These bacteria may infect the urinary or respiratory tract, intravenous catheters used to give drugs or fluids, burns, wounds made during surgery, or the bloodstream.
Identifying the bacteria in a sample taken from blood or from infected tissue confirms the diagnosis.
Infections caused by all three bacteria are treated with antibiotics given by vein (intravenously).
(See also Overview of Bacteria Overview of Bacteria Bacteria are microscopic, single-celled organisms. They are among the earliest known life forms on earth. There are thousands of different kinds of bacteria, and they live in every conceivable... read more .)
Klebsiella, Enterobacter, and Serratia bacteria reside in the intestine of many healthy people and rarely cause infection in them. Infections with these bacteria are often acquired in hospitals and long-term care facilities. They usually occur in people whose resistance to infection is weakened and/or who have a medical device (such as catheters, drains, and airway tubes) in their body.
These bacteria may infect different places in the body:
Urinary or respiratory tract (causing pneumonia Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs (alveoli) and the tissues around them. Pneumonia is one of the most common causes of death worldwide. Often, pneumonia is the final... read more , bladder infections Bladder Infection Cystitis is infection of the bladder. Usually, bacteria are the cause of cystitis. A frequent need to urinate and pain or burning while urinating are the most common symptoms. Doctors can often... read more , or kidney infections Kidney Infection Pyelonephritis is a bacterial infection of one or both kidneys. Infection can spread up the urinary tract to the kidneys, or uncommonly the kidneys may become infected through bacteria in the... read more )
Catheters inserted into a vein (intravenous catheter), used to administer drugs or fluids
Wounds made during surgery
Bloodstream (causing bacteremia Bacteremia Bacteremia is the presence of bacteria in the bloodstream. Bacteremia may result from ordinary activities (such as vigorous toothbrushing), dental or medical procedures, or from infections ... read more or sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more )
Rarely, Klebsiella bacteria cause pneumonia in people who live outside a health care facility (in the community), usually in people with an alcohol use disorder, older people, people with diabetes, or people with a weakened immune system. Typically, this severe infection causes cough, bringing up a sticky, dark brown or dark red sputum, and collections of pus (abscesses Abscess in the Lungs A lung abscess is a pus-filled cavity in the lung surrounded by inflamed tissue and caused by an infection. A lung abscess is usually caused by bacteria that normally live in the mouth and are... read more ) in the lungs or in the membrane between the lungs and chest wall (empyema).
One species of Klebsiella produces a toxin that can cause inflammation of the colon and bleeding (hemorrhagic colitis) after antibiotics are taken. This disorder is called antibiotic-associated colitis. The antibiotics kill bacteria that normally reside in the intestine. Then Klebsiella bacteria are able to multiply and produce the toxin. However, antibiotic-associated colitis usually results from toxins produced by Clostridioides difficile Clostridioides (formerly Clostridium) difficile-Induced Colitis Clostridioides difficile (C. difficile)–induced colitis is an inflammation of the large intestine (colon) that results in diarrhea. The inflammation is caused by toxin produced... read more .
Examination and culture of a sample of infected tissue
Doctors suspect one of these infections in people at high risk of getting one, such as people who live in a long-term care facility or in a place when there was an outbreak.
To confirm the diagnosis, doctors take a sample of sputum, lung secretions (obtained through a bronchoscope), blood, urine, or infected tissue. The sample is stained with Gram stain, cultured, and examined under a microscope. These bacteria can be readily identified.
Other tests depend on the type of infection. They may include imaging tests, such as ultrasonography, x-rays, and computed tomography (CT).
Bacteria identified in samples are tested to determine which antibiotics are likely to be effective (a process called susceptibility testing Testing a Microorganism's Susceptibility and Sensitivity to Antimicrobial Drugs Infectious diseases are caused by microorganisms, such as bacteria, viruses, fungi, and parasites. Doctors suspect an infection based on the person's symptoms, physical examination results,... read more ).
Antibiotics given by vein (intravenously)
Infections caused by any of these three bacteria are treated with antibiotics given intravenously. Antibiotics include cephalosporins, cefepime, carbapenems, fluoroquinolones, piperacillin/tazobactam, or aminoglycosides. However, sometimes these bacteria are resistant to many antibiotics, so doctors do susceptibility testing. If an infection with any of these three bacteria is acquired in a health care facility, the infection can be difficult to treat because bacteria acquired in such facilities are usually resistant to many antibiotics.