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Background Reducing the burden of multidrug-resistant organism (MDRO) colonization and infection among renal transplant recipients (RTRs) may improve patient outcomes. We aimed to assess whether the detection of an MDRO or a comparable antibiotic-susceptible organism (CSO) during the early post-transplant (EPT) period was associated with graft loss and mortality among RTRs. Methods We conducted a retrospective cohort study of RTRs transplanted between 2005 and 2021. EPT positivity was defined as a positive bacterial culture within 30 days of transplant. The incidence and prevalence of EPT MDRO detection were calculated. The primary outcome was a composite of 1-year allograft loss or mortality following transplant. Multivariable Cox hazard regression, competing risk, propensity score–weighted sensitivity, and subgroup analyses were performed. Results Among 3507 RTRs, the prevalence of EPT MDRO detection was 1.3% (95% CI, 0.91%–1.69%) with an incidence rate per 1000 EPT-days at risk of 0.42 (95% CI, 0.31–0.57). Among RTRs who met survival analysis inclusion criteria (n = 3432), 91% (3138/3432) had no positive EPT cultures and were designated as negative controls, 8% (263/3432) had a CSO detected, and 1% (31/3432) had an MDRO detected in the EPT period. EPT MDRO detection was associated with the composite outcome (adjusted hazard ratio [aHR], 3.29; 95% CI, 1.21–8.92) and death-censored allograft loss (cause-specific aHR, 7.15; 95% CI, 0.92–55.5; subdistribution aHR, 7.15; 95% CI, 0.95–53.7). A similar trend was seen in the subgroup and sensitivity analyses. Conclusions MDRO detection during the EPT period was associated with allograft loss, suggesting the need for increased strategies to optimize prevention of MDRO colonization and infection. [ABSTRACT FROM AUTHOR]

Background: Bacteriuria is common among kidney transplant recipients (KTR). Risk factors and outcomes associated with bloodstream infection due to a urinary source (BSIU) in KTR are poorly understood. Methods: This single center case‐control study from 2010 to 2022 compared KTR with BSIU to those with bacteria without bloodstream infection (BU). Multivariable logistic regression identified BSIU risk factors, and Cox models assessed its impact on graft failure. Results: Among 3435 patients, who underwent kidney transplantation at Emory Hospital, 757 (22%) developed bacteriuria, among whom 142 (18.8%) were BSIU. Male sex, presence of Escherichia coli, Klebsiella pneumoniae, or Pseudomonas species in urine culture, urethral stricture, neuromuscular bladder disorder, and history of diabetes‐induced renal failure were independently associated with increased odds of BSIU (Male sex: aOR 2.29, 95% CI 1.52, 3.47, E. coli: aOR 5.14, 95% CI 3.02, 9.13; K. pneumoniae aOR 3.19, 95% CI 1.65, 6.27, Pseudomonas spp aOR 3.06, 95% CI 1.25, 7.18; urethral stricture: 4.10, 95% CI 1.63, 10.3, neuromuscular bladder disorder aOR 1.98, 95% CI 1.09, 3.53, diabetes: aOR 1.64, 95% CI 1.08, 2.49). BSIU was associated with increased hazard of graft failure (HR 1.52, 95% CI 1.05, 2.20). Conclusion: Close monitoring is warranted for male KTR with bacteriuria, those with urine cultures positive for Pseudomonas spp, K. pneumoniae, or E. coli, as well as KTR with a history of diabetes‐induced renal failure, urethral stricture, or neuromuscular bladder disorder due to their risk for developing BSIU. Future research should explore strategies to mitigate BSIU risk in these high‐risk KTR and reduce the associated risk of long‐term graft failure. [ABSTRACT FROM AUTHOR]

Background: Cytomegalovirus (CMV) infection has broad implications for morbidity and mortality in renal transplant recipients (RTR). Routine surveillance for CMV replication with PCR‐based quantitative nucleic acid testing (qNAT) assays is standard practice in most transplant centers, but the impact of assay sensitivity on antiviral decision‐making and virologic outcomes has not been studied. We investigated the effects of an ultrasensitive CMV qNAT assay on multiple clinical outcomes, including time to detection and duration of CMV DNAemia. Methods: We conducted a single‐center cohort study contrasting RTRs monitored with a qNAT with a higher lower limit of quantification (LLOQ >300 IU/mL) with those monitored with a more sensitive qNAT (LLOQ >35 IU/mL). Patients were stratified by donor (D)/recipient (R) CMV serostatus (D+/R−: high risk; any R+: moderate risk). CMV viral load monitoring was performed monthly post transplantation, with the primary outcomes being time to CMV DNAemia and its duration. Results: Total 1382 patients were analyzed from 2014 to 2016 and 2019 to 2021. Moderate‐risk RTRs monitored with the more sensitive assay experienced a greater hazard for the development of a first episode of CMV DNAemia (aHR: 1.95, 95% confidence interval [CI]: 1.55–2.46) and an average of 24 (95% CI: 16.40–31.98) additional days of DNAemia. There was no difference in CMV end‐organ disease or 1‐year all‐cause mortality between moderate‐risk RTRs. Conclusions: The more sensitive assay was associated with earlier detection and extended durations of CMV DNAemia in moderate‐risk RTRs, without altering clinical outcomes. These findings inform optimal use of these assays and antiviral stewardship in RTRs. Key Summary: The use of ultrasensitive CMV qNAT assays in moderate‐risk CMV renal transplant recipients is associated with earlier detection and longer durations of CMV DNAemia without impacting CMV end‐organ disease or 1‐year mortality. [ABSTRACT FROM AUTHOR]

Multidrug-resistant organism (MDRO) colonization is a fundamental challenge in antimicrobial resistance. Limited studies have shown that fecal microbiota transplantation (FMT) can reduce MDRO colonization, but its mechanisms are poorly understood. We conducted a randomized, controlled trial of FMT for MDRO decolonization in renal transplant recipients called PREMIX (NCT02922816). Eleven participants were enrolled and randomized 1:1 to FMT or an observation period followed by delayed FMT if stool cultures were MDRO positive at day 36. Participants who were MDRO positive after one FMT were treated with a second FMT. At last visit, eight of nine patients who completed all treatments were MDRO culture negative. FMT-treated participants had longer time to recurrent MDRO infection versus PREMIX-eligible controls who were not treated with FMT. Key taxa (Akkermansia muciniphila, Alistipes putredinis, Phocaeicola dorei, Phascolarctobacterium faecium, Alistipes species, Mesosutterella massiliensis, Barnesiella intestinihominis, and Faecalibacterium prausnitzii) from the single feces donor used in the study that engrafted in recipients and metabolites such as short-chain fatty acids and bile acids in FMT-responding participants uncovered leads for rational microbiome therapeutic and diagnostic development. Metagenomic analyses revealed a previously unobserved mechanism of MDRO eradication by conspecific strain competition in an FMT-treated subset. Susceptible Enterobacterales strains that replaced baseline extended-spectrum β-lactamase–producing strains were not detectable in donor microbiota manufactured as FMT doses but in one case were detectable in the recipient before FMT. These data suggest that FMT may provide a path to exploit strain competition to reduce MDRO colonization. Editor's summary: Those who must use antibiotic prophylaxis to prevent opportunistic infections are at high risk for intestinal colonization and infection by multi-drug resistant organisms (MDROs). Here, Woodworth and colleagues conducted a randomized controlled trial to compare the safety, efficacy, and strain dynamics of MDRO eradication after bowel preparation plus fecal microbiota transfer (FMT) versus bowel preparation alone in 11 renal transplantation recipients. FMT resulted in faster MDRO decolonization and protected study participants from recurrent infection. In some participants, extended spectrum β-lactamase (ESBL)–producing strains were replaced by non-ESBL strains, suggesting that strain competition rather than eradication may occur after FMT. These findings support the efficacy of FMT and provide valuable insights into the mechanisms by which FMT may lead to MDRO decolonization. —Melissa Norton [ABSTRACT FROM AUTHOR]

Background: Belatacept improves long‐term graft survival, but control of some primary viral infections may be impaired. We evaluated the impact of belatacept and tacrolimus on cytomegalovirus (CMV) viral control, remission and relapse in CMV high‐risk and moderate‐risk recipients. Methods: Using a multistate Markov model, we evaluated viral load state transitions of 173 kidney transplant recipients with at least one episode of viremia within 1 year after transplant: state 1, undetectable/low viral load; state 2, moderate viremia; and state 3, severe viremia. Results: Among high‐risk recipients, belatacept‐treated recipients exhibited a significantly higher probability of entering moderate viremia (.36; 95% CI =.31,.41) than tacrolimus‐treated recipients (.20; 95% CI =.13,.29). The expected number of days in viremic states differed. High‐risk belatacept‐treated recipients persisted in moderate viremia for significantly longer (128 days, 95% CI = 110, 146) than did tacrolimus‐treated recipients (70.0 days, 95% CI = 45.2, 100) and showed a trend of shorter duration in low/undetectable viral load state (172 days, 95% CI = 148, 195) than did tacrolimus‐treated recipients (239 days, 95% CI = 195, 277). Moderate‐risk recipients showed better viral load control and with no differences by immunosuppression. Conclusion: High‐risk belatacept‐treated recipients showed defects in sustaining viral control relative to tacrolimus‐treated recipients. Avoidance of initial use belatacept in high‐risk recipients or development of modified management protocols should be considered. [ABSTRACT FROM AUTHOR]

The adoption of de novo belatacept in kidney transplant (kTx) recipients was hampered by an increased risk of acute cellular rejection (ACR) with variation in adopted belatacept based immunosuppressive therapies across centers. We used data from the Scientific Registry of Transplant Recipients (SRTR) to evaluate the temporal trends in belatacept use and describe the associated induction and maintenance regimens in US adult kTx recipients transplanted between June 2011 and December 2018. The number of patients receiving de novo‐belatacept based immunosuppressive therapy increased from.74% in 2011 to 3.11% in 2016. In 2016, 66/207 centers used de novo belatacept‐based regimen with 3.03% using it in over 50% of their patients. The use of T‐cell depleting agents increased with time. Since 2012, the rate of calcineurin inhibitor (CNI) use in combination with belatacept remained stable around 50% and ∼30% remained under belatacept/CNI combination at 1‐year post‐transplantation. The adoption of belatacept as de novo immunosuppressive regimen has been slow and its use remains low in the United States. Various regimens have been used to modulate the risk of ACR. Further studies evaluating the long‐term outcomes of these regimens and assessing their safety especially with regard to the risk of infection are needed. [ABSTRACT FROM AUTHOR]

Cytomegalovirus (CMV) is one of the most commonly recognized opportunistic pathogens and remains the most influential known parameter in shaping an individual's immune system. As such, T cells induced by CMV infection could have a long-term impact on subsequent immune responses. Accumulating evidence indicates that memory T cells developed during past bacterial and viral infection can cross-react with unrelated pathogens, including transplant antigens, and can alter responses to de novo infections, vaccines, cancers, or rejection. Therefore, careful examination of T cell responses elicited by CMV is warranted to understand their potentially beneficial or harmful roles in future major immune events. Our detailed exploration of the distribution, phenotype, TCR repertoire and transcriptome of CD4+ T cells within CMV seropositive healthy individuals using high-dimensional flow cytometry and single cell multi-omics sequencing reveals that CMV seropositivity has highly significant age-independent effects, leading to a reduction in CD4+ naïve T cells and an expansion of CD4+ effector memory T cells and CD45RA+ effector memory T cells. These induced CD4+ effector memory T cells undergo a specific differentiation trajectory resulting in a subpopulation of CD57+CD27-CD28-CD244+ CD4+ T cells with cytotoxic function and TCR oligoclonality for optimal controlled coexistence with cytomegalovirus. Through gene set enrichment analysis, we found that this subpopulation is similar to virus-specific CD8+ T cells and T cells that mediate acute rejection in patients using tacrolimus and belatacept, a selective costimulation blocker. Together, these data suggest that memory CD4+ T cells induced by cytomegalovirus are formed via a distinct differentiation program to acquire cytotoxic function and can be potentially detrimental to transplant patients adopting costimulation blockade immunosuppressive regimen. [ABSTRACT FROM AUTHOR]