Clinical significance of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci colonization in liver transplant recipients

The impact of colonization by multidrug resistant bacteria on graft survival, risk of infection, and mortality in recipients of solid organ transplant: systematic review and meta-analysis

BACKGROUND

The Global increase in colonization by multidrug-resistant (MDR) bacteria poses a significant concern. The precise impact of MDR colonization in solid organ transplant recipients (SOTR) remains not well established.

OBJECTIVES

To assess the impact of MDR colonization on SOTR's mortality, infection, or graft loss.

METHODS AND DATA SOURCES

Data from PROSPERO, OVID Medline, OVID EMBASE, Wiley Cochrane Library, ProQuest Dissertations, Theses Global, and SCOPUS were systematically reviewed, spanning from inception until 20 March 2023. The study protocol was registered with PROSPERO (CRD42022290011) and followed the PRISMA guidelines. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, INTERVENTIONS, AND ASSESSMENT OF RISK OF BIAS: Cohorts and case-control studies that reported on adult SOTR colonized by Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum β-lactamase (ESBL) or carbapenem-resistant Enterobacteriaceae. (CRE), or MDR-pseudomonas, and compared to noncolonized, were included. Two reviewers assessed eligibility, conducted a risk of bias evaluation using the Newcastle-Ottawa Scale, and rated certainty of evidence using the GRADE approach.

METHODS OF DATA SYNTHESIS

We employed RevMan for a meta-analysis, using random-effects models to compute pooled odds ratios (OR) and 95% confidence intervals (CI). Statistical heterogeneity was determined using the I2 statistic.

RESULTS

15,202 SOTR (33 cohort, six case-control studies) were included, where liver transplant and VRE colonization (25 and 14 studies) were predominant. MDR colonization significantly increased posttransplant 1-year mortality (OR, 2.35; 95% CI, 1.63-3.38) and mixed infections (OR, 10.74; 95% CI, 7.56-12.26) across transplant types (p < 0.001 and I2 = 58%), but no detected impact on graft loss (p 0.41, I2 = 0). Subgroup analysis indicated a higher association between CRE or ESBL colonization with outcomes (CRE: death OR, 3.94; mixed infections OR, 24.8; ESBL: mixed infections OR, 10.3; no mortality data) compared to MRSA (Death: OR, 2.25; mixed infection: OR, 7.75) or VRE colonization (Death: p 0.20, mixed infections: OR, 5.71).

CONCLUSIONS

MDR colonization in SOTR, particularly CRE, is associated with increased mortality. Despite the low certainty of the evidence, actions to prevent MDR colonization in transplant candidates are warranted.

European Society of Clinical Microbiology and Infectious Diseases/European Committee on infection control clinical guidelines on pre-operative decolonization and targeted prophylaxis in patients colonized by multidrug-resistant Gram-positive bacteria before surgery

SCOPE

The aim of these guidelines is to provide recommendations for decolonization and perioperative antibiotic prophylaxis (PAP) in multidrug-resistant Gram-positive bacteria (MDR-GPB) adult carriers before inpatient surgery.

METHODS

These European Society of Clinical Microbiology and Infectious Diseases/European Committee on Infection Control guidelines were developed following a systematic review of published studies targeting methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, methicillin-resistant coagulase-negative Staphylococci, and pan-drug-resistant-GPB. Critical outcomes were the occurrence of surgical site infections (SSIs) caused by the colonizing MDR-GPB and SSIs-attributable mortality. Important outcomes included the occurrence of SSIs caused by any pathogen, hospital-acquired infections, all-cause mortality, and adverse events associated with the interventions, including resistance development to the agents used and the incidence of Clostridioides difficile infections. The last search of all databases was performed on 1 November 2023. The level of evidence and the strength of each recommendation were defined according to the Grading of Recommendations Assessment, Development, and Evaluation approach. Consensus of a multidisciplinary expert panel was reached for the final list of recommendations. Antimicrobial stewardship considerations were included.

RECOMMENDATIONS

The guideline panel reviewed the impact of decolonization, targeted PAP, and combined interventions (e.g. decolonization and targeted PAP) on the risk of SSIs and other outcomes in MDR-GPB carriers, according to the type of bacteria and type of surgery. We recommend screening for S. aureus before high-risk operations, such as cardiothoracic and orthopaedic surgery. Decolonization with intranasal mupirocin with or without a chlorhexidine bath is recommended in patients colonized with S. aureus before cardiothoracic and orthopaedic surgery and suggested in other surgeries. The addition of vancomycin to standard prophylaxis is suggested for MRSA carriers in cardiothoracic surgery, orthopaedic surgery, and neurosurgery. Combined interventions (e.g. decolonization and targeted prophylaxis) are suggested for MRSA carriers undergoing cardiothoracic and orthopaedic surgery. No recommendation could be made regarding screening, decolonization and targeted prophylaxis for vancomycin-resistant enterococci because of the lack of data. No evidence was retrieved for methicillin-resistant coagulase-negative Staphylococci and pan-drug-resistant-GPB. Careful consideration of the laboratory workload and involvement of antimicrobial stewardship and infection control teams are warranted before implementing screening procedures or performing changes in PAP policy. Future research should focus on novel decolonizing techniques, on the monitoring of resistance to decolonizing agents and PAP regimens, and on standardized combined interventions in high-quality studies.

Perioperative daptomycin for prophylaxis of vancomycin-resistant Enterococcus infection in colonized liver transplant recipients

BACKGROUND

Infection with vancomycin-resistant Enterococcus (VRE) in liver transplant recipients (LTR) has been associated with extended hospital stays, increased readmission rates, graft failure, and death. A tailored perioperative surgical prophylaxis regimen targeting VRE may reduce postoperative infections in VRE-colonized patients. This study investigated the outcomes of perioperative daptomycin in this patient population.

METHODS

This retrospective, single-center cohort study included LTR ≥ 18 years old who were VRE-colonized from June 2018 to November 2022. VRE colonization was identified by a VRE rectal swab screen or a positive VRE culture prior to transplant. Two groups were analyzed: daptomycin versus no daptomycin. All LTR received perioperative piperacillin-tazobactam for 24 h. If VRE-colonized, one dose of daptomycin (6 mg/kg) was given pre- and postoperatively. Demographics, clinical characteristics, risk factors for VRE infection, and daptomycin dose were collected. The primary outcome was VRE infection at 14 days and 90 days post-transplant.

RESULTS

There were 36 VRE-colonized LTR; 19 received daptomycin and 17 did not. Baseline characteristics and risk factors for VRE infection were similar between groups. More VRE infections occurred in the no daptomycin group within 14 days post-transplant (24% vs. 0%, p = .04), but at 90 days posttransplant there was no significant difference (29% vs. 16%, p = .43). The average daptomycin dose was 7.1 mg/kg.

CONCLUSION

Perioperative daptomycin reduced the rate of VRE infections in VRE-colonized LTR within 14 days posttransplant but not at 90 days. Future studies should evaluate if higher doses and/or longer duration of perioperative daptomycin can reduce VRE infections beyond 14 days post-transplant.

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.

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.

Importance of daptomycin dosage on the clinical outcome in liver transplant recipients with vancomycin-resistant enterococci infection

We retrospectively studied 16 (3 colonization and 13 infections) early post-liver transplant (≤60-day after transplantation) patients with vancomycin-resistant enterococci (VRE) colonization/infection from 2016 to 2019. All VRE isolates were Enterococcus faecium. Of 13 patients with VRE infection, 12 (92.3%) underwent living-donor liver transplantation and 1 underwent deceased donor liver transplantation. Among these 13 patients, the median time from transplant to emergence of VRE infection was 12 days. The median interval from VRE infection to death was 27 days. Of these 13 patients, eleven patients (8 survived; 3 died) received daptomycin therapy for VRE. Among them, 4 (36.3%) received daptomycin doses <8 mg/kg. Non-survivors (n = 3) received significantly lower daptomycin dose than survivors (n = 8; p = .040). Daptomycin doses <8mg/kg were more frequently associated with non-survivors (n = 3) than with survivors (n = 8; p = .024). In summary, the suboptimal dosage of daptomycin may have contributed to a higher rate of in-hospital mortality. Doses ≥8 mg/kg may be needed to adequately treat VRE infection in liver transplant recipients.

Reduced pannexin 1-IL-33 axis function in donor livers increases risk of MRSA infection in liver transplant recipients

Liver transplantation patients are at increased risk for methicillin-resistant Staphylococcus aureus (MRSA) infection, but the molecular mechanism remains unclear. We found that genetic predisposition to low pannexin 1 (PANX1) expression in donor livers was associated with MRSA infection in human liver transplantation recipients. Using Panx1 and Il-33-knockout mice for liver transplantation models with MRSA tail vein injection, we demonstrated that Panx1 deficiency increased MRSA-induced liver injury and animal death. We found that decreased PANX1 expression in the liver led to reduced release of adenosine triphosphate (ATP) from hepatocytes, which further reduced the activation of P2X2, an ATP-activating P2X receptor. Reduced P2X2 function further decreased the NLRP3-mediated release of interleukin-33 (IL-33), reducing hepatic recruitment of macrophages and neutrophils. Administration of mouse IL-33 to Panx1^-/- mice significantly (P = 0.011) ameliorated MRSA infection and animal death. Reduced human hepatic IL-33 protein abundance also associated with increased predisposition to MRSA infection. Our findings reveal that genetic predisposition to reduced PANX1 function increases risk for MRSA infection after liver transplantation by decreasing hepatic host innate immune defense, which can be attenuated by IL-33 treatment.

Clinical Outcome of Vancomycin-Resistant Enterococcus Colonization Among Liver Transplant Recipients at Shiraz Organ Transplant Center

OBJECTIVES

Liver transplant recipients are more susceptible to vancomycin-resistant enterococci colonization than healthy individuals. We investigated the prevalence of vancomycin-resistant enterococci colonization and its effect on the outcomes of liver transplant recipients.

MATERIALS AND METHODS

Patients who had undergone primary liver transplant at the Shiraz Organ Transplant Center from 2015 to 2017 were enrolled in this study. Demographic characteristics, laboratory test results, duration of stay in the intensive care unit, total duration of hospital stay, and clinical outcome data were extracted from the Shiraz Organ Transplant Center database. Posttransplant outcomes such as graft rejection, mortality, hospital stay, and kidney function tests were included for the first 90 days after transplant.

RESULTS

A total of 753 liver transplant recipients (470 males and 283 females) were included in this study. Vancomycin-resistant enterococci colonization was identified in 51 patients (6.8%) after transplant at the time of intensive care unit admission. Our study found no significant difference between outcomes for patients with vancomycin-resistant enterococci colonization and outcomes for patients without colonization, including graft rejection, mortality, hospital stay, and kidney function tests.

CONCLUSIONS

Our study revealed that asymptomatic vancomycin-resistant enterococci colonization in liver transplant patients has no adverse effect on the duration of posttransplant hospital stay, early mortality rate, graft rejection rate, or kidney function compared with noncolonized patients.

Transplantation of a kidney from a donor with vancomycin-resistantEnterococci

The colonization of vancomycin-resistant Enterococci before and after solid organ transplantation is associated with an increased risk of its infection. The prevalence of these bacterial colonies in renal transplant recipients are as high as that in intensive care unit patients. However, it is unclear whether donors with vancomycin-resistant Enterococci colonization can be considered in renal transplantation. Herein, we report a case wherein a kidney was transplanted from a deceased donor with vancomycin-resistant Enterococci colonies in urine and rectal swab. After transplant, the recipient had no vancomycin-resistant Enterococci infection and maintained relatively good renal function.

Vancomycin-resistant Enterococcus in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation address vancomycin-resistant enterococci (VRE) infections in SOT candidates and recipients. VRE are an important cause of infection and have been named by the CDC as a serious public threat. Typically, a commensal of the gastrointestinal tract, VRE may become pathogenic after abdominal organ manipulation like transplantation. This guideline reviews the microbiology, antimicrobial resistance mechanisms, epidemiology, and clinical manifestations of VRE infection in the context of solid organ transplantation. Treatment regimens including combination therapies and novel investigational agents are also reviewed. Finally, an updated appraisal of infection control measures relevant to VRE infection and colonization is presented.

The direct and indirect effects of vancomycin-resistant enterococci colonization in liver transplant candidates and recipients

Introduction: Vancomycin-resistant enterococci (VRE) colonization and subsequent infection results in increased morbidity, mortality and use of health-care resources. The burden of VRE colonization in liver transplant candidates and recipients is significant. VRE colonization is a marker of gut dysbiosis and its impact on the microbiota-liver axis, may negatively affect graft function and result in negative outcomes pre- and post-transplantation. Areas covered: In this article we describe the epidemiology of VRE colonization, risk factors for VRE infection, health-care costs associated with VRE, with a focus on the impact of VRE colonization on liver transplant recipients' fecal microbiota, the therapeutic strategies for VRE decolonization and proposed pathophysiologic mechanisms of VRE colonization in liver transplant recipients. Expert opinion: VRE colonization results in a significant loss of bacterial microbiome diversity. This may have metabolic consequences, with low production of short-chain fatty acids which may, in turn, result in immune dysregulation. As antibiotics have failed to decolonize the gut, alternative strategies such as fecal microbiota transplantation (FMT), stimulation of intestinal antimicrobial peptides and phage therapy warrants future studies.

Factors Associated with Vancomycin-Resistant Enterococcus Colonization in Patients Transferred to Emergency Departments in Korea

BACKGROUND

Vancomycin-resistant enterococci (VRE) infections have become a major healthcare-associated pathogen problem worldwide. Nosocomial VRE infections could be effectively controlled by screening patients at high risk of harboring VRE and thereby lowering the influx of VRE into healthcare centers. In this study, we evaluated factors associated with VRE colonization in patients transferred to emergency departments, to detect patients at risk for VRE carriage.

METHODS

This study was conducted in the emergency department of a medical college-affiliated hospital in Korea. Every patient transferred to the emergency department and admitted to the hospital from January to December 2016 was screened for VRE using rectal cultures. In this cross-sectional study, the dependent variable was VRE colonization and the independent variables were demographic and clinical factors of the patients and factors related to the transferring hospital. Patients were divided into two groups, VRE and non-VRE, and previously collected patient data were analyzed. Then we performed logistic regression analyses of characteristics that differed significantly between groups.

RESULTS

Out of 650 patients, 106 (16.3%) had positive VRE culture results. Significant variables in the logistic analysis were transfer from geriatric long-term care hospital (adjusted odds ration [aOR]: 8.017; 95% confidence interval [CI]: 1.378-46.651), hospital days (4-7 days; aOR: 7.246; 95% CI: 3.229-16.261), duration of antimicrobial exposure (1-3 days; aOR: 1.976; 95% CI: 1.137-3.436), and age (aOR: 1.025; 95% CI: 1.007-1.043).

CONCLUSION

VRE colonization in patients transferred to the emergency department is associated primarily with factors related to the transferred hospitals rather than demographic and clinical characteristics.

Predictors of postoperative infectious complications in liver transplant recipients: experience of 185 consecutive cases

BACKGROUND/AIMS

Infections following liver transplant (LT) remain a major cause of mortality. This study was conducted to evaluate risk factors for infection and to review clinical characteristics.

METHODS

Medical records of patients who underwent LT from 2010 to 2014 were retrospectively analyzed. Binary logistic regression analysis was used to investigate risk factors of infection. Kaplan-Meier analysis was used to predict prognosis of infected and non-infected groups.

RESULTS

Of 185 recipients, 89 patients experienced infectious complications. The median follow-up period was 911 days (range, 9 to 2,031). The infected group had higher 1-year mortality (n = 22 [24.7%] vs. n = 8, [8.3%], p = 0.002), and longer postoperative admission days (mean: 53.7 ± 35.8 days vs. 28.3 ± 13.0 days, p &lt; 0.001), compared to the non-infected group. High preoperative Model for End-Stage Liver Disease (MELD) score (odds ratio [OR], 1.057; 95% confidence interval [CI], 1.010 to 1.105; p = 0.016), deceased-donor type (OR, 5.475; 95% CI, 2.442 to 12.279; p &lt; 0.001), and acute rejection (OR, 3.042; 95% CI, 1.241 to 7.454; p = 0.015) were independent risk factors associated with infection. Intra-abdominal infection (n = 35, 20.8%) was the major infectious complication. Among identified bacteria, Enterococcus species (28.4%) were major pathogens, followed by Escherichia coli and Klebsiella species.

CONCLUSIONS

High preoperative MELD score, deceased-donor type, and acute rejection were risk factors associated with infection. To prevent infections following surgery, it is important to determine the appropriate time of operation before the recipient has a high MELD score.

Epidemiology and outcomes of pretransplant methicillin-resistant Staphylococcus Aureus screening in pediatric solid organ transplant candidates

MRSA infection following SOT is an important cause of morbidity and mortality, but epidemiology and risk factors for colonization prior to pediatric SOT remain unclear. A retrospective cohort of SOT patients ≤21 years of age from 2009 to 2014 was evaluated. Demographics, MRSA screens, timing of transplantation, and MRSA infection were abstracted. From 2013 to 2014, 130 SOT candidates were screened or had known prior MRSA infection. Seventeen patients (13%) were MRSA colonized. Liver transplant candidates were least likely to be colonized (OR 0.22, CI:0.06-0.81, P = .02); greatest risk of colonization was in lung (OR 18.7, CI:1.9-182.3, P = .03), abdominal multivisceral (OR 7.5, CI:1.5-38.6, P = .02), and cardiac patients with history of cardiothoracic surgery (OR 8.0, CI:1.7-36.0, P = .007). In univariable analysis, African American patients were more likely to be colonized (OR 7.1, CI:2.49-19.41, P = .0005). There were 3 early MRSA infections in screened patients, incidence of 3.9%; only one in a colonized patient. Thirteen percent of screened pediatric SOT candidates were MRSA colonized, with greatest risk in lung, multivisceral and cardiac patients with prior cardiothoracic surgery. Early MRSA infection occurred in 3.9% of transplanted patients. Cardiothoracic and multivisceral organ transplant candidates may benefit the most from targeted MRSA screening.

Methicillin-resistant Staphylococcus aureus bacteremia among liver transplant recipients: epidemiology and associated risk factors for morbidity and mortality

Bacteremia due to Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), complicates the clinical course of liver transplantation and is associated with high morbidity and mortality. Intravascular catheters had been reported to be the most frequent source of MRSA bacteremia. Among bacteremic liver recipients, 26.3%-100% of S. aureus were MRSA. Previous studies identified pre-transplant and post-transplant acquired S. aureus carriage, greater severity of liver disease, hepatocellular carcinoma and infection with immuno-modulatory viruses as predictors of S. aureus bacteremia in liver recipients. MRSA bacteremia accompanied by pneumonia and abdominal infections was related to mortality. Vancomycin, as well as daptomycin, is a first-line antibiotic for MRSA bacteremia. The purpose of this review is to better understand the characteristics of MRSA bacteremia by summarizing the epidemiology and antimicrobial resistance of S. aureus, the primary source, and related risk factors for morbidity and mortality of MRSA bacteremia. We have also explored the diagnostic, therapeutic and preventive measures for MRSA bacteremia to improve the outcomes of liver recipients.

Virulence and resistance profiles of MRSA isolates in pre- and post-liver transplantation patients using microarray

Methicillin-resistant Staphylococcus aureus (MRSA) screening plays a great role in preventing infections in surgical patients. This study aims to evaluate clonality, virulence and resistance of MRSA in pre- and post-liver transplantation (LT) patients. Nasal and groin swabs of 190 patients were collected. PCR for virulence genes and staphylococcal cassette chromosome mec (SCCmec) types, microarray, PFGE, multilocus sequence typing and MIC were performed. MRSA carriers were detected in 20.5 % (39/190) of the patients. However, only three colonized patients developed infections post-LT. Sixty-nine MRSA isolates were identified, and the most frequent SCCmec type was type II (29/69; 42.0 %). Most isolates (57/69; 82.6 %) were susceptible to trimethoprim-sulfamethoxazole (TMP/SMX) and harboured the lukD, lukE, clf and fnbA genes as determined by PCR. Five sequence types (ST) were identified among nine clones; 36.2 % (25/69) isolates belonged to a predominant clone (ST105 and SCCmec type II) that was susceptible to TMP/SMX, mupirocin and chlorhexidine, which had 87.9 % similarity with the New York/Japan clone. The array showed virulence difference in isolates of the same clone and patients and that colonized isolates (pre-LT patients) were less virulent than those post-LT and those infected. Therefore, despite the high frequency of MRSA colonization, infection due to MRSA was uncommon in our LT unit. MRSA isolates presented great diversity. Isolates of the same clone expressed different virulence factors by array. Colonizing isolates pre-LT expressed less virulent factors than post-LT and infecting isolates.

Infection Prevention in Transplantation

The number of patients undergoing hematopoietic cell and solid organ transplantation are increasing every year, as are the number of centers both transplanting and caring for these patients. Improvements in transplant procedures, immunosuppressive regimens, and prevention of transplant-associated complications have led to marked improvements in survival in both populations. Infections remain one of the most important sources of excess morbidity and mortality in transplant, and therefore, infection prevention strategies are a critical element for avoiding these complications in centers caring for high-risk patients. This manuscript aims to provide an update of recent data on prevention of major healthcare-associated infections unique to transplantation, reviews the emergence of antimicrobial resistant infections, and discusses updated strategies to both identify and prevent transmission of these pathogens in transplant recipients.