Outbreaks of Acinetobacter baumannii typically occur in intensive care units and healthcare settings with very ill patients. The superbug can cause life-threatening lung and bloodstream infections that are often resistant to many commonly prescribed antibiotics. But a new study has unlocked a critical step in how one Acinetobacter bacterium is transmitted to another, shedding light on how antibiotic resistance spreads.

Researchers at the Washington University School of Medicine mutated plasmids within Acinetobacter strains to determine how Acinetobacter reproduces. Plasmids, small loops of DNA, promote drug resistance by invading nearby bacteria with resistance genes to reproduce and infect more bacteria. Still, plasmids require close contact among bacteria to spread, and Acinetobacter baumannii doesn’t mingle well. The bacteria protects itself by injecting lethal proteins into unrelated bacteria that approach too closely. If that’s the case, how does the Acinetobacter bacterium spread?

What Does the Research Show?

The researchers determined that plasmids within Acinetobacter strains disable the bacterium’s internal self-defense system so that plasmids in neighboring bacteria aren’t killed before they can be injected with copies of the Acinetobacter bacterium.

As the next steps, the researchers suggest that preventing the spread of antibiotic resistance may begin with preventing plasmid spread. They seek to develop compounds that deter plasmids from disrupting bacterial inner defense systems. They assert that such therapies, which aim to prevent bacteria from becoming drug-resistant, will be much more effective than trying to develop new antibiotics, which will eventually become resistant.

What Can Healthcare Providers Do?

In the meantime, at least 2 million patients in the US continue to be infected with antibiotic-resistant bacteria, and at least 23,000 people die each year as a result. To prevent the threat of superbugs in hospitals and other healthcare settings, the US Centers for Disease Control and Prevention (CDC) recommends that healthcare providers take these precautions:

• Identify patients by asking about any recent travel or health care. Those who have received care at another facility or in another country are at the greatest risk for antibiotic resistance.

• Prescribe an antibiotic only when it’s likely to benefit a patient.

• Encourage patients to use a prescribed antibiotic only as directed.

• Practice good hygiene by hand washing or using alcohol-based hand sanitizer to keep.

• Prescribe an antibiotic that targets the bacteria most likely causing their patient’s illness when an antibiotic is likely to provide benefit.

• Prevent surgery and/or catheter placement infections and improve antibiotic use through stewardship.

• In hospital settings, place patients with unusual resistance on contact precautions and assess and enhance infection control.

• Be prepared. Plan for unusual resistance in your facility and work with the health department to screen others.

• Communicate about resistance status when patients are transferred to another facility and ask colleagues to use an infection control transfer form.

• If an outbreak occurs, continue infection control assessments and colonization screenings until the spread is controlled.

For more information about preventing antibiotic resistance, visit the CDC’s Antibiotic Resistance Solutions Initiative.