Klebsiella pneumoniae
Overview
 
Klebsiella pneumoniae is a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, non-motile, encapsulated, lactose
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...

 fermenting
Fermentation (biochemistry)
Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...

, facultative anaerobic, rod shaped bacterium found in the normal flora of the mouth, skin, and intestines.

It is clinically the most important member of the Klebsiella
Klebsiella
Klebsiella is a genus of non-motile, Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. It is named after the German microbiologist Edwin Klebs...

genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of Enterobacteriaceae
Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...

.

Seven species of the Klebsiella genus, with demonstrated similarities in DNA homology are known. These are (1) Klebsiella pneumoniae, (2) Klebsiella ozaenae, (3) Klebsiella terrigena
Klebsiella terrigena
Klebsiella terrigena is a Gram-negative bacterial species of the genus Klebsiella. It has primarily been isolated from soil and water samples but rarely from humans. As such, it has shown no connection with disease in humans despite expressing many of the virulence factors expressed by other...

, (4) Klebsiella rhinoscleromatis, (5) Klebsiella oxytoca
Klebsiella oxytoca
Klebsiella oxytoca is a Gram-negative, rod-shaped bacterium that is closely related to K. pneumoniae, from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate.- Industrial uses...

, (6) Klebsiella planticola, and (7) Klebsiella ornithinolytica.
Encyclopedia
Klebsiella pneumoniae is a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, non-motile, encapsulated, lactose
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...

 fermenting
Fermentation (biochemistry)
Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...

, facultative anaerobic, rod shaped bacterium found in the normal flora of the mouth, skin, and intestines.

It is clinically the most important member of the Klebsiella
Klebsiella
Klebsiella is a genus of non-motile, Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. It is named after the German microbiologist Edwin Klebs...

genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of Enterobacteriaceae
Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...

.

Seven species of the Klebsiella genus, with demonstrated similarities in DNA homology are known. These are (1) Klebsiella pneumoniae, (2) Klebsiella ozaenae, (3) Klebsiella terrigena
Klebsiella terrigena
Klebsiella terrigena is a Gram-negative bacterial species of the genus Klebsiella. It has primarily been isolated from soil and water samples but rarely from humans. As such, it has shown no connection with disease in humans despite expressing many of the virulence factors expressed by other...

, (4) Klebsiella rhinoscleromatis, (5) Klebsiella oxytoca
Klebsiella oxytoca
Klebsiella oxytoca is a Gram-negative, rod-shaped bacterium that is closely related to K. pneumoniae, from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate.- Industrial uses...

, (6) Klebsiella planticola, and (7) Klebsiella ornithinolytica. Of these, K oxytoca and K rhinoscleromatis have also been demonstrated in human clinical specimens.

In recent years, klebsiellae have become important pathogens in nosocomial infections.

It is closely related to K. oxytoca
Klebsiella oxytoca
Klebsiella oxytoca is a Gram-negative, rod-shaped bacterium that is closely related to K. pneumoniae, from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate.- Industrial uses...

from which it is distinguished by being indole
Indole test
The indole test is a biochemical test performed on bacterial species to determine the ability of the organism to split indole from the amino acid tryptophan...

-negative and by its ability to grow on both melezitose
Melezitose
Melezitose, also spelled melicitose, is a nonreducing trisaccharide sugar that is produced by many plant sap eating insects, including aphids such as Cinara pilicornis by an enzyme reaction. This is beneficial to the insects, as it reduces the stress of osmosis by reducing their own water potential...

 and 3-hydroxybutyrate. It naturally occurs in the soil, and about 30% of strains can fix nitrogen
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...

 in anaerobic conditions. As a free-living diazotroph
Diazotroph
Diazotrophs are bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia.A diazotroph is an organism that is able to grow without external sources of fixed nitrogen. Examples of organisms that do this are rhizobia and Frankia and Azospirillum. All diazotrophs...

, its nitrogen fixation system has been much studied.

Members of the Klebsiella genus typically express 2 types of antigens on their cell surface. The first, O antigen, is a component of the lipopolysaccharide
Lipopolysaccharide
Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...

 (LPS), of which 9 varieties exist. The second is K antigen, a capsular polysaccharide with more than 80 varieties. Both contribute to pathogenicity and form the basis for serogrouping.

History

The Danish scientist Hans Christian Gram
Hans Christian Gram
Hans Christian Joachim Gram was a Danish bacteriologist.He was the son of Frederik Terkel Julius Gram, a professor of jurisprudence, and Louise Christiane Roulund....

 (1853–1938), developed the technique now known as Gram staining
Gram staining
Gram staining is a method of differentiating bacterial species into two large groups ....

 in 1884 to discriminate between K. pneumoniae and Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...

.

Klebsiella was named after the German bacteriologist Edwin Klebs
Edwin Klebs
Theodor Albrecht Edwin Klebs was a German-Swiss pathologist. He is mainly known for his work on infectious diseases. He is the father of Arnold Klebs.-Life:...

 (1834–1913).

Multiple-resistant Klebsiella pneumoniae have been killed in vivo via intraperitoneal, intravenous or intranasal administration of phages
Phage therapy
Phage therapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections. Although extensively used and developed mainly in former Soviet Union countries circa 1920, this method of therapy is still being tested for treatment of a variety of bacterial and poly-microbial...

 in laboratory tests. While this treatment has been available for some time, a greater danger of bacterial resistance exists to phages than to antibiotics. Resistance to phage may cause a bloom in the number of the microbe in environment as well as among humans (if not obligate pathogenic). This is why phage therapy is only used in conjunction with antibiotics, to supplement their activity instead of replacing it altogether.

Clinical significance

K. pneumoniae can cause the disease Klebsiella pneumonia. They cause destructive changes to human lungs inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 and hemorrhage with cell death (necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

) that sometimes produces a thick, bloody, mucoid sputum (currant jelly sputum). Typically these bacteria gain access after a person aspirates colonizing oropharyngeal microbes into the lower respiratory tract.

As a general rule, Klebsiella infections are mostly seen in people with a weakened immune system. Most often illness affects middle-aged and older men with debilitating diseases. This patient population is believed to have impaired respiratory host defenses, including persons with diabetes, alcoholism
Alcoholism
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...

, malignancy, liver disease, Chronic obstructive pulmonary diseases (COPD), Glucocorticoid
Glucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...

 therapy, Renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...

, and certain occupational exposures (such as paper mill workers). Many of these infections are obtained when a person is in the hospital for some other reason (a nosocomial infection
Nosocomial infection
A nosocomial infection , also known as a hospital-acquired infection or HAI, is an infection whose development is favoured by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff...

).

The most common infection caused by Klebsiella bacteria outside the hospital is pneumonia, typically in the form of bronchopneumonia
Bronchopneumonia
Bronchopneumonia or bronchial pneumonia or "Bronchogenic pneumonia" is the acute inflammation of the walls of the bronchioles...

 and also bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...

. These patients have an increased tendency to develop lung abscess
Abscess
An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...

, cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...

, empyema
Empyema
Pleural empyema is an accumulation of pus in the pleural cavity. Most pleural empyemas arise from an infection within the lung , often associated with parapneumonic effusions. There are three stages: exudative, fibrinopurulent and organizing. In the exudative stage, the pus accumulates...

, and pleural adhesions. It has a high death rate of about 50% even with antimicrobial
Antimicrobial
An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes or prevent the growth of microbes...

 therapy. The mortality rate can be nearly 100% for persons with alcoholism and bacteremia.

In addition to pneumonia, Klebsiella can also cause infections in the urinary tract, lower biliary tract, and surgical wound sites. The range of clinical diseases includes pneumonia, thrombophlebitis
Thrombophlebitis
Thrombophlebitis is phlebitis related to a thrombus . When it occurs repeatedly in different locations, it is known as "Thrombophlebitis migrans" or "migrating thrombophlebitis".-Signs and symptoms:...

, urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...

 (UTI), cholecystitis
Cholecystitis
-Signs and symptoms:Cholecystitis usually presents as a pain in the right upper quadrant. This is known as biliary colic. This is initially intermittent, but later usually presents as a constant, severe pain. During the initial stages, the pain may be felt in an area totally separate from the site...

, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, upper respiratory tract infection, wound infection, osteomyelitis
Osteomyelitis
Osteomyelitis simply means an infection of the bone or bone marrow...

, meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

, and bacteremia and septicemia. If a person has an invasive device in their body then contamination of the device becomes a risk; for example respiratory support equipment and urinary catheters put patients at increased risk. Also, the use of antibiotics can be a factor that increases the risk of nosocomial infection with Klebsiella bacteria. Sepsis and septic shock can follow entry of the bacteria into the blood.

Two unusual infections of note are from Klebsiella are rhinoscleroma
Rhinoscleroma
Rhinoscleroma, or simply Scleroma, is a chronic granulomatous bacterial disease of the nose that can sometimes infect the upper respiratory tract. It most commonly affects the nasal cavity—the nose is involved in 95-100 per cent of cases—however, it can also affect the nasopharynx, larynx, trachea,...

 and ozena. Rhinoscleroma is a chronic inflammatory process involving the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...

. Ozena is a chronic atrophic rhinitis
Rhinitis
Rhinitis , commonly known as a stuffy nose, is the medical term describing irritation and inflammation of some internal areas of the nose. The primary symptom of rhinitis is nasal dripping. It is caused by chronic or acute inflammation of the mucous membrane of the nose due to viruses, bacteria or...

 that produces necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

 of nasal mucosa and mucopurulent nasal discharge
Rhinorrhea
Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant amount of mucous fluid. The condition, commonly known as "runny nose", occurs relatively frequently and is not usually considered dangerous. Rhinorrhea is a common symptom of allergies or certain diseases,...

.

Research conducted at King's College, London has implicated molecular mimicry
Molecular mimicry
Molecular mimicry is defined as the theoretical possibility that sequence similarities between foreign and self-peptides are sufficient to result in the cross-activation of autoreactive T or B cells by pathogen-derived peptides...

 between HLA-B27
HLA-B27
Human Leukocyte Antigen B27 is a class I surface antigen encoded by the B locus in the major histocompatibility complex on chromosome 6 and presents antigenic peptides to T cells...

 and two Klebsiella surface moleculars as the cause of ankylosing spondylitis
Ankylosing spondylitis
Ankylosing spondylitis , previously known as Bekhterev's disease, Bekhterev syndrome, and Marie-Strümpell disease is a chronic inflammatory disease of the axial skeleton with variable involvement of peripheral joints and nonarticular structures...

.

New antibiotic resistant
Antibiotic resistance
Antibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacteria in a...

 strains of K. pneumoniae are appearing, and it is increasingly found as a nosocomial infection
Nosocomial infection
A nosocomial infection , also known as a hospital-acquired infection or HAI, is an infection whose development is favoured by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff...

.

Klebsiella ranks second to E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

for urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...

s in older persons. It is also an opportunistic pathogen
Opportunistic infection
An opportunistic infection is an infection caused by pathogens, particularly opportunistic pathogens—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system...

 for patients with chronic pulmonary disease, enteric pathogenicity, nasal mucosa atrophy, and rhinoscleroma
Rhinoscleroma
Rhinoscleroma, or simply Scleroma, is a chronic granulomatous bacterial disease of the nose that can sometimes infect the upper respiratory tract. It most commonly affects the nasal cavity—the nose is involved in 95-100 per cent of cases—however, it can also affect the nasopharynx, larynx, trachea,...

. Feces are the most significant source of patient infection, followed by contact with contaminated instruments.

Resistant strains

Infection with carbapenem-resistant Enterobacteriaceae (CRE) or carbapenemase-producing Enterobacteriaceae is emerging as an important challenge in health-care settings. One of many carbapenem-resistant Enterobacteriaceae (CRE) 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
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

 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 24 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, particularly among persons with prolonged hospitalization and those who are 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. The worry is that new slight mutations could result in infections for which there is very little, if anything, healthcare professionals can do to treat patients with resistant organisms.

There are a number of mechanisms of Carbapenem Resistance in Enterobacteriaceae. These include (1) Hyperproduction of ampC beta-lactamase with an outer membrane porin mutation (2) CTX-M extended-spectrum beta-lactamase with a porin mutation or drug efflux, and (3) Carbapenemase production. When bacteria such as Klebsiella pneumoniae produce an enzyme known as a carbapenemase, they are referred to as carbapenem-resistant Klebsiella pneumoniae (CRKP).

Put another way, 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
Transposon
Transposable elements are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either "copy and paste" or "cut and paste". Transposition can create phenotypically significant mutations and alter the cell's...

; 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 minimal inhibitory concentrations
Minimum inhibitory concentration
In microbiology, minimum inhibitory concentration is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation. Minimum inhibitory concentrations are important in diagnostic laboratories to confirm resistance of microorganisms...

 (MICs) 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
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 is also unknown but is suspected to be within a range of 12.5% to as high as 44%. The likelihood of an epidemic
Epidemic
In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...

 or pandemic
Pandemic
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...

 in the future remains uncertain.

The Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 (CDC) released guidance for aggressive infection control to combat CRKP.

Place all patients colonized or infected with CRE or carbapenemase-producing Enterobacteriaceae
Enterobacteriaceae
The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the...

 on contact precautions. Acute care facilities are to establish a protocol, in conjunction with the guidelines of the Clinical and Laboratory Standards Institute
Clinical and Laboratory Standards Institute
Clinical and Laboratory Standards Institute is a volunteer driven, membership supported, nonprofit, standards organization. CLSI promotes the development and use of voluntary laboratory consensus standards and guidelines within the health care community....

 (CLSI), to detect nonsusceptibility and carbapenemase production in Enterobacteriaceae, particularly 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 who have been cared for by the same health-care personnel).

The reasons that the CDC is only recommending the detection of carbapenem resistance or carbapenemase production for Klebsiella spp. and E. coli are 1) this facilitates performing the test in the microbiology laboratory without the use of molecular methods and 2) these organisms represent the majority of CRE 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.

Treatment

As with many bacteria, the recommended treatment has changed as the organism has developed resistances. Klebsiella organisms are often resistant to multiple antibiotics. Current evidence implicates a plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...

 as the source of the resistant genes. Klebsiella with the ability to produce extended-spectrum beta-lactamases ESBL are resistant to many classes of antibiotics. The most frequent resistances include resistance to aminoglycosides, fluoroquinolones, tetracyclines, chloram-phenicol, and sulfamethoxazole-trimethoprim.

The choice of a specific antimicrobial agent or agents depends on local susceptibility patterns and on the part of the body that is infected. For patients with severe infections, a prudent approach is the use of an initial short course (48-72 h) of combination therapy, followed by a switch to a specific mono-therapy once the susceptibility pattern is known for the specific patient.

If the specific Klebsiella in a particular patient does not have antibiotic resistance, then the antibiotics used to treat such susceptible isolates include ampicillin/sulbactam, piperacillin/tazobactam, ticarcillin/clavulanate, ceftazidime, cefepime, levofloxacin, norfloxacin, gaitfloxacin, moxifloxacin, meropenem, and ertapenem. Some experts recommend the use of Meropenem for patients with ESBL producing Klebsiella. The claim is that meropenem produces the best bacterial clearing. The use of antibiotics is usually not enough. Surgical clearing (frequently done as interventional radiology drainage) is often needed after the patient is started on antimicrobial agents.

External links

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