Containment Strategy Guidelines

Interim Guidance for a Public Health Response to Contain Novel or Targeted Multidrug-resistant Organisms (MDROs)

The Containment Strategy Guidelines address the initial response to new identifications of novel and targeted MDROs, such as Candida auris and carbapenemase-producing Enterobacterales, Pseudomonas spp., and Acinetobacter. If you are looking for the 2006 Management of Multidrug-Resistant Organisms in Healthcare Settings Guideline, see the Infection Control Website.

Cover to Interim guidance for a Public health response to contain novel and targeted MDRO's

This document is intended for use by state and local health departments and healthcare facilities and serves as general guidance for the initial response for the containment of novel or targeted multidrug-resistant organisms (MDROs) or resistance mechanisms. It is not intended to describe all the actions that might be required for control of an outbreak (e.g., sustained transmission within a facility or region). In addition, further evaluation might be required based on the findings of the initial response described in this document.

Print Version: Interim Guidance for a Public Health Response to Contain Novel or Targeted Multidrug-resistant Organisms (MDROs) [PDF – 16 Pages].

Updates to the 2017 Interim Guidance:

  • Added definitions for Healthcare Facility, Colonization Screening, and Response Tiers.
  • Expanded the “Response Recommendations by Tier” to include additional detail, particularly for contact investigations and retrospective and prospective surveillance strategies.
  • Added section, Containment Strategies for Healthcare Facilities at High Risk for Transmission of MDROs
  • Removed Figure 1 and 2
  • Added:
    • Table 1: Summary of Response Recommendations for MDRO Containment by Tier
    • Summary of CDC Recommendations to Assess Transmission of Novel or Targeted MDROs

Goals of initial containment response include:

  1. Identify affected patients.
  2. Ensure appropriate control measures are promptly implemented to contain further spread.
  3. Determine if transmission and dissemination is occurring.
  4. Characterize the organism or mechanism in order to guide further response actions, patient management, and future responses.

In addition to this general guidance, further pathogen-specific guidance for some MDROs can be found here:

General Recommendations

Healthcare facilities and laboratories should contact state or local public health authorities promptly when targeted resistant organisms (e.g., pan-resistant organism) or mechanisms are identified (e.g., VIM-producing Enterobacterales).

Health departments should utilize the expanded capacity for antimicrobial resistance-related laboratory testing through the Antimicrobial Resistance Laboratory Network (e.g. carbapenemase and Candidia auris colonization screening, carbapenemase detection, Candida species identification) and should contact the laboratory for their region to discuss the availability of specific testing and to coordinate specimen submission.

Health Departments conducting these investigations are encouraged to consult with CDC by contacting the healthcare outbreak duty officer at


Healthcare Facility

For this guidance, the term ‘healthcare facility’ refers to all acute care hospitals and post-acute care facilities that care for patients or residents who remain overnight and require medical care, nursing care or rehabilitation services.  This generally excludes assisted living facilities.

Colonization Screening

When an emerging MDRO is identified, colonization screening is recommended by CDC as an essential component of the public health response. Colonization screening identifies unrecognized carriers so that infection control measures can be targeted to prevent the spread of antimicrobial resistance.

The colonization screening recommendations in this guidance apply to all healthcare facility types.  Additionally, depending on the scope of the investigation and type of organism identified, colonization screening might be recommended for community settings.

Recommendations for colonization screening are described in detail for each response tier.

Response Tiers

The following describes criteria for three different categories of organisms and resistance mechanisms (Tiers 1-3) and the recommended approach to each. Although general definitions of each tier are accompanied by examples of organisms and resistance mechanisms, health departments should use local epidemiology to guide assignment of organisms to tiers 2 and 3.

Tier 1 organisms:

This category includes (1) organisms for which no current treatment options exist (pan-resistant) and that have the potential to spread more widely within a region and (2) organisms and resistance mechanisms that have never (or very rarely) been identified in the United States and for which experience is extremely limited and a more extensive evaluation is needed to define the risk for transmission.

Tier 2 organisms:

Organisms in this group include MDROs that are primarily associated with healthcare settings and are not commonly identified in the region. These organisms might be found more commonly in other areas of the United States. Information is available about how transmission of these organisms occurs and the groups primarily at risk.

Examples include carbapenem-resistant Enterobacterales with the less common carbapenemases (e.g., New Delhi Metallo-β-lactamase) and carbapenemase-producing Pseudomonas spp. In many areas of the United States, carbapenem-resistant Enterobacterales producing Klebsiella pneumoniae carbapenemase (KPC-CRE) meets the Tier 2 criteria.

Tier 3 organisms:

Organisms in this group include MDROs targeted by the facility or region that have been identified regularly but are not considered to be endemic. These organisms might be found more commonly in other areas of the United States. Information is available about how transmission of these organisms occurs and the groups primarily at risk.

Examples include KPC-CRE and Acinetobacter baumannii with plasmid-mediated oxacillinases with carbapenemase activity (e.g., OXA-23, OXA-24/40, OXA-58) in certain regions of the United States where these organisms are more regularly identified but are not endemic.

Response Recommendations by Tier

The components of the initial response will vary depending on the organism involved; click to expand each window below for recommendations for the expected response, containment and control for each group.