Eliseo Albert

Impact of cytomegalovirus DNAemia on overall and non-relapse mortality in allogeneic stem cell transplant recipients

We conducted a retrospective single‐center study to investigate the potential impact of cytomegalovirus (CMV) DNAemia on mortality in allogeneic stem cell transplant (allo‐SCT) recipients.

Dynamics of Torque Teno virus plasma DNAemia in allogeneic stem cell transplant recipients

BACKGROUND Torque Teno virus (TTV) plasma DNA load directly correlate with the level of immunosuppresion in different clinical settings. It is uncertain whether this may be the case in allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). OBJECTIVES We characterized the dynamics of TTV DNAemia in patients undergoing T-cell replete allo-SCT. STUDY DESIGN Retrospective single-center observational study including 72 allo-HSCT patients. Plasma TTV DNA loads were quantified before initiating the conditioning regimen and at different time-points after transplant by real-time PCR. White blood cells (WBC) and absolute lymphocyte counts (ALC) were measured by flow cytometry. RESULTS A dramatic drop in plasma TTV DNA load was observed shortly after conditioning. The TTV DNA load increased steadily after engraftment reaching its peak at day +90 after transplant. The increase in TTV DNA load paralleled that of ALC, and was of greater magnitude in patients who developed severe (grades II-IV) acute graft vs. host disease. CONCLUSION Repopulation of lymphocytes early after allo-HSCT correlates with an increase of plasma TTV DNA load. Prospective studies are nevertheless needed to determine whether the kinetics of TTV DNAemia may allow inference of the degree of overall immunocompetence in these patients.

The kinetics of torque teno virus plasma DNA load shortly after engraftment predicts the risk of high-level CMV DNAemia in allogeneic hematopoietic stem cell transplant recipients

Monitoring Torque teno virus (TTV) DNA load helps to estimate the risk of opportunistic infections in solid organ transplant recipients. We investigated whether the early kinetic pattern of plasma TTV DNA load after allogeneic hematopoietic stem cell transplantation (allo-HSCT) associates with subsequent CMV and EBV DNAemia. This study included 71 allo-HSCT patients. We found that the area under the curve (AUC) for log10 TTV DNA loads quantified by days 20 and 30 after transplantation (TTV DNA load AUC20-30), was significantly lower (P=0.036) in patients who subsequently developed CMV DNAemia requiring preemptive antiviral therapy (n=17) than in those who did not (n=8) or had no CMV DNAemia (n=19). Patients displaying TTV DNA load AUC20-30⩽2.8 copies × days × mL−1 were more likely to have high-level CMV DNAemia. A trend towards a direct correlation between TTV DNA AUC20-30 and CMV-specific interferon-γ CD8+ T-cell counts by day +30 was noted (P=0.095). However, this dynamic parameter was not useful for anticipating the occurrence of either CMV recurrences (n=12) or EBV DNAemia (n=34). In summary, it may be possible to identify a subset of allo-HSCT patients at a high risk of developing high-level CMV DNAemia by analyzing the kinetics of plasma TTV DNA load early after engraftment.

High vancomycin MICs within the susceptible range in Staphylococcus aureus bacteraemia isolates are associated with increased cell wall thickness and reduced intracellular killing by human phagocytes

Vancomycin minimum inhibitory concentrations (MICs) at the upper end of the susceptible range for Staphylococcus aureus have been associated with poor clinical outcomes of bloodstream infections. We tested the hypothesis that high vancomycin MICs in S. aureus bacteraemia isolates are associated with increased cell wall thickness and suboptimal bacterial internalisation or lysis by human phagocytes. In total, 95 isolates were evaluated. Original vancomycin MICs were determined by Etest. The susceptibility of S. aureus isolates to killing by phagocytes was assessed in a human whole blood assay. Internalisation of bacterial cells by phagocytes was investigated by flow cytometry. Cell wall thickness was evaluated by transmission electron microscopy. Genotypic analysis of S. aureus isolates was performed using a DNA microarray system. Vancomycin MICs were significantly higher (P=0.006) in isolates that were killed suboptimally (killing index <60%) compared with those killed efficiently (killing index >70%) and tended to correlate inversely (P=0.08) with the killing indices. Isolates in both killing groups were internalised by human neutrophils and monocytes with comparable efficiency. The cell wall was significantly thicker (P=0.03) in isolates in the low killing group. No genotypic differences were found between the isolates in both killing groups. In summary, high vancomycin MICs in S. aureus bacteraemia isolates were associated with increased cell wall thickness and reduced intracellular killing by phagocytes.

Early Post-Transplant Torquetenovirus Viremia Predicts Cytomegalovirus Reactivations In Solid Organ Transplant Recipients

Monitoring the human virome has been recently suggested as a promising and novel area of research for identifying new biomarkers which would help physicians in the management of transplant patients. Imbalance of the immune system in transplant recipients has a significant impact on replication of Torquetenovirus (TTV), the most representative and abundant virus of human virome. TTV kinetic was studied by real-time PCR in 280 liver or kidney transplant recipients who underwent different drug regimens to maintain immunosuppression. During one-year post-transplant follow-up, TTV viremia fluctuated irrespective of transplanted organ type but consistent with the immunosuppression regimen. TTV kinetic in patients who manifested cytomegalovirus (CMV) reactivation within the first four months post-transplant differed from that observed in patients who did not experience CMV complications. Importantly, plasma TTV load measured between day 0 and 10 post-transplant was significantly higher in CMV DNA positive than in CMV DNA negative patients. TTV viremia above 3.45 log DNA copies/ml within the first 10 days post-transplant correlates with higher propensity to CMV reactivation following transplantation. This study provides further evidence for using early post-transplant TTV viremia to predict CMV reactivation in liver or kidney transplant recipients.

Kinetics of torque teno virus DNA load in saliva and plasma following allogeneic hematopoietic stem cell transplantation: ALBERT et al.

Plasma torque teno virus (TTV) DNA load directly correlates with the degree of T‐cell immune reconstitution early after allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Here, the kinetics of oral TTV DNA shedding was examined to assess whether quantitation of TTV DNA load in saliva may either replace or complement that in plasma for predicting lymphocyte (ALC) reconstitution after engraftment. This prospective observational study enrolled 38 nonconsecutive allo‐HSCT recipients. Saliva and plasma specimens were collected at baseline (pretransplant) and at around days +30, +50, and +90 after allo‐HSCT. TTV DNA was quantitated in both specimen types by real‐time PCR. ALCs were measured by cytometry. A total of 104 paired saliva and plasma specimens were available for TTV PCR analyses. TTV DNA was detected more frequently in saliva than in plasma specimens at all time points (overall, 94.2% vs 86.5%). Increasing levels of TTV DNA were seen in both specimen types from day +30 to day +90 after transplantation. Overall, TTV DNA loads were significantly higher in saliva than in plasma specimens (P = .0002) and correlated significantly (P ≤ .0001). A direct correlation between TTV DNA loads in saliva and plasma and ALCs was observed after engraftment (P = .034 and P = .002, respectively). Future studies should be aimed at determining whether monitoring of oral TTV DNA shedding may be of any utility for inference of immune reconstitution after allo‐HSCT.

A survey on practices for active surveillance of carriage of multidrug-resistant bacteria in hospitals in the Autonomous Community of Valencia, Spain

A questionnaire-based cross-sectional study was conducted to gather information on current microbiological practices for active surveillance of carriage of multidrug-resistant (MDR) bacteria in hospitals from 14 health departments of the Autonomous Community of Valencia (ACV), Spain, which together provided medical attention to 3,271,077 inhabitants in 2017, approximately 70% of the population of the ACV. The survey consisted of 35 questions on MDR bacteria screening policies, surveillance approach chosen (universal vs. targeted), and microbiological methods and processes in use for routine detection and reporting of colonization by MDR bacteria, including the anatomical sites scheduled to be sampled for each MDR bacterial species, and the methodology employed (culture-based, molecular-based, or both). Our study revealed striking differences across centers, likely attributable to the lack of consensus on optimal protocols for sampling, body sites for screening, and microbiological testing, thus underscoring the need for consensus guidelines on these issues.

Pre-engraftment cytomegalovirus DNAemia in allogeneic hematopoietic stem cell transplant recipients: incidence, risk factors, and clinical outcomes

To gauge the risk of delaying initiation of prophylaxis with letermovir from the time of donor infusion to prevent CMV infection in allo-HSCT recipients we investigated the clinical outcomes of CMV DNAemia episodes occurring before engraftment, and compared to that of episodes developing after engraftment (up to day +365). A total of 197 consecutive adult patients were included. Plasma CMV DNA load was monitored by real-time PCR assays [limit of detection: 31 IU/ml]. A total of 150 out of 197 patients had CMV DNAemia (cumulative incidence of 77%; 95% CI, 73–81%), and 38 out of the 197 patients developed it before engraftment (cumulative incidence, 19%; 95% CI, 10–30.3%). Nine episodes of CMV DNAemia were detected prior to the time of donor progenitor cell infusion. A greater number of post-engraftment episodes required preemptive antiviral therapy compared with pre-engraftment episodes (62.5% vs 44.7%; P = 0.05). The cellular content of the donor progenitor cell infusion and transplant characteristics of patients did not differ between patients with pre-engraftment or post-engraftment CMV DNAemia. The cumulative incidence of overall mortality by days 100 and 365, aGvHD by day 100 and relapse by day 365 were not significantly different between patients with pre-engraftment or post-engraftment CMV DNAemia.

Refractory cytomegalovirus DNAemia after allogeneic hematopoietic stem cell transplantation: when should genotypic drug resistance testing be requested?

Persisting cytomegalovirus (CMV) DNAemia in spite of appropriate antiviral therapy is a risk factor for CMV disease and non-relapse mortality in allogeneic hematopoietic stem cell transplant recipients (allo-HSCT) [1], and may be due to a lack of adequate expansion of functional CMVspecific T cells in response to viral replication (clinical resistance), to the emergence of antiviral resistant strains carrying specific point mutations or deletions within the sequence of the viral genes UL97, UL54 (virological resistance) or both [2, 3]. Currently, there is no consensus on when antiviral CMV resistance should be suspected and genotypic drug resistance testing be ordered. Several indicators reflecting therapeutic refractoriness have been proposed: [3–5] increase in CMV DNA load >20% (inter-assay coefficient of variation of the real-time PCR assays used) after 2 weeks of adequate treatment (Group 1), increase in CMV DNA load >0.5 log10 (Group 2) or >1 log10 (Group 3) after 2 weeks of treatment, and decrease in CMV DNA load <1 log10 after 2 (Group 4) or 2 (Group 5) weeks of treatment, in all categories with respect to CMV DNA load at the time of treatment initiation. In this study, refractory CMV DNAemia met one or more of the above criteria. A total of 203 patients who underwent allo-HSCT between January 2010 and June 2017 were included in this retrospective observational study. The median age of patients was 55 years (range, 18-69 years). Plasma CMV DNA load was monitored as previously indicated [6], using the CMV PCR Kit or the CMV RealTime CMV PCR (both from Abbott Molecular, Des Plaines, IL, USA). Antiviral therapy with (val)ganciclovir or foscarnet at conventional doses was initiated when the plasma CMV DNA load reached levels of >1500 IU/ml, or when the CMV dt was ≤2.0 days, whatever occurred first (this latter strategy since May 2014) [7]. A total of 147 patients had CMV DNAemia within the first year after allo-HSCT (cumulative incidence, 72.38%; 95% CI, 67.80%–76.41%), of whom 79 developed a single episode and 68 experienced one or more recurrences. The total number of episodes of CMV DNAemia was 246, of which 123 (50%) occurring in 96 patients required antiviral therapy (Table 1). (Val)ganciclovir was the first-choice drug in 110 episodes, whereas the remaining 13 episodes were initially treated with foscarnet. Switching of antiviral therapy was done in 30 episodes due either to hematological toxicity (n= 19) or to CMV DNAemia persistence through 3–4 weeks after treatment inception (n= 11). Out of the 123 treated episodes, 113 eventually cleared; the remaining 10 were still ongoing at the time of patient’s death. A total of 14 episodes in 14 patients (11.3%) were deemed to be refractory (Table 2). Specifically, 9, 3, 2, 12, and 6 episodes met Group 1, 2, 3, 4, and 5 criteria, respectively. Most of these were first episodes that occurred within the first 100 days after allo-HSCT and were initially treated with (val)ganciclovir. The CMV-serostatus pair D −/R+ and the occurrence of grades II–IV acute GvHD, both known factors associated with protracted or severely impaired reconstitution of CMV-specific T-cell immunity [2], were overrepresented in these episodes. Regretably, the * David Navarro david.navarro@uv.es

The impact of virus population diversity on the dynamics of cytomegalovirus DNAemia in allogeneic stem cell transplant recipients

Mixed cytomegalovirus (CMV) infections are associated with delayed viral clearance in solid organ transplant recipients. We investigated whether this could be extrapolated to allogeneic stem cell transplant (allo-SCT) recipients. A total of 48 plasma specimens, obtained during 29 episodes of active CMV infection in 25 non-consecutive allo-SCT patients, were analysed. Baseline blood specimens, drawn shortly prior to the inception of pre-emptive antiviral therapy (pre-treatment specimen; n=29), as well as follow-up samples obtained either after the initiation of antiviral therapy (post-treatment specimen; n=15) or during recurrent episodes (n=4) were analysed. Plasma CMV DNA loads were quantified by real-time PCR and the CMV genotyping was performed by ultra-deep sequencing of hypervariable regions in the genes coding for glycoproteins N (gN) and O (gO). A trend towards higher CMV DNA peak loads, longer CMV DNAemia episode durations and slower CMV DNAemia decay rates was observed for episodes with mixed CMV genotype populations compared to those caused by single CMV variants, although the differences did not reach statistical significance. The length of the treatment course required to clear DNAemia was significantly longer in these mixed episodes (P=0.002). Significant changes in the number or frequency of CMV gN or gO genetic variants were documented following the initiation of antiviral therapy or in recurrent episodes. CMV diversity may have a major impact on the kinetics of CMV DNAemia clearance during the treatment of active CMV infection episodes in allo-SCT recipients.