Biomedical Engineering Reference
In-Depth Information
continuously submerse their hands in groundwater, are particularly at risk
for exposure. Most humans exposed to the bacteria do not develop disease,
but diabetic patients and individuals with chronic diseases are highly sus-
ceptible. Incubation may be short (one day) or long (decades). Symptoms
and the severity of disease vary widely: fever, pneumonia, and joint pain
may occur. Abscesses arising in various organs are a common finding in
melioidosis.
The Burkholderia cepacia complex is a collection of more than half a
dozen related species. Burkholderia cepacia is found in soil and water, and
produces pneumonia in individuals who have an underlying lung disease (such
as cystic fibrosis), or who have weakened immune systems. Infection can be
passed from person to person. Burkholderia cepacia organisms are difficult to
treat (i.e., demonstrate antibiotic resistance) and difficult to remove from the
environment (i.e., withstand common disinfectant procedures).
Genus Burkholderia was previously known as Genus Pseudomonas. You
may occasionally see species misdesignations in older textbooks.
Beta Proteobacteria
Neisseriales
Neisseriaceae
*Eikenella
*Neisseria
*Kingella
Class Neisseriaceae are strictly aerobic and grow chiefly in pairs (i.e., diplococci)
or small clusters.
Eikenella corrodens is a normal inhabitant of the mouth, but can produce
a bacteremia if mechanically forced into the bloodstream (e.g. chewing bite).
It can also act opportunistically in diabetics and immune-compromised
individuals. Eikenella corrodens can cause cellulitis, as well as endocarditis
and is included with the HACEK group of endocarditis-producing organisms
(see Glossary item, HACEK).
In Chapter 10, we will describe another oral inhabitant, Prevotella dentalis
(Class Bacteroidetes), that can cause a bite bacteremia.
Genus Neisseria contains two important pathogens: Neisseria gonorrhoeae,
the cause of gonorrhea; and Neisseria meningitidis, a cause of meningitis.
Gonorrhea is a sexually transmitted disease. Approximately 1.5 million new
cases of gonorrhea occur annually in North America, where gonorrhea is the
third most common sexually transmitted disease [32]. The second most com-
mon sexually transmitted disease is chlamydia (Class Chlamydiae, Chapter 13),
with about 4 million new cases each year in North America [32]. The most
common sexually transmitted disease is trichomoniasis (Class Metamonada,
Chapter 16), with about 8 million new cases each year in North America [32].
Neisseria meningitidis is sometimes referred to as meningococcal
meningitis, and the organism is oftencalledbyanabbreviatedform,
