Multicenter surveillance of in vitro activities of cefepime-zidebactam, cefepime-enmetazobactam, omadacycline, eravacycline, and comparator antibiotics against Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii complex causing bloodstream infection in Taiwan, 2020

Objectives To determine the in vitro activities of novel and comparator antibiotics against Gram-negative bacteria (GNB) in Taiwan. Methods Isolates of Escherichia coli (n = 335), Klebsiella pneumoniae (n = 316; 144 isolates with hyperviscosity characteristics), Pseudomonas aeruginosa (n = 271), Acinetobacter baumannii complex (n = 187), and non-typhoidal Salmonella species (n = 226), Shigella species (n = 13) from miscellaneous culture sources were collected in 2020 in Taiwan. The MICs of the isolates to test antibiotics were determined using the broth microdilution method. GeneXpert was used to detect genes encoding carbapenemases among the carbapenem-non-susceptible (NS) Enterobacterales isolates. Results The MIC values of the cefepime-enmetazobactam combination against extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae isolates (MIC90 <= 0.5 mg/L), bla(KPC)-harboring E. coli isolates (0.25 mg/L; n = 2), and 80% of bla(OXA-48)-like gene-harboring K. pneumoniae isolates (<= 2 mg/L) were low. The MIC ranges of the cefepime-zidebactam against carbapenemase-producing Enterobacterales isolates (irrespective of the carbapenemase type [MIC90 <= 4 mg/L]) and carbapenem-NS or ceftolozane-tazobactam-NS P. aeruginosa isolates (MIC90 value, 8 mg/L) were significantly lower than those of the cefepime-enmetazobactam. Conclusions The efficacy of novel antibiotics against important drug-resistant GNB must be monitored and validated during the clinical treatment of patients.

Automated summary

In this study conducted in Taiwan in 2020, the in vitro activities of novel and comparator antibiotics against Gram-negative bacteria were evaluated. The results showed that certain novel antibiotics demonstrated promising activity against drug-resistant Gram-negative bacteria, indicating their potential in clinical treatment.