Difference Between Epidermidis and Aureus

Thekey differencebetween epidermidis and aureus is thatStaphylococcus epidermidisis a non-haemolytic bacterium whileStaphylococcus aureusis a haemolytic bacterium.

Epidermidis and aureus are species names of two bacteria in the bacterial genusStaphylococcus.他们最常见的医疗device-mediated原因infections. Therefore, it is very important to understand their characteristics and the difference betweenepidermidisandaureus. Causatives, drug resistance, virulent factors, and identifying characteristics are different between S.aureusand S.epidermidis.

CONTENTS

1.Overview and Key Difference
2.What is Epidermidis
3.What is Aureus
4.Similarities Between Epidermidis and Aureus
5.Side by Side Comparison – Epidermidis vs Aureus in Tabular Form
6.Summary

What is Epidermidis?

Epidermidisis afacultative anaerobe. It is also agram-positivecoccus. The bacterium appears as a bunch of grapes-like colonies composed of round, small, and whitecolourraised colonies. They arenon-haemolyticin blood agar. Similar to otherstaphylococci, S. epidermidisis also catalase positive. However,S. epidermidisreacts negatively tothe coagulasetest and oxidase test. Furthermore,S. epidermidisshows a positive response forthe nitratereductase test and urease test.

Epidermidisis usually infected through catheters and implants sinceS. epidermidisbiofilms are able to grow on plastic devices placed inside the bodies. Furthermore, this bacterium commonly lives on the skin and mucosa as a commensal bacterium. However, it is not pathogenic unless the host has a weak immune system. In case of an infection, it is not easy to stop them through antibiotics. But it is also not impossible. The severe infections can go as high as up to deathly endocarditis.

What is Aureus?

Aureusis also a facultative anaerobic gram-positive coccus of the genus Staphylococcus. Similar toS. epidermidis, S. aureusalso appears as a bunch of grapes-like colonies. However, unlikeS. epidermidiscolonies,S. aureusproduces large, smooth, and round colonies, which are golden in colour. Furthermore, unlikeS. epidermidis, S. aureusshows haemolysis during their growth inblood agar. Also, this bacterium reacts positively to the catalase test, which is important to identify them fromEnterococciandStreptococci.One of the most important characteristics ofS. aureusis that this bacterium is coagulase positive.S. aureussynthesizes coagulase enzyme that causes clot formation. Thus, this feature is helpful in order to differentiate them from otherStaphylococcusspecies.

Aureusis a part of the normal skin flora and the nose as well. However, this bacterium is resistant to most antibiotics. The bacteria can produceenterotoxins, and these enzymes are the virulent factors that cause a vast range of diseases. Enterotoxins can destroy the mucosal cells of the intestine by changing the permeability of the apical membrane. Additionally, their infections can spread through contact with pus from infected wounds, direct skin contact, or clothes and towels, etc. They have a vast range of pathogenicity from simple pimples to deathlyendocarditis.

What are the Similarities Between Epidermidis and Aureus?

• Epidermidis and aureus are two bacterial species belonging to the same bacterial genus Staphylococcus.
• They are facultative anaerobes.
• Also, both are gram-positive.
• Additionally, they are commensal bacteria.
• Furthermore, they are spherical bacteria. Hence, they are cocci.
• Moreover, they cause the most common medical device-mediated infections.
• They are positive for the catalase test.
• Importantly, both their infections can become severe as endocarditis.

What is the Difference Between Epidermidis and Aureus?

Epidermidisis a nonhaemolytic bacterium whileS. aureusis a haemolytic bacterium on blood agar. So, this is the key difference betweenepidermidisandaureus.Furthermore, a significant difference betweenepidermidisandaureusis that theS. epidermidiscolonies are small, round and white in colour whileS. aureuscolonies are large, smooth and golden in colour. Also, another significant difference betweenepidermidisandaureusis that theS. epidermidisis coagulase negative whileS. aureusis coagulase positive.

In addition,S. epidermidisproduces biofilms whileS. aureusproduces enterotoxins.S. aureusis more virulent thanS. epidermidis. Moreover,S. aureusis resistant to a vast range of antibiotics whileS. epidermidisis not. Therefore, this also adds to the difference betweenepidermidisandaureus.

Below infographic summarizes the difference betweenepidermidisandaureus.

Summary – Epidermidis vs Aureus

Staphylococcusis a genus of gram-positive bacteria comprising over 40 species. Among them,S. epidermidisandS. aureusare two bacterial species which are facultative anaerobes and clinically important. Both species are part of the normal human flora. They become opportunistic pathogens in immune-compromised people.S. epidermidisis a nonhaemolytic bacterium whileS. aureusis a haemolytic. Therefore, this is the key difference betweenepidermidisandaureus. Also, another difference betweenepidermidisandaureusis thatS. epidermidisreacts negatively to coagulate test whileS. aureusreacts positively to the coagulase test. In addition,S. epidermidis能够产生生物膜的塑料表面whileS. aureusis able to produce enterotoxins. Furthermore,S. aureusshows resistance against a vast range of antibiotics whileS. epidermidisis not. Thus, this is a summary of the difference betweenepidermidisandaureus.

Reference:

1. “Staphylococcus Epidermidis.” Wikipedia, Wikimedia Foundation, 4 Feb. 2019,Available here.
2. Taylor, Tracey A. “Staphylococcus Aureus.” StatPearls [Internet]., U.S. National Library of Medicine, 27 Oct. 2018,Available here.

Image Courtesy:

1. “Staphylococcus epidermidis 01” By Janice CarrContent Providers(s): CDC/ Segrid McAllister – Centers for Disease Control and Prevention’s Public Health Image Library (PHIL), (Public Domain) viaCommons Wikimedia
2. “Staphylococcus aureus VISA 2” By CDC/ Matthew J. Arduino, DRPH, Photo Credit: Janice Haney Carr – from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL) (Public Domain) viaCommons Wikimedia