Activity of Ceftolozane-Tazobactam (C/T) against Escherichia coli Isolates from U.S. Veterans in Relation to Co-resistance and Sequence Type 131 (ST131) H30/H30Rx Status. (4th October 2017)

• Record Type: Journal Article
• Authors: Johnston, Brian D; Thuras, Paul; Johnson, James R
• Is Part Of: Open forum infectious diseases. Volume 4(2017)Supplement 1
• Page Start: S374
• Page End: S374
• Publication Date: 2017-10-04
• Subjects: Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofx163.921
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: E. coli ST131, with its resistance-associated H 30 and H 30Rx clonal subsets, causes most antimicrobial-resistant E. coli infections, especially among veterans. The activity of the novel combination agent C/T against ST131 is undefined. Methods: E. coli clinical isolates ( n = 595), including (per VAMC) 10 each ciprofloxacin-resistant and susceptible isolates, plus archived ESBL isolates, were collected from 24 VAMCs across the U.S. (2011). ST131, H 30, and H 30Rx were detected by clonal PCR. Microdilution MICs were determined for C/T and 5 comparators (piperacillin-tazobactam [TZP], levofloxacin [LVX], gentamicin [GEN], ceftazidime [CAZ], and meropenem [MEM]). Categorical resistance and MICs were compared statistically with resistance category and H 30/ H 30Rx status. Results: Total resistance prevalence was < 5% for C/T (3.5%) and MEM (0%), vs. from 7.9% (TZP) to 59% (LVX) for other comparators (Table 1). Resistance prevalence generally increased by resistance category from FQ-S through FQ-R to ESBL, and by clonal subgroup from non- H 30 through H 30 to H 30Rx. Conclusion: C/T is broadly active against E. coli clinical isolates from veterans, notwithstanding significant variation by resistance category and ST131- H 30/ H 30Rx status; it outperformed all non-carbapenem comparators. C/T should prove useful as a carbapenem-sparing agent against multidrug-resistant E. coli ST131 infections. Disclosures: B. D. Johnston, Merck Sharpe & Dohme, Corp.: Collaborator, Research support Actavis: Collaborator, Research support; J. R. Johnson, Merck: Grant Investigator, Research grant Grant Investigator, Research grant