Mid stream urine: >100x 106 cfu/L Escherichia coli (Carbapenemase producer)  – Shipped August 2014


The challenge was a simulated midstream urine sample obtained from a 45 year old ICU patient who returned from having surgery in India.

Laboratories were expected to isolate, identify, and report carbapenem-resistant Escherichia coli. Participants were asked to report susceptibility results for the following antimicrobial agents: 3rd generation cephalosporins, carbapenems, aminoglycosides, trimethoprim-sulfamethoxazole (SXT), piperacillin-tazobactam, nitrofurantoin, and ciprofloxacin. Laboratories were also expected to report the isolate to Infection Control because it is a carbapenem-resistant enterobacteria (CRE).


  1. Carbapenemase-producing Enterobacteriaceae (CPE) are frequently multi-drug resistant and require expanded antimicrobial susceptibility testing.
  2. Clinical laboratories need to be able to identify carbapenem-resistant Enterobacteriaceae (CRE) and have an established procedure to determine if these isolates are CPE. Potential isolates of CPE (i.e., CRE) should be reported to Infection Control.

Full critique (PDF)

Posted in Clinical Bacteriology Results, critiques