What Is Acinetobacter Baumannii?

Acinetobacter baumannii is a bacterium that can cause a range of diseases.

It typically infects people inside a healthcare facility — doctors refer to these as “nosocomial” infections.

There are many different species of Acinetobacter that can cause disease, but A. baumannii accounts for most of the reported Acinetobacter infections in the United States, according to the Centers for Disease Control and Prevention (CDC). Based on recent CDC tracking data, there were an estimated 8,500 cases of Acinetobacter-related infections and 700 deaths in 2017.

Acinetobacter Risks

Healthy people have a very low risk of getting an A. baumannii infection, according to the CDC.

The following factors increase the risk of infection:

• Having a weakened immune system
• Being in an intensive care unit
• Lengthy hospital stays
• Illnesses that require the use of a hospital ventilator
• Having an open wound treated in the hospital
• Treatments requiring invasive devices like urinary catheters or catheters in the vein

Acinetobacter bacteria are not airborne, but can be spread through direct contact with surfaces, objects, or the skin of people that are contaminated with A. baumannii.

Acinetobacter Infection Symptoms

Acinetobacter is an opportunistic bacterium that causes a variety of different diseases with different symptoms.

Per the Virginia Department of Health, types of possible A. baumannii infections include:

• Pneumonia
• Bloodstream infections (bacteremia and sepsis)
• Meningitis (an infection or inflammation of the meninges, the membranes covering the brain and spinal cord)
• Wound and surgical site infections
• Urinary tract infections (UTI)

Symptoms of A. baumannii infections are often clinically indistinguishable from those of infections caused by other opportunistic bacteria, such as Klebsiella pneumoniae and Streptococcus pneumoniae.

Bloodstream infections often initially cause symptoms like fever and chills, rash, and confusion or other altered mental states, and are often associated with an elevated lactic acid level that’s found with severe sepsis, notes MedlinePlus.

UTIs typically cause various urinary symptoms, including pain or burning sensations while urinating, foul-smelling urine that may be cloudy or bloody, and a strong urge to urinate frequently.

Meningitis may cause a number of flu-like symptoms, including fever, headache, confusion, sensitivity to bright light, and nausea (with or without vomiting).

Pneumonia may cause a range of symptoms, including but not limited to:

• Chills
• Fever
• Headache
• Breathing problems
• Muscle pain and chest pain
• Cough, sometimes with yellow, green, or bloody mucus

In some cases, A. baumannii may colonize a site, such as an open wound or a tracheostomy site, without causing any infection or symptoms.

Acinetobacter Treatment and ‘Superbug’ Antibiotic Resistance

The CDC considers Acinetobacter, including A. baumannii, a serious public health threat because it’s often resistant to multiple antibiotics.

Before the 1970s, A. baumannii infections could be treated with a range of different antibiotics, such as aminoglycosides, ß-lactams, and tetracyclines, according to research.

Today, however, some strains of A. baumannii are resistant to most antibiotics, including first-line antibiotics and carbapenems, which are often used only as a last resort.

Treating an A. baumannii infection generally requires drug susceptibility tests, which check for antibiotics that are still effective against the particular strain of bacteria.

In some cases, ampicillin-sulbactam and trimethoprim-sulfamethoxazole still work against A. baumannii when other antibiotics fail, but even they are just 39 percent and 34 percent effective, respectively, per the CDC.