Comparison of risk factors and outcomes of daptomycin-susceptible and -nonsusceptible vancomycin-resistant Enterococcus faecium infections in liver transplant recipients

Management of vancomycin-resistant Enterococci and daptomycin-resistant Enterococci infections in liver transplant recipients in a single academic center

INTRODUCTION

Vancomycin-resistant Enterococci (VRE) infections cause significant morbidity and mortality in liver transplant (LT) recipients. Management is challenging, especially in the setting of daptomycin resistance (DR).

METHODS

Single-center retrospective review of patients who underwent LT between January 1, 2020, and December 31, 2022, and developed VRE infections. Descriptive statistics were used and Kaplan-Meier curves estimated freedom from treatment failure and survival.

RESULTS

Forty-two patients (median age 58; 64% female; 67% white) were included. Alcohol-related cirrhosis (48%) and metabolic dysfunction-associated steatohepatitis (31%) were the most common indications for LT, and most were from deceased donors (86%). VRE infection occurred at a median of 21 days after LT, and 16% had known prior VRE colonization. Common infection sites were blood (45%, n = 19), intraabdominal (36%, n = 15), and urine (36%, n = 15). Most were initially treated with daptomycin alone (64%) or in combination with other agents (21%); 7% received linezolid alone. Twelve (29%) developed breakthrough infections during treatment and 11 (26%) had recurrent infections after discontinuation of treatment. All-cause mortality was 36% (n = 15) at a median of 90 days after VRE infection diagnosis and was nearly twice as high in patients with DR (63%).

CONCLUSION

VRE infection in LT recipients relapsed or recurred in over 25%. Mortality was high, especially in cases with DR. More data is needed to establish an optimal treatment approach, particularly for relapse and DR.

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.

Top-Down Genomic Surveillance Approach To Investigate the Genomic Epidemiology and Antibiotic Resistance Patterns of Enterococcus faecium Detected in Cancer Patients in Arkansas

Control of hospital-associated Enterococcus faecium infection is a strenuous task due to the difficulty of identifying transmission routes and the persistence of this nosocomial pathogen despite the implementation of infection control measures that have been successful with other important nosocomial pathogens. This study provides a comprehensive analysis of over 100 E. faecium isolates collected from 66 cancer patients at the University of Arkansas for Medical Sciences (UAMS) between June 2018 and May 2019. In the top-down approach used in this study, we employed, in addition to the 106 E. faecium UAMS isolates, a filtered set of 2,167 E. faecium strains from the GenBank database to assess the current population structure of E. faecium species and, consequently, to identify the lineages associated with our clinical isolates. We then evaluated the antibiotic resistance and virulence profiles of hospital-associated strains from the species pool, focusing on antibiotics of last resort, to establish an updated classification of high-risk and multidrug-resistant nosocomial clones. Further investigation of the clinical isolates collected from UAMS patients using whole-genome sequencing analytical methodologies (core genome multilocus sequence typing [cgMLST], core single nucleotide polymorphism [coreSNP] analysis, and phylogenomics), with the addition of patient epidemiological data, revealed a polyclonal outbreak of three sequence types occurring simultaneously in different patient wards. The integration of genomic and epidemiological data collected from the patients increased our understanding of the relationships and transmission dynamics of the E. faecium isolates. Our study provides new insights into genomic surveillance of E. faecium to assist in monitoring and further limiting the spread of multidrug-resistant E. faecium. IMPORTANCE Enterococcus faecium is a member of the gastrointestinal microbiota. Although its virulence is low in healthy, immunocompetent individuals, E. faecium has become the third leading cause of health care-associated infections in the United States. This study provides a comprehensive analysis of over 100 E. faecium isolates collected from cancer patients at the University of Arkansas for Medical Sciences (UAMS). We employed a top-down analytical approach (from population genomics to molecular biology) to classify our clinical isolates into their genetic lineages and thoroughly evaluate their antibiotic resistance and virulence profiles. The addition of patient epidemiological data to the whole-genome sequencing analytical methodologies performed in the study allowed us to increase our understanding of the relationships and transmission dynamics of the E. faecium isolates. This study provides new insights into genomic surveillance of E. faecium to help monitor and further limit the spread of multidrug-resistant E. faecium.

Daptomycin-Resistant Enterococcus Bacteremia Is Associated with Prior Daptomycin Use and Increased Mortality after Liver Transplantation

Background

Risk factors for acquisition of vancomycin-resistant Enterococcus (VRE) include immunosuppression, antibiotic exposure, indwelling catheters, and manipulation of the gastrointestinal tract, all of which occur in liver transplant recipients. VRE infections are documented in liver transplantation (LT); however, only one single center study has assessed the impact of daptomycin-resistant Enterococcus (DRE) in this patient population.

Methods

We conducted a retrospective multicenter cohort study comparing liver transplant recipients with either VRE or DRE bacteremia. The primary outcome was death within 1 year of transplantation. Multivariable logistic regression analyses were performed to calculate adjusted odds ratios for outcomes of interest.

Results

We identified 139 cases of Enterococcus bacteremia following LT, of which 78% were VRE and 22% were DRE. When adjusted for total intensive care unit days in the first transplant year, liver-kidney transplantation, and calcineurin inhibitor use, patients with DRE bacteremia were 2.65 times more likely to die within 1 year of transplantation (adjusted odds ratio [aOR], 2.648; 95% CI, 1.025–6.840; P = .044). Prior daptomycin exposure was found to be an independent predictor of DRE bacteremia (aOR, 30.62; 95% CI, 10.087–92.955; P < .001).

Conclusions

In this multicenter study of LT recipients with Enterococcus bacteremia, DRE bacteremia was associated with higher 1-year mortality rates when compared with VRE bacteremia. Our data provide strong support for dedicated infection prevention and antimicrobial stewardship efforts for transplant patients. Further research is needed to support the development of better antibiotics for DRE and practical guidance focusing on identification and prevention of colonization and subsequent infection in liver transplant recipients at high risk for DRE bacteremia.

Rates and causative pathogens of surgical site infections attributed to liver transplant procedures and other hepatic, biliary, or pancreatic procedures, 2015-2018

Liver transplant recipients are at high risk for surgical site infections (SSIs). Limited data are available on SSI epidemiology following liver transplant procedures (LTPs). We analyzed data on SSIs from 2015 to 2018 reported to CDC's National Healthcare Safety Network to determine rates, pathogen distribution, and antimicrobial resistance after LTPs and other hepatic, biliary, or pancreatic procedures (BILIs). LTP and BILI SSI rates were 5.7% and 5.9%, respectively. The odds of SSI after LTP were lower than after BILI (adjusted odds ratio = 0.70, 95% confidence interval 0.57-0.85). Among LTP SSIs, 43.1% were caused by Enterococcus spp., 17.2% by Candida spp., and 15.0% by coagulase-negative Staphylococcus spp. (CNS). Percentages of SSIs caused by Enterococcus faecium or CNS were higher after LTPs than BILIs, whereas percentages of SSIs caused by Enterobacteriaceae, Enterococcus faecalis, or viridans streptococci were higher after BILIs. Antimicrobial resistance was common in LTP SSI pathogens, including E. faecium (69.4% vancomycin resistant); Escherichia coli (68.8% fluoroquinolone non-susceptible and 44.7% extended spectrum cephalosporin [ESC] non-susceptible); and Klebsiella pneumoniae and K. oxytoca (39.4% fluoroquinolone non-susceptible and 54.5% ESC non-susceptible). National LTP SSI pathogen and resistance data can help prioritize studies to determine effective interventions to prevent SSIs and reduce antimicrobial resistance in liver transplant recipients.

Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review

Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.

Daptomycin perioperative prophylaxis for the prevention of vancomycin-resistant Enterococcus infection in colonized liver transplant recipients

BACKGROUND

Vancomycin-resistant Enterococcus (VRE)-colonized liver transplantation (LT) recipients have increased post-LT morbidity, mortality, and higher rates of VRE infections compared with their non-colonized counterparts. Pre-LT screening for VRE colonization and inclusion of daptomycin in the perioperative antibiotic prophylaxis regimen may mitigate this risk.

METHODS

We performed a retrospective chart review of liver transplant recipients aged ≥ 18 years between 2013 and August 2019 to identify pre-LT VRE-colonized recipients and whether they received daptomycin perioperative prophylaxis (DPP). Demographic and clinical characteristics, including risk factors for VRE infection, were collected. Outcomes measured were VRE-related infection and all-cause mortality within 90 days of LT.

RESULTS

Of the 27 VRE-colonized liver transplant recipients within the study period, 25 received DPP. All recipients were admitted to the intensive care unit postoperatively, six (24%) required reoperation, fifteen (60%) required renal replacement therapy, and eight (32%) experienced postoperative hemorrhage within 90 days post-transplant. Two recipients (8%) experienced acute cellular rejection, but no primary graft failure was seen within 90 days. Among those who received DPP, no infections related to VRE or death was seen within 90 days of LT. The two VRE-colonized recipients who did not receive DPP both developed VRE bacteremia in the early post-LT period.

CONCLUSION

Despite having multiple risk factors for post-LT VRE infection, VRE-colonized recipients who received DPP did not develop VRE-related infections in the first 90 days post-LT. Our experience demonstrates that pre-LT VRE screening and DPP may be associated with a reduction in VRE infection in the early post-LT period, but this strategy warrants further evaluation in prospective studies.