Streptococcus and enterococcus identification

Media

1 BAP or sheep blood agar

Beta Streptococcus Group A bacteria are

1. beta hemolytic 2. bacitracin sensitive 3. SXT resistant.

Bacteria

BAP w S. pneumonia and enterococcus

Growth in 6.5% salt broth differentiates between Enterococcus sp. and Streptococci Gr. D. Enterococcus because

Enterococcus sp. grows in high salt concentrations and Streptococci Gr. D. Enterococcus does not

Beta Streptococcus Group B

Streptococcus agalactiae (genus and species)

Beta Streptococcus Group B

These bacteria cause infections in neonates resulting in septicemia, pneumonia, or meningitis.

Streptococcus Group D bacteria

are normal flora of many sites of the body, and rarely cause serious infections.

Viridans Streptococcus

are normal flora of mucous membranes. This bacteria causes dental caries (cavities) and sometimes endocarditis.

Beta Streptococcus Group B bacteria

are usually beta hemolytic and give a positive result with the CAMP test.

Growth in 6.5 % NaCL broth is indicated

by a distinct cloudy appearance to the media

Strep GR. D bacteria

can be alpha, beta, or gamma

Streptococci and enterococci are

common inhabitants of the environment and are normal flora in many sites of the body. However, some can be pathogenic resulting in serious infection.

Some bacteria produce a factor called CAMP factor which

enhances the beta hemolytic activity of Staph aureus on BAP.

Enterococcus species

frequently can cause urinary tract, intra-abdominal and wound infections.

Streptococci and Enterococci (family streptococcaceae) are classified as gram __

gram positive cocci usually occuring in pairs or chains.

equipment

inoculating loop, forceps, bunsen burner

Bacitracin

is a antimicrobial agent. The Bacitracin test aids in differentiating Beta Strep Gr. A-sensitive to bacitracin from other Beta Streptococci but the SXT disc test is needed too.

SXT

is a antimicrobial agent. The SXT test aids in differentiating Beta Strep Gr. A-(resistant) to SXT to other Beta Streptococci but the bacitracin test is needed too.

Streptococcus pneumoniae

is the most common cause of bacterial pneumonia. This bacteria causes bacteremia and meningitis. Also, always Alpha hemolytic.

Enterococcus species -(previously called Streptococcus ) bacteria are

normal flora of the gastrointestinal tract, and the bacteria may cause sub-acute bacterial endocarditis. The bacteria can be alpha, beta, or gamma hemolytic.

The inhibition of S. pneumonia by

optochin differentiates this bacterium from other Streptococci.

Viridans Streptococcus

produce negative results with optochin, bile esculin, and salt test, and this bacteria may be alpha or gamma hemolytic.

Beta Streptococcus Group B commonly causes

puerperal sepsis, female genital tract infections, and urinary tract infections.

On Bap, the colonies appear

small and translucent.

Beta Streptococcus Group A (Streptococcus pyogenes (genus and species) infections include

strep throat, acute endocarditis, acute glomerulonephritis, scarlet fever, rheumatic fever, septicemia, pneumonia, erysipelas, and many other illnesses.

Streptococcus Group D are common cause of

sub-acute bacterial endocarditis.

Differentiating Strep GR. D from other streptococci and enterococci involves using

the bile esculin test (positive) and 6.5 % salt test (negative).

These genera vary in

the hemolysis of red blood cells and are catalase negative.

Esculetin reacts with ferric ions in

the medium to produce a blackening of the medium. A positive must have at least half of the medium turning dark. Less than that is negative.

Differentiating Enterococcus from Strep GR D require

the use of bile esculin (positive) and the 6.5 % salt broth (positive).

6.5 % NaCL broth test determines

whether an organism can grow in a high salt environment.