Facilitating Laboratory-Based Surveillance for Carbapenem-Resistant Enterobacteriaceae, MN, 2010

Background: Carbapenem-resistant Enterobacteriaceae (CRE) and CR Acinetobacter baumannii (CR-AB) infections present significant treatment challenges and can spread readily in healthcare settings. Rapid and accurate detection of these organisms is therefore important for clinical care and infection prevention. Surveillance data are also needed for public health professionals and policymakers to gauge the impact of these resistant organisms on population health. 

Objective:   When CRE is detected, CDC recommends that acute care facilities review their microbiology records for the preceding 6-12 months for previously unrecognized CRE. As part of the Emerging Infections Program, we surveyed MN labs to determine the feasibility for active lab-based, population-based surveillance of CRE and CR-AB. This included collection of prevalence data for a large population, identifying barriers that labs face in identifying CRE and CR-AB, and developing mechanisms to conduct ongoing active surveillance for these organisms.

Methods:   Thirteen clinical labs including 3 reference labs were identified as serving inpatient, ambulatory, and long-term care facilities in the 2 most populous counties in MN (Hennepin and Ramsey; population of 1,631,461). A 6 question phone survey was conducted in April 2010 with each lab regarding detection practices for CRE and CR-AB in terms of automated screening and confirmatory tests, including obtaining specific information on antimicrobial breakpoints used on gram-negative bacilli. Labs were surveyed regarding their reporting procedures for CRE and the ability to query their lab information system (LIS) for resistant microorganisms.

Results: Twelve sites participated in the phone survey; 67% flagged carbapenem resistant organisms, and 100% recorded MIC data. 67% reported these organisms to either the MN Dept of Health (MDH) or their infection control department. 52% were able to query LIS for CRE and CR-AB, and 42% could “probably” query their LIS. Three different automated systems (Vitek, Microscan, and Phoenix) were used for detection and susceptibility testing with wide variability in the susceptibility cards used. 

Conclusions:   Surveying labs in MN has been useful in understanding different practices. Variations occur in MN labs regarding susceptibility methods, reporting to public health and the ability to access results through LIS. Survey results have allowed us to identify barriers to initiating surveillance for CRE and CR-AB. We have subsequently worked with industry representatives to develop simplified queries that will allow labs to query their automated instruments and report data regarding CRE and CR-AB prevalence to MDH.