Webster's New World Medical Dictionary

strain 1
An injury to a ligament, tendon, or mus-
cle that results from overuse or trauma.
2
A
hereditary tendency that originates from a common
ancestor.
3
To exert maximum effort.
4
To filter.
strawberry hemangioma or strawberry mark
See 
hemangioma, capillary.
strep
See
streptococcus.
strep throat
An infection caused by group A
streptococcus bacteria that can lead to serious com-
plications if not adequately treated. Treatment usu-
ally involves use of antibiotics. See 
streptococcus.
streptococcus
A group of bacteria that causes a
multitude of diseases. Under a microscope, strepto-
coccus bacteria look like a twisted bunch of round
berries. Illnesses caused by streptococcus include
strep throat, strep pneumonia, scarlet fever, rheu-
matic fever (and rheumatic heart valve damage),
glomerulonephritis, the skin disorder erysipelas,
and PANDAS. Familiarly known as strep.
streptococcus, group A
See 
Streptococcus
pyogenes.
streptococcus, group B
A major cause of infec-
tions, including those involving pregnant women
and newborn infants. Group B strep can infect the
mother’s uterus, placenta, and urinary tract; in fact,
it is present in the vagina of around 10 to 25 percent
of all pregnant women. Group B strep can be trans-
ferred between heterosexual couples via oral sex.
Infants develop the infection in utero or at the time
of delivery from women who have vaginal group B
strep. Of infants who acquire the infection, about
1-2% develop the clinical disease. Neonatal sepsis
from group B streptococci is more common in pre-
mature infants and in the setting of prolonged rup-
ture of the membranes. Infections in the infant can
be localized, or it may involve the entire body. In
babies, strep infections are divided into early-onset
and late-onset disease. Early-onset disease presents
within the first 6 days of life, with breathing diffi-
culty, shock, pneumonia, and occasionally infection
of the spinal fluid and brain (meningitis). Late-
onset disease presents between the seventh day and
the third month of age, with a bloodstream infection
(bacteremia) or meningitis. The bacteria can also
infect an area of bone; a joint, such as the knee or
hip; or the skin. Group B strep infection in a new-
born is a serious and potentially life-threatening
event, particularly because fever and warning signs
are often minimal or absent and because the 
newborn’s immune system is not mature. Early signs