Colonization with multidrug-resistant organisms is associated with in increased mortality in liver transplant candidates

The role of gut barrier dysfunction in postoperative complications in liver transplantation: pathophysiological and therapeutic considerations

PURPOSE

Gut barrier dysfunction is a pivotal pathophysiological alteration in cirrhosis and end-stage liver disease, which is further aggravated during and after the operational procedures for liver transplantation (LT). In this review, we analyze the multifactorial disruption of all major levels of defense of the gut barrier (biological, mechanical, and immunological) and correlate with clinical implications.

METHODS

A narrative review of the literature was performed using PubMed, PubMed Central and Google from inception until November 29th, 2023.

RESULTS

Systemic translocation of indigenous bacteria through this dysfunctional barrier contributes to the early post-LT infectious complications, while endotoxin translocation, through activation of the systemic inflammatory response, is implicated in non-infectious complications including renal dysfunction and graft rejection. Bacterial infections are the main cause of early in-hospital mortality of LT patients and unraveling the pathophysiology of gut barrier failure is of outmost importance.

CONCLUSION

A pathophysiology-based approach to prophylactic or therapeutic interventions may lead to enhancement of gut barrier function eliminating its detrimental consequences and leading to better outcomes for LT patients.

Fecal Carriage of Multidrug-Resistant Organisms Increases the Risk of Hepatic Encephalopathy in Cirrhotic Patients: Insights from Gut Microbiota and Metabolite Features

Background

Impact of fecal colonization by multidrug-resistant organisms (MDROs) on changes in gut microbiota and associated metabolites, as well as its role in cirrhosis-associated outcomes, has not been thoroughly investigated.

Methods

Eighty-eight cirrhotic patients and 22 healthy volunteers were prospectively enrolled with analysis conducted on plasma metabolites, fecal MDROs, and microbiota. Patients were followed for a minimum of one year. Predictive factors for cirrhosis-associated outcomes were identified using Cox proportional hazards regression models, and risk factors for fecal MDRO carriage were assessed using logistic regression model. Correlations between microbiota and metabolic profiles were evaluated through Spearman's rank test.

Results

Twenty-nine (33%) cirrhotic patients exhibited MDRO carriage, with a notably higher rate of hepatic encephalopathy (HE) in MDRO carriers (20.7% vs. 3.2%, p = 0.008). Cox regression analysis identified higher serum lipopolysaccharide levels and fecal MDRO carriage as predictors for HE development. Logistic regression analysis showed that MDRO carriage is an independent risk factor for developing HE. Microbiota analysis showed a significant dissimilarity of fecal microbiota between cirrhotic patients with and without MDRO carriage (p = 0.033). Thirty-two metabolites exhibiting significantly different expression levels among healthy controls, cirrhotic patients with and without MDRO carriage were identified. Six of the metabolites showed correlation with specific bacterial taxa expression in MDRO carriers, with isoaustin showing significantly higher levels in MDRO carriers experiencing HE compared to those who did not.

Conclusion

Fecal MDRO carriage is associated with altered gut microbiota, metabolite modulation, and an elevated risk of HE occurrence within a year.

Acute and non-acute decompensation of liver cirrhosis (47/130)

In the traditional view, the occurrence of cirrhosis-related complications, such as hepatic encephalopathy, formation of ascites or variceal haemorrhage, marks the transition to the decompensated stage of cirrhosis. Although the dichotomous stratification into a compensated and decompensated state reflects a prognostic water-shed moment and remains to hold its prognostic validity, it represents an oversimplification of clinical realities. A broadening understanding of pathophysiological mechanisms underpinning decompensation have led to the identification of distinct prognostic subgroups, associated with different clinical courses following decompensation. Data provided by the PREDICT study uncovered three distinct sub-phenotypes of acute decompensation (AD). Moreover, acute-on-chronic liver failure (ACLF) has been established as a distinct clinical entity for many years, which is associated with a high short-term mortality. Recently, non-acute decompensation (NAD) has been proposed as a distinct pathway of decompensation, complementing current concepts of the spectrum of decompensation. In contrast to AD, NAD is characterized by a slow and progressive development of complications, which are often presented at first decompensation and/or in patients in an earlier stage of chronic liver disease. Successful treatment of AD or NAD may lead to a clinical stabilization or even the concept of recompensation. This review aims to provide an overview on current concepts of decompensation and to delineate recent advances in our clinical and pathophysiological understanding.

New Antibiotics Against Multidrug-Resistant Gram-Negative Bacteria in Liver Transplantation: Clinical Perspectives, Toxicity, and PK/PD Properties

Antimicrobial resistance is a growing global health problem, and it is especially relevant among liver transplant recipients where infections, particularly when caused by microorganisms with a difficult-to-treat profile, are a significant cause of morbidity and mortality. We provide here a complete dissection of the antibiotics active against multidrug-resistant Gram-negative bacteria approved over the last years, focusing on their activity spectrum, toxicity profile and PK/PD properties, including therapeutic drug monitoring, in the setting of liver transplantation. Specifically, the following drugs are presented: ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, cefiderocol, and eravacycline. Overall, studies on the safety and optimal employment of these drugs in liver transplant recipients are limited and especially needed. Nevertheless, these pharmaceuticals have undeniably enhanced therapeutic options for infected liver transplant recipients.

Colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae does not affect subsequent infection and liver transplant outcomes: a retrospective observational cohort study

Objective

To investigate the colonization rate of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), subsequent infections by ESBL-E and ESBL-producing gram-negative bacilli (ESBL-GNB), and the effect of ESBL-E colonization on clinical outcomes in liver transplantation (LT) recipients.

Methods

This is a retrospective cohort study that included patients who underwent LT at Shanghai Renji Hospital between July 2016 and December 2017. Rectal swabs from LT patients at the postoperative ICU enrollment were screened anonymously for ESBL-E carriage. Demographics data, laboratory indexes, operative complications, and clinical course information were also obtained. The extent of ESBL-E colonization, the subsequent infection rates of ESBL-E and ESBL-GNB, and the clinical outcomes were compared between ESBL-E colonized and non-colonized patients.

Results

In total, 496 liver transplant recipients (387 males) were included in this study. ESBL-E colonization was detected in 240 patients (48.4%). There was no significant difference between the rates of ESBL-E infection (5.8 vs. 3.1%, p = 0.143), Ischemia-reperfusion ≥ 3 (27.9 vs. 24.6%, p = 0.403), acute kidney injury (39.6 vs. 38.7%, p = 0.835), acute rejection (2.1 vs. 1.6%, p = 0.664), graft versus host reaction (1.3 vs. 1.2%, p = 0.937), duration of hospitalization (22 vs. 23 days, p = 0.568), 90-day mortality (7.1 vs. 4.7%, p = 0.262) and 1-year mortality (12.9 vs. 9.3%, p = 0.265) in patients with and without ESBL-E colonization. Though the ESBL-GNB infection rate was higher in ESBL-E colonized patients (12.1 vs. 6.6%, p = 0.037), multivariate analysis showed that ESBL-E colonization did not increase the risk of ESBL-GNB infection (Model 1: aOR 1.755, 95% CI: 0.911-3.380, p = 0.093; Model 2: aOR 1.556, 95% CI: 0.761-3.181, p = 0.226). The ESBL-producing bacteria spectrum of colonization was significantly different from that of infections occurring after LT, with only three colonization events leading to infection by the same pathogen identified.

Conclusion

ESBL-E colonization in liver transplant patients is not associated with ESBL-E infection, nor is it a risk factor for post-transplant ESBL-GNB infection. Additionally, ESBL-E colonization does not lead to worse prognoses when compared with non-colonized patients.

Clinical trial registration

Chinese Clinical Trial Registry, Identifier [ChiCTR2100043034].

Early Intra-Abdominal Bacterial Infections after Orthotopic Liver Transplantation: A Narrative Review for Clinicians

Despite recent advances in the transplant field, infectious complications after orthotopic liver transplantation (OLT) are major causes of morbidity and mortality. Bacterial intra-abdominal infections (IAIs) are predominant during the first month post-transplantation and affect patient and graft survival. Recently, the emergence of multidrug resistant bacteria has generated great concern in OLT patients. We performed this narrative review of the literature in order to propose a "ready-to-use" flowchart for reasoned empirical antibiotic therapy in the case of suspected post-OLT IAIs. The review was ultimately organized into four sections: "Epidemiology and predisposing factors for IAI"; "Surgical-site infections and perioperative prophylaxis"; "MDRO colonization and infections"; and "Reasoned-empirical antibiotic therapy in early intra-abdominal infections post OLT and source control". Multidisciplinary teamwork is warranted to individualize strategies for the prevention and treatment of IAIs in OLT recipients, taking into account each patient's risk factors, the surgical characteristics, and the local bacterial epidemiology.

Gut Microbiota and Liver Transplantation: Immune Mechanisms behind the Rejection

Liver transplantation (LT) is the treatment of choice for patients with cirrhosis, decompensated disease, acute liver failure, and hepatocellular carcinoma (HCC). In 3-25% of cases, an alarming problem is acute and chronic cellular rejection after LT, and this event can lead to the need for new transplantation or the death of the patient. On the other hand, gut microbiota is involved in several mechanisms sustaining the model of the "gut-liver axis". These include modulation of the immune response, which is altered in case of gut dysbiosis, possibly resulting in acute graft rejection. Some studies have evaluated the composition of the gut microbiota in cirrhotic patients before and after LT, but few of them have assessed its impact on liver rejection. This review underlines the changes in gut microbiota composition before and after liver transplantation, hypothesizing possible immune mechanisms linking dysbiosis to transplantation rejection. Evaluation of changes in the gut microbiota composition in these patients is therefore essential in order to monitor the success of LT and eventually adopt appropriate preventive measures.

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.

Challenges and recommendations when selecting empirical antibiotics in patients with cirrhosis

There is abundant evidence that bacterial infections are severe complications in patients with cirrhosis, being the most frequent trigger of acute-on-chronic liver failure and causing death in one of every four patients during hospitalization. For these reasons, early diagnosis and effective treatment of infections are mandatory to improve patient outcomes. However, treating physicians are challenged in daily practice since diagnosing bacterial infections is not always straightforward. This situation might lead to delayed antibiotic initiation or prescription of ineffective regimens, which are associated with poor outcomes. On the other hand, prescribing broad-spectrum antibiotics to all patients suspected of bacterial infections might favor bacterial resistance development. This is a significant concern given the alarming number of infections caused by multidrug-resistant microorganisms worldwide. Therefore, it is paramount to know the local epidemiology to propose tailored guidelines for empirical antibiotic selection in patients with cirrhosis in whom bacterial infections are suspected or confirmed. In this article, we will revise current knowledge in this area and highlight the importance of surveillance programs.

Carriage of multidrug-resistant Gram-negative bacilli: duration and risk factors

Identification of risk factors influencing the duration of carriage of multidrug-resistant Gram-negative bacilli (MDR-GNB) may be useful for infection control. The aim of this study is to estimate the impact of several factors collected for routine hospital surveillance on the duration of carriage of selected MDR-GNB. From January 2015 to July 2021, patients with at least two clinical/surveillance samples positive for MDR-GNB different from ESBL-producing E. coli or AmpC - exclusively producing Enterobacterales were assessed. Microorganisms, age, number of admissions, clinical or rectal sample, sex, and admission service were evaluated as risk factors. Multivariate analysis was performed by a Cox proportional hazard model. A total of 1981 episodes of colonization were included. Involved microorganisms were ESBL-Klebsiella pneumoniae (KP) in 1057 cases (53.4%), other ESBL-non-E. coli Enterobacterales in 91 (4.6%), OXA-48-KP in 263 (13.3%), KPC-KP in 90 (4.5%), VIM-KP in 29 (1.5%), carbapenemase-producing non-KP Enterobacterales (CP-non-KP) in 124 (6.3%), and MDR Pseudomonas aeruginosa (MDR-PAER) in 327 (16.5%). No differences in duration of colonization were observed among ESBL-KP (median colonization time 320 days), ESBL-non-E. coli Enterobacterales (226 days), OXA48-KP (305 days), and MDR-PAER (321 days). For each group, duration of colonization was significantly longer than that of KPC-KP (median colonization time 60 days), VIM-KP (138 days), and CP-non-KP (71 days). Male sex (HR = 0.88; 95% CI 0.78-0.99), detection in Hepatology-Gastroenterology (HR = 0.71; 95% CI 0.54-0.93), clinical sample (HR = 0.61; 95% CI 0.53-0.69), and > 2 admissions after first detection (HR = 0.47; 95% CI 0.42-0.52) were independent predictors of longer carriage, whereas VIM-KP (HR = 1.61; 95% CI 1.04-2.48), KPC-KP (HR = 1.85; 95% CI 1.49-2.3), and CP-non-KP (HR = 1.92; 95% CI 1.49-2.47) were associated with shorter colonization time. Duration of colonization was significantly longer for ESBL-KP, other ESBL-non-E. coli Enterobacterales, OXA-48-KP, and MDR-PAER. For these microorganisms, prolonging surveillance up to 2.5-3 years should be considered. Male sex, clinical sample, multiple readmissions, admission service, and type of microorganism are independent predictors of the duration of carriage.

Multidrug-resistant Enterobacterales infections in abdominal solid organ transplantation

BACKGROUND

Transplant recipients are highly susceptible to multidrug-resistant (MDR) related infections. The lack of early appropriate antimicrobial treatment may contribute to the high mortality due to MDR-related infections in transplant recipients especially in case of metallo-β-lactamases.

OBJECTIVES

In this review, we present the current state of knowledge concerning multidrug-resistant Gram negative bacilli's risk management in the care of solid-organ transplant recipients and suggest control strategies.

SOURCES

We searched for studies treating MDR g-negative bacilli related infections in the renal and hepatic transplant patient population. We included randomized and observational studies.

CONTENT

Solid-organ transplant is the best therapeutic option for patients diagnosed with end-stage organ disease. While the incidence of opportunistic infections is decreasing due to better prevention, the burden of "classical" infections related to MDR bacteria especially related to Gram-negative bacteria is constantly increasing. Over the last two decades, various MDR pathogens have emerged as a relevant cause of infection in this specific population associated with significant mortality. Several factors related to the management of transplant donor candidates and recipients increase the risk of MDR infections in transplant recipients. The awareness of this high susceptibility of transplant recipients to MDR-related infections challenges the choice of empirical therapy, while its appropriateness can only be validated a posteriori. Indeed, the lack of early appropriate antimicrobial treatment may contribute to the high mortality due to MDR-related infections in transplant recipients especially in case of metallo-β-lactamases.

IMPLICATIONS

Multidrug-resistant Gram-negative bacteria are associated with high morbidity and mortality in solid organ transplant recipients. It seems important to identify patients at risk of colonization/MDR bacteria to evaluate strategies to limit the risk of secondary infections and to minimize the inappropriate use of broad-spectrum antibiotics.

Role of bacteriophage therapy for resistant infections in transplant recipients

PURPOSE OF REVIEW

Multidrug-resistant organisms (MDROs) are prevalent in transplant recipients and associated with poor outcomes. We review recent cases of phage therapy used to treat recalcitrant infections in transplant recipients and explore the future role of such therapy in this setting.

RECENT FINDINGS

Individual case reports and small case series suggest possible efficacy of phage therapy for the treatment of MDRO infections in pre and posttransplant patients. Importantly, there have been no serious safety concerns in the reported cases that we reviewed. There are no applicable randomized controlled trials (RCTs) to better guide phage therapy at this time.

SUMMARY

Given the safety and possibility of successful salvage therapy of MDRO infections using bacteriophages, it is reasonable to pursue phage therapy for difficult-to-treat infections on a compassionate use basis, but RCT data are critically needed to better inform management.

Donor Simvastatin Treatment Is Safe and Might Improve Outcomes After Liver Transplantation: A Randomized Clinical Trial

BACKGROUND

The current curative approaches for ischemia/reperfusion injury on liver transplantation are still under debate for their safety and efficacy in patients with end-stage liver disease. We present the SIMVA statin donor treatment before Liver Transplants study.

METHODS

SIMVA statin donor treatment before Liver Transplants is a monocentric, double-blind, randomized, prospective tial aiming to compare the safety and efficacy of preoperative brain-dead donors' treatment with the intragastric administration of 80 mg of simvastatin on liver transplant recipient outcomes in a real-life setting. Primary aim was incidence of patient and graft survival at 90 and 180 d posttransplant; secondary end-points were severe complications.

RESULTS

The trial enrolled 58 adult patients (18-65 y old). The minimum follow-up was 6 mo. No patient or graft was lost at 90 or 180 d in the experimental group (n = 28), whereas patient/graft survival were 93.1% ( P = 0.016) and 89.66% ( P = 0.080) at 90 d and 86.21% ( P = 0.041) and 86.2% ( P = 0.041) at 180 d in the control group (n = 29). The percentage of patients with severe complications (Clavien-Dindo ≥IIIb) was higher in the control group, 55.2% versus 25.0% in the experimental group ( P = 0.0307). The only significant difference in liver tests was a significantly higher gamma-glutamyl transferase and alkaline phosphatase at 15 d ( P = 0.017), ( P = 0.015) in the simvastatin group.

CONCLUSIONS

Donor simvastatin treatment is safe, and may significantly improve early graft and patient survival after liver transplantation, although further research is mandatory.

Colonization with Carbapenem-Resistant Enterobacteriaceae Contributes to Unfavorable Outcomes in End-Stage Liver Disease Patients

Carbapenem-resistant Enterobacteriaceae (CRE) are the highest priority pathogens of the World Health Organization, and their prevalence in end-stage liver disease (ESLD) patients is increasing. CRE colonization is an independent risk factor for CRE infections. We aimed to assess risk factors and explore the relationship between CRE colonization, infection, and prognosis in patients with ESLD. A total of 311 patients with ESLD were screened for CRE colonization by fecal swabs from October 2020 to January 2022. Antimicrobial susceptibility was tested using the broth microdilution method. Carbapenem resistance genes, multilocus sequence type, and capsular serotype were analyzed by polymerase chain reaction (PCR). Seventeen CRE strains were detected, among which the most common was Klebsiella pneumoniae. The CRE colonization rate was 5.5%. Artificial liver support was an independent risk factor for CRE colonization. Compared to the non-CRE colonization group, the colonization group had a higher incidence of CRE infection and a worse prognosis. Furthermore, these strains were not closely related, and all were sensitive to polymyxin and tigecycline. There was a high colonization rate in ESLD patients, and colonization strains were highly diverse. CRE colonization deserves attention in these patients, especially when treated with artificial liver support.

Secondary Sclerosing Cholangitis Following Coronavirus Disease 2019 (COVID-19): A Multicenter Retrospective Study

BACKGROUND

Secondary sclerosing cholangitis (SSC) is a rare disease with poor prognosis. Cases of SSC have been reported following coronavirus disease 2019 (COVID-SSC). The aim of this study was to compare COVID-SSC to SSC in critically ill patients (SSC-CIP) and to assess factors influencing transplant-free survival.

METHODS

In this retrospective, multicenter study involving 127 patients with SSC from 9 tertiary care centers in Germany, COVID-SSC was compared to SSC-CIP and logistic regression analyses were performed investigating factors impacting transplant-free survival.

RESULTS

Twenty-four patients had COVID-SSC, 77 patients SSC-CIP, and 26 patients other forms of SSC. COVID-SSC developed after a median of 91 days following COVID-19 diagnosis. All patients had received extensive intensive care treatment (median days of mechanical ventilation, 48). Patients with COVID-SSC and SSC-CIP were comparable in most of the clinical parameters and transplant-free survival was not different from other forms of SSC (P = .443, log-rank test). In the overall cohort, the use of ursodeoxycholic acid (UDCA) (odds ratio [OR], 0.36 [95% confidence interval {CI}, .16-.80], P = .013; log-rank P < .001) and high serum albumin levels (OR, 0.40 [95% CI, .17-.96], P = .040) were independently associated with an increased transplant-free survival, while the presence of liver cirrhosis (OR, 2.52 [95% CI, 1.01-6.25], P = .047) was associated with worse outcome. Multidrug-resistant organism (MDRO) colonization or infection did not impact patients' survival.

CONCLUSIONS

COVID-SSC and CIP-SSC share the same clinical phenotype, course of the disease, and risk factors for its development. UDCA may be a promising therapeutic option in SSC, though future prospective trials are needed to confirm our findings.

Rectal colonization by resistant bacteria increases the risk of infection by the colonizing strain in critically ill patients with cirrhosis

BACKGROUND & AIMS

It remains unclear whether rectal colonization with multidrug-resistant organisms (MDROs) is prevalent and predisposes to infections by the same pathogens in patients with cirrhosis.

METHODS

Two series of critically ill patients were evaluated. In the Barcelona cohort, 486 consecutive patients were prospectively evaluated, 129 with and 357 without cirrhosis (2015-2016). Rectal swabs were performed at admission and weekly thereafter (until intensive care unit [ICU] discharge) to detect MDRO colonization. Risk factors for colonization and infection by MDROs were evaluated. A retrospective cohort from Frankfurt (421 patients with cirrhosis; 2010-2018) was investigated to evaluate MDRO rectal colonization in another epidemiological scenario.

RESULTS

In the Barcelona cohort, 159 patients were colonized by MDROs (32.7%), 102 (64.2%) at admission and 57 (35.8%) during follow-up. Patients with cirrhosis showed higher rates of rectal colonization at admission than those without cirrhosis (28.7% vs. 18.2%, p = 0.01) but similar colonization rates during ICU stay. Extended-spectrum beta-lactamase-Enterobacterales were the most frequent MDROs isolated in both groups. Colonization by MDROs independently increased the risk of infection by MDROs at admission and during follow-up. Risk of new infection by the colonizing strain was also significantly increased in patients with (hazard ratio [HR] 7.41) and without (HR 5.65) cirrhosis. Rectal colonization by MDROs was also highly prevalent in Frankfurt (n = 198; 47%; 131 at admission [66.2%] and 67 [33.8%] during follow-up), with vancomycin-resistant enterococci being the most frequent colonizing organism. Rectal colonization by MDROs was also associated with an increased risk of infection by MDROs in this cohort. Infections occurring in MDR carriers were mainly caused by the colonizing strain.

CONCLUSION

Rectal colonization by MDROs is extremely frequent in critically ill patients with cirrhosis. Colonization increases the risk of infection by the colonizing resistant strain.

LAY SUMMARY

Rectal colonization by multidrug-resistant organisms (MDROs) is a prevalent problem in patients with cirrhosis requiring critical care. The pattern of colonizing bacteria is heterogeneous with relevant differences between centers. Colonization by MDROs is associated with increased risk of infection by the colonizing bacteria in the short term. This finding suggests that colonization data could be used to guide empirical antibiotic therapy and de-escalation policies in patients with cirrhosis.

Challenges of Antimicrobial Resistance and Stewardship in Solid Organ Transplant Patients

Purpose of Review

Without effective antimicrobials, patients cannot undergo transplant surgery safely or sustain immunosuppressive therapy. This review examines the burden of antimicrobial resistance in solid organ transplant recipients and identifies opportunities for antimicrobial stewardship.

Recent Findings

Antimicrobial resistance has been identified to be the leading cause of death globally. Multidrug-resistant pathogens are associated with significant morbidity and mortality in transplant recipients. Methicillin-resistant S. aureus affects liver and lung recipients, causing bacteremia, pneumonia, and surgical site infections. Vancomycin-resistant enterococci is a nosocomial pathogen primarily causing bacteremia in liver recipients. Multidrug-resistant Gram-negative pathogens present urgent and serious threats to transplant recipients. Extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae commonly cause bacteremia and intra-abdominal infections in liver and kidney recipients. Carbapenemase-producing Enterobacterales, mainly K. pneumoniae, are responsible for infections early-post transplant in liver, lung, kidney, and heart recipients. P. aeruginosa and A. baumannii continue to be critical threats. While there are new antimicrobial agents targeting resistant pathogens, judicious prescribing is crucial to minimize emerging resistance. The full implications of the COVID-19 global pandemic on antimicrobial resistance in transplant recipients remain to be understood. Currently, there are no established standards on the implementation of antimicrobial stewardship interventions, but strategies that leverage existing antimicrobial stewardship program structure while tailoring to the needs of transplant recipients may help to optimize antimicrobial use.

Summary

Clinicians caring for transplant recipients face unique challenges tackling emerging antimcirobial resistance. Coordinated antimicrobial stewardship interventions in collaboration with appropriate expertise in transplant and infectious diseases may mitigate against such threats.

Implications and Management of Cirrhosis-Associated Immune Dysfunction Before and After Liver Transplantation

Cirrhosis-associated immune dysfunction (CAID) describes a panacea of innate and adaptive deficits that result from the sequelae of cirrhotic portal hypertension that is similar in its manifestations regardless of etiology of chronic liver injury. CAID is associated with synchronous observations of dysregulated priming of innate immune effector cells that demonstrate a proinflammatory phenotype but are functionally impaired and unable to adequately prevent invading pathogens. CAID is mainly driven by gut-barrier dysfunction and is associated with deficits of microbial compartmentalization and homeostasis that lead to tonic activation, systemic inflammation, and exhaustion of innate-immune cells. CAID leads to a high frequency of bacterial and fungal infections in patients with cirrhosis that are often associated with acute decompensation of chronic liver disease and acute-on-chronic liver failure and carry a high mortality rate. Understanding the deficits of mucosal and systemic immunity in the context of chronic liver disease is essential to improving care for patients with cirrhosis, preventing precipitants of acute decompensation of cirrhosis, and improving morbidity and survival. In this review, we summarize the detailed dynamic immunological perturbations associated with advanced chronic liver disease and highlight the importance of recognizing immune dysregulation as a sequela of cirrhosis. Furthermore, we address the role of screening, prevention, and early treatment of infections in cirrhosis in improving patient outcomes in transplant and nontransplant settings.

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.

Association between Gut Colonization of Vancomycin-resistant Enterococci and Liver Transplant Outcomes

BACKGROUND

Vancomycin-resistant enterococci (VRE) colonization is common in liver transplant recipients and has been associated with worse post-transplant outcomes.

METHODS

We conducted a retrospective cohort study at the University of Alberta Hospital including patients who underwent a liver transplant between September 2014 and December 2017.

RESULTS

Of 343 patients, 68 (19.8%) had pre-transplant VRE colonization and 27 (27/275, 9.8%) acquired VRE post-transplant, 67% were males and the median age was 56.5 years. VRE colonized patients at baseline had higher MELD scores and required longer post-transplant hospitalization. VRE colonization was associated with increased risk of early acute kidney injury (AKI) (64% vs 52%, p = 0. 044), clinically significant bacterial/fungal infection (29% vs 17%, p = 0. 012) and invasive VRE infection (5% vs 1%, p = 0. 017). Mortality at 2-years was 13% in VRE-colonized versus 7% in non-colonized (p = 0.085). On multivariate analysis, VRE colonization increased the risk of post-transplant AKI (HR 1.504, 95% CI: 1.077-2.100, p = 0.017) and clinically significant bacterial or fungal infection at 6 months (HR 2.038, 95%CI: 1.222-3.399, p = 0.006), and was associated with non-significant trend towards increased risk of mortality at 2-years post-transplant (HR 1.974 95% CI 0.890-4.378; p = 0.094).

CONCLUSIONS

VRE colonization in liver transplant patients is associated with increased risk of early AKI, clinically significant infections, and a trend towards increased mortality at 2-years. This article is protected by copyright. All rights reserved.

[Bacterial hepatobiliary infections : Pathogen spectrum, antimicrobial resistance and current treatment concepts]

Ascending cholangitis and pyogenic liver abscesses are acute febrile bacterial hepatobiliary diseases. Nowadays they frequently occur in patients with structural changes of the biliary system and are usually treated by a combination of interventional drainage procedures and antimicrobial therapy. While Gram-negative Enterobacterales were identified as major causes in the past, biliary tract interventions and antibiotic exposure have contributed to an increase in enterococcal species and extended spectrum beta-lactamase (ESBL)-producing Enterobacterales. When selecting an appropriate empirical treatment the treating internist must consider local and individual risk factors for antimicrobial resistance in addition to pharmacokinetic aspects and disease severity to reduce the likelihood of treatment failure.

Molecular Surveillance of Carbapenem-Resistant Gram-Negative Bacteria in Liver Transplant Candidates

Background: Carbapenem-resistant Gram-negative bacteria (CRGN) cause life-threatening infections due to limited antimicrobial treatment options. The occurrence of CRGN is often linked to hospitalization and antimicrobial treatment but remains incompletely understood. CRGN are common in patients with severe illness (e.g., liver transplantation patients). Using whole-genome sequencing (WGS), we aimed to elucidate the evolution of CRGN in this vulnerable cohort and to reconstruct potential transmission routes.

Methods: From 351 patients evaluated for liver transplantation, 18 CRGN isolates (from 17 patients) were analyzed. Using WGS and bioinformatic analysis, genotypes and phylogenetic relationships were explored. Potential epidemiological links were assessed by analysis of patient charts.

Results: Carbapenem-resistant (CR) Klebsiella pneumoniae (n=9) and CR Pseudomonas aeruginosa (n=7) were the predominating pathogens. In silico analysis revealed that 14/18 CRGN did not harbor carbapenemase-coding genes, whereas in 4/18 CRGN, carbapenemases (VIM-1, VIM-2, OXA-232, and OXA-72) were detected. Among all isolates, there was no evidence of plasmid transfer-mediated carbapenem resistance. A close phylogenetic relatedness was found for three K. pneumoniae isolates. Although no epidemiological context was comprehensible for the CRGN isolates, evidence was found that the isolates resulted of a transmission of a carbapenem-susceptible ancestor before individual radiation into CRGN.

Conclusion: The integrative epidemiological study reveals a high diversity of CRGN in liver cirrhosis patients. Mutation of carbapenem-susceptible ancestors appears to be the dominant way of CR acquisition rather than in-hospital transmission of CRGN or carbapenemase-encoding genetic elements. This study underlines the need to avoid transmission of carbapenem-susceptible ancestors in vulnerable patient cohorts.

High Acquisition Rate of Gram-Negative Multi-Drug Resistant Organism Colonization During Hospitalization: A Perspective from a High Endemic Setting

Objective

The aim of the study was to compare the rate of gram-negative multi-drug resistant organism (GN-MDRO) colonization at admission and during hospitalization and to describe the strains and antibiotic resistance genes acquired during hospitalization.

Methods

Rectal swabs were collected from patients hospitalized at the National Trauma Center (NTC), Mongolia, at the time of admission and after 14 days of hospitalization as has been detailed on our previous study. GN-MDRO antibiotic resistance was determined using EUCAST standards, and resistance genes were detected using multiplex PCR.

Results

A total of 158 patients were screened, and baseline colonization rate at admission was 29.1% (46/158). The rate went up to 69.9% (110/158) after 14 days of hospitalization (p<0.001). Of all participants, 74 patients (46.8%) screened GN-MDRO negative at admission acquired colonization by day 14. Other 36 patients (22.8%) maintained colonization that was screened positive at both time points. Only 38 patients (24.0%) remained free of GN-MDRO during hospitalization. There was a difference in GN-MDRO acquisition between these groups. Patients who were negative at admission acquired up to 3 GN-MDRO species, and there were 10 different species isolated. Reversely, patients who were screened positive at both time points had fairly homogenous isolates; up to 5 species of Enterobacterales were identified at admission and day 14 hospitalization. Overall, Enterobacterales were the dominant colonizers (61.4%, 97/158), and all Enterobacterales were resistant to cefotaxime as CTX-M resistance was our inclusion criteria.

Conclusion

GN-MDRO baseline colonization rate on admission was high and, alarmingly, doubled during hospitalization in the study area. Enterobacterales was the predominant colonizer and was highly resistant to 3rd generation cephalosporin. This data supports a need for an improved infection control policy including routine surveillance of the GN-MDROs and improved antibiotic stewardship program.

The time is now: antimicrobial stewardship in solid organ transplantation

PURPOSE OF REVIEW

To provide a summary of complications of antimicrobials and opportunities for antimicrobial stewardship (AS) in solid organ transplant (SOT) patient care.

RECENT FINDINGS

Personalized, precision antimicrobial prescribing in SOT aiming to avoid negative consequences of antimicrobials is essential to improving patient outcomes. The positive impact AS efforts in transplant care has been recognized and bespoke activities tailored to special interests of transplant patients and providers are evolving. Strategies to optimize stewardship interventions targeting antibacterial, antiviral, and antifungal drug selection and dosing in the transplant population have been recently published though clinical integration using a 'handshake' stewardship model is an optimal starting point in transplant care. Other recent studies involving transplant recipients have identified opportunities to shorten duration or avoid antimicrobials for certain commonly encountered clinical syndromes. This literature, informing recent consensus clinical practice guidelines, may help support institutional practice guidelines and protocols. Proposals to track and report stewardship process and outcome measures as a routine facet of programmatic transplant quality reporting have been published. However, developing novel metrics accounting for nuances of transplant patients and programs is critical. Important studies are needed to evaluate organizational transplant prescribing cultures and optimal behavioral science-based interventions relevant to antimicrobial use in this population.

SUMMARY

Consequences of antimicrobial use, such as drug toxicities, and Clostridiodes difficile (CDI) and multidrug-resistant organisms colonization and infection disproportionately affect SOT recipients and are associated with poor allograft and patient outcomes. Stewardship programs encompassing transplant patients aim to personalize antimicrobial prescribing and optimize outcomes. Further studies are needed to better understand optimal intervention strategies in SOT.

Colonization with multidrug-resistant organisms impairs survival in patients with hepatocellular carcinoma

Introduction

MDRO-colonization has been shown to impair survival in patients with hematological malignancies and solid tumors as well as in patients with liver disease. Despite the increasing spread of multidrug-resistant organisms (MDRO), its impact on patients with hepatocellular carcinoma (HCC) has not been studied. We conducted this retrospective study to analyze the impact of MDRO-colonization on overall prognosis in HCC patients.

Materials and methods

All patients with confirmed HCC diagnosed between January 2008 and December 2017 at the University Hospital Frankfurt were included in this study. HCC patients with a positive MDRO screening before or within the first 90 days after diagnosis of HCC were defined as colonized HCC patients, HCC patients with a negative MDRO screening were defined as noncolonized HCC patients.

Results

59 (6%) colonized and 895 (94%) noncolonized HCC patients were included. Enterobacterales with extended-spectrum β-lactamase-like phenotype with or without resistance to fluoroquinolones (ESBL/ ± FQ) were the most frequently found MDRO with 59%, followed by vancomycin-resistant Enterococcus faecium with 37%. Colonized HCC patients had more severe cirrhosis and more advanced HCC stage compared to noncolonized HCC patients. Colonized HCC patients showed an impaired survival with a median OS of 189 days (6.3 months) compared to a median OS of 1001 days (33.4 months) in noncolonized HCC patients. MDRO-colonization was identified as an independent risk factor associated with survival in multivariate analysis.

Conclusion

MDRO-colonization is an independent risk factor for survival in patients with HCC highlighting the importance of regular MDRO screening, isolation measures as well as interdisciplinary antibiotic steward-ship programs to guide responsible use of antibiotic agents.