Healthcare-Associated Infections: Reportable Multidrug-Resistant Organisms
Multidrug-resistant organisms (MDROs) are an ongoing threat to patient health and safety. The potential for rapid spread in health care facilities and difficulties of treating infections make it critically important for public health to conduct surveillance across settings and promote aggressive infection control measures.
According to the CDC (Centers for Disease Control and Prevention), more than 2.8 million antibiotic resistant infections (PDF) occur in the U.S. each year and more than 35,000 people die from them.
This webpage lists the MDROs that are currently reportable in Wisconsin as well as prevention, surveillance, testing, and reporting resources for health care facilities and local and Tribal health departments (LTHDS).
What are MDROs?
MDROs are microorganisms, mainly bacteria, that are resistant to one or more classes of antimicrobial agents (antibiotics and antifungals). This means these antimicrobials can no longer be used to control or kill the microorganism. Infections caused by MDROs can be difficult to treat due to limited treatment options and have the ability to spread rapidly, especially in health care settings.
There are many different MDROs, and some are of more concern than others, such as carbapenemase-producing organisms (CPOs). CPOs are particularly worrisome as carbapenemase enzymes can inactivate carbapenem antibiotics, as well as other beta-lactam antibiotics. Moreover, some CPOs can transfer this ability to inactivate carbapenem antibiotics to other bacteria, which can lead to the spread of antibiotic resistance.
The potential for rapid spread, increasing antibiotic resistance, and difficulty treating infections caused by these organisms, underscore the need for a timely response to the presence of MDROs, especially in health care settings.
A person who is infected with an MDRO has the organism in or on their body and it is causing symptoms or illness. It is important to note that people can also be “colonized” with MDROs.
A person who is colonized with an MDRO is carrying the organism in or on their body, often for very long periods of time, but it is not causing symptoms or making the person ill. People who are colonized with an MDRO can, however, spread the organism to surfaces in their environment and to other people.
An individual who is colonized with an MDRO can also become infected later with the organism.
Reportable MDROs in Wisconsin
Systematic, statewide surveillance for key MDROs is an essential part of controlling their spread. Confirmed and probable cases of the following organisms are considered category II reportable communicable diseases in Wisconsin. Select below for organism-specific information and resources such as fact sheets and memos.
Carbapenemase-producing carbapenem-resistant Acinetobacter baumannii (CP-CRAB)
Acinetobacter baumannii is a key cause of healthcare-associated infections, CRAB bacteria can be very difficult to treat. CRAB can cause pneumonia, as well as wound, bloodstream, and urinary tract infections.
Carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE)
Enterobacterales is commonly found in the human digestive tract. Many species of Enterobacterales are necessary for digestion and are usually harmless. However, these bacteria can cause serious infections when outside of the digestive tract.
Carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA)
Pseudomonas aeruginosa, can cause infections in humans including pneumonia, bloodstream infections, and surgical site infections. Some Pseudomonas aeruginosa bacteria are resistant to antibiotics.
Candida auris (C. auris)
Candida auris (C. auris) is a rare but potentially life-threatening type of fungus that is resistant to most antifungal medications. C. auris mainly makes people sick who spend a lot of time in health care settings, have weakened immune systems, and who already have medical problems.
Vancomycin-intermediate Staphylococcus aureus (VISA) and vancomycin resistant Staphylococcus aureus (VRSA)
Staphylococcus aureus, or staph, is a bacterium that are usually harmless, but they can sometimes cause serious infections.
Testing
Early identification of MDRO infection or colonization, paired with immediate implementation of containment strategies, is critical to mitigating the risk of transmission. People may be tested for an MDRO due to active infection. Conditions sometimes caused by MDROs are pneumonia, wound infections, bloodstream infections, and urinary tract infections.
People who are colonized with an MDRO may be discovered from testing upon admission to a health care facility or through large-scale screening (called point-prevalence screening) of health care facilities to detect possible transmission. Specimen sites used for colonization detection are most commonly skin swabs (axilla [armpits] and groin) or rectal swabs.
Testing is usually coordinated by public health and often involves multiple steps. Isolates that are carbapenem-resistant undergo confirmatory testing at the Wisconsin State Laboratory of Hygiene (WSLH) to determine whether the organism is carbapenemase-producing. WSLH will also determine whether unusual Candida species isolates are C. auris.
Disease reporting and investigation
Confirmed and probable cases of reportable MDROs will automatically be sent by WSLH to the Wisconsin Electronic Disease Surveillance System (WEDSS) for local public health follow-up. The WEDSS Surveillance and Response for Targeted Multidrug-Resistant Organisms: Wisconsin Protocol for Local and Tribal Health Departments, P-03263 (PDF) and Reportable MDRO Reference Guide, P-03263a (PDF) can help LTHDs interpret lab results and determine the appropriate follow-up needed. The Wisconsin HAI Prevention Program infection preventionists can also assist in case investigations. Additional resources for reporting and investigation are available in the tabs below.
- Communicable Disease Case Reporting and Investigation Protocol: Carbapenemase-Producing Organisms (EpiNet), P-02187 (PDF)
- Communicable Disease Case Reporting and Investigation Protocol: Candida auris (EpiNet), P-03234 (PDF)
- Surveillance for Carbapenemase-Producing Carbapenem-Resistant Acinetobacter baumannii (CP-CRAB), Carbapenemase-Producing Carbapenem-Resistant Pseudomonas aeruginosa (CP-CRPA), and Candida auris, BCD Memo 2022-06 (PDF)
- Carbapenem-Resistant Enterobacterales (CRE) as a Reportable Condition in Wisconsin (BCD Memo 2022-05) (PDF)
- VISA/VRSA Case Reporting and Investigation Protocol (EpiNet), P-01862 (PDF)
- WEDSS Surveillance and Response for Targeted Multidrug-Resistant Organisms: Wisconsin Protocol for Local and Tribal Health Departments, P-03263 (PDF)
- Reportable MDRO Follow-Up Reference Guide for Local and Tribal Health Departments, P-03263a (PDF)
Additional information on disease reporting methods and contact information is available on the Department of Health Service (DHS) disease reporting webpage.
Surveillance
Conducting surveillance for reportable MDROs in Wisconsin is important for understanding the prevalence of these organisms, both statewide, as well as in specific regions. Surveillance activities for reportable MDROs include identifying potential sources of transmission, determining prevalence, monitoring rates of transmission within health care facilities, and determining host risk factors for carriage.
Health care facilities, such as nursing homes, may conduct surveillance activities such as:
- Maintaining line lists of residents known to be infected or colonized with MDROs.
- Obtaining swabs of all high-risk residents upon admission to detect colonization or infection with targeted MDROs.
- Performing point prevalence screening to determine the extent of spread of the targeted MDRO within the facility.
Cases of reportable MDROs in Wisconsin
| MDRO type | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|
| CP-CRAB | 41 | 153 | 112 | 153 | 139 |
| CP-CRE | 30 | 42 | 45 | 37 | 69 |
| CP-CRPA | 2 | 2 | 4 | 3 | 1 |
| C. auris | 0 | 1 | 5 | 21 | 23 |
| VISA | 1 | 1 | 2 | 4 | 0 |
Data source: WEDSS
CP-CRAB, CP-CRE, CP-CRPA, and C. auris became reportable communicable disease conditions in Wisconsin in 2022. Data on CP-CRAB, CP-CRPA, and C. auris before 2022 are based on voluntary submission of isolates by clinical laboratories to the WSLH. VISA and VRSA have been reportable conditions in Wisconsin since 2007.
While the prevalence of these cases may appear low compared to other reportable diseases and conditions, systematic surveillance and one-on-one follow up on each case is an essential part of controlling their spread. Timely public health response and intervention helps prevent the potential for rapid increases of MDRO cases, which have been seen in other areas of the country.
The MDRO case counts listed are deduplicated and include both clinical and colonization screening isolates, besides VISA. Colonization screenings for VISA are not conducted at this time.
MDRO prevention
Strict adherence to infection prevention and control measures can help reduce transmission of MDROs and other HAIs. Infection prevention and control measures used to prevent transmission of MDROs will depend on the type of health care facility and the prevalence of MDROs in the facility.
General prevention and control measures that should be instituted by all health care facilities include:
- Infection prevention and control plans
- Hand hygiene practices
- Cleaning and disinfection
- Standard precautions
- Transmission-based precautions
- Institution-specific considerations, such as enhanced barrier precautions in nursing homes
Below are administrative measures that should be included in facility infection prevention programs and committees.
- A designated infection prevention staff member and multidisciplinary infection prevention committee should oversee infection prevention activities throughout the facility.
- Rates of compliance with hand hygiene, appropriate use of personal protective equipment (PPE), and cleaning and disinfection practices among patient care staff should be routinely monitored with regular performance feedback given to staff, managers, and administrative personnel.
- Adherence to infection prevention guidelines applicable to the facility type will help reduce the risk of spreading MDROs and other HAIs.
- The facility should provide education for staff, patients, and families, on the source of MDROs and how they are spread in health care facilities, the significance of MDRO infections, and how to prevent and control the spread of resistant organisms.
- Administrative leadership should develop collaborative relationships and regional strategies such as partnerships between health care systems and LTHDs. In addition, facilities are encouraged to use the DHS Health Care Facility Transfer Form (PDF). This template form can be used when transferring patients or residents to an admitting health care facility to communicate communicable disease status.
The Wisconsin HAI Prevention Program has developed guidance for preventing and control MDROs for all health care settings, P-42513 (PDF), as well as nursing homes, P-03250 (PDF) and assisted living facilities, P-03250a (PDF).
Additional resources
DHS MDRO office hours
Join the Wisconsin HAI Prevention Program in a monthly call series focused on MDROs. MDRO office hours are an opportunity for health care and public health partners to connect, ask questions, and learn about MDROs and related topics.
Register for MDRO office hours
DHS webinar recordings
- Infection Preventionist Lunch and Learn: Multidrug-Resistant Organisms
- Long-Term Care Education Series: MDROs in Wisconsin
- MDROs in Wisconsin: Information for Health Care Providers
- Infection Prevention and Control of Multidrug-Resistant Organisms
- Reportable MDROs in Wisconsin: Which are Reportable and Why? (starts at minute 40)
Documents from DHS
- Guidelines for Prevention and Control of Multidrug-Resistant Organisms for Health Care Settings, P-42513 (PDF)
- Recommendations for Prevention and Control of Targeted Multidrug-Resistant Organisms in Wisconsin Nursing Homes, P-03250 (PDF)
- Recommendations for Prevention and Control of Targeted Multidrug-Resistant Organisms for Assisted Living Facilities, P-03250a (PDF)
Documents from CDC
For health care facilities
- MDRO Fact Sheet for Health Care Personnel, P-03172 (PDF)
- Disinfectant Considerations for MDROs, P-03400 (PDF)
- MDRO Fact Sheet for Housekeeping Staff, P-03147 (PDF)
- MDRO Colonization Screening Fact Sheet for Health Care Personnel, P-03171 (Available in English and Spanish)
- Fact sheets on specific MDROs are also available, including:
For patients, residents, and families
- MDRO Fact Sheet for Residents and Families, P-03149 (Available in English, Spanish and Hmong)
- MDRO Screening Fact Sheet for Residents and Families, P-03110 (Available in English and Spanish)
Questions about HAIs? Contact us!
Phone: 608-267-7711 | Fax: 608-261-4976 | Email: DHSWIHAIPreventionProgram@dhs.wisconsin.gov