[Source: Journal of Infectious Diseases, full page: (LINK). Abstract, edited.]
Ceftazidime-Avibactam in Combination With Fosfomycin: A Novel Therapeutic Strategy Against Multidrug-Resistant Pseudomonas aeruginosa
Krisztina M Papp-Wallace, Elise T Zeiser, Scott A Becka, Steven Park, Brigid M Wilson, Marisa L Winkler, Roshan D’Souza, Indresh Singh, Granger Sutton, Derrick E Fouts, Liang Chen, Barry N Kreiswirth, Evelyn J Ellis-Grosse, George L Drusano, David S Perlin, Robert A Bonomo
The Journal of Infectious Diseases, jiz149, https://doi.org/10.1093/infdis/jiz149
Published: 17 May 2019
Previously, by targeting penicillin-binding protein 3, Pseudomonas-derived cephalosporinase (PDC), and MurA with ceftazidime-avibactam-fosfomycin, antimicrobial susceptibility was restored among multidrug-resistant (MDR) Pseudomonas aeruginosa. Herein, ceftazidime-avibactam-fosfomycin combination therapy against MDR P. aeruginosa clinical isolate CL232 was further evaluated. Checkerboard susceptibility analysis revealed synergy between ceftazidime-avibactam and fosfomycin. Accordingly, the resistance elements present and expressed in P. aeruginosa were analyzed using whole-genome sequencing and transcriptome profiling. Mutations in genes that are known to contribute to β-lactam resistance were identified. Moreover, expression of blaPDC, the mexAB-oprM efflux pump, and murA were upregulated. When fosfomycin was administered alone, the frequency of mutations conferring resistance was high; however, coadministration of fosfomycin with ceftazidime-avibactam yielded a lower frequency of resistance mutations. In a murine infection model using a high bacterial burden, ceftazidime-avibactam-fosfomycin significantly reduced the P. aeruginosa colony-forming units (CFUs), by approximately 2 and 5 logs, compared with stasis and in the vehicle-treated control, respectively. Administration of ceftazidime-avibactam and fosfomycin separately significantly increased CFUs, by approximately 3 logs and 1 log, respectively, compared with the number at stasis, and only reduced CFUs by approximately 1 log and 2 logs, respectively, compared with the number in the vehicle-treated control. Thus, the combination of ceftazidime-avibactam-fosfomycin was superior to either drug alone. By employing a “mechanism-based approach” to combination chemotherapy, we show that ceftazidime-avibactam-fosfomycin has the potential to offer infected patients with high bacterial burdens a therapeutic hope against infection with MDR P. aeruginosa that lack metallo-β-lactamases.
Pseudomonas aeruginosa, β-lactams, fosfomycin, combination therapy
Topic: pseudomonas aeruginosa – ceftazidime – fosfomycin – lactams – infection – mice – avibactam – avibactam/ceftazidime
Issue Section: Major Article
Keywords: Antibiotics; Drugs Resistance; Pseudomonas aeruginosa; Avibactam; Ceftazidime; Fosfomycin.