Lab Test

Culture, MDR CRE Screen

Multi-Drug Resistant, Extremely Drug Resistant

Test Codes





These cultures detect microorganisms that are Carbapenem Resistant Enterobacteriaceae (CRE) and are possibly Multi-Drug Resistant (MDR).

Specimen Collection Criteria

Rectal swabs: submitted in Amies transport medium (E-swab). Fecal material must be visible on the swab.

Stool specimen in a sterile collection container (NOT in Para-Pak media). 

Physician Office/Draw Specimen Preparation

Rectal swabs in Amies transport medium should be refrigerated (2-8°C or 36-46°F) prior to transport, but can be maintained at room temperature (20-26°C or 68-78.8°F).

Stool specimens must be refrigerated (2-8°C or 36-46°F) and transported to the Laboratory immediately. 

Preparation for Courier Transport

Transport: Stool specimen or rectal swab in the appropriate container, at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F), as described above.

Rejection Criteria

  • Stools in 10% formalin, SAF, or PVA fixatives are NOT suitable for testing.
  • Fresh stools received more than 2 hours after collection will not be tested.
  • Rectal swabs with no visible fecal material will not be tested.
  • Rectal swabs more than 24 hours old will not be tested.

Inpatient Specimen Preparation

Transport specimens immediately to the Laboratory for testing.


Specimen Stability for Testing: 

Rectal Swabs: 
Room Temperature: (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours

Stool Specimens:
Room Temperature (20-26°C or 68-78.8°F): 2 hours (Unpreserved)
Refrigerated (2-8°C or 36-46°F): 2 hours (Unpreserved)
Frozen (-20°C/-4°F or below): Unacceptable (Unpreserved)

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 4 days


Dearborn Microbiology Laboratory
Taylor, Trenton and Wayne sent to Dearborn Microbiology Laboratory for testing.

Royal Oak Microbiology Laboratory
Farmington Hills, Grosse Pointe, and Troy sent to Royal Oak Microbiology Laboratory for testing. 


Sunday – Saturday, 24 hours a day.
Preliminary results available in 24 hours.

Reference Range

Negative – No carbapenem non-susceptible Escherichia coli, K. oxytoca, K. pneumoniae, E. aerogenes or E. cloacae complex.

Test Methodology

Bacterial Culture.


This screening test can identify carbapenem non-susceptible Escherichia coli, K. oxytoca, K. pneumoniae, E. aerogenes or E. cloacae complex. However, a negative result does not preclude the presence of CRE organisms.

Clinical Utility

This test identifies individuals colonized or infected with CRE organisms for infection control purposes in a healthcare setting. 

Clinical Disease

MDR and CRE organisms are a major concern in the healthcare setting. Carbapenem Resistant Enterobacteriaceae (CRE) are increasing in prevalence and their ability to transfer this resistance to other bacteria makes them a formidable opponent. Individuals may be colonized or infected with (CRE). Infections commonly include urinary tract infections, bacteremia, and pelvic, wound, and tissue infections.


MDRs and CREs are transmitted by the same routes as antimicrobial susceptible infectious agents (1). Patient-to-patient transmission in healthcare settings, usually via hands of HCWs, has been a major factor accounting for the increase in incidence and prevalence in acute care facilities (1). Preventing the emergence and transmission of these pathogens requires a comprehensive approach that includes numerous infection control measures, education and training of medical and other healthcare personnel, judicious antibiotic use, comprehensive surveillance for targeted organisms, environmental measures, and decolonization therapy when appropriate (1).


Hands, fomites.


  1. Siegel, J.D. et al. HICPAC, 2007. Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings.

CPT Codes



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