streptococcus

American  

[strep-tuh-kok-uhs] / ˌstrɛp təˈkɒk əs /

noun

Bacteriology.

streptococci plural

1. any of several spherical or oval bacteria of the genus Streptococcus, occurring in pairs or chains, certain species of which are pathogenic for humans, causing scarlet fever, tonsillitis, etc.

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streptococcus British  

/ ˌstrɛptəʊˈkɒkəl, -ˈkɒksɪk, ˌstrɛptəʊˈkɒkəs, ˌstrɛptəʊˈkɒkɪk /

noun

1. Often shortened to: strep.  any Gram-positive spherical bacterium of the genus Streptococcus, typically occurring in chains and including many pathogenic species, such as S. pyogenes, which causes scarlet fever, sore throat, etc: family Lactobacillaceae

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streptococcus Scientific  

/ strĕp′tə-kŏk′əs /

streptococci plural

1. Any of various bacteria of the genus Streptococcus that are gram-positive cocci and are normally found on the skin and mucous membranes and in the digestive tract of mammals. One type of streptococcus, Group A, is a common pathogen in humans and causes various infections, including strep throat, scarlet fever, pneumonia, and some types of impetigo.

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streptococcus Cultural  

1. A category of bacteria that can cause various infections in humans, including scarlet fever and strep throat.

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Other Word Forms

Derived Forms

• streptococcal
  adjective
• streptococcic
  adjective

Inflected Forms

Nouns

• streptococci
  plural

Etymology

Origin of streptococcus

From New Latin, dating back to 1875–80; see origin at strepto-, coccus

Example Sentences

See Examples For:

streptococcus streptococci

A jury inquest which concluded on 8 October 2025 found the medical cause of death to be an "invasive streptococcus pyogenes infection following male circumcision".

From BBC ● Jan. 2, 2026

And she decides that the bacteria she’s going to target with her vaccine is hemolytic streptococcus, which had been showing up again and again in flu patients.

From Scientific American ● Oct. 19, 2023

"High numbers of scarlet fever, which is caused by group A streptococcus, also continue to be reported."

From BBC ● Jan. 2, 2023

Some U.S. hospitals and European health authorities also report out-of-season increases in scarlet fever and Group A streptococcus infections.

From Washington Post ● Dec. 15, 2022

Pick off streptococcus colonies and subcultivate upon nutrient agar exactly as directed in steps 14, 15 and 16.

From The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. by Eyre, J. W. H. (John William Henry)

However, arginine treatment led to a significant reduction in the mitis/oralis group of streptococci.

From Science Daily ● Jan. 9, 2026

And it suggests that hemolytic streptococci vaccines provided “significant protection” against pneumonia and mortality.

From Scientific American ● Oct. 19, 2023

The scratch became infected by streptococci and staphylococci and spread to his eyes and scalp, according to “The Mold in Dr. Florey’s Coat.”

From Washington Post ● Jul. 11, 2020

Necrotizing fasciitis can be caused by group-A streptococci or by staphylococci, common bacteria that live on people's skin and in their noses, he said.

From Reuters ● May 17, 2012

The toxins of diphtheria bacilli and streptococci are produced when the organisms have been infected by bacteriophage; it is the virus that provides the code for toxin.

From "The Lives of a Cell" by Lewis Thomas