Centers for Disease Control and Prevention

Antimicrobial Resistance Threats Report

Carbapenem-resistantAcinetobacter

Threat Level: URGENT

In the United States in 2023:

CDC changed methodologies and data sources to produce the most comprehensive AR Threats Report to date. Direct comparison of this threat's data to previous reports is not recommended.

What you need to know

Acinetobacter bacteria commonly live in the environment—such as in soil and water—and on surfaces, including in healthcare facilities. People can also carry Acinetobacter on their skin and in their body without having signs or symptoms of infection. People carrying Acinetobacter can spread the bacteria to surfaces and objects around them, which can result in spread of the bacteria to other people. Acinetobacter can cause infections almost anywhere in the body, including the lungs, wounds, urinary tract, and blood.

Many Acinetobacter bacteria are resistant to some of our most powerful antibiotics used to treat infections, including carbapenem antibiotics. Some carbapenem-resistant Acinetobacter bacteria produce enzymes called carbapenemases, which enable the bacteria to destroy carbapenems.

Carbapenem-resistant Acinetobacter infections are a major concern for patients in healthcare settings, such as hospitals or nursing homes. These bacteria spread through contaminated surfaces, equipment, and hands, and can cause outbreaks in healthcare facilities. Patients who have been on antibiotics, have been in an intensive care unit, have medical devices such as ventilators or catheters, or who have had a long hospital stay are at higher risk of developing carbapenem-resistant Acinetobacter infections.

Carbapenem-resistant Acinetobacter infections have limited treatment options. As a result, healthcare providers may have to prescribe treatments that are less effective.

Carbapenem-resistant Acinetobacter data

In 2023, there were an estimated 9,497 cases of carbapenem-resistant Acinetobacter in hospitalized patients and 817 people who died due to their carbapenem-resistant Acinetobacter infection. CDC estimates that carbapenem-resistant Acinetobacter cases were responsible for more than $355 million in healthcare costs in 2023. Because carbapenem-resistant Acinetobacter infections can be difficult to treat, infection prevention and control measures are critical.

Number of carbapenem-resistant Acinetobacter cases in hospitalized patients (N=9,497) by location of onset and specimen type in 2023 in the U.S.

In 2023, 37% of carbapenem-resistant Acinetobacter cases in hospitalized patients were hospital-onset and 63% were community-onset. Hospital-onset cases occur when specimens (samples) taken from patients on or after day four of hospitalization test positive for carbapenem-resistant Acinetobacter. Community-onset cases occur when specimens taken from patients immediately before or within the first three days of hospitalization test positive for carbapenem-resistant Acinetobacter. Community-onset cases may be in patients with recent healthcare exposure prior to their hospitalization, including nursing home residents.

Seven percent of hospital-onset carbapenem-resistant Acinetobacter cases and 8% of community-onset carbapenem-resistant Acinetobacter cases were invasive. Invasive cases mean carbapenem-resistant Acinetobacter bacteria are found in normally sterile (free from germs) body sites, such as blood or cerebrospinal fluid. Non-invasive cases mean carbapenem-resistant Acinetobacter bacteria are found in non-sterile sites, such as the urinary tract, the respiratory tract, or wounds.

Most reported carbapenem-resistant Acinetobacter cases are non-invasive. Non-invasive infections can be mild or severe, and some non-invasive infections, like pneumonia, can be deadly. Invasive infections are very serious and can be deadly, often resulting in significant healthcare needs, antibiotic use, and an increased risk for sepsis. Preventing carbapenem-resistant Acinetobacter infections, whether they are invasive or non-invasive, is critically important, since they can be difficult to treat.

For the first time, data from CDC's National Healthcare Safety Network (NHSN) Antimicrobial Use and Resistance Module were used to estimate the burden of carbapenem-resistant Acinetobacter as shown in the figure above.

For the figure below, data from a complementary CDC program, the Antimicrobial Resistance Laboratory Network (AR Lab Network), were used to examine changes in carbapenemase-producing carbapenem-resistant Acinetobacter. The AR Lab Network tracks the emergence and spread of specific types of carbapenem-resistant Acinetobacter and shares the data with public health partners to help inform response, prevent spread, and protect people.

Number of New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Acinetobacter baumannii (CRAB) isolates and percentage among all CRAB isolates in the U.S. by year

An analysis of data from CDC's AR Lab Network based on a previously published study, shown in the figure above, indicates one type of carbapenemase-producing carbapenem-resistant Acinetobacter, known as New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Acinetobacter baumannii (CRAB), increased rapidly in the United States in recent years [1,2]. Although the percentage of NDM-CRAB is low among all CRAB identified, this increase is concerning [1]. There are very few treatment options for NDM-CRAB infections, and some of these bacteria are not susceptible to any available antibiotics.

NDM-CRAB bacteria have caused large outbreaks in healthcare settings, making rapid detection and response to NDM-CRAB cases and infection prevention and control measures critical for protecting patients.

Stopping carbapenem-resistant Acinetobacter in Missouri

Preventing Infections in Your Nursing Home Community

In this video, find out the everyday actions residents and staff of nursing homes can take to prevent infections in their community.

A Missouri hospital discovered two patients carrying carbapenem-resistant Acinetobacter and a third patient was identified within 30 days. All three had been transferred from one long-term care facility (LTCF), where residents receive complex medical care. The hospital and the LTCF moved quickly to stop the spread to other patients and residents.
CDC funds and supports Healthcare-associated Infection/Antimicrobial Resistance (HAI/AR) Programs in 65 state, local, and territorial health departments to help detect and respond to resistant germs like carbapenem-resistant Acinetobacter.
After the hospital sounded the alarm, Missouri's HAI/AR Program tested at-risk residents at the original LTCF to see if they were carrying the germ without symptoms, which can result in the germ spreading unknowingly to others. With support from CDC's Antimicrobial Resistance Laboratory Network partners, Missouri's HAI/AR Program identified five more carbapenem-resistant Acinetobacter cases. Whole genome sequencing showed the cases were closely related, indicating spread within the facility.
The HAI/AR Program also used CDC's Infection Control Assessment and Response (ICAR) tool to review the LTCF's infection prevention practices and identify and close prevention gaps. Based on the HAI/AR Program's ICAR recommendations, the LTCF strengthened its infection prevention practices by improving use of personal protective equipment, using dedicated medical equipment for patients with carbapenem-resistant Acinetobacter, and enhancing infection prevention practices during wound care. Additional testing showed spread had stopped within eight weeks.
The parent organization of the LTCF has since applied these improvements across its other facilities—showing how strong relationships between a jurisdiction's healthcare facilities and the CDC-supported HAI/AR Program can provide the timely support needed to identify and stop healthcare outbreaks.

How CDC combats carbapenem-resistant Acinetobacter

  • Supporting laboratory capacity and testing

    CDC supports the Antimicrobial Resistance Laboratory Network so that health departments can quickly identify local carbapenem-resistant Acinetobacter threats and track trends in resistance in healthcare settings. This testing can inform infection prevention experts, outbreak response, and national guidance to protect patients from carbapenem-resistant Acinetobacter. CDC encourages clinical laboratories to expand specialized mechanism testing for carbapenem-resistant Acinetobacter to identify which carbapenemases are present. This information can help guide treatment and infection control decisions.

  • Tracking infections

    CDC monitors carbapenem-resistant Acinetobacter infections and tracks resistance mechanisms through the National Healthcare Safety Network and the Emerging Infections Program to protect patients, guide strategies to prevent healthcare-associated infections (HAIs), and measure the progress of HAI prevention actions.

  • Collaborating through partnerships

    CDC works closely with health departments, other federal agencies, healthcare facilities and providers, and patients to prevent Acinetobacter infections and stop the spread of resistant bacteria. This includes communication efforts to encourage healthcare and public health professionals to stay aware of local carbapenem-resistant Acinetobacter trends, use lab testing to determine the best treatment plan, and use appropriate infection control precautions to prevent further spread.

Carbapenem-resistant Acinetobacter resources

Illustration of Carbapenem-resistant Acinetobacter