What is Acinetobacter?
Acinetobacter is a type of bacteria that doesn’t move and needs oxygen to survive. Among its many species, A. baumannii is the most relevant for medical purposes. This bacteria is found in places like soil and water and is often found in patient samples taken from urine, saliva, respiratory fluids and open wounds. It’s also known to thrive in fluids used for injections and other medical procedures.
Generally, Acinetobacter is not very harmful but can cause infections in people with weak immune systems, especially those with a low white blood cell count. Most of these infections happen in hospital settings and often result from the bacteria spreading and growing rather than starting a new infection. Therefore, when Acinetobacter is found, it requires careful examination to determine whether it is causing an infection or is just present without causing harm. The risk factors for an Acinetobacter infection include a long stay in the intensive care unit, long-term use of antibiotics, use of a breathing machine, use of a tube that goes into a large vein, and kidney dialysis.
Acinetobacter infections usually occur in groups and it’s rare to find isolated cases. The infections can complicate treatment involving an IV tube, a breathing machine, or peritoneal dialysis, which filters the blood inside the body. In many cases, if Acinetobacter is found in the respiratory fluids of patients on breathing machines, it usually indicates the bacteria is present but not necessarily causing an infection.
What Causes Acinetobacter?
Acinetobacter is mainly an infection that is caught in a hospital setting and is commonly found in patients who have been hospitalized. However, it’s important to figure out if the Acinetobacter found in a patient is actually causing an illness or if it is just present without causing harm. Acinetobacter is a bacteria that thrives in water and tends to occupy organs in the body that contain fluid.
Because of this, in patients who have been in the hospital, Acinetobacter can often be found in areas with fluids, such as the belly (the peritoneal fluid), the fluid around the brain and spine (cerebrospinal fluid), saliva, lung secretions, and the urinary tract.
Risk Factors and Frequency for Acinetobacter
Acinetobacter is a type of bacteria that became concerning in the 1960s when hospitals started to grow their Intensive Care Units. Despite it being a rather weak bacteria, its ability to survive for long periods in various environments allows it to spread easily in hospitals. This transmission often happens through medical staff, respiratory equipment like ventilators, and other medical devices.
This bacteria can be found in all kinds of bodily fluids and secretions such as wounds, saliva, urine, and blood. It may not cause high-risk infections, but it can still infect patients with weakened immunity or those who have had an organ transplant. Acinetobacter has also been identified in wounds of soldiers returning from Iraq and Afghanistan.
The health risk posed by Acinetobacter is mainly dependent on the patient’s existing medical conditions and their overall immune health. More worryingly, the bacteria can become resistant to drugs due to various internal mechanisms. There have been recorded instances of Acinetobacter resistance to multiple types of antibiotics, which is a growing concern in the medical community.
- The Centers for Disease Control categorized multi-drug resistant Acinetobacter as a ‘serious’ threat in their 2013 antimicrobial resistance report.
- Even though Acinetobacter is not dangerous by itself, it can cause significant health concerns in patients with multiple organ diseases.
- If infected with resistant strains of Acinetobacter, patients may face mortality rates of up to 70%.
Signs and Symptoms of Acinetobacter
Acinetobacter is a type of bacteria that often colonizes patients who have had long stays in the hospital or have been on antibiotics for an extended period. However, it’s important to note that it’s more common for these bacteria to simply exist on a patient’s body without causing disease. This is referred to as colonization. Patients with this type of colonization typically do not show any physical signs.
The majority of patients who do get an Acinetobacter infection are usually already in the hospital. The lungs are the most commonly affected organ, mainly due to the bacteria’s ability to colonize the airways and respiratory equipment used for mechanical ventilation.
Acinetobacter infections can take various forms, including:
- Pneumonia
- Wound infections
- Infections associated with catheters
- Meningitis acquired within a healthcare setting
However, Acinetobacter infections have no unique signs that set them apart from other infections caused by similar types of bacteria, such as Enterobacter, Burkholderia, Pseudomonas, and Serratia. Therefore, doctors have to be careful when determining whether Acinetobacter is the actual cause of an infection, especially as it’s primarily a colonizing organism.
Testing for Acinetobacter
Acinetobacter is a germ usually found in patients in intensive care or those having several health issues. It tends to cause infections mainly in people with weakened immune systems and those having heart and lung issues. Even though we can easily test for this germ, understanding a patient’s symptoms and general health condition is central in diagnosis.
Lab Tests
Patients may show high white blood cells in lab results, typically seen in infection, but these results are quite vague and may not always signal a bacterial infection like Acinetobacter. By testing body fluids, like blood or urine, a lab can quickly detect Acinetobacter especially when several patients present symptoms at the same time.
Imaging Tests
If pneumonia is suspected, a chest X-ray is the go-to test. The choice of other imaging tests relies much on what the doctor considers based on the patient’s signs and symptoms.
Procedures
If there’s a fear that meningitis, a serious infection of the brain and spine, is present, fluid around the spinal cord, called cerebrospinal fluid, may need to be tested and cultured for the germ.
Histologic Findings
There’s no specific microscopic appearance of an Acinetobacter infection that would set it apart from other similar bacteria. It relies upon other factors like symptoms and lab results for conclusive identification.
Treatment Options for Acinetobacter
Acinetobacter, a bacterium, has built up resistance to numerous drugs. Medications such as cephalosporins, macrolides, and penicillins don’t tend to work well against this type of bacterial infection, and using these drugs could even create ideal conditions for Acinetobacter infection to thrive.
If you have a medical device such as a long-term catheter or a pacemaker when there’s a suspected infection, it should be removed. This also goes for any infected medical items like tubes, shunts, or drains – these must be taken out in order to fully eliminate the infection.
In case there is a pus-filled abscess or dead tissue, these areas need to be cleaned out thoroughly. It’s important to note that treating colonization, which occurs when the bacteria is present but not causing harm, is typically avoided because it can encourage more antibiotic resistance.
In recent years, resistance to antibiotics has become a common issue in the US. However, some medications such as meropenem, sulbactam/durlobactam, colistin, polymyxin B, and amikacin may still be effective against Acinetobacter. Other alternatives could include minocycline, rifampin, and tigecycline. Usually, a single drug is used as using a combination hasn’t proven to be more beneficial. Treatment often lasts between 7 to 10 days, depending on the severity of the patient’s condition.
What else can Acinetobacter be?
- Infection by Burkholderia cepacia
- Bloodstream infection associated with catheter use
- Infection by Enterobacter species
- Flavobacterium meningosepticum infection, associated with meningitis
- Healthcare-associated meningitis
- Pneumonia, an infection that inflames the air sacs in one or both lungs
- Infection by Pseudomonas aeruginosa, a common bacteria that can cause disease
- Infection by Serratia marcescens, a type of bacteria
- Infection by Stenotrophomonas maltophilia, a bacteria that is commonly resistant to antibiotics
- Wound infections that occur after a wound, such as a cut or scrape, becomes infected with bacteria