Useful tips

What does Staphylococcus epidermidis do?

What does Staphylococcus epidermidis do?

Together with other micro-organisms, they produce substances from sweat, bringing about the body odour associated with perspiration. These bacteria, just like other Staphylococci cluster together like bunches of grapes. Staphylococcus epidermidis protects us from harmful bacteria, such as Staphylococcus aureus.

How do you identify a Staphylococcus species?

Staphylococcus aureus has traditionally been identified by tube coagulase tests that detect staphylocoagulase or “free coagulase”. However, detection of surface proteins such as clumping factor (slide coagulase test) and/or protein A (commercial latex tests) may be used for rapid identification.

Is Staphylococcus aureus PYR positive?

aureus are catalase and coagulase positive, only SIG species are PYR positive. Both are negative for ornithine decarboxylase. However, an ornithine-positive Staphylococcus species that also gives a positive reaction in latex agglutination and PYR testing is Staphylococcus lugdunensis.

What is the size of Staphylococcus epidermidis?

S. epidermidis cells are spherical (0.5–1.5 μm in diameter) and gram-positive.

What type of hemolysis is Staphylococcus epidermidis?

Staphylococcus is usually either beta hemolytic or not hemolytic at all (called gamma hemolysis). Pathogenic Staphylococci can produce a variety of virulence factors, including toxins,coagulase, leucocidins, and hydrolytic enzymes that can damage host tissues.

What is the epidemiology of Staphylococcus epidermidis?

epidermidis was responsible for 56 of the 184 infections which occurred in the unit during the study period (30.4%). More precisely, S. epidermidis accounted for 35 bloodstream infections (39.8%), 14 surface infections (29.8%), and 7 cases of meningitis (58.3%). Other less frequently isolated pathogens were S.

How can you tell the difference between S. aureus and epidermidis?

aureus is often hemolytic on blood agar; S. epidermidis is non hemolytic. Staphylococci are facultative anaerobes that grow by aerobic respiration or by fermentation that yields principally lactic acid. The bacteria are catalase-positive and oxidase-negative.

What is the PYR test?

PYR is a rapid colorimetic method for presumptive identification of enterococci and Group A Streptococcus based on the activity of the enzyme pyrolidonyl arylamidase. L-pyroglutamic acid beta-napthylamide is impregnated into the test disk and serves as the substrate for the detection of pyrolidonyl arylamidase.

How do you grow S. epidermidis?

Conditions for Growth: S. epidermidis is facultatively anaerobic and has a temperature range for growth from 15° to 45°C. However, the species grows best at 30° to 37°C in aerobic conditions.