BMS204 Infective Endocarditis SGD Flashcards

Vocabulary-style flashcards covering the diagnostic approach, microbial causative agents, and phenotypic identification methods for infective endocarditis.

Staphylococci

Gram-positive cocci arranged in clusters that are catalase test positive.

Streptococci

Gram-positive cocci arranged in chains that are catalase test negative.

Catalase test

A test performed by adding a colony to a drop of $3\%$ hydrogen peroxide; catalase-positive cultures produce $O_2$ bubbles.

Viridans group streptococci

Gram-positive cocci in chains that are a-hemolytic, forming a green zone around their colonies, and show resistance to optochin.

Pneumococci

Gram-positive diplococci that are a-hemolytic and susceptible to optochin.

Optochin test

A diagnostic test used to differentiate S.viridians (resistant) from S. pneumoniae (susceptible) using an optochin disk.

Enterococci

Gram-positive cocci that are part of the normal human intestinal flora, catalase negative, and grow on bile esculin medium producing a black color.

Staphylococcus aureus

A species that is coagulase positive, demonstrates $\beta$-hemolysis on blood agar, forms golden yellow colonies, and ferments mannitol.

Coagulase negative staphylococci (CONS)

Staphylococci such as Staphylococcus epidermidis that are non-hemolytic, produce white colonies, and do not ferment mannitol.

Mannitol salt agar (MSA)

A selective and differential medium where S. aureus produces yellow mannitol-fermenting colonies and S. epidermidis produces pink non-mannitol fermenting colonies.

Coagulase Test

A test used to differentiate Staphylococcus aureus (Coag +) from other staphylococci like S. epidermidis (Coag -).

Pseudomonas Spp.

Gram-negative bacilli that are catalase and oxidase-positive and produce non-fermenting colonies on Triple Sugar Iron agar.

Pyocyanin

A characteristic blue-green pigment produced by many Pseudomonas species, especially P. aeruginosa.

Oxidase test

A biochemical test used in the identification of Pseudomonas Spp., which are oxidase-positive.

Triple Sugar Iron (TSI) agar

A medium used to identify Pseudomonas Spp., which produce non-fermenting colonies on it.