Viridans streptococci have long been recognized as a major organism
causing 22% to 38% of cases of bacterial endocarditis.
The majority of children with bacterial endocarditis have underlying
congenital heart defects and usually have undergone cardiac surgery
(see Chapter 235).2 Rheumatic
heart disease is the second most common cardiac abnormality predisposing
to endocarditis. Fever and fatigue in the background of a changing
cardiac exam are the most common presenting symptoms of endocarditis.
An elevated erythrocyte sedimentation rate and anemia are the most
common laboratory findings. When compared to infections with S
aureus, those caused by viridans streptococci respond to
therapy more quickly with more rapid defervescence and clearing
of the bacteremia. Complications and need for heart surgery are significantly
less frequent with viridans streptococcal infections.
Viridans streptococci are also important pathogens in some immunocompromised hosts.
In cancer patients and children receiving hematopoietic stem cell
transplants, viridans streptococci account for 5% to 30% of cases
of bacteremia, mainly associated with indwelling vascular catheters,
mucositis, gastrointestinal toxicity, and neutropenia.3,4 Pneumonia
and septic shock are common complications. Rare cases of early-onset
sepsis have been described in neonates. While large-colony group
C and group G streptococci are implicated as a cause of pharyngitis
in children and adults, they are most commonly associated with food-borne
outbreaks. In a recent Delaware study, conducted over a 1-year period,
of 2085 children with pharyngitis and 195 controls, large-colony
group C or G streptococci were isolated from 3.1% of patients and
1.5% of controls, a difference that was not statistically
significant.5 These organisms are not a cause of
acute rheumatic fever. Infrequently, group C and group G streptococci cause
a variety of pyogenic infections: pneumonia, epiglottitis, osteomyelitis,
septic arthritis, pyomyositis, brain abscess, meningitis, cellulitis,
endocarditis, sinusitis, urinary tract infections, bacteremia; and
toxic shock syndrome.6-8 All of these occur very
infrequently.
Group D streptococci (S bovis) are a rare cause
of disease in children. There are few reports of endocarditis (seen
mainly in adults), meningitis, or bacteremia, particularly in newborns.9