< em > In vitro < /em > Susceptibility of Multidrug-Resistant < em > Pseudomonas aeruginosa < /em > following Treatment-emergent Resistance to Ceftolozane-tazobactam

Antimicrob Agents Chemother. 2021 Apr 5:AAC.00084-21. doi: 10.1128/AAC.00084-21. Online ahead of print.ABSTRACTWe compared the in vitro susceptibility of multidrug-resistant Pseudomonas aeruginosa isolates collected before and after treatment-emergent resistance to ceftolozane-tazobactam. Median baseline and post-exposure ceftolozane-tazobactam MICs were 2 and 64 μg/mL, respectively. Whole-genome sequencing identified treatment-emergent mutations in ampC among 79% (11/14) of paired isolates. AmpC mutations were associated with cross-resistance to ceftazidime-avibactam, but increased susceptibility to piperacillin-tazobactam and imipenem. Eighty-one percent (12/16) of ceftolozane-tazobactam resistant isolates with ampC mutations were susceptible to imipenem-relebactam.PMID:33820773 | DOI:10.1128/AAC.00084-21

Source: Antimicrobial Agents and Chemotherapy - April 6, 2021 Category: Microbiology Authors: Abigail M Rubio Ellen G Kline Chelsea E Jones Liang Chen Barry N Kreiswirth M Hong Nguyen Cornelius J Clancy Vaughn S Cooper Ghady Haidar Daria Van Tyne Ryan K Shields Source Type: research