1220. Is MIC all that matters? MIC Distributions of Ceftazidime and Cefepime in Ceftriaxone-Resistant E. coli and Klebsiella spp

Background The Clinical and Laboratory Standards Institute (CLSI) lowered MIC breakpoints for many beta-lactam antibiotics to enhance detection of resistance among Enterobacterales. This shift was also meant to eliminate the need for routine testing for extended-spectrum beta-lactamases (ESBLs). The recommended treatment for ESBL-producing Enterobacterales is carbapenems. The IDSA guidelines for MDR-GN organisms recommend using ceftriaxone (CRO) resistance as a proxy for ESBL production and thus carbapenem treatment. Under CLSI guidelines, alternative beta-lactams such as ceftazidime (CAZ) and cefepime (FEP) may still be reported as susceptible and thus used by clinicians even in light of IDSA recommendations. The aim of this project was to characterize the MIC distributions of CAZ and FEP stratified by CRO susceptibility. Methods Clinical E. coli, K. pneumoniae, and K. oxytoca isolates from blood cultures in adult patients from Nov 2016-Dec 2018 that had MICs tested by the Vitek-2 automated susceptibility testing system for CRO, FEP and CAZ were identified. Descriptive statistics were used to compare MIC distributions across the antibiotics of interest (SPSS). Results 573 isolates were included, of these, 17.3% were CRO resistant. Most (53%) CRO-R isolates had FEP MICs ≤2 which is considered susceptible per CLSI; 19% had FEP MICs of 4-8 which would be considered S-DD by CLSI (Figure 1A; breakpoints noted by dashed lines). Using the EUCAST breakpoint of ≤1, only 11% of CRO-R isolates would be reported as FEP-S. For CAZ, 40% of CRO-R isolates had CAZ MICs ≤4, which is considered S by CLSI. Using the EUCAST breakpoint of ≤1, only 12% of CRO-R isolates would be reported as CAZ-S (Figure 1B). Cefepime MIC Distribution for Ceftriaxone Resistant Isolates Distribution of MICs for cefepime for ceftriaxone resistant isolates with the breakpoints for EUCAST and CLSI noted with a dashed line Ceftazidime MIC Distribution for Ceftriaxone Resistant Isolates Distribution of MICs for ceftazidime for ceftriaxone resistant isolates with the breakpoints for EUCAST and CLSI noted with a dashed line Conclusion Half of CRO-R E. coli, K. pneumoniae and K. oxytoca have FEP and CAZ MICs at or below the current CLSI breakpoints. This may lead to their use for serious ESBL infections where a carbapenem is preferred. To prevent unnecessary use, laboratories should consider suppressing FEP and CAZ susceptibilities when CRO-R or adopting more the aggressive EUCAST breakpoints for these agents. Disclosures Emily Heil, PharmD, MS, BCIDP, Nothing to disclose Kimberly C. Claeys, PharmD, GenMark (Speaker’s Bureau)

Here in the Real World: The Performance of Alternative Beta

We examine the realized performance of alternative beta strategies using a database of returns since 2008. Despite diversified portfolios of risk premia strategies offered by global investment banks achieving satisfactory Sharpe ratios of 0.80–1.07 during the decade to 2017, up to two thirds of the performance can be explained by exposure to traditional benchmarks. Furthermore, the outcomes are very sensitive to the estimated all-in fees incurred by investors. We find no evidence of positive alpha in the aggregate industry returns, and document a pattern of time-varying, asymmetric, and statistically significant betas to global equities and bonds. Our results suggest that the poor performance of the strategies in 2018–20 was not an aberration, but rather a continuation of patterns already present in earlier data. The findings are representative of the wider risk premia industry, as returns of managed alternative risk premia funds and those of diversified investment bank strategy portfolios appear closely aligned.

New Stratified Bayesian Estimators Using Warner’s Randomized Response Technique Through Mixed Priors

In this paper, we propose new stratified Bayesian estimators of population proportion of a sensitive trait by adopting a mixture of alternative beta distributions as quantification of prior information in a stratified random sampling situation. Data were collected through Warner’s randomized response technique. To study the performance of the newly developed stratified estimators, mean squared error and absolute bias were used as performance criteria. The proposed estimators were compared with the existing one. We observed that the proposed estimators are more sensitive to responses than the existing one at various sample sizes respectively.

Asset Allocation Strategies and Commodities

As a result of the financial crisis of 2007–2008 and subsequent central banking decisions, the asset management industry changed its asset allocation choices. Asset managers are focusing their attention on the search for new asset classes by taking advantage of the new opportunities to capture risk premia with the aim of exceeding the returns given by traditional investments, including traded equities, fixed income securities, and cash. By doing so, they are trying to improve the selection of alternative assets, such as commodities that sometimes have relatively low correlations with traditional assets. The chapter begins by describing the principles of asset allocation, distinguishing between passive and active asset allocation, also focusing on beta and alternative beta. It then concentrates on how investors can gain exposure to commodities through different investment vehicles and strategies.

Current Hedge Fund Debates and Controversies

The hedge fund industry has grown to nearly $3 trillion over the last 20 years. High-net-worth individuals and institutional investors expect high returns and low correlation with traditional asset classes in exchange for the fees paid. The standard fee structure is “2 and 20,” 2 percent of assets under management and 20 percent of profits, representing high fees for active management. Hedge funds are largely unregulated and somewhat mysterious. As a result, they are the subject of debates and controversies among market participants and policymakers alike. Debates focus on fee structures, alpha versus alternative beta, weakening returns, activist investors, and leverage. The Securities and Exchange Commission has targeted hedge fund misconduct and malfeasance, pursuing perpetrators of fraud, insider trading, and conflicts of interest in the industry. Several high-ranking Wall Street hedge fund executives have been charged with, and in some cases convicted of, breaking securities laws.

Bayesian Analysis of Warner’s Randomized Response Technique

This paper proposed alternative beta estimators of the population proportion of a sensitive attribute when life data were obtained through the administration of survey questionnaires on abortion of some matured women. The results showed that the proposed alternative beta estimators were more efficient in capturing responses from respondents than the simple beta estimator proposed by Winkler and Franklin for relatively small, medium as well as large sample sizes respectively.