Klebsiella pneumoniae causes a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically, K. pneumoniae has caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore, K. pneumoniae strains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity in K. pneumoniae strains, and not every factor plays the same critical role in all virulent Klebsiella strains. Recent studies have identified additional K. pneumoniae virulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.
- Who Gets It?
- How Klebsiella Pneumoniae Spreads
- Resistant strains
- Treatment of Klebsiella Infections
Infections are rare in healthy people because their immune systems are strong enough to fend off the germs. But infections are more likely if you have health problems like:
- Kidney failure
- Liver disease
- Lung disease
Taking certain antibiotics for a long time or other treatments also can raise your chances for a klebsiella infection.
K. pneumoniae infections are typically “nosocomial” infections, which means they’re contracted in a hospital or healthcare setting.
People who have weakened immune systems, or sick or injured people who are undergoing procedures for various health issues, are more likely to get a Klebsiella infection.
Healthy people usually don’t have to worry about getting K. pneumoniae infections, according to the Centers for Disease Control and Prevention (CDC).
The bacteria are not airborne, so you can’t contract a K. pneumoniae infection by breathing the same air as an infected person.
Instead, K. pneumoniae is spread through direct person-to-person contact, such as when someone with contaminated hands touches a wound.
Infections can also occur through the use of contaminated medical equipment.
For example, people on ventilators can contract Klebsiella pneumonia if breathing tubes are contaminated with the bacteria.
Similarly, the use of contaminated intravenous catheters can lead to bloodstream infections.
Taking antibiotics over a long course of time can also increase a person’s risk of getting a Klebsiella infection.
Klebsiella organisms are often resistant to multiple antibiotics. Current evidence implicates plasmids as the primary source of the resistance genes. Klebsiella species with the ability to produce extended-spectrum beta-lactamases (ESBL) are resistant to virtually all beta-lactam antibiotics, except carbapenems. Other frequent resistance targets include aminoglycosides, fluoroquinolones, tetracyclines, chloramphenicol, and trimethoprim/sulfamethoxazole.
Infection with carbapenem-resistant Enterobacteriaceae (CRE) or carbapenemase-producing Enterobacteriaceae is emerging as an important challenge in health-care settings. One of many CREs is carbapenem-resistant Klebsiella pneumoniae (CRKP). Over the past 10 years, a progressive increase in CRKP has been seen worldwide; however, this new emerging nosocomial pathogen is probably best known for an outbreak in Israel that began around 2006 within the healthcare system there. In the USA, it was first described in North Carolina in 1996; since then CRKP has been identified in 41 states; and is recovered routinely in certain hospitals in New York and New Jersey. It is now the most common CRE species encountered within the United States.
CRKP is resistant to almost all available antimicrobial agents, and infections with CRKP have caused high rates of morbidity and mortality, in particular among persons with prolonged hospitalization and those critically ill and exposed to invasive devices (e.g., ventilators or central venous catheters). The concern is that carbapenem is often used as a drug of last resort when battling resistant bacterial strains. New slight mutations could result in infections for which healthcare professionals can do very little, if anything, to treat patients with resistant organisms.
A number of mechanisms cause carbapenem resistance in the Enterobacteriaceae. These include hyperproduction of ampC beta-lactamase with an outer membrane porin mutation, CTX-M extended-spectrum beta-lactamase with a porin mutation or drug efflux, and carbapenemase production. The most important mechanism of resistance by CRKP is the production of a carbapenemase enzyme, blakpc. The gene that encodes the blakpc enzyme is carried on a mobile piece of genetic material (a transposon; the specific transposon involved is called Tn4401), which increases the risk for dissemination. CRE can be difficult to detect because some strains that harbor blakpc have minimum inhibitory concentrations that are elevated, but still within the susceptible range for carbapenems. Because these strains are susceptible to carbapenems, they are not identified as potential clinical or infection control risks using standard susceptibility testing guidelines. Patients with unrecognized CRKP colonization have been reservoirs for transmission during nosocomial outbreaks.
The extent and prevalence of CRKP within the environment is currently unknown. The mortality rate is also unknown, but has been observed to be as high as 44%. The Centers for Disease Control and Prevention released guidance for aggressive infection control to combat CRKP:
Place all patients colonized or infected with carbapenemase-producing Enterobacteriaceae on contact precautions. Acute-care facilities are to establish a protocol, in conjunction with the guidelines of the Clinical and Laboratory Standards Institute, to detect nonsusceptibility and carbapenemase production in Enterobacteriaceae, in particular Klebsiella spp. and Escherichia coli, and immediately alert epidemiology and infection-control staff members if identified. All acute-care facilities are to review microbiology records for the preceding 6–12 months to ensure that there have not been previously unrecognized CRE cases. If they do identify previously unrecognized cases, a point prevalence survey (a single round of active surveillance cultures) in units with patients at high risk (e.g., intensive-care units, units where previous cases have been identified, and units where many patients are exposed to broad-spectrum antimicrobials) is needed to identify any additional patients colonized with carbapenem-resistant or carbapenemase-producing Klebsiella spp. and E. coli. When a case of hospital-associated CRE is identified, facilities should conduct a round of active surveillance testing of patients with epidemiologic links to the CRE case (e.g., those patients in the same unit or patients having been cared for by the same health-care personnel).
One specific example of this containment policy could be seen in Israel in 2007. This policy had an intervention period from April, 2007, to May, 2008. A nationwide outbreak of CRE (which peaked in March, 2007 at 55.5 cases per 100,000 patient days) necessitated a nationwide treatment plan. The intervention entailed physical separation of all CRE carriers and appointment of a task force to oversee efficacy of isolation by closely monitoring hospitals and intervening when necessary. After the treatment plan (measured in May, 2008), the number of cases per 100,000 patient days decreased to 11.7. The plan was effective because of strict hospital compliance, wherein each was required to keep detailed documentation of all CRE carriers. In fact, for each increase in compliance by 10%, incidence of cases per 100,000 patient days decreased by 0.6. Therefore, containment on a nationwide scale requires nationwide intervention.
In the United States, the reasons the CDC is recommending the detection of carbapenem resistance or carbapenemase production only for Klebsiella spp. and E. coli are: this facilitates performing the test in the microbiology laboratory without the use of molecular methods, and these organisms represent the majority of CREs encountered in the United States. Effective sterilization and decontamination procedures are important to keep the infection rate of this antibiotic-resistant strain, CRKP, as low as possible.
In mid-August 2016, a resident of Washoe County was hospitalized in Reno due to a CRE (specifically Klebsiella pneumoniae) infection. In early September of the same year, she developed septic shock and died. On testing by CDC an isolate from the patient was found to be resistant to all 26 antibiotics available in the US, including drug of last resort colistin. It is believed she may have picked up the microbe while hospitalized in India for two years due to a broken right femur and subsequent femur and hip infections.
They depend on where the infection is. For example, if the bacteria gives you pneumonia, you may have:
- Chest pain
- Trouble breathing
- More mucus, which may be thick and bloody
Klebsiella pneumoniae can hit other parts of your body, too. For example, your surgical wound could be infected. You could also get an infection in your:
- Blood (bacteremia or septicemia)
- Brain (meningitis)
- Heart (endocarditis)
- Skin (cellulitis)
- Urinary tract (UTIs)
If you or a loved one has signs of infection, talk to your doctor. Symptoms alone can’t tell whether klebsiella is the cause. So your doctor will test your spit, blood, urine, or other fluids to find out what type of bug is to blame.
Doctors typically use antibiotics to treat K. pneumoniae infections.
However, the rise of antibiotic-resistant strains of the bacteria has complicated matters.
Some “superbug” strains of K. pneumoniae are resistant to most antibiotics, including carbapenems, which are considered last-resort drugs.
These bacteria produce enzymes called Klebsiella pneumoniae carbapenemases (KPC), which render the antibiotics ineffective.
These hardy, high-threat-level microbes are part of a group called carbapenem-resistant Enterobacteriaceae, or CRE.
Carbapenem-resistant Klebsiella is the most common type of CRE, and is responsible for about 7,900 infections and 520 deaths each year, according to the CDC.
To treat CRE, doctors rely on several powerful antibiotics that still have some effectiveness against the bacteria, particularly when used in combination, according to a January 2013 report in the journal Diagnostic Microbiology & Infectious Disease.
These drugs include:
One of the best ways to protect yourself is simple. Always wash your handsbefore you:
- Touch your eyes, nose, or mouth
- Change bandages on a cut
And wash your handsafter you:
- Use the bathroom
- Blow your nose, cough, or sneeze
- Touch things that might have germs on them, especially in doctor’s offices or hospitals
If you check into the hospital for treatment, take steps to protect yourself.
- Before you go, make sure to follow your treatment plan for any ongoing health conditions, like diabetes.
- Ask the staff what they do to prevent infections.
- Tell your nurse or doctor if your bandages get wet or IV tubes fall out of place.
- If you need a catheter or other device, ask to have it taken out as soon as you don’t need it anymore.
- Ask anyone who comes into your room to wash their hands first.
- Teach your family about fever and other signs of infection so they can call for help quickly.