Biomedical Engineering Reference
In-Depth Information
Klebsiella pneumoniae, the most common pathogen in humans, inhabits the
gastrointestinal tracts of diverse animals, either chronically or transiently, and is
found in sewage and soil [35]. Klebsiella pneumoniae, as its name suggests,
causes pneumonia in humans. Klebsiella pneumoniae and its closely related rel-
ative, Klebsiella oxytoca, are capable of producing a wide range of conditions
in humans, particularly sepsis and urinary tract infections.
Klebsiella granulomatis, formerly Calymmatobacterium granulomatis,
formerly Donovania granulomatis, is the cause of granuloma inguinale, also
known as donovanosis, also known as granuloma venereum. Infection produces
genital ulcers, and can be mistaken clinically with two other diseases that are
characterized by genital ulcers: syphilis (Class Spirochaetae, Chapter 9), and
chancroid (see below). In addition, granuloma venereum, caused by Klebsiella
granulomatis, must not be confused with lymphogranuloma venereum, caused
by Chlamydia trachomatis (Class Chlamydiae, Chapter 13).
Rhinoscleroma is a granulomatous disease, endemic to Africa, Southeast
Asia, South America, and some parts of Eastern Europe. Cases may occur
in the USA. The nose is involved by rhinoscleroma in over 95% of cases.
Readers should not confuse rhinscleroma, caused by Klebsiella rhino-
scleromatis (Class Gamma Proteobacteria, Chapter 7), with rhinosporidiosis,
caused by Rhinosporidium seeberi (Choanozoa, Chapter 23).
Morganella is a genus of anaerobic organisms, only one of which is infectious
in humans: Morganella morganii. This organism lives in the intestines of animals
(including humans). It can cause a wide variety of diseases, including enteritis
(causing so-called summer diarrhea), sepsis, and organ infections. The bacterial
genus Morganella should not be confused with the fungal genus of the same name.
Genus Proteus contains rod-shaped bacteria that inhabit soil and water.
Species in the genus produce urease. The genus contains three opportunistic
pathogens that are sometimes found in the human intestinal tract: Proteus
mirabilus, Proteus vulgaris, and Proteus penneri. All of the Proteus species
are capable of causing urinary tract infections. The species most commonly
found in Proteus-caused infections is Proteus mirabilis.
Proteus species have a particular association with struvite stones of the
kidney. Because Proteus species produce urease, the resulting high levels of
ammonia in urine leads to alkalinity, which in turn favors the crystallization
of struvite (an ammonia-containing mineral) in urine. Kidney stones passed in
urine, or surgically extracted, are routinely analyzed for chemical composition.
Stones composed of struvite are uncommon. Most stones contain calcium
oxalate, calcium phosphate, or uric acid. A struvite stone should alert
clinicians that the patient may have a Proteus urinary tract infection.
Genus Providencia contains species that are found in soil, water, and
sewage. In humans, Providencia species are opportunistic pathogens, super-
infecting burns or causing urinary tract infections in patients with indwelling
catheters. Providencia stuartii is a common cause of so-called purple urine bag
syndrome, a condition associated with various infectious members of Class
