Streptococcus bacteremia

Background

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 and three Viridans group streptococci, 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
Streptococcus 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)

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
Alternatively, can use an approach based on species, number of positive blood culture bottles, and presence of risk factors (native valve disease, previous IE, prosthetic valve, or cardiac device)1

Risk	Species	<3 Bottles		≥3 Bottles
Risk	Species	No RFs	RFs	No RFs	RFs
low	Streptococcus intermedius	no echo			TTE
	Streptococcus pneumoniae
	Streptococcus pyogenes
moderate	Streptococcus agalactiae	no echo	TTE		TTE+TEE
	Streptococcus anginosus
	Streptococcus constellatus
	Streptococcus dysgalactiae
	Streptococcus salivarius
	Streptococcus thermophilus
high	Granulicatella adiacens	TTE	TTE+TEE
	Streptococcus mitis/oralis
	Streptococcus parasanguinis
very high	Streptococcus gallolyticus	TTE+TEE
	Streptococcus gordonii
	Streptococcus mutans
	Streptococcus sanguinis

a b Sandra Chamat-Hedemand, Anders Dahl, Lauge Østergaard, Magnus Arpi, Emil Fosbøl, Jonas Boel, Louise Bruun Oestergaard, Trine K. Lauridsen, Gunnar Gislason, Christian Torp-Pedersen, Niels Eske Bruun. Prevalence of Infective Endocarditis in Streptococcal Bloodstream Infections Is Dependent on Streptococcal Species. Circulation. 2020;142(8):720-730. doi:10.1161/circulationaha.120.046723.