Clinical Outcomes and Risk Factors for Carbapenem-resistant Enterobacterales Bloodstream Infection in Solid Organ Transplant Recipients

BACKGROUND

The clinical outcomes associated with, and risk factors for, carbapenem-resistant Enterobacterales (CRE) bloodstream infections (BSIs) in solid organ transplant (SOT) recipients remain ill-defined.

METHODS

A multicenter retrospective cohort study was performed, including SOT recipients with an Enterobacterales BSI between 2005 and 2018. Exposed subjects were those with a CRE BSI. Unexposed subjects were those with a non-CRE BSI. A multivariable survival analysis was performed to determine the association between CRE BSI and risk of all-cause mortality within 60 d. Multivariable logistic regression analysis was performed to determine independent risk factors for CRE BSI.

RESULTS

Of 897 cases of Enterobacterales BSI in SOT recipients, 70 (8%) were due to CRE. On multivariable analysis, CRE BSI was associated with a significantly increased hazard of all-cause mortality (adjusted hazard ratio, 2.85; 95% confidence interval [CI], 1.68-4.84; P < 0.001). Independent risk factors for CRE BSI included prior CRE colonization or infection (adjusted odds ratio [aOR] 9.86; 95% CI, 4.88-19.93; P < 0.001)' liver transplantation (aOR, 2.64; 95% CI, 1.23-5.65; P = 0.012)' lung transplantation (aOR, 3.76; 95% CI, 1.40-10.09; P = 0.009)' and exposure to a third-generation cephalosporin (aOR, 2.21; 95% CI, 1.17-4.17; P = 0.015) or carbapenem (aOR, 2.80; 95% CI, 1.54-5.10; P = 0.001) in the prior 6 months.

CONCLUSIONS

CRE BSI is associated with significantly worse outcomes than more antibiotic-susceptible Enterobacterales BSI in SOT recipients.

949. Risk Factors for Subsequent Multidrug-Resistant Gram-Negative Bloodstream Infection Following an Initial Gram-Negative Bloodstream Infection among Solid Organ Transplant Recipients

Background

Multidrug-resistant (MDR) Gram-negative (GN) bloodstream infections (BSI) are a major cause of morbidity and mortality among solid organ transplant recipients (SOTR). We determined risk factors associated with subsequent MDR-GN BSI following an initial Enterobacterales (EB) BSI among SOTRs.

Methods

A retrospective cohort study was performed. All SOTR with an EB BSI at the Hospital of the University of Pennsylvania and University of Maryland Medical Center between 1 Jan 2007 and 30 June 2018 and The Johns Hopkins Hospital between 1 Jan 2005 and 31 Dec 2015 were included. The primary outcome was any MDR-GN BSI within 60 days of the EB BSI, including MDR-EB (defined by ceftriaxone MIC ≥8μg/mL), and MDR-Pseudomonas and Acinetobacter (defined by resistance to three or more antibiotic classes). Unadjusted analyses were performed to identify possible risk factors, using a Fisher’s exact or χ 2 test for categorical and Student’s t-test for continuous variables.

Results

Of 988 SOTR with an EB BSI, 138 (14%) had a MDR-GN BSI within 60 days. In unadjusted analyses, possible risk factors for a subsequent MDR-GN BSI (Table 1) included: (1) an index BSI due to extended-spectrum beta-lactamase (ESBL)-producing EB (compared to a susceptible index EB BSI); (2) a carbapenem-resistant EB (CRE) index BSI (compared to a susceptible index EB BSI); (3) exposure to piperacillin-tazobactam or carbapenems in the 6 months prior to the index EB BSI; (4) prior liver transplantation; and (5) need for reoperation within four weeks of the original transplantation. There was no significant association between recurrent MDR-GN BSI and immunosuppression at time of infection, induction immunosuppression history, acute rejection history, or primary graft dysfunction.

Table 1. Risk factors for subsequent MDR-GN BSI following EB BSI among SOTR.

Conclusion

This study shows that liver transplantation, reoperation following transplantation, an index ESBL-EB or CRE BSI, and recent exposure to broad-spectrum beta-lactam antibiotics are associated with an increased odds of subsequent MDR-GN BSI in SOTR, and underscores the need for future studies aimed at preventing emergence of MDR-GN infections in this vulnerable population.

Disclosures

Jennifer Han, MD, MSCE, GlaxoSmithKline (Employee, Shareholder) Ebbing Lautenbach, MD, MPH, MSCE, Merck (Other Financial or Material Support, Member of Data and Safety Monitoring Board (DSMB)) Pranita Tamma, MD, MHS, Nothing to disclose Emily Blumberg, MD, Amplyx (Other Financial or Material Support, Member of Data and Safety Monitoring Board (DSMB))Hologic (Research Grant or Support)Merck (Grant/Research Support, Other Financial or Material Support, Member of Scientific Advisory Committee)Takeda (Research Grant or Support, Other Financial or Material Support, Member of Scientific Advisory Committee) Judith A. Anesi, MD, MSCE, Nothing to disclose

In vitro protective effects of resveratrol and stilbene alkanoic derivatives on induced oxidative stress on C2C12 and MCF7 cells

Resveratrol (3,4’,5-trihydroxy-trans-stilbene) is a natural phytoalexin found in grapes and wine, which has been extensively studied for a wide range of biological effects. A large number of stilbene-containing derivatives have displayed antioxidant and antiproliferative activities on various cancer cell lines. In this study, a series of stilbene hybrids 1-9, previously reported as peroxisome proliferator-activated receptor (PPAR) agonists, were assessed at micromolar concentrations using MTT cell viability assay in C2C12 and MCF7 cell lines. The modulation of oxidative stress was also evaluated by measuring the protective effects on reactive oxygen species (ROS) production induced or not by oxidative stimulus. Among these, compounds 2 and 8 showed significant radical scavenging activity.

Assessing the Threat of Amphibian Chytrid Fungus in the Albertine Rift: Past, Present and Future

Batrachochytrium dendrobatidis (Bd), the cause of chytridiomycosis, is a pathogenic fungus that is found worldwide and is a major contributor to amphibian declines and extinctions. We report results of a comprehensive effort to assess the distribution and threat of Bd in one of the Earth’s most important biodiversity hotspots, the Albertine Rift in central Africa. In herpetological surveys conducted between 2010 and 2014, 1018 skin swabs from 17 amphibian genera in 39 sites across the Albertine Rift were tested for Bd by PCR. Overall, 19.5% of amphibians tested positive from all sites combined. Skin tissue samples from 163 amphibians were examined histologically; of these two had superficial epidermal intracorneal fungal colonization and lesions consistent with the disease chytridiomycosis. One amphibian was found dead during the surveys, and all others encountered appeared healthy. We found no evidence for Bd-induced mortality events, a finding consistent with other studies. To gain a historical perspective about Bd in the Albertine Rift, skin swabs from 232 museum-archived amphibians collected as voucher specimens from 1925–1994 were tested for Bd. Of these, one sample was positive; an Itombwe River frog (Phrynobatrachus asper) collected in 1950 in the Itombwe highlands. This finding represents the earliest record of Bd in the Democratic Republic of Congo. We modeled the distribution of Bd in the Albertine Rift using MaxEnt software, and trained our model for improved predictability. Our model predicts that Bd is currently widespread across the Albertine Rift, with moderate habitat suitability extending into the lowlands. Under climatic modeling scenarios our model predicts that optimal habitat suitability of Bd will decrease causing a major range contraction of the fungus by 2080. Our baseline data and modeling predictions are important for comparative studies, especially if significant changes in amphibian health status or climactic conditions are encountered in the future.

Synthesis of diastereomerically enriched 2-bromoesters and their reaction with nucleophiles

2-Bromoesters enriched in the (S,R)-diastereoisomer can be easily prepared by coupling of racemic 2-bromoacids with (R)-pantolactone. Displacement of the bromine atom with nucleophiles, under suitable reaction conditions, occurs without epimerization of starting compounds, giving (R,R)-2-substituted carboxylic acid derivatives.