Therapeutic Management of Pseudomonas aeruginosa Bloodstream Infection Non-Susceptible to Carbapenems but Susceptible to "Old" Cephalosporins and/or to Penicillins

Ronit Zaidenstein, Asaf Miller, Ruthy Tal-Jasper, Hadas Ofer-Friedman, Menachem Sklarz, David E Katz, Tsillia Lazarovitch, Paul R Lephart, Bethlehem Mengesha, Oran Tzuman, Mor Dadon, Chen Daniel, Jacob Moran-Gilad, Dror Marchaim

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

It is unknown as to whether other beta-lactams can be used for bloodstream infections (BSI) resulting from Pseudomonas aeruginosa (PA) which are non-susceptible to one or more carbapenem. We conducted a retrospective cohort study at the Assaf Harofeh Medical Center (AHMC) from January 2010 to August 2014. Adult patients with PA-BSI non-susceptible to a group 2 carbapenem but susceptible to ceftazidime or piperacillin (with or without tazobactam), were enrolled. We compared the outcomes of patients who received an appropriate beta-lactam antibiotic ("cases") to those who received an appropriate non-beta-lactam antibiotic ("controls"). Whole genome sequencing was performed for one of the isolates. Twenty-six patients with PA-BSI met inclusion criteria: 18 received a beta-lactam and 8 a non-beta-lactam (three a fluoroquinolone, two colistin, one a fluoroquinolone and an aminoglycoside, one a fluoroquinolone and colistin, and one colistin and an aminoglycoside). All clinical outcomes were similar between the groups. There were large variations in the phenotypic susceptibilities of the strains. A detailed molecular investigation of one isolate revealed a strain that belonged to MLST-137, with the presence of multiple efflux pumps, OXA-50, and a chromosomally mediated Pseudomonas-derived cephalosporinase (PDC). The oprD gene was intact. Non-carbapenem-β-lactams may still be effective alternatives for short duration therapy (up to 14 days) for BSI caused by a carbapenem non-susceptible (but susceptible to ceftazidime, piperacillin, and/or piperacillin-tazobactam) PA strain. This observation requires further confirmatory analyses. Future molecular investigations should be performed, in order to further analyze additional potential mechanisms for this prevalent phenotype.

Original languageEnglish GB
Article number9
JournalMicroorganisms
Volume6
Issue number1
DOIs
StatePublished - 16 Jan 2018

Keywords

  • BSI
  • Gram-negative
  • ICU
  • MDRO
  • Non-fermenter
  • Nosocomial infections

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)
  • Virology

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