IDCases (Jan 2018)
Unusual carbapenem resistant but ceftriaxone and cefepime susceptible Klebsiella oxytoca isolated from a blood culture: Case report and whole-genome sequencing investigation
Abstract
A carbapenem resistant but ceftriaxone and cefepime susceptible Klebsiella oxytoca was isolated from the blood of a patient with polymicrobial bacteremia after 2 weeks of ertapenem treatment. Whole-genome sequencing identified no carbapenemase gene nor plasmid, but only blaOXY-2-8 gene with a mutation in the promoter that’s been reported to increase its expression. Two other specific carbapenem resistance mechanisms including mutated porin genes and the AcrAB-TolC efflux system genes were also identified. Clinicians need to be aware of such unusual antibiogram and should not assume carbapenems are always broader spectrum antibiotics than expanded-spectrum cephalosporins.
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