Vol.66 No.5 September 2018

In vitro antimicrobial activity of ceftolozane/tazobactam against clinical isolates from Japan

Yusuke Hidaka¹⁾, Naoko Kishi²⁾, Satoru Matsumoto²⁾, Tomoko Yoshinari³⁾ and Masahiko Mori¹⁾

¹⁾Non-clinical Development, Regulatory Affairs Area, Japan Development, MSD K.K., Kitanomaru Square, 1-13-12 Kudan-kita, Chiyoda-ku, Tokyo, Japan

²⁾Microbiological Testing Group, Infectious Diseases Testing Department, Clinical Laboratory Center, Medical Solution Segment, LSI Medience Corporation.

³⁾Infectious Disease, Clinical Research Area, Japan Development, MSD K.K.

Abstract

Ceftolozane/tazobactam is a new antibacterial drug consisting of ceftolozane (CTLZ), a novel cephalosporin combined with tazobactam (TAZ), a β-lactamase inhibitor. In vitro antibacterial activity of CTLZ/TAZ was evaluated against clinical isolates from Japan (2050 isolates collected in 2016) according to the susceptibility standard method of the Clinical and Laboratory Standard Institutes.
The MIC_50/90 of CTLZ/TAZ against major pathogens including Escherichia coli, Klebsiella pneuminiae, Proteus mirabilis and Pseudomonas aeruginosa (each 100 isolates) were 0.25/0.5, 0.25/0.5, 0.25/0.5 and 1/2 μg/mL, respectively. In addition, the MIC_50/90 against AmpC-producing P. aeruginosa (15 isolates) was 1/2 μg/mL. CTLZ/TAZ showed a broad spectrum of antibacterial activity against some Gram-positive pathogens, anaerobic pathogens and most Gram-negative pathogens including extended-spectrum β-lactamase-producing and AmpC-producing pathogens. CTLZ/TAZ demonstrated the most potent activity against P. aeruginosa including AmpC-producing strains among imipenem, meropenem, piperacillin/tazobactam, ampicillin/sulbactam, cefoperazone/sulbactam, ceftazidime, cefepime and levofloxacin.
In conclusion, CTLZ/TAZ demonstrated broad actibacterial activity against Gram-negative isolates in Japan including the resistant pathogens. It is therefore anticipated that TAZ/CTLZ could be an excellent antibacterial drug, showing clinical efficacy.

Key word

tazobactam/ceftolozane, cephalosporins, susceptibility, Pseudomonas aeruginosa

Received

December 25, 2017

Accepted

April 2, 2018

Jpn. J. Chemother. 66 (5): 567-577, 2018