Streptococcus bacteremia

Background

Risk of Infective Endocarditis

• Among all patients with Streptococcus bacteremia, the prevalence of infective endocarditis is about 7%1
  • This varies greatly by species, with the highest-risk species being Streptococcus gallolyticus, Streptococcus sanguinis, Streptococcus gordonii, and Streptococcus mutans

Species	Risk of IE	Number of BSIs
Streptococcus pneumoniae	1.2%	2,598
Streptococcus dysgalactiae	6.6%	901
Streptococcus pyogenes	1.9%	592
Streptococcus agalactiae	9.1%	441
Streptococcus anginosus group	4.8%	437
Streptococcus mitis or oralis	19.4%	408
Streptococcus gallolyticus	30.7%	225
Streptococcus salivarius	5.8%	191
Streptococcus sanguinis	34.6%	133
Streptococcus parasanguinis	10.3%	107
Streptococcus gordonii	44.2%	95
Streptococcus constellatus	<4%	91
Streptococcus mutans	47.9%	48
Streptococcus thermophilus	<4%	45
Granulicatella adiacens	12.2%	41
Streptococcus intermedius	0%	40
Streptococcus vestibularis	low	26
Streptococcus lutetiensis	low	23
Streptococcus infantarius	low	14
Streptococcus equinus	low	12
Streptococcus peroris	0	10
Streptococcu cristatus or sinensis	44%	9
Streptococcus massiliensis	0	5
Granulicatella elegans	0	5
Streptococcus pluranimalium	0	<4
Streptococcus equi	0	<4
Streptococcus sobrinus	0	<4
Streptococcus suis	0	<4
Streptococcus alactolyticus	0	<4

• Other risk factors include ≥3 positive BC bottles, prosthetic valve, native valve disease, cardiac device, previous endocarditis, and male sex (in descending order of important)

Investigations

• For non-β-hemolytic streptococci, consider using the HANDOC score to risk stratify for need for echocardiography
  • Can effectively exclude the diagnosis of IE without needing imaging