AmpC E. coli UTI

A 27 year-old woman was seen in the emergency department with fever (38.7°C), pain on passing urine, abdominal pain and vomiting. A urine sample was collected and demonstrated 4 + leukocytes and 4+ RBCs. Empirical treatment with intravenous ceftriaxone was implemented. The patient is transferred to the ward and for the next two days she remains febrile with only slight clinical improvement.

The laboratory reports an Escherichia coli isolate [> 10⁵ CFU/mL] with the susceptibility pattern presented below.

Phenotypic tests (i.e. synergy with clavulanate) indicate that the E. coli isolate is NOT an extended-spectrum β-lactamase (ESBL) producer but it is confirmed to be an AMPc producer as suggested by the high MIC to cefazolin. The patient does not have renal or hepatic impairments, and her BMI is within normal values.

Antimicrobial Interpretation
Ampicillin R
Amoxicillin-clavulanate R
Piperacillin-tazobactam R
Cefazolin R
Ceftriaxone R
Imipenem S
Ertapenem S
Gentamicin I
Tobramycin S
Trimethoprim/sulfamethoxazole  R
Ciprofloxacin R
Nitrofurantoin S
Fosfomycin S


Would you change therapy and, if so, to what antibiotic?

See my suggestions here AmpC E.coli Discussion

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