Biomedical Engineering Reference
In-Depth Information
*Enterococcus
Streptococcaceae
*Streptococcus
The human pathogens in Class Bacilli are split into two groups: Class
Bacillales, the catalase positive genera; and Class Lactobacillales, the catalase-
negative genera.
Bacilli
Bacillales (catalase positive)
Listeriaceae
*Listeria
Listeria monocytogenes is the organism that causes listeriosis. Though
Listeria monocytogenes is widely known as a cause of food-borne outbreaks,
readers should understand that it is an opportunistic infection that rarely
causes disease when it infects healthy adults. Disease, when it occurs, often
manifestsassepsisormeningitis,and can be fulminant, with a high mor-
tality (25%). Listeria is one of the few bacterial organism that produce
meningoencephalitis. Other bacterial causes of meningitis include Neisseria
meningitidis (Class Beta Proteobacteria, Chapter 6), and Elizabethkingia
meningoseptica (Class Bacteroidete, Chapter 10). Listeriosis should not be
confused with the similar-sounding disease, leptospirosis (Class Spirochaetae,
Chapter 9).
Another species of Genus Listeria is Listeria invanovii, a pathogen for
non-human animals, particularly ruminants. Like Listeria monocytogenes,
it is opportunistic, and is a rare cause of disease in immune-compromised
individuals [54]. It can produce an enteritis with bacteremia.
Bacilli
Bacillales (catalase positive)
Staphylococcaceae
*Staphylococcus
Members of Genus Staphylococcus are round cocci (from the Greek, “kokkos”
meaning berry-like) despite their inclusion in Class Bacilli (from the Latin,
“bacillum,” meaning small rod). The two most prevalent pathogenic species
are Staphylococcus aureus and Staphylococcus epidermidis.
Staphylococcus aureus lives as a non-pathogenic commensal on the skin
and on the nasal mucosa of a significant portion of the human population
(about 20%). It can cause skin disease (acne, skin abscesses, cellulitis,
staphylococcal scalded skin syndrome) and is a common source of wound
infections. If sepsis occurs, it can produce multi-organ disease, and is a cause
of toxic shock syndrome in women. It is a common cause of nosocomial
(hospital-acquired) infections, and strains of Staphylococcus aureus have
emerged that are resistant
to standard antibiotic treatment. The bacteria
