Evaluation of In vitro Activity of Cefiderocol and Ceftolozane-Tazobactam against Extended-Spectrum β-Lactamase–Producing Coliform and Multidrug Resistant Acinetobacter baumannii and Pseudomonas aeruginosa

Background: A worrisome escalation in multidrug-resistant (MDR) Gram-negative bacterial infections which are accompanied with worse outcomes due to inadequate treatment options. There is an imperative requirement to explore new antimicrobials to oppose these resistant strains. Objectives: Assessment of antibacterial activity of Cefiderocol and Ceftolozane-Tazobactam against ESBL–Producing coliform and MDR A. baumannii and P. aeruginosa. Methodology: A total of 332 clinical samples were obtained from surgical ICU cases. Pathogenic microorganisms were identified. Antibiotic susceptibility was done for gram negative isolates. Third-generation cephalosporins resistant coliforms were screened for ESBL detection. Ceftolozane-Tazobactam and Cefiderocol activity on ESBL coliform and MDR P. aeruginosa and A. baumannii isolates was investigated. Results: The susceptibility of both ESBL E. coli, K. pneumoniae, MDR P. aeruginosa, and A. baumannii to ceftolozane/tazobactam was 77%, 70% ,63% and 58% respectively. ESBL E. coli and K. pneumonaie exhibited MIC 50/90 value of (0.19/0.25μg/mL) and (0.25/0.5μg/mL) for ceftolozane/tazobactam respectively. MDR P. aeruginosa showed MIC 50/90 value (2/4μg/mL). MDR A. baumannii exhibited high MIC 50/90 value (16/24μg/mL). Cefiderocol was 100% effective against most isolates with different MIC 50/90 values. For ESBL-E. coli and K. pneumoniae, the MIC 50/90 value was (0.5/1.5μg/mL). For MDR P. aeruginosa and A. baumannii, the MIC 50/90 value was (0.75/2μg/mL) and (0.25/2μg/mL) respectively. Conclusion: Cefiderocol exhibits superior activity against ESBL coliform and MDR A. baumannii, P. aeruginosa compared to ceftolozane-Tazobactam.