Therapy of Mycobacterium abscessus Infections in Solid Organ Transplant Patients.

Mycobacterium abscessus complex (MABC), a rapidly growing Mycobacterium, is one of the most common causes of non-tuberculous mycobacteria (NTM) infections in the United States of America, and it has been associated with a wide spectrum of infections in immunocompetent and immunosuppressed individuals. Eradicating MABC is very challenging, even with prolonged combination therapies. The management of MABC infections in solid organ transplant (SOT) patients is usually complex given their net state of immunosuppression, associated comorbidities, and potential drug-drug interactions, among other things. In this manuscript, we discussed the antimicrobial management of pulmonary and extrapulmonary MABC infections. In addition, we reviewed promising novel therapies such as clofazimine, omadacycline, bedaquiline, and inhaled tigecycline that could join the existing antimicrobial armamentarium to fight this infection associated with significant morbidity and mortality. However, further studies are needed, especially among the immunocompromised host.

HIV-Positive Liver Transplant Does not Alter the Latent Viral Reservoir in Recipients With Antiretroviral Therapy-Suppressed HIV.

The latent viral reservoir (LVR) remains a major barrier to HIV-1 curative strategies. It is unknown whether receiving a liver transplant from a donor with HIV might lead to an increase in the LVR because the liver is a large lymphoid organ. We found no differences in intact provirus, defective provirus, or the ratio of intact to defective provirus between recipients with ART-suppressed HIV who received a liver from a donor with (n = 19) or without HIV (n = 10). All measures remained stable from baseline by 1 year posttransplant. These data demonstrate that the LVR is stable after liver transplantation in people with HIV. Clinical Trials Registration. NCT02602262 and NCT03734393.

Clinical characteristics and outcomes in CMV infection in intestinal transplant recipients: A single-center experience.

BACKGROUND: Cytomegalovirus (CMV) infection is one of the most common posttransplantation infections and has been associated with increased rejection and mortality. Data in intestinal transplants recipients are limited. METHODS: This is a single-center, retrospective cohort study of all intestinal transplants performed between January 1, 2009, and August 31, 2020. We included recipients of all ages who were at risk of CMV infection. To identify the risk factors, we conducted at first univariate and multivariate analysis. For the multivariate analysis, we developed a logistic regression model based on the result of univariate analysis. RESULTS: Ninety five patients with a median age of 32 (interquartile range [IQR] 4, 50) were included. CMV donor seropositive/recipient seronegative were 17 (17.9%). Overall, 22.1% of the recipients developed CMV infection at a median time of 155 (IQR 28-254) days from transplant, including 4 CMV syndrome and 6 CMV end-organ disease. Overall, 90.4%, (19/21) developed DNAemia while on prophylaxis. Median peak viral load and time to negativity was 16 000 (IQR 1034-43 892) IU/mL and 56 (IQR 49-109) days, respectively. (Val)ganciclovir and foscarnet were utilized in 17 (80.9%) and 1 (4.76%) recipients, respectively. Recurrences of CMV DNAemia and graft rejection were observed in three and six recipients, respectively. Younger age was identified as a risk factor (p = .032, odds ratio 0.97, 95% confidence interval 0.95-0.99) to develop CMV DNAemia. CONCLUSION: A significant proportion of intestinal transplant recipients developed CMV infection while on prophylaxis. Better methods such as CMV cell mediated immunity guided prophylaxis should be used to prevent infections in this population.

A Pilot Single-Blinded, Randomized, Controlled Trial Comparing BNT162b2 vs. JNJ-78436735 Vaccine as the Third Dose After Two Doses of BNT162b2 Vaccine in Solid Organ Transplant Recipients.

Solid Organ Transplant (SOT) recipients are at significant higher risk for COVID-19 and due to immunosuppressive medication, the immunogenicity after vaccination is suboptimal. In the previous studies, booster method showed significant benefit in this population. In the current study, we compared using a mix-and-match method vs. same vaccine as a third dose in SOT recipients. This was a patient-blinded, single center, randomized controlled trial comparing BNT162b2 vs. JNJ-78436735 vaccine as the third dose after two doses of BNT162b2 vaccine. We included adult SOT recipients with functional graft who had received two doses of BNT162b2 vaccine. Participants were randomly assigned to receive either BNT162b2 or JNJ-78436735 in one-to-one ratio. Primary outcome was SARS-CoV-2 IgG positivity at 1 month after the third dose. Sixty SOT recipients, including 36 kidney, 12 liver, 2 lung, 3 heart, and 5 combined transplants, were enrolled, and 57 recipients were analyzed per protocol. There were no statistically significant differences between the two vaccine protocols for IgG positivity (83.3% vs. 85.2% for BNT162b2 and JNJ-78436735, respectively, p = 0.85, Odds Ratio 0.95, 95% Confidence Interval 0.23-4.00). Comparison of the geometric mean titer demonstrated a higher trend with BNT162b2 (p = 0.09). In this pilot randomized controlled trial comparing mix and match method vs. uniform vaccination in SOT recipients, both vaccines were safely used. Since this was a small sample sized study, there was no statistically significant difference in immunogenicity; though, the mix and match method showed relatively lower geometric mean titer, as compared to uniform vaccine. Further studies need to be conducted to determine duration of this immunogenicity. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT05047640?term=20210641&draw=2&rank=1, identifier 20210641.

Validation of the INCREMENT-SOT-CPE score in a large cohort of liver transplant recipients with carbapenem-resistant Enterobacterales infection.

BACKGROUND: Management of infections due to carbapenemase-resistant Enterobacterales (CRE) in solid organ transplant (SOT) recipients remains a difficult challenge. The INCREMENT-SOT-CPE score has been specifically developed from SOT recipients to stratify mortality risk, but an external validation is lacking. METHODS: Multicenter retrospective cohort study of liver transplant (LT) recipients colonized with CRE infection who developed infection after transplant over 7-year period. Primary endpoint was all-cause 30-day mortality from infection onset. A comparison between INCREMENT-SOT-CPE and other selected scores was performed. A two-level mixed effects logistic regression model with random effects for the center was fitted. Performance characteristics at optimal cut-point were calculated. Multivariable Cox regression analysis of risk factors for all-cause 30-day mortality was carried out. RESULTS: Overall, 250 CRE carriers developed infection after LT and were analyzed. The median age was 55 years (interquartile range [IQR]: 46-62) and 157 were males (62.8%). All-cause 30-day mortality was 35.6%. A sequential organ failure assessment (SOFA) score ≥ 11 showed a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 69.7%, 76.4%, 62.0%, 82.0%, and 74.0%, respectively. An INCREMENT-SOT-CPE ≥ 11 reported a sensitivity, specificity, PPV, NPV, and accuracy of 73.0%, 62.1%, 51.6%, 80.6% and 66.0%, respectively. At multivariable analysis acute renal failure, prolonged mechanical ventilation, INCREMENT-SOT-CPE score ≥ 11 and SOFA score ≥ 11 were independently associated with all-cause 30-day mortality, while a tigecycline-based targeted regimen was found to be protective. CONCLUSIONS: Both INCREMENT-SOT-CPE ≥ 11 and SOFA ≥ 11 were identified as strong predictors of all-cause 30-day mortality in a large cohort of CRE carriers developing infection after LT.

Pulmonary Infections in Intestinal Transplant Recipients With Preexisting Pulmonary Nodules.

BACKGROUND: Pulmonary nodules in asymptomatic patients could represent latent pulmonary infections. Intestinal transplant (ITx) recipients with preexisting lung nodules might be at higher risk for pulmonary infections. However, data is scarce. METHODS: This retrospective study included adult patients who underwent ITx from May 2016 to May 2020. Chest computed tomography scans performed within 12 months before ITx were obtained to evaluate for preexisting pulmonary nodules. Screening for endemic mycoses, Aspergillus, Cryptococcus, and latent tuberculosis infection performed within 12 months before ITx was obtained. We assessed for worsening pulmonary nodules, and fungal and mycobacterial infections during the first year post-transplant. Survival and graft loss at 1-year post-transplant was also assessed. RESULTS: Forty-four patients underwent ITx. Thirty-one had preexisting lung nodules. No invasive fungi were recorded in the pretransplant period and one individual had latent tuberculosis infection. In the post-transplant period, one individual developed probable invasive aspergillosis and had worsening nodular opacities, whereas one had disseminated histoplasmosis with stable lung nodules in chest computed tomography. No mycobacterial infections were documented. The cohort survival was 84% at 12 months after transplant. CONCLUSION: Preexisting pulmonary nodules were common in the cohort (71%), yet latent and active pulmonary infections were rare. Appearance of new or worsening pulmonary nodules does not appear to directly correlate with pulmonary infections in the post-transplant period. Routine chest computed tomography is not recommended in the pretransplant period, but follow-up is favored in patients with confirmed nodular opacities. Clinical monitoring is essential.

Difference between SARS-CoV-2, seasonal coronavirus, influenza, and respiratory syncytial virus infection in solid organ transplant recipients.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been raging since the end of 2019 and has shown worse outcomes in solid organ transplant (SOT) recipients. The clinical differences as well as outcomes between respiratory viruses have not been well defined in this population. METHODS: This is a retrospective cohort study of adult SOT recipients with nasopharyngeal swab or bronchoalveolar lavage PCR positive for either SARS-CoV-2, seasonal coronavirus, respiratory syncytial virus (RSV) or influenza virus from January 2017 to October 2020. The follow up period was 3 months. Clinical characteristics and outcomes were evaluated. RESULTS: A total of 377 recipients including 157 SARS-CoV-2, 70 seasonal coronavirus, 50 RSV and 100 influenza infections were identified. The most common transplanted organ was kidney 224/377 (59.4%). Lower respiratory tract infection (LRTI) was found in 210/377 (55.7%) and the risk factors identified with multivariable analysis were SARS-CoV-2 infection, steroid use, and older age. Co- and secondary infections were seen in 77/377 (20.4%) recipients with bacterial pathogens as dominant. Hospital admission was seen in 266/377 (67.7%) recipients without significant statistical difference among viruses, however, ICU admission, mechanical ventilation and mortality were higher with SARS-CoV-2 infection. In the multivariable model, the risk factors for mortality were SARS-CoV-2 infection and older age. CONCLUSIONS: We found higher incidence of ICU admission, mechanical ventilation, and mortality among SARS-CoV-2 infected recipients. Older age was found to be the risk factor for lower respiratory tract infection and mortality for SARS-CoV-2, coronaviruses, RSV and influenza virus groups.

Is the Omicron variant truly less virulent in solid organ transplant recipients?

Solid organ transplant (SOT) recipients are at high risk for severe disease with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Emerging variants of concern have disproportionately affected this population. Data on severity and outcomes with the Omicron variant in SOT recipients are limited. Thus we conducted this single-center, retrospective cohort study of SOT recipients diagnosed with SARS-CoV-2 infection from December 18, 2021 to January 18, 2022, when prevalence of the Omicron variant was more than 80%-95% in the community. Univariate and multivariate logistic regression analysis was performed to identify risk factors for hospital admission. We identified 166 SOT patients: 112 (67.5%) kidney, 22 (13.3%) liver, 10 (6.0%) lung, seven (4.2%) heart, and 15 (9.0%) combined transplants. SARS-CoV-2 vaccine series was completed in 59 (35.5%) recipients. Ninety-nine (59.6%) and 13 (7.8%) recipients received casirivimab/imdevimab and sotrovimab, respectively. Fifty-three (32%) recipients required hospital admission, of which 19 (35.8%) required intensive care unit level of care. Median follow-up was 50 (interquartile range, 25-59) days, with mortality reported in six (3.6%) patients. Risk factors identified for hospital admission were African American race (p < .001, odds ratio [OR] 4.00, 95% confidence interval [CI] 1.84-8.70), history of coronary artery disease (p = .031, OR 3.50, 95% CI 1.12-10.87), and maintenance immunosuppression with corticosteroids (p = .048, OR 2.00, 95% CI 1.01-4.00). In conclusion, contrary to that in the general population, we found a higher hospital admission rate in SOT recipients with omicron variant infection. Further studies to investigate the efficacy of newer treatments are necessary, even as outcomes continue to improve.

Mycobacterium abscessus Infections in Solid Organ Transplant Recipients: Single-Center Experience in the United States, 2013-2018.

Background: Mycobacterium abscessus is increasingly recognized as a human pathogen causing life-threatening infections in immunocompromised patients. There is a paucity of data around this topic in solid organ transplant (SOT) recipients. Methods: This work was a single-center retrospective cohort study of all SOT recipients with a positive culture for M abscessus between 2013 and 2018. Results: A total of 20 patients (55% female) met inclusion criteria, including 1 kidney recipient (5.0%), 2 liver recipients (10.0%), 12 lung recipients (60.0%), 1 heart recipient (5.0%), and 4 combined organ recipients (20.0%). The median time from SOT to infection was 100 days (range, 30-431 days). Thirteen (65.0%) patients (1 kidney, 1 heart, 7 lung, 1 liver, 1 intestine, and 2 multivisceral) were treated with a median duration of 185 antibiotic days (range, 20-523 days). Among them, M abscessus was isolated from respiratory samples in 8 and nonrespiratory samples in 5; 4 of 13 (30.8%) patients had treatment failure and 3 of 13 (23.1%) had unrelated deaths within 1 year after diagnosis. Seven patients (5 lung transplant recipients) with the organism isolated from respiratory samples were not treated as their cultures represented airway colonization or contamination; of those, 2 (28.6%) died (unrelated to infection) and 5 (71.4%) were alive without the infection after 1 year of follow-up. Conclusions: Mycobacterium abscessus infections affect SOT recipients with a high proportion of clinical failures. However, in lung recipients, not all positive cultures correlated with infection, and without treatment some patients had good clinical outcomes. Thus, differentiating colonization from infection is important, and infection prevention measures and novel therapeutic agents are needed for SOT recipients.

Cefazolin plus ertapenem and heart transplantation as salvage therapy for refractory LVAD infection due to methicillin-susceptible Staphylococcus aureus: A case series.

The use of left ventricular assist devices (LVADs) is increasingly more common as the availability of donor organs in relation to failing hearts is outstandingly limited. Infections are the most common complications in LVAD recipients, particularly those caused by Staphylococcus spp. Refractory LVAD-related infections are not uncommon as achieving adequate source control is often not feasible before heart transplantation. Evidence suggest that cefazolin plus ertapenem is effective in refractory methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, but this approach has not been described in LVAD recipients. In this article, we report two cases of refractory MSSA bacteremia in LVAD recipients that were successfully treated with salvage therapy with cefazolin plus ertapenem and subsequent heart transplantation. This treatment strategy should be considered in patients with refractory LVAD-associated infection due to MSSA that are not responding to standard treatment.

When is it safe to perform abdominal transplantation in patients with prior SARS-CoV-2 infection: A case series.

BACKGROUND: The Coronavirus disease 2019(COVID-19) pandemic has negatively impacted worldwide organ transplantation. However, there is limited information on recipients transplanted after SARS-CoV-2 infection. A full understanding of this scenario is required, as transplantation is a life-saving procedure and COVID-19 remains an ongoing threat. METHODS: Abdominal organ transplant recipients diagnosed with COVID-19 prior to transplantation were identified by chart review and clinical data were collected. The primary outcome was the transplant outcome including graft loss, rejection and death, and reactivation of infection post-transplant. RESULTS: We identified 14 patients who received abdominal organ transplants after symptomatic PCR confirmed SARS-CoV-2 infection; four patients had a positive PCR at the time of admission for transplantation. The median time of follow-up was 79 (22-190) days. One recipient with negative PCR before transplant tested positive 9 days after transplant. One of 14 transplanted patients developed disseminated mold infection and died 86 days after transplant. During the follow-up, only one patient developed rejection; thirteen patients had favorable graft outcomes. CONCLUSIONS: We were able to perform abdominal transplantation for patients with COVID-19 before transplant, even with positive PCR at the time of transplant. Larger studies are needed to determine the time to safe transplant after SARS-CoV-2 infection.

A Less Restrictive Policy for Liver Transplantation in Coronavirus Disease 2019 Positive Patients, Based Upon Cycle Threshold Values.

Coronavirus disease 2019 drastically impacted solid organ transplantation. Lacking scientific evidence, a very stringent but safer policy was imposed on liver transplantation (LT) early in the pandemic. Restrictive transplant guidelines must be reevaluated and adjusted as data become available. Before LT, the prevailing policy requires a negative severe acute respiratory syndrome coronavirus 2 real-time polymerase chain reaction (RT-PCR) of donors and recipients. Unfortunately, prolonged viral RNA shedding frequently hinders transplantation. Recent data reveal that positive test results for viral genome are frequently due to noninfectious and prolonged convalescent shedding of viral genome. Moreover, studies demonstrated that the cycle threshold of quantitative RT-PCR could be leveraged to inform clinical transplant decision-making. We present an evidence-adjusted and significantly less restrictive policy for LT, where risk tolerance is tiered to recipient acuity. In addition, we delineate the pretransplant clinical decision-making, intra- and postoperative management, and early outcome of 2 recipients of a liver graft performed while their RT-PCR of airway swabs remained positive. Convalescent positive RT-PCR results are common in the transplant arena, and the proposed policy permits reasonably safe LT in many circumstances.

Development of a Risk Prediction Model for Carbapenem-resistant Enterobacteriaceae Infection After Liver Transplantation: A Multinational Cohort Study.

BACKGROUND: Patients colonized with carbapenem-resistant Enterobacteriaceae (CRE) are at higher risk of developing CRE infection after liver transplantation (LT), with associated high morbidity and mortality. Prediction model for CRE infection after LT among carriers could be useful to target preventive strategies. METHODS: Multinational multicenter cohort study of consecutive adult patients underwent LT and colonized with CRE before or after LT, from January 2010 to December 2017. Risk factors for CRE infection were analyzed by univariate analysis and by Fine-Gray subdistribution hazard model, with death as competing event. A nomogram to predict 30- and 60-day CRE infection risk was created. RESULTS: A total of 840 LT recipients found to be colonized with CRE before (n = 203) or after (n = 637) LT were enrolled. CRE infection was diagnosed in 250 (29.7%) patients within 19 (interquartile range [IQR], 9-42) days after LT. Pre- and post-LT colonization, multisite post-LT colonization, prolonged mechanical ventilation, acute renal injury, and surgical reintervention were retained in the prediction model. Median 30- and 60-day predicted risk was 15% (IQR, 11-24) and 21% (IQR, 15-33), respectively. Discrimination and prediction accuracy for CRE infection was acceptable on derivation (area under the curve [AUC], 74.6; Brier index, 16.3) and bootstrapped validation dataset (AUC, 73.9; Brier index, 16.6). Decision-curve analysis suggested net benefit of model-directed intervention over default strategies (treat all, treat none) when CRE infection probability exceeded 10%. The risk prediction model is freely available as mobile application at https://idbologna.shinyapps.io/CREPostOLTPredictionModel/. CONCLUSIONS: Our clinical prediction tool could enable better targeting interventions for CRE infection after transplant.