2019 IDWeek, Washington DC,  October 3-7

Activity of Novel β-Lactamase Inhibitor QPX7728 Combined with β-Lactam Agents When Tested against Carbapenem-Resistant Enterobacteriaceae (CRE) Isolates (#677)

Mariana Castanheira, Jill Lindley, Holly Juynh, Rodrigo Mendes, and Olga Lomovskaya

QPX7728 restored the activity of several BLs when tested against 508 CRE isolates that produce serine and metallo carbapenemases.  

In Vitro Activity of the β-lactamase Inhibitor QPX7728 in Combination with Several β-lactams against Acinetobacter baumannii and Pseudomonas aeruginosa (#681)

Olga Lomovskaya, Jill Lindley, Debora Rubio-Aparicio, Kirk Nelson, and Mariana Castanheira. QPX7728 restored the activity of meropenem against carbapenem-resistant Acinetobacter baumannii, with  >95% of isolates inhibited by ≤8 µg/ml of meropenem. In a representative panel of Pseudomonas aeruginosa, multiple beta-lactam antibiotics tested in combination with QPX7728 resulted in >90% susceptibility. For a challenge panel of highly drug-resistant Pseudomonas aeruginosa, QPX7728 in combination with ceftolozane or piperacillin were the most potent combinations. 

Potency of the Beta-Lactamase Inhibitor QPX7728 Is Minimally Affected by KPC Mutations that Reduce Potency of Ceftazidime-Avibactam (#727)

Kirk Nelson, Debora Rubio-Aparicio, and Olga Lomovskaya

Mutations in the KPC enzyme that result in microbiological and clinical resistance to ceftazidime-avibactam do not affect the potency of QPX7728 in combination with various beta-lactam antibiotics, including ceftazidime. 

Activity of a Novel Polymyxin Analog, QPX9003, Tested against Resistant Gram-Negative Pathogens, including Carbapenem-Resistant Acinetobacter, Enterobacterales, and Pseudomonas (#690)

Mariana Castanheira, Jill Lindley, Holly Juynh, Rodrigo Mendes, and Olga Lomovskaya

QPX9003 had potent activity against the collection of highly resistant gram-negative isolates that included multidrug resistant Pseudomonas aeruginosa, carbapenem-resistant Acinetobacter baumannii and CRE. Against the PSA and CRAB isolates, QPX9003 was four-fold more active than colistin.

QPX9003: Pharmacology of a Novel Polymyxin in Mice and Rats (#707)

Mojgan Sabet, Ziad Tarazi, Jonathan Parkinson, Kade D. Roberts, Philip E. Thompson, Roger L. Nation, Tony Velkov, Scott J. Hecker, Olga Lomovskaya, Michael N. Dudley, Jian Li, and David C. Griffith

The activity and the safety of QPX9003 and polymyxin B was studied in animal models of infection and toxicology. QPX9003 was found to have a wider therapeutic index in being more effective and less toxic than polymyxin B,. 

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