The Journal of the Arkansas Medical Society Med Journal Jan 2020 | Page 15

Figure 1.
as normal flora of the respiratory female geni-
tal tracts.¹ The S. anginosus group presents as
gram-positive, catalase-negative cocci like other
members of the Streptococcus genus.² Many of
the strains of this infection are either enhanced
by the presence of carbon dioxide or anaerobic.²
The Streptococcus anginosus group has been not-
ed to be particularly important in the pathogene-
sis of respiratory infections.³
The most telling symptom of S. anginosus
infection is an abscess. This is what sets it apart
from other pathogenic streptococci.² S. angino-
sus is also commonly associated with invasive
pyogenic infections. Unlike less virulent viridans
streptococci, S. anginosus should be considered
true pathogens when isolated. Patients who
have had previous trauma, surgery, or who have
a history of diabetes or immunodeficiency are
most likely to get infections from the pathogen,
although this was not the case with our patient.¹
While initial studies linked the organism
to oral infections, S. anginosus can infect most
parts of the body including the head and neck;
the central nervous system; the abdomen in the
form of liver abscess, cholangitis, peritonitis,
appendicitis, subphrenic abscess, or pelvic ab-
scess; the thoracic cavity in the form of pneumo-
nia, mediastinitis, empyema, or lung abscess;
the heart (endocarditis); or as bacteremia in any
of the above-listed locations.¹
Volume 116 • Number 7
Figure 2.
Common treatments include drainage of the
abscess, most often surgically, and long-term an-
tibiotics. It should be noted that S. anginosus is
largely susceptible to B-lactams but resistance to
quinolones can develop easily.
In the thoracic cavity, S. anginosus has
significant morbidity and mortality rates. Typ-
ically, infection occurs most in men, alcoholics,
patients with cancer, or those with cystic fibro-
sis.² The infection is often complicated by pleu-
ral effusion or epyema.³
Antibiotic therapy with ceftriaxone is the
first-line treatment. However, monotherapy
with a beta-lactum/beta-lactamase inhibitor
can also be used.²
Conclusions
S. anginosus is a rare and often misdi-
agnosed medical problem. The bacterium is
often considered to be flora in the oral cavity,
oropharynx, gastrointestinal tract, and vagina,
but can cause infections throughout the body.
S. anginosus should be considered as part of a
differential diagnosis when abscess or bactere-
mia is present.
References
1. Gray T, Streptococcus anginosus Group: Clin-
ical Significance of an Important Group of
Pathogens. Clinical Microbiology Newsletter,
(27) 20:155-159.
2. Stratton C, Infections due to Streptococcus
anginosus (Streptococcus milleri) group. Up-
ToDate, June 2017.
Figure 3.
3. Noguchi S, Yatera K, Kawanami T, Yamasaki
K, Naito K, Akata K, Shimabukaro I, Ishimoto
H, Yoshii C, Mukae H. The clinical features of
respiratory infections caused by the Strep-
tococcus anginosus group. BMC Pulmonary
Medicine (2015) 15:133. •
January 2020 • 163