Browsing by Author "Humphries, Romney M"
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Item Open Access Can ceftazidime/avibactam and aztreonam overcome β-lactam resistance conferred by metallo-β-lactamases in Enterobacteriaceae?(Antimicrob Agents Chemother, 2017-02-06) Marshall, Steven; Hujer, Andrea M; Rojas, Laura J; Papp-Wallace, Krisztina M; Humphries, Romney M; Spellberg, Brad; Hujer, Kristine M; Marshall, Emma K; Rudin, Susan D; Perez, Federico; Wilson, Brigid M; Wasserman, Ronald B; Chikowski, Linda; Paterson, David L; Vila, Alejandro J; van Duin, David; Kreiswirth, Barry N; Chambers, Henry F; Fowler, Vance G; Jacobs, Michael R; Pulse, Mark E; Weiss, William J; Bonomo, Robert ABased upon knowledge of the hydrolytic profile of major β-lactamases found in Gram negative bacteria, we tested the effectiveness of the combination of ceftazidime/avibactam (CAZ/AVI) with aztreonam (ATM) against carbapenem-resistant enteric bacteria possessing metallo-β-lactamases (MBLs). Disk-diffusion and agar based antimicrobial susceptibility testing were initially performed to determine the in vitro efficacy of a unique combination of CAZ/AVI and ATM against 21 representative Enterobacteriaceae isolates with a complex molecular background that included blaIMP, blaNDM, blaOXA-48, blaCTX-M, blaAmpC, and combinations thereof. Time-kill assays were conducted, and the in vivo efficacy of this combination was assessed in a murine neutropenic thigh infection model. By disk diffusion assay, all 21 isolates were resistant to CAZ/AVI alone, and 19/21 were resistant to ATM. The in vitro activity of CAZ/AVI in combination with ATM against diverse Enterobacteriaceae possessing MBLs was demonstrated in 17/21 isolates, where the zone of inhibition was ≥ 21 mm. All isolates demonstrated a reduction in CAZ/AVI agar dilution MICs with the addition of ATM. At 2 h, time-kill assays demonstrated a ≥ 4 log10 CFU decrease for all groups that had CAZ/AVI plus ATM (8 μg/ml) added, compared to the CAZ/AVI alone group. In the murine neutropenic thigh infection model, an almost 4 log10 reduction in CFUs was noted at 24 h for CAZ/AVI (32 mg/kg q8h) plus ATM (32 mg/kg q8h) vs. CAZ/AVI (32 mg/kg q8h) alone. The data presented herein, requires us to carefully consider this new therapeutic combination to treat infections caused by MBL-producing Enterobacteriaceae.Item Open Access RADx-UP Testing Core: Access to COVID-19 Diagnostics in Community-Engaged Research with Underserved Populations.(Journal of clinical microbiology, 2023-08) Narayanasamy, Shanti; Veldman, Timothy H; Lee, Mark J; Glover, William A; Tillekeratne, L Gayani; Neighbors, Coralei E; Harper, Barrie; Raghavan, Vidya; Kennedy, Scott W; Carper, Miranda; Denny, Thomas; Tsalik, Ephraim L; Reller, Megan E; Kibbe, Warren A; Corbie, Giselle; Cohen-Wolkowiez, Michael; Woods, Christopher W; Petti, Cathy AResearch on the COVID-19 pandemic revealed a disproportionate burden of COVID-19 infection and death among underserved populations and exposed low rates of SARS-CoV-2 testing in these communities. A landmark National Institutes of Health (NIH) funding initiative, the Rapid Acceleration of Diagnostics-Underserved Populations (RADx-UP) program, was developed to address the research gap in understanding the adoption of COVID-19 testing in underserved populations. This program is the single largest investment in health disparities and community-engaged research in the history of the NIH. The RADx-UP Testing Core (TC) provides community-based investigators with essential scientific expertise and guidance on COVID-19 diagnostics. This commentary describes the first 2 years of the TC's experience, highlighting the challenges faced and insights gained to safely and effectively deploy large-scale diagnostics for community-initiated research in underserved populations during a pandemic. The success of RADx-UP shows that community-based research to increase access and uptake of testing among underserved populations can be accomplished during a pandemic with tools, resources, and multidisciplinary expertise provided by a centralized testing-specific coordinating center. We developed adaptive tools to support individual testing strategies and frameworks for these diverse studies and ensured continuous monitoring of testing strategies and use of study data. In a rapidly evolving setting of tremendous uncertainty, the TC provided essential and real-time technical expertise to support safe, effective, and adaptive testing. The lessons learned go beyond this pandemic and can serve as a framework for rapid deployment of testing in response to future crises, especially when populations are affected inequitably.