINICAL TRIAL NOTATION

German Clinical Trials Register: DRKS00023236, Registered 07 October 2020, https://drks.de/search/en/trial/DRKS00023236.

Microbiological and molecular studies on a multidrug-resistant Pseudomonas aeruginosa from a liver transplant patient with urinary tract infection in Egypt

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen responsible for complicated UTIs and exhibits high antibiotic resistance, leading to increased mortality rates, especially in cases of multidrug-resistant strains. This study aimed to investigate the antibiotic susceptibility patterns and genomic characterization of XDR strains identified in end-stage liver disease patients who underwent liver transplants.

METHODS

In this study, a number of 30 individuals who underwent liver transplants were registered. Ninety urine and 60 wound site swab samples were collected and processed for culturing, identification, and antimicrobial sensitivity. Extensively drug-resistant strain EMARA01 was confirmed through Sanger sequencing and was then processed for whole genome sequencing to characterize the genomic pattern. Sequencing data were processed for de novo assembly using various tools and databases, including genome annotation, serotype identification, virulence factor genes, and antimicrobial resistance gene. Pangenome analysis of randomly selected 147 reference strains and EMAR01 sequenced strain was performed using the Bacterial Pan Genome Analysis (BPGA) software.

RESULTS

Of these total examined samples, nosocomial infection due to P. aeruginosa was detected in twelve patients' samples. AST analysis showed that P. aeruginosa strains exhibit resistance to tobramycin, erythromycin, and gentamicin, followed by piperacillin and ofloxacin, and no strains exhibit resistance to meropenem and imipenem. The CARD database identified 59 AMR genes similar to the EMAR01 strain genome and mostly belong to the family involved in the resistance-nodulation-cell division (RND) antibiotic efflux pump. Five genes; nalC, nalD, MexR, MexA, and MexB, exhibit resistance to 14 classes of antibiotics, while two AMR; CpxR, and OprM, exhibit resistance to 15 classes of drugs. Pangenome analysis revealed that the pan-genome remained open, suggesting the potential for acquiring accessory and unique genes. Notably, the genes predominantly involved in amino acid transport metabolism were identified using the KEGG database.

CONCLUSIONS

This study provides valuable insights into the antimicrobial resistance profile, genetic features, and genomic evolution of P. aeruginosa strains causing UTIs in liver transplant patients. The findings emphasize the significance of comprehending AMR mechanisms and genetic diversity in P. aeruginosa for developing effective treatment strategies and infection control measures.

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.

Epidemiology and Management of Infections in Liver Transplant Recipients

Background: Improvements in liver transplant (LT) outcomes are attributed to advances in surgical techniques, use of potent immunosuppressants, and rigorous pre-LT testing. Despite these improvements, post-LT infections remain the most common complication in this population. Bacteria constitute the most common infectious agents, while fungal and viral infections are also frequently encountered. Multi-drug-resistant bacterial infections develop because of polymicrobial overuse and prolonged hospital stays. Immediate post-LT infections are commonly caused by viruses. Conclusions: Appropriate vaccination, screening of both donor and recipients before LT and antiviral prophylaxis in high-risk individuals are recommended. Antimicrobial drug resistance is common in high-risk LT and associated with poor outcomes; epidemiology and management of these cases is discussed. Additionally, we also discuss the effect of coronavirus disease 2019 (COVID-19) infection and monkeypox in the LT population.

Comparative phenotypic and genotypic analysis of community-acquired and hospital-acquired intra-abdominal infections among liver transplanted patients

AIM

During liver transplantation, both hospital-acquired (HA) and community-acquired (CA) intra-abdominal infections (IAIs) are involved causing life-threatening diseases. Therefore, comparative studies of aerobic and facultative anaerobic HA-IAIs and CA-IAIs after liver transplantation surgery are necessary.

METHODS AND RESULTS

The species of detected isolates (310) from intra-abdominal fluid were identified and classified into hospital-acquired intra-abdominal infections (HA-IAIs) and community-acquired intra-abdominal infections (CA-IAIs). Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii were the most commonly detected species. The resistant phenotypes were commonly detected among the HA-IAIs; however, the virulent phenotypes were the predominant strains of CA-IAIs. Regrettably, the resistance profiles were shocking, indicating the inefficacy of monotherapy in treating these isolates. Therefore, we confirmed the use of empirical combination therapies of amikacin and meropenem for treating all IAIs (FICI ≤ 0.5). Unfortunately, the high diversity and low clonality of all identified HA and CA-IAIs were announced with D-value in the range of 0.992-1.

CONCLUSION

This diversity proves that there are infinite numbers of infection sources inside and outside healthcare centers.

Bacterial Infections After Liver Transplantation and the Role of Oral Selective Digestive Decontamination: A Retrospective Cohort Study

BACKGROUND

Bacterial infections are common after liver transplantation (LT) and cause serious morbidity and mortality. In our center, prolonged selective digestive decontamination (SDD) is the standard of care, which may lead to a reduced number and severity of bacterial infections. The aim of the current study was to investigate bacterial infection rates, the causative pathogens, localization, and the possible influence of SDD within the first year after LT.

METHODS

A retrospective single-center cohort study was performed. Patients within their first year after LT between 2012 and 2017 were included. Patients received SDD for 3 weeks immediately after LT. The type of infection, bacterial subtype, CSI classification, severity, and potential interventions were recorded.

RESULTS

One hundred eighty-six patients were included in the study. Seventy-eight patients (41.9%) had a bacterial infection within the first year after LT. The most common types of infection were cholangitis (25.8%) and secondary infected abdominal fluid collections (25.3%). The most common bacteria were Gram-positive enterococcal- (36.5%) and Gram-negative enterobacterial species (34.2%). 35.5% of the infections occurred within the first month after LT, mainly caused by Gram-positive bacteria (76.7%).

CONCLUSIONS

Cholangitis and infected abdominal fluid are the most common types of infection within one year after LT, mainly caused by enterococcal- and enterobacterial species. Within the first month after LT, infections were mostly caused by Gram-positive bacteria, which could be a consequence of protocol use of SDD. The results can be used for the choice of empirical antibiotic therapy based on the most common types of bacteria and the time frame after LT.

Antimicrobial approach of abdominal post-surgical infections

Abdominal surgical site infections (SSIs) are infections that occur after abdominal surgery. They can be superficial, involving the skin tissue only, or more profound, involving deeper skin tissues including organs and implanted materials. Currently, SSIs are large global health problem with an incidence that varies significantly depending on the United Nations' Human Development Index. The purpose of this review is to provide a practical update on the latest available literature on SSIs, focusing on causative pathogens and treatment with an overview of the ongoing studies of new therapeutic strategies.

No Additional Risk of Ampicillin Rash Among Pediatric Liver Transplant Recipients With Concurrent Epstein-Barr Virus Infection

BACKGROUND

Epstein-Barr virus (EBV) infection frequently develops in children undergoing liver transplantation (LT) because of mandated immunosuppressive therapy. There is a risk of ampicillin rash when penicillin derivatives are used in patients with EBV-associated infectious mononucleosis. Hence, the administration of penicillin derivatives may raise concerns about ampicillin rash in patients with high EBV loads. However, no studies confirmed the risk of administering penicillin derivatives to EBV-infected children after LT.

METHODS

This retrospective study was conducted at the largest pediatric transplantation center in Japan. We investigated all pediatric liver transplant recipients who received penicillin derivatives within 2 years of LT between 2014 and 2020. We separated the cohort into EBV-positive and EBV-negative groups to assess the frequency of ampicillin and antibiotic-associated rash.

RESULTS

Two hundred eighty-six liver transplant recipients were enrolled. There were 111 recipients in the EBV-positive group and 175 recipients in the EBV-negative group. In the EBV-positive group, 49 patients had high EBV DNA loads (≥1000 copies/µg DNA). None of the patients in either group developed ampicillin rash, and the frequency of antibiotic-associated rash did not differ [8/111 (7.2%) vs. 10/175 (5.7%), P = 0.797]. Additional subgroup analysis revealed no difference in the frequency of antibiotic-associated rashes regardless of the presence or absence of high EBV loads.

CONCLUSIONS

In this study, ampicillin rash was not observed, and antibiotic-associated rash was not associated with concurrent EBV infection. Penicillin derivatives can be used safely, even in liver transplant recipients with persistent asymptomatic EBV infection.

Risk factors of early bacterial infection and analysis of bacterial composition, distribution and drug susceptibility after cadaveric liver transplantation

BACKGROUND

This study provided a theoretical basis for the clinical diagnosis and treatment of bacterial infection after liver transplantation through analyzing the pathogenic distribution, drug sensitivity and risk factors of bacterial infection after liver transplantation.

METHODS

We collected clinical data from 207 recipients undergoing liver transplantation of graft from donation after citizens' death donors in the Third Xiangya Hospital of Central South University from January 2019 to December 2021 and analyzed the composition and distribution of bacterial pathogens, drug resistance and risk factors of infection.

RESULTS

A total of 90 bacterial infections occurred in 55 recipients within two months after liver transplantation, and the incidence of bacterial infection was 26.6% (55/207). The gram-negative bacteria (46/90, 51.1%) were more prevalent than gram-positive bacteria (44/90, 48.9%). Common sites of infection were the abdominal/biliary tract (26/90, 28.9%), lung (22/90, 22.4%) and urinary tract (22/90, 22.4%). Fourteen cases (6.8%) died after liver transplantation. Klebsiella pneumoniae (17/90, 18.9%) was the most frequent gram-negative bacteria causing infection in liver transplant recipients and 58.7%, 50%, 80.4% and 89.1% of gram-negative bacteria were sensitive to amikacin, minocycline, tigecycline and polymyxin B, respectively. The most common gram-positive bacteria was Enterococcus faecium (30/90, 33.3%) and 97.7%, 100%, 86.4%, 100% and 100% of gram-positive bacteria were sensitive to vancomycin, teicoplanin, daptomycin, tigecycline and linezolid, respectively. Univariate analysis revealed that bacterial infection was associated with female, age (≥ 50 years old), preoperative albumin (≤ 30 g/L), operation duration (≥ 400 min), intraoperative blood loss (≥ 3000 ml) and postoperative ventilator support. Binary Logistic regression analysis showed that female (OR = 3.149, 95% CI: 1.418-6.993, P = 0.005), operation duration (≥ 400 min) (OR = 2.393, 95% CI: 1.202-4.765, P = 0.013) and intraoperative blood loss (≥ 3000 ml) (OR = 2.052, 95% CI: 1.007-4.183, P = 0.048) were independent risk factors for bacterial infection after liver transplantation.

CONCLUSION

The incidence of early bacterial infection after liver transplantation was high, and the infection sites were mainly abdominal/biliary tract, respiratory tract and urinary tract. The most common pathogenic bacterium was gram-negative bacterium. Our study also identified several independent risk factors for bacterial infection after liver transplantation, including female gender, operation duration of 400 min or more, and intraoperative blood loss of 3000 ml or more. By addressing these risk factors, such as implementing strategies to optimize surgical procedures and minimize blood loss, healthcare professionals can work towards reducing the incidence of bacterial infections following liver transplantation.

Epidemiology and Prevention of Early Infections by Multi-Drug-Resistant Organisms in Adults Undergoing Liver Transplant: A Narrative Review

Invasive bacterial infections are a leading cause of morbidity and mortality after liver transplant (LT), especially during the first months after LT, and infections due to multi-drug-resistant organisms (MDRO) are increasing in this setting. Most of the infections in patients in intensive care unit arise from the endogenous microflora and, for this reason, pre-LT MDRO rectal colonization is a risk factor for developing MDRO infections in the post-LT. Moreover, the transplanted liver may carry an increased risk of MDRO infections due to organ transportation and preservation, to donor intensive care unit stay and previous antibiotic exposure. To date, little evidence is available about how MDRO pre-LT colonization in donors and recipients should address LT preventive and antibiotic prophylactic strategies, in order to reduce MDRO infections in the post-LT period. The present review provided an extensive overview of the recent literature on these topics, with the aim to offer a comprehensive insight about the epidemiology of MDRO colonization and infections in adult LT recipients, donor-derived MDRO infections, possible surveillance, and prophylactic strategies to reduce post-LT MDRO infections.

Invasive Fungal Infections: The Early Killer after Liver Transplantation

BACKGROUND

Liver transplantation is a standard of care and a life-saving procedure for end-stage liver diseases and certain malignancies. The evidence on predictors and risk factors for poor outcomes is lacking. Therefore, we aimed to identify potential risk factors for mortality and to report on overall 90-day mortality after orthotopic liver transplantation (OLT), especially focusing on the role of fungal infections.

METHODS

We retrospectively reviewed medical charts of all patients undergoing OLT at a tertiary university center in Europe.

RESULTS

From 299 patients, 214 adult patients who received a first-time OLT were included. The OLT indication was mainly due to tumors (42%, 89/214) and cirrhosis (32%, 68/214), including acute liver failure in 4.7% (10/214) of patients. In total, 8% (17/214) of patients died within the first three months, with a median time to death of 15 (1-80) days. Despite a targeted antimycotic prophylaxis using echinocandins, invasive fungal infections occurred in 12% (26/214) of the patients. In the multivariate analysis, patients with invasive fungal infections had an almost five times higher chance of death (HR 4.6, 95% CI 1.1-18.8; p = 0.032).

CONCLUSIONS

Short-term mortality after OLT is mainly determined by infectious and procedural complications. Fungal breakthrough infections are becoming a growing concern. Procedural, host, and fungal factors can contribute to a failure of prophylaxis. Finally, invasive fungal infections may be a potentially modifiable risk factor, but the ideal perioperative antimycotic prophylaxis has yet to be determined.

Characteristics of Gram-positive cocci infection and the therapeutic effect after liver transplantation

OBJECTIVES

Gram-positive cocci is the main pathogen responsible for early infection after liver transplantation (LT), posing a huge threat to the prognosis of liver transplant recipients. This study aims to analyze the distribution and drug resistance of Gram-positive cocci, the risk factors for infections and efficacy of antibiotics within 2 months after LT, and to guide the prevention and treatment of these infections.

METHODS

In this study, data of pathogenic bacteria distribution, drug resistance and therapeutic efficacy were collected from 39 Gram-positive cocci infections among 256 patients who received liver transplantation from donation after citizens' death in the Third Xiangya Hospital of Central South University from January 2019 to July 2022, and risk factors for Gram-positive cocci infection were analyzed.

RESULTS

Enterococcus faecium was the dominant pathogenic bacteria (33/51, 64.7%), followed by Enterococcus faecalis (11/51, 21.6%). The most common sites of infection were abdominal cavity/biliary tract (13/256, 5.1%) and urinary tract (10/256, 3.9%). Fifty (98%) of the 51 Gram-positive cocci infections occurred within 1 month after LT. The most sensitive drugs to Gram-positive cocci were teicoplanin, tigecycline, linezolid and vancomycin. Vancomycin was not used in all patients, considering its nephrotoxicity. Vancomycin was not administered to all patients in view of its nephrotoxicity.There was no significant difference between the efficacy of daptomycin and teicoplanin in the prevention of cocci infection (P>0.05). Univariate analysis indicated that preoperative Model for End-Stage Liver Disease (MELD) score >25 (P=0.005), intraoperative red blood cell infusion ≥12 U (P=0.013) and exposure to more than 2 intravenous antibiotics post-LT (P=0.003) were related to Gram-positive cocci infections. Multivariate logistic regression analysis revealed that preoperative MELD score >25 (OR=2.378, 95% CI 1.124 to 5.032, P=0.024) and intraoperative red blood cell transfusion ≥ 12 U (OR=2.757, 95% CI 1.227 to 6.195, P=0.014) were independent risk factors for Gram-positive cocci infections after LT. Postoperative Gram-positive cocci infections were reduced in LT recipients exposing to more than two intravenous antibiotics post-LT (OR=0.269, 95% CI 0.121 to 0.598, P=0.001).

CONCLUSIONS

Gram-positive cocci infections occurring early after liver transplantation were dominated by Enterococcus faecalis infections at the abdominal/biliary tract and urinary tract. Teicoplanin, tigecycline and linezolid were anti-cocci sensitive drugs. Daptomycin and teicoplanin were equally effective in preventing cocci infections due to Gram-positive cocci. Patients with high preoperative MELD score and massive intraoperative red blood cell transfusion were more likely to suffer Gram-positive cocci infection after surgery. Postoperative Gram-positive cocci infections were reduced in recipients exposing to more than two intravenous antibiotics post-LT.

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.

Bacteremia in Pediatric Liver Transplant Recipients

BACKGROUND

We aimed to determine the frequency of bacteremia, septic shock and bacterial meningitis in pediatric liver transplant recipients (pLTRs) in the outpatient setting and to identify clinical factors associated with bacteremia.

METHODS

Multicenter retrospective study of pLTRs evaluated in the emergency department or outpatient clinic between 2010 and 2018 for suspected infection, defined as fever ≥38 °C or a blood culture obtained. We excluded patients with nontransplant immunodeficiency, multiorgan transplants or intestinal failure. The primary outcome was bacteremia; secondary outcomes included fluid-refractory septic shock, bacterial meningitis and antibiotic resistance. The unit of analysis was the encounter.

RESULTS

A total of 151 children had 336 encounters for infection evaluation within 2 years of transplant. Of 307 (91.4%) encounters with blood cultures, 17 (5.5%) had bacteremia, with 10 (58.8%) occurring within 3 months of transplant. Fluid-refractory septic shock and bacterial meningitis occurred in 7 out of 307 (2.8%) and 0 out of 307 encounters, respectively. Factors associated with bacteremia included closer proximity to transplant (<3 months) [odds ratio (OR): 3.6; 95% confidence interval (CI): 1.3-9.8; P = 0.01], shorter duration of illness (OR: 4.3; 95% CI: 1.5-12.0; P < 0.01) and the presence of a central venous catheter (CVC) (OR: 12.7; 95% CI: 4.4-36.6; P < 0.01). However, 5 (29.4%) encounters with bacteremia had none of these factors. Among Gram-positive pathogens, 1 out of 7 (14.2%) isolates were resistant to vancomycin. Among Gram-negative pathogens, 3 out of 13 (23.1%) isolates were resistant to 3rd generation cephalosporins.

CONCLUSIONS

Bacteremia was an important cause of infection within 2 years of pLTR. Clinical factors increased the risk of bacteremia. Further, large sample studies should derive multivariable models to identify those at high and low risk of bacteremia to optimize antibiotic use.

miR-27a-5p inhibits acute rejection of liver transplantation in rats by inducing M2 polarization of Kupffer cells through the PI3K/Akt pathway

Liver transplantation (LT), a major therapy for end-stage liver disease, is often associated with acute rejection (AR). MicroRNAs (miRNAs) have been implicated in AR-related gene regulation. In this experiment, the mechanism of miR-27a-5p in AR of LT was studied. Allotransplantation model (LEW-BN) and syngeneic transplantation model (LEW-LEW) of rat orthotopic liver transplantation (OLT) were established. miR-27a-5p was overexpressed in recipient rats 28 days before LT to detect its effects on LT pathology, liver function, and survival time. Kupffer cells (KCs) were isolated and treated with lipopolysaccharide (LPS) and miR-27a-5p overexpression. miR-27a-5p overexpression reduced lymphocyte numbers around portal areas and central veins after LT and mitigated degeneration of epithelial cells of the bile duct. Expression levels of IL-10 and TGF-β1 were increased while IL-12 was decreased. Liver function damage was alleviated and the survival time of rats with LT was prolonged. miR-27a-5p induced M2 polarization of rats with AR after LT and LPS-treated KCs in vitro and promoted activation of the PI3K/Akt pathway in KCs. Inhibition of the PI3K/Akt pathway averted induction of miR-27a-5p on M2 polarization of KCs. Taken together, miR-27a-5p inhibited AR after LT in rats by inducing M2 polarization of KCs through the PI3K/Akt pathway.

Incidence, mortality, and risk factors associated with carbapenem-resistant Acinetobacter baumannii bacteremia within 30 days after liver transplantation

Carbapenem-resistant Acinetobacter baumannii bacteremia (CRAB-B) is a fatal infectious complication of liver transplantation (LT). This study investigated the incidence, effects, and risk factors associated with CRAB-B during the early post-LT period. Among 1051 eligible LT recipients, 29 patients experienced CRAB-B within 30 days of LT with a cumulative incidence of 2.7%. In the patients with CRAB-B (n = 29) and matched controls (n = 145) by nested-case control design, the cumulative incidence of death on days 5, 10, and 30 from the index date was 58.6%, 65.5%, and 65.5%, and 2.1%, 2.8%, and 4.2%, respectively (p < .001). Pre-transplant MELD (OR 1.11, 95% confidence interval [CI] 1.04-1.19, p = .002), severe encephalopathy (OR 4.62, 95% CI 1.24-18.61, p = .025), donor body mass index (OR .57, 95% CI .41-.75, p < .001), and reoperation (OR 6.40, 95% CI 1.19-36.82, p = .032) were independent risk factors for 30-day CRAB-B. CRAB-B showed extremely high mortality within 30 days after LT, especially within 5 days after its occurrence. Therefore, assessment of risk factors and early detection of CRAB, followed by proper treatment, are necessary to control CRAB-B 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.

Incidence of Invasive Fungal Infections in Liver Transplant Recipients under Targeted Echinocandin Prophylaxis

Invasive fungal infections (IFIs) are one of the most important infectious complications after liver transplantation, determining morbidity and mortality. Antimycotic prophylaxis may impede IFI, but a consensus on indication, agent, or duration is still missing. Therefore, this study aimed to investigate the incidence of IFIs under targeted echinocandin antimycotic prophylaxis in adult high-risk liver transplant recipients. We retrospectively reviewed all patients undergoing a deceased donor liver transplantation at the Medical University of Innsbruck in the period from 2017 to 2020. Of 299 patients, 224 met the inclusion criteria. We defined patients as being at high risk for IFI if they had two or more prespecified risk factors and these patients received prophylaxis. In total, 85% (190/224) of the patients were correctly classified according to the developed algorithm, being able to predict an IFI with a sensitivity of 89%. Although 83% (90/109) so defined high-risk recipients received echinocandin prophylaxis, 21% (23/109) still developed an IFI. The multivariate analysis identified the age of the recipient (hazard ratio-HR = 0.97, p = 0.027), split liver transplantation (HR = 5.18, p = 0.014), massive intraoperative blood transfusion (HR = 24.08, p = 0.004), donor-derived infection (HR = 9.70, p < 0.001), and relaparotomy (HR = 4.62, p = 0.003) as variables with increased hazard ratios for an IFI within 90 days. The fungal colonization at baseline, high-urgency transplantation, posttransplant dialysis, bile leak, and early transplantation showed significance only in a univariate model. Notably, 57% (12/21) of the invasive Candida infections were caused by a non-albicans species, entailing a markedly reduced one-year survival. The attributable 90-day mortality rate of an IFI after a liver transplant was 53% (9/17). None of the patients with invasive aspergillosis survived. Despite targeted echinocandin prophylaxis, there is still a notable risk for IFI. Consequently, the prophylactic use of echinocandins must be critically questioned regarding the high rate of breakthrough infections, the increased occurrence of fluconazole-resistant pathogens, and the higher mortality rate in non-albicans Candida species. Adherence to the internal prophylaxis algorithms is of immense importance, bearing in mind the high IFI rates in case algorithms are not followed.

Nutritional Strategies to Manage Malnutrition and Sarcopenia following Liver Transplantation: A Narrative Review

Persisting or newly developed malnutrition and sarcopenia after liver transplant (LT) are correlated with adverse health outcomes. This narrative review aims to examine the literature regarding nutrition strategies to manage malnutrition and sarcopenia after LT. The secondary aims are to provide an overview of the effect of nutrition strategies on the incidence of infections, hospital length of stay (LOS), acute cellular rejection (ACR), and mortality after LT. Four databases were searched. A total of 25 studies, mostly of mid-high quality, were included. Six studies found a beneficial effect on nutritional parameters using branched-chain amino acids (BCAA), immunomodulating diet (IMD), or enteral nutrition (EN) whereas two studies using beta-hydroxy-beta-methylbutyrate (HMB) found a beneficial effect on muscle mass and function. Fourteen studies using pre- or pro-biotics, IMD, and EN were effective in lowering infection and six studies using IMD, BCAA or HMB reported reduced hospital LOS. Finally, four studies using HMB and vitamin D were effective in reducing ACR and one study reported reduced mortality using vitamin D after LT. In conclusion, nutritional intervention after LT has different beneficial effects on malnutrition, sarcopenia, and other advert outcomes. Additional large and well-constructed RCTs using validated tools to assess nutritional status and sarcopenia are warranted to ensure more robust conclusions.

Early relaparotomy following pediatric living-donor liver transplantation: experience in an Indonesian national referral hospital

Background

Living donor liver transplantation (LDLT) remains the only curative treatment for children with end-stage liver disease; however, complications of the procedure are associated with indications for early relaparotomy. Several risk factors associated with early relaparotomy after liver transplantation include pediatric end-stage liver disease (PELD) score, warm ischemia time (WIT), and cold ischemia time (CIT). Our study investigated the incidence and indications of early relaparotomy in postoperative pediatric LDLT recipients and compared the outcomes with patients who did not require relaparotomy.

Methods

A retrospective cohort study of pediatric LDLT recipients from Cipto Mangunkusumo Hospital, Jakarta, Indonesia, was collected from 2010 to August 2022. Indications for early relaparotomy were investigated. Factors analyzed in the early relaparotomy group compared with the nonrelaparotomy group included intraoperative blood loss, surgery duration, CIT, WIT, and PELD score.

Results

The highest indication for early relaparotomy was biliary leakage. Most patients who underwent early relaparotomy only had one incidence of relaparotomy (60%). The surgery duration in subjects with early relaparotomy was longer by a median of 3 hours compared with those without early relaparotomy (p=0.289). Intraoperative blood loss was greater in early relaparotomy subjects than in subjects without early relaparotomy (95 vs 77 mL/kg, p=0.552). Other factors, such as PELD score, CIT, and WIT, also showed no significant difference between the two groups.

Conclusion

Biliary leakage was the most common indication for early relaparotomy in our center. There were no preoperative or intraoperative factors that significantly influenced the incidence of early relaparotomy due to the limited sample size and the early advancement of our liver transplant center.

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.

Epidemic, risk factors of carbapenem-resistant Klebsiella pneumoniae infection and its effect on the early prognosis of liver transplantation

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection remains a major cause of morbidity and mortality in early-stage post-liver transplantation (LT).

Methods

We retrospectively analyzed the demographic and clinical infections characteristics of all LT recipients in our hospital between January 2019 and December 2021.

Results

Among the 272 LT recipients who received LT between January 2019 and December 2021, sixty-two patients had at least one infection within 3-months post-LT, with a prevalence of 22.8% (62/272). The prevalence of CRKP infections was 7.0% (19/272), and the 3-months post-LT mortality was 19.4% (12/62). The risk factors independently related to 3-months mortality were age (Odds ratio (OR)= 1.126, 95% Confidence interval (CI): 1.009~1.257; P=0.034), mechanical ventilation (MV) (OR=1.206, 95% CI: 1.039~1.401; P =0.014), and CRKP infection (OR=18.240, 95% CI: 2.206~150.842; P =0.007). In CRKP infection, the length of ICU stay (OR=1.067, 95% CI: 1.015~1.122; P=0.011), pre-operation infection (POI) (OR=6.733, 95% CI: 1.160~39.088; P=0.034), and hepatocellular carcinoma (HCC) (OR=26.772, 95% CI: 1.747~410.187; P=0.018) were the independent risk factors. With COX multivariate regression analysis, the 3-months survival rate of CRKP infected patients was significantly lower than that without CRKP infection post-LT.

Conclusions

CRKP infection is closely correlated with poor prognosis in 3-months post-LT.

Pathogen distribution and risk factors of bacterial and fungal infections after liver transplantation

OBJECTIVES

Liver transplant recipients have a high rate of postoperative infection, and identification of patients at high risk for bacterial and fungal infections will help prevent disease and improve long-term outcomes for them. This study aims to understand the composition, distribution, prognosis of bacterial and fungal infections within 2 months after liver transplantation and to analyze their risk factors.

METHODS

The data of pathogen composition, distribution, and prognosis of bacterial and fungal infections among liver transplant recipients in the Third Xiangya Hospital of Central South University from May 2020 to October 2021 were collected, and the risk factors for these infections were analyzed.

RESULTS

A total of 106 episodes of bacterial or fungal infections occurred in 71.4% of liver transplant recipients (75/105). Gram-negative bacteria were the dominant pathogenic bacteria (49/106, 46.2%), followed by Gram-positive bacteria (31/106, 29.2%). The most common Gram-negative bacterium was Acinetobacter baumannii (13/106, 12.3%). The most common Gram-positive bacterium was Enterococcus faecium (20/106, 18.9%). The most common infections were pulmonary (38/105, 36.2%) and multiple site infections (30/105, 28.6%). Six (6/105, 5.7%) patients with infections died within 2 months after liver transplantation. Univariate analysis showed that the model for end-stage liver disease (MELD) score ≥25, antibiotic use within half a month before transplantation, infections within 2 months prior to transplantation, intraoperative red blood cell infusion≥8 U, indwelling urinary tract catheter ≥4 days after transplantation, and the dosage of basiliximab use ≥40 mg were associated with infections. Multivariate logistic regression analysis revealed that only infections within 2 months prior to transplantation (OR=5.172, 95% CI 1.905-14.039, P<0.01) was an independent risk factor for bacterial and fungal infections after liver transplantation. Postoperative bacterial and fungal infections were reduced in liver transplant recipients receiving basiliximab ≥40 mg (OR=0.197, 95% CI: 0.051-0.762, P<0.05).

CONCLUSIONS

The incidence of bacterial and fungal infections is high in the early stage after liver transplantation, and the mortality after infection is significantly higher than that of non-infected patients. The most common infection is respiratory infection, and the dominant pathogens is Gram-negative bacteria. Patients infected within 2 months prior to liver transplantation are prone to bacterial and fungal infections. Standard use of basiliximab can reduce the incidence of infections after liver transplantation.

Risk factors and management of biliary stones after living donor liver transplant and its effect on graft outcome

Background

Bile stones are associated with numerous complications in liver transplant recipients. Endoscopic retrograde cholangiopancreatography (ERCP) has been proven to be safe and highly effective in dealing with most post-transplant biliary complications.

Objective

The objective of this study was to identify the possible risk factors for bile stone formation on top of biliary stricture, the effects of stones on graft outcomes, and their management.

Methods

This case–control study included 83 patients who underwent living donor liver transplant (LDLT) and suffered from postoperative biliary stricture with or without stones. Patients were divided into two groups. Group 1 (n = 55) included patients with biliary strictures with no stones and group 2 (n = 28) included patients who developed stones on top of biliary strictures. Data about the recipient and donor characteristics, surgical technique, blood lipid profile, immunosuppressive drugs, post-transplant complications, and interventions were collected from the medical records.

Results

The frequency of hepatitis C virus (HCV) was significantly higher in group 2 compared to group 1 (71.4% vs. 47.3%, p = 0.036). The body mass index (BMI) of the donors was significantly higher in group 2 than in group 1 (25.17 ± 2.53 vs. 23.68 ± 2.63, p = 0.015). Episodes of acute rejection were significantly higher in group 2 than in group 1 (21.4% vs. 5.5%, p = 0.027). The ERCP was sufficient in most of the cases (89.2%) to ensure biliary drainage. The identified independent risk factors for biliary stones included HCV, biliary drain, donor's BMI, and serum cholesterol level.

Conclusion

Positive HCV, biliary drain insertion, donor's BMI, and serum cholesterol level were independent risk factors for developing bile stones on top of biliary strictures. Biliary stones were associated with high episodes of acute graft rejection, and they could be successfully managed by the ERCP modality.

Carbapenems versus Cephalosporin or Piperacillin-Tazobactam as Perioperative Antibiotic Prophylaxis in Liver Transplant Recipients with Model for End-Stage Liver Disease Scores of ≥30: A Retrospective Study in a Chinese Population

Objective

Perioperative prophylaxis, commonly with a third-generation cephalosporin plus ampicillin or piperacillin-tazobactam, is usually employed to prevent infections in liver transplantation (LT) recipients. Patients with a high Model for End-Stage Liver Disease (MELD) score have an increased infection risk after LT. However, whether carbapenems could be used as surgical prophylaxis in these high-risk patients remains unclear. Therefore, this study aimed at comparing the effectiveness of carbapenems with that of cephalosporin or piperacillin-tazobactam for surgical prophylaxis in high-risk LT recipients with a MELD score ≥30.

Design or Methods

This retrospective study included adult patients with a MELD score ≥30 who underwent LT between May 2018 and September 2020. We comparatively analyzed the infection rate and outcome between patients using cefoperazone-sulbactam or piperacillin-tazobactam and those using carbapenems as surgical prophylaxis.

Results

This study included 105 LT recipients. Seventy-eight and 27 patients used non-carbapenem and carbapenem antibiotics, respectively, as surgical prophylaxis. The corresponding infection incidence rates within 30 days were 38.5% and 66.7% (p = 0.011). Multivariate analysis revealed that reoperation and the Child–Pugh score were independent risk factors for infections within 30 days after LT. The following four risk factors were associated with the 180-day post-LT survival: MELD score, vascular complication, intra-abdominal bleeding, and infection with carbapenem-resistant organisms (CROs). There was no significant difference in CRO infection incidence between the carbapenem and non-carbapenem groups (18.5% vs 11.5%; p = 0.345).

Conclusion

Carbapenem use as surgical prophylaxis was not associated with infection incidence within 30 days after LT, 180-day post-LT survival or CRO infection. Therefore, carbapenems are not superior to cephalosporin or piperacillin-tazobactam for perioperative antibiotic prophylaxis in LT recipients with a MELD score ≥30.

Systematic review and meta-analysis of the diagnostic accuracy of procalcitonin for post-operative sepsis/infection in liver transplantation

BACKGROUND

Post-operative infection is a major cause of morbidity and mortality in Liver Transplantation (LT). Early diagnosis and antimicrobial treatment improves outcomes and ruling out sepsis aids immunosuppression decisions. Procalcitonin (PCT) has recently become part of such decision making in COVID-19 pneumonia but its role in LT is not established. We assessed the diagnostic accuracy of PCT as a diagnostic biomarker for infection or sepsis following LT.

METHODS

A systematic search was conducted for studies reporting diagnostic performance of PCT for infection/sepsis following LT. Studies were assessed for reporting of diagnostic accuracy, relevance and quality.

RESULTS

Eight studies with 363 participants reported data on the diagnostic accuracy of PCT, with pooled sensitivity, specificity, diagnostic odds ratio and summary receiver operator curve of 70% (95% CI 62-78), 77% (95% CI 73-83), 15.82 (95% CI 5.82-43.12) and 0.871 respectively. There was variability in the timing of sampling (post-operative day 1-8) and range of cut-off values (0.48 to 42.8 ng/mL). Heterogeneity was reduced when only studies with adult LT recipients were considered.

CONCLUSIONS

PCT performs moderately well as a diagnostic test for postoperative infection/sepsis following LT. This marker is more suited for use in adult LT populations.

Concurrent Change in Serum Cholinesterase Activity and Midregional-Proadrennomedullin Level Could Predict Patient Outcome following Liver Transplantation

Background: After liver transplantation (LTX), patients are susceptible to opportunistic infections resulting in reduced outcomes within the early post-transplantation period. The postoperative monitoring of LTX patients has gained much importance in recent years. However, reliable plasmatic markers predicting 90-day outcomes are still lacking. Methods: In the post hoc analysis of a prospective, observational study, butyrylcholinesterase (BChE), mid-regional proadrenomedullin (MR-proADM), as well as conventional inflammatory markers (procalcitonin, C-reactive protein) were evaluated in 93 patients at seven consecutive timepoints within the first 28 days following LTX. Results: Persistently reduced activity of BChE and elevated MR-proADM levels indicated reduced 90-day survival following LTX. Furthermore, reduced BChE and increased MR-proADM activity could indicate early post-transplantation bacterial infections, whereas conventional inflammatory biomarkers showed no diagnostic efficacy within the observation period. Conclusion: Concurrent assessment of BChE and MR-proADM activity might serve as a bedside diagnostic tool for early bacterial infections following liver transplantation. Thus, a combined utilization of the two biomarkers may be a useful tool in the risk evaluation of patients following liver transplantation.

Diagnostic Value and Clinical Application of mNGS for Post-Liver Transplantation Infection: A Cross-Sectional Study With Case Reports

Liver transplantation is widely acknowledged as the only effective treatment for end-stage liver disease, and infection is reportedly an important cause of postoperative death. Clinical use of metagenomic next-generation sequencing (mNGS) to diagnose postoperative infection and successfully guide drug therapy remains rare. This study included patients with infectious complications after liver transplantation from July 2019 to December 2020 and was divided into three groups: pneumonia, unknown fever, and others (including hepatic failure, kidney failure, cirrhosis after LT, and other postoperative complications that predispose to infection). The mNGS sequencing was used to detect microorganisms, and the results were compared with traditional culture. We found that mNGS yielded improved sensitivity over culture (85.19 vs. 22.22%; p<0.0001) but lower specificity (35.71 vs. 89.28%; p<0.0001). Among the 48 kinds of pathogens detected, the Torque teno virus 22 (15/122) was the most common, followed by Primate erythroparvovirus 1 (13/122). The top four bacteria included Klebsiella pneumoniae (n = 8), Enterococcus faecium (n = 5), Stenotrophomonas maltophilia (n = 4), and Escherichia coli (n = 4). Aspergillus fumigatus was the most common fungus. The bronchoalveolar lavage fluid (BALF) exhibited the highest proportion of positive findings among sample types, with viral, fungal, and bacterial mixed infection being the most common (n = 6, 19.35%). Besides, using mNGS for early diagnosis of infection after liver transplantation may effectively prolong patient survival. This is the first study to explore the application value of mNGS and its comparison with traditional culture in pneumonia and other infections in post-liver transplantation patients. The simultaneous application of these two methods suggested that the Torque teno virus 22, Klebsiella pneumoniae, and the Aspergillus fumigatus are the most common pathogens of viruses, bacteria, and fungi after LT, suggesting that these pathogens may be associated with postoperative pathogen infection and patient prognosis. The mNGS technique showed distinct advantages in detecting mixed, viral, and parasitic infections in this patient population. Further studies are warranted to systematically elucidate the dynamic evolution and molecular characteristics of infection after liver transplantation.

Immunosuppressive therapy after solid organ transplantation and the gut microbiota: Bidirectional interactions with clinical consequences

Our understanding of the involvement of the gut microbiota (GM) in human health has expanded exponentially over the last few decades, particularly in the fields of metabolism, inflammation, and immunology. Immunosuppressive treatment (IST) prescribed to solid organ transplant (SOT) recipients produces GM changes that affect these different processes. This review aims at describing the current knowledge of how IST changes the GM. Overall, SOT followed by IST results in persistent changes in the GM, with a consistent increase in proteobacteria including opportunistic pathobionts. In mice, Tacrolimus induces dysbiosis and metabolic disorders, and alters the intestinal barrier. The transfer of the GM from Tacrolimus-treated hosts confers immunosuppressive properties, suggesting a contributory role for the GM in this drug's efficacy. Steroids induce dysbiosis and intestinal barrier alterations, and also seem to depend partly on the GM for their immunosuppressive and metabolic effects. Mycophenolate Mofetil, frequently responsible for digestive side effects such as diarrhea and colitis, is associated with pro-inflammatory dysbiosis and increased endotoxemia. Alemtuzumab, m-TOR inhibitors, and belatacept have shown more marginal impact on the GM. Most of these observations are descriptive. Future studies should explore the underlying mechanism of IST-induced dysbiosis in order to better understand their efficacy and safety characteristics.

Epidemiology, Risk Factors and Outcome Due to Multidrug Resistant Organisms in Paediatric Liver Transplant Patients in the Era of Antimicrobial Stewardship and Screening

(1) Background: Multidrug-resistant organisms (MDRO) are a growing problem in liver transplant recipients (LTR), associated with high morbidity and mortality. We reviewed the impact of antimicrobial stewardship (AMS) and active screening of MDRO on the epidemiology and outcomes in paediatric LTR. (2) Methods: Single-centre retrospective review of paediatric LTR from January 2017 to December 2018. (3) Results: Ninety-six children were included; 32 (33%) patients were colonised with ≥1 MDRO and 22 (23%) patients had MDRO infections. Median (IQR) duration for start of infection was 9.5 (1.8−16.0) days. Colonisation rate with Gram-positive MDRO was 15.6%, with infection rate of 6.2%; majority due to Vancomycin-Resistant Enterococcus faecium (VRE). Colonisation with Gram-negative MDRO was 27.0%, with infection rate of 16.6%; majority due to extended-spectrum β-lactamase producing Enterobacteriaceae. Colonisation and infection rate due to Carbapenem-resistant Enterobacteriaceae was 6% and 3%, respectively, during screening and AMS, compared to historical control of 25% and 30%, respectively, without screening and AMS. There was significant reduction in VRE and CRE infection during AMS period in comparison to historical control. Pre-transplant risk factors including bacterial infections pre-transplant (p < 0.01), diagnosis of biliary atresia (p = 0.03), exposure to antibiotics (p < 0.01), EBV viraemia (p = 0.01), and auxiliary transplantation (p < 0.01) were associated with post-transplant MDRO infections. Patients with MDRO infections had longer length of hospital and paediatric intensive care unit stay days (p < 0.01) but associated with no mortality. (4) Conclusions: Our results demonstrate low incidence of colonisation and infections with MDRO, which were associated with high morbidity but no mortality in paediatric LTR. There was significant reduction in MRSA, VRE, and CRE during AMS period compared to pre-AMS era. Some risk factors are unavoidable but antibiotic overuse, early initiation of appropriate antibiotic therapy and effective infection prevention strategies can be monitored with multifaceted approach of AMS and screening of MDRO. With limited therapeutic options for MDRO and efficacy data of newer antibiotics in paediatric LTR, robust infection control practices are of paramount importance.

Eliminated routine postorthotopic liver transplant antibiotics in uncomplicated patients leads to equivalent safety outcomes

Objective:

The purpose of this retrospective study was to evaluate safety and efficacy end points of a postoperative antibiotic prophylaxis protocol in liver transplant (LT) patients, which was revised to limit antibiotic use.

Methods:

In the routine antibiotics group (RA), patients routinely received prophylactic antibiotics for around 3 days postoperatively for a variety of rationales, versus the limited antibiotics group (LA), in which patients received antibiotics for the treatment of secondary peritonitis. Patients were included if they were 18 or older and underwent liver transplant between January 2016 and September 2019. In total, 216 patients remained after exclusion: 118 patients in the RA group and 98 patients in the LA group.

Results:

We detected a significant difference in the primary end point of postoperative antibiotic days of therapy. The median days of therapy was 2 for the RA group and 0 for the LA group (P < 0.005). Significantly fewer patients received only intraoperative antibiotics in the RA group versus the LA group: 42 (35.6%) versus 76 (73.5%) respectively (P < .005). There was no significant difference in secondary or safety outcomes, including surgical site infections.

Conclusions:

This study provides evidence that limiting the duration of prophylactic antibiotics postoperatively and treating most patients with only intraoperative antibiotics is safe.

Prevention and Treatment of Carbapenem-Resistant Organism Bacilli from Liver Transplantation Donors - Single Center Experience

Objective

To evaluate and explore the effectiveness of the new prevention and control measures for the donor-derived infection (DDI) associated with CRO after liver transplantation.

Methods

The data of 120 organ donors and recipients from January 2018 to May 2020 were retrospectively analyzed at The Liver Transplantation Center of Beijing Youan Hospital, Capital Medical University, to investigate the epidemiological status of CRO in donors. The cases were divided into two groups. The implemented group was treated according to the execution of a clustered CRO prevention and control measure based on active screening combined with early initiation of prophylactic/therapeutic administration of antibiotics. The effectiveness of the prevention and control measures was evaluated by comparing the length of postoperative ICU stay, total postoperative length of hospital stay, duration of ventilator use, duration of restricted antibiotics use, the incidence of DDI, incidence and composition distribution of DDI-related CRO, and incidence of severe DDI-relevant adverse events between the two groups.

Results

There was a high detection rate of 39.32% (105 strains) of drug-resistant bacteria in the donors. Fifty-six strains of CRO were detected. Participants in group B, which implemented the new prevention and control measures, were transferred out of the ICU sooner (P = 0.023), used fewer restrictive antibiotics (P = 0.003), and were discharged more quickly (P = 0.013) than those in group A. Postoperative DDI incidences (P = 0.113) and severe DDI-related adverse events were not statistically different between the two groups (P = 0.062). CR-Kp-related DDI was less common in group B (P = 0.021).

Conclusion

The situation of donor-derived drug-resistant bacterial infections remains critical. The clustered prevention and control measures for CRO based on active screening combined with early initiation of prophylactic/therapeutic application of antibiotics would be beneficial.

Efficacy of Ceftazidime-Avibactam in the Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infection After Kidney Transplantation

Purpose

The clinical efficacy of ceftazidime-avibactam (CAZ-AVI) in treating carbapenem-resistant Klebsiella pneumoniae (CRKP)-infected recipients after kidney transplantation (KT) has not been well evaluated. We aimed to assess its efficacy in a single-center cohort of KT recipients infected with CRKP.

Materials and Methods

We retrospectively observed KT recipients diagnosed with CRKP infection from June 2019 to July 2021. The primary outcome was 30-day mortality and secondary outcomes were 14-day clinical cure and 14-day microbiological cure. Logistic regression analysis was used to evaluate the relationship between CAZ-AVI treatment and prognosis.

Results

A total of 54 CRKP-infected KT recipients were recorded in this study. Twenty-two recipients received CAZ-AVI and 32 received other antibiotic regimens. Recipients in both groups had similar baseline characteristics, with the most common site of infection being surgical site infections (n=27; 50.0%) and bloodstream infections (n=23; 42.6%). Recipients treated with CAZ-AVI had significantly lower 30-day mortality (3/22 vs 14/32, P=0.019), significantly higher 14-day clinical cure (18/22 vs 17/32, P=0.030) and 14-day microbiological cure (19/22 vs 15/32, P=0.003) compared with recipients receiving other treatment regimens. Kaplan–Meier survival curves for 30-day mortality confirmed the findings (log-rank=0.014). In a multivariate logistic regression model, receiving CAZ-AVI was found to be an independent protective factor for 30-day mortality (odds ratio=0.148, 95% confidence interval, 0.027–0.800; P=0.026). No significant side effects were recorded.

Conclusion

CAZ-AVI may be more valuable than other antibiotic regimens for the treatment of CRKP infection after kidney transplantation, and further large randomized controlled trials are needed to assess its efficacy.

Analysis of Risk Factors for Carbapenem-Resistant Klebsiella pneumoniae Infection and Its Effect on the Outcome of Early Infection After Kidney Transplantation

Background

Infections remain a major cause of morbidity and mortality in kidney transplant (KT) recipients. This study was performed to identify the overall prevalence of early infections, prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection after KT, one-year postoperative mortality in patients with early infections and risk factors for CRKP infections.

Methods

We conducted a retrospective study of all patients who received KT in our hospital between January 2017 and December 2019. We evaluated the demographic, clinical, infection characteristics and the one-year postoperative outcomes.

Results

Among the 419 patients who received KT between January 2017 and December 2019, 150 patients had at least one infection within 90 days after KT. The total prevalence of early infections was 36.1% (150/415), the prevalence of early CRKP infections was 10.4% (43/415), and the one-year postoperative mortality was 15.3% (23/150) in patients with early infections. The risk factors independently related to one-year postoperative mortality were mechanical ventilation (MV) > 48 h (Odds ratio (OR)= 13.879, 95%Confidence interval (CI): 2.265~85.035; P=0.004) and CRKP infection (OR=6.751, 95% CI: 1.051~43.369; P =0.044). MV> 48 h was independently related to CRKP infection (OR=3.719, 95% CI: 1.024~13.504; P=0.046). Kaplan-Meier survival curves showed that the one-year survival rate of patients infected with CRKP in the early postoperative stage was significantly lower than that of uninfected patients.

Conclusions

In general, the prevalence of early infections after KT is high, and CRKP infection is closely correlated with poor prognosis. The effective prevention and treatment of CRKP infection is an important way to improve the one-year survival rate after KT.

Impact of sarcopenia in infants with liver transplantation for biliary atresia

While sarcopenia is an important predictor of LT outcomes in adults, few studies have examined the association of sarcopenia with LT outcomes in pediatric patients. We investigated the clinical influence of sarcopenia on the post-transplant outcomes in infants with BA. To define sarcopenia in infants, the cross-sectional area of the tPMA in 93 healthy control infants was measured by computed tomography. Sarcopenia was defined as a tPMA lower than two standard deviations below the mean of healthy control infants. Eighty-nine infants with BA with a median age at LT of 7.6 months old were enrolled. The clinical characteristics and outcomes of LT were verified in the sarcopenia group (n = 21) and non-sarcopenia group (n = 68). The sarcopenia group had a significantly longer operation time and greater blood loss during LT than the non-sarcopenia group (P = .03 and 0.02). The incidence of portal vein stenosis and post-operative bloodstream infection was also significantly higher in the sarcopenia group than in the non-sarcopenia group (23.8% vs 4.4%, P = .02 and 28.6% vs 10.3%, P = .04, respectively). The total length of hospital stay did not differ significantly. The 1-year patient and graft survival rates tended to be lower in the sarcopenia group than in the non-sarcopenia group (90.5% vs 98.5%, P = .07 and 85.7% vs 97.1%, P = .05, respectively). Sarcopenia in infants with BA may be associated with the patient survival and serve as an effective marker for post-operative outcomes of LT.

Morbidity and mortality of iatrogenic hemothorax occurring in a cohort of liver transplantation recipients: a multicenter observational study

Hemothorax (HT) is a life-threatening condition, mainly iatrogenic and poorly explored in Liver Transplantation (LT) recipients. The aim of this study is to report and analyze for the first time incidence and outcomes of HT in LT recipients, as well as to suggest a management strategy. Data concerning 7130 consecutive adult liver and liver-kidney transplant recipients were retrospectively collected from ten Transplantation Centers' institutional databases, over a 10-year period. Clinical parameters, management strategies and survival data about post-operative HT were analyzed and reported. Thirty patients developed HT during hospitalization (0.42%). Thoracentesis was found to be the most common cause of HT (16 patients). A non-surgical management was performed in 17 patients, while 13 patients underwent surgery. 19 patients developed thoracic complications after HT treatment, with an overall mortality rate of 50%. The median length of stay in Intensive Care Units was 22 days (IQR_25-75 5-66.5). Postoperative hemothorax is mainly due to iatrogenic causes in LT recipients. Despite rare, it represents a serious complication with a high mortality rate and a challenging medical and surgical management. Its occurrence should always be prevented.

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.

Sequential Organ Failure Assessment (SOFA) Score-Based Factors Predict Early Mortality in High-Risk Patients with Living Donor Liver Transplant

Background

Patients with a Sequential Organ Failure Assessment (SOFA) score >7 on post-transplant day (POD) 7 have been reported to have a higher risk of short-term mortality after living donor liver transplant (LDLT). We sought to identify factors that were associated with early mortality in this high-risk population.

Material/Methods

A total of 102 patients with a high SOFA score (>7) on POD 7 were enrolled, of which 72 (70.6%) were assigned to the survivor group, and the other 30 (29.4%) patients were assigned to the non-survivor group according to post-transplant 3-month results. Demographics, clinical data, operative parameters, and individual SOFA component scores were collected. Independent risk factors for 3-month mortality were identified by multivariate logistic regression analysis using backward elimination procedures.

Results

Of 102 high SOFA score patients, the 3-month mortality rate after LDLT in our study was 29.4%. Four independent risk factors were indicative for early death: graft-to-recipient weight ratio (GRWR) <0.8 (hazard ratio [HR]=3.00; 95% CI=1.05–8.09; P=0.041), longer warm ischemia time (HR=37.84; 95% CI=1.63–880.77; P=0.024), high liver component of the SOFA score, and cardiovascular component of the SOFA score (liver component: HR=10.39; 95% CI=1.77–60.89; P=0.009 and cardiovascular component: HR=13.34; 95% CI=2.22–80.12; P=0.005).

Conclusions

In conclusion, 3-month mortality among patients with high SOFA score on POD 7 is associated with multiple independent risk factors, including smaller GRWR, longer warm ischemia time, and higher category of liver and cardiovascular component of SOFA score. By recognizing high-risk patients earlier, the LDLT outcomes may be improved by timely intensive therapies.

Association between surgical volumes and hospital mortality in patients: a living donor liver transplantation single center experience

Background

Many factors cause hospital mortality (HM) after liver transplantation (LT).

Methods

We performed a retrospective research in a single center from October 2005 to June 2019. The study included 463 living donor LT patients. They were divided into a no-HM group (n = 433, 93.52%) and an HM group (n = 30, 6.48%). We used logistic regression analysis to determine how clinical features and surgical volume affected HM. We regrouped patients based on periods of surgical volume and analyzed the clinical features.

Results

Multivariate analysis revealed that donor age (OR = 1.050, 95% CI 1.011–1.091, p = 0.012), blood loss (OR = 1.000, 95% CI 1.000–1.000, p = 0.004), and annual surgical volumes being < 30 LTs (OR = 2.540, 95% CI 1.011–6.381, p = 0.047) were significant risk factors. A comparison of years based on surgical volume found that when the annual surgical volumes were at least 30 the recipient age (p = 0.023), donor age (p = 0.026), and ABO-incompatible operations (p < 0.001) were significantly higher and blood loss (p < 0.001), operative time (p < 0.001), intensive care unit days (p < 0.001), length of stay (p = 0.011), rate of re-operation (p < 0.001), and HM (p = 0.030) were significantly lower compared to when the annual surgical volumes were less than 30.

Conclusions

Donor age, blood loss and an annual surgical volume < 30 LTs were significant pre- and peri-operative risk factors. Hospital mortality and annual surgical volume were associated with statistically significant differences; surgical volume may impact quality of care and transplant outcomes.

Developing a Novel Scoring System for Risk Stratification in Living Donor Liver Transplantation

Background: We aimed to develop a novel scoring system for risk stratification specific to living donor liver transplantation (LDLT) recipients, to improve the accuracy of predicting short-term outcomes. Methods: The sequential organ failure assessment (SOFA) score at postoperative day 7 was collected and simplified by dichotomization, and these categories and other clinical factors were subjected to univariate and multivariate logistic regression analyses to select independent risks in constructing a “graft-to-recipient weight ratio (GRWR)-SOFA” scoring system. Results: We enrolled 519 patients who underwent LDLT. The GRWR-SOFA score comprises a sum of six factors: cardiovascular (mean arterial pressure < 70 mmHg, scored 3), coagulation (serum platelet < 50 × 10³/μL, scored 2), renal (creatinine > 1.2 mg/dL, scored 2), liver (serum total bilirubin > 5.9 mg/dL, scored 5), neurological (Glasgow coma scale < 15, scored 2), and GRWR < 0.8, scored 2. The GRWR-SOFA contained four classes: The early mortality rate at 3 months and 1 year after LDLT was 1.3% and 6.9% for class I (scores of 0–4), 9.1% and 16.7% for class II (scores of 5–8), 25.5% and 34% for class III (scores of 9–10), and 61.3% and 67.7% for class IV (scores ≥ 11), respectively. The area under the receiver operating characteristic curve of GRWR-SOFA in the 3-month mortality prediction was 0.881 (95% confidence interval (CI): 0.818–0.944). Conclusions: The GRWR-SOFA model demonstrates superior discriminatory power for predicting short-term mortality. It enables clinicians to identify the right level of care for distinct subgroups of patients receiving LDLT.