Multicenter surveillance of activities of cefepime-zidebactam, cefepime-enmetazobactam, omadacycline, eravacycline, and comparator antibiotics against , and complex causing bloodstream infection in Taiwan, 2020.

Objectives: To determine the activities of novel and comparator antibiotics against Gram-negative bacteria (GNB) in Taiwan.

Methods: Isolates of (n = 335), (n = 316; 144 isolates with hyperviscosity characteristics), (n = 271), complex (n = 187), and non-typhoidal species (n = 226), 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) isolates.

Results: The MIC values of the cefepime-enmetazobactam combination against extended-spectrum β-lactamase-producing and isolates (MIC ≤ 0.5 mg/L), -harboring isolates (0.25 mg/L; n = 2), and 80% of -like gene-harboring isolates (≤2 mg/L) were low. The MIC ranges of the cefepime-zidebactam against carbapenemase-producing isolates (irrespective of the carbapenemase type [MIC ≤ 4 mg/L]) and carbapenem-NS or ceftolozane-tazobactam-NS isolates (MIC 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.