In vitro activity of ceftazidime–avibactam, ceftolozane–tazobactam, and other comparable agents against clinically important Gram-negative bacilli: Results from the 2017 surveillance of multicenter antimicrobial resistance in Taiwan (SMART)

Shio Shin Jean, Min Chi Lu, Zhi Yuan Shi, Shu Hui Tseng, Ting Shu Wu, Po Liang Lu, Pei Lan Shao, Wen Chien Ko, Fu Der Wang, Po Ren Hsueh

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Objectives: We investigated the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria (GNB) from 16 major teaching hospitals in Taiwan in 2017. Materials and methods: Escherichia coli (n=686) and Klebsiella pneumoniae bloodstream isolates (n=673), non-typhoid Salmonella (NTS; n=221) from various sources, Shigella species (n=21) from fecal samples, and Neisseria gonorrhoeae (n=129) from the genitourinary tract were collected. Antibiotic minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. Alleles encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-β-lactamases (NDMs), Verona integron-encoded metallo-β-lactamase, imipenemase, OXA-48-like, and mcr-1-5 genes were detected by molecular methods in Enterobacteriaceae isolates. Results: Five (0.7%) E. coli isolates harbored mcr-1 alleles. Twenty-four (3.6%), seven (1.0%), four (0.6%), and one (0.15%) K. pneumoniae isolates contained blaKPC, blaOXA-48-like, mcr-1, and blaNDM, respectively. Three (1.4%) NTS and no Shigella isolates harbored mcr-1 genes. Seventy-one (10.5%) K. pneumoniae isolates displayed non-susceptibility (NS) to carbapenem agent(s). Phenotypically extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae isolates showed significantly higher rates of ertapenem, tigecycline, and ceftolozane–tazobactam (CLZ– TAZ) NS (40.2%, 16.3%, and 71%–80%, respectively) than E. coli isolates exhibiting ESBL phenotypes (5.4%, 0.7%, and 18%–28%, respectively). All phenotypically ESBL-producing E. coli isolates were ceftazidime–avibactam (CAZ–AVB) susceptible. Two (8.3%) KPC-producing K. pneumoniae isolates showed CAZ–AVB NS. Hospital-acquired K. pneumoniae isolates were significantly less susceptible to ertapenem and CLZ–TAZ than hospital-acquired E. coli isolates. Conclusion: Third-generation cephalosporins remain the optimal choice for treating NTS, Shigella, and gonococcal infections in Taiwan. Hospital-acquired and phenotypically ESBL-producing K. pneumoniae are a heavy resistance burden in Taiwan.

Original languageEnglish
Pages (from-to)1983-1992
Number of pages10
JournalInfection and Drug Resistance
Publication statusPublished - Jan 1 2018



  • Carbapenemase
  • Ceftazidime-avibactam
  • Ceftolozane-tazobactam
  • Enterobacteriaceae
  • Extended-spectrum β-lactamases
  • Neisseria gonorrhoeae

ASJC Scopus subject areas

  • Pharmacology
  • Infectious Diseases
  • Pharmacology (medical)

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