BETA-HEMOLYTIC STREPTOCOCCI

(catalase negative (-) (hydrogen peroxide) (bubble)

STREPTOCOCCI

are (_________________) meaning streptococci group of

organisms do not produce the enzyme catalase and so

once the grown colonies of an unknown Streptococci is

treated with (________________), expect that streptococci

organisms are distracted by such disinfectant.

• Remember that the catalase test is done to

differentiate staphylococci from streptococci

or vice versa.

Do not produce the enzyme catalase

When H2O2 is added to a streptococci and produces a

(____________), it is distracted by such disinfectant.

are gram-positive (+) organisms that grow in the chain

so that means the arrangement of streptococci under the

microscope is cocci in chains.

To qualify that it is correctly Streptococci, the chains that

should be seen in the morphology of the organism should

be long chains that should be 20 or more cocci

organisms arranged in chains

Streptococci family is a wide family there are a lot of

species under the Streptococci genus. Streptococci

organisms are grouped according to the hemolytic

pattern they produced in the blood agar medium.

(BETA-HEMOLYSIS) (yellow)

(_________________)

The complete destruction or lysis of the RBC, causing

discoloration in the blood agar medium which is (______).

(ALPHA-HEMOLYSIS) (brown)

(________________)

The Incomplete lysis of the RBC causing a (________)

discoloration to the blood agar medium.

GAMMA-HEMOLYSIS

• No hemolysis or discoloration to the blood agar medium

• Non-pathogenic streptococci

• Least studied streptococci

LANCEFIELD CLASSIFICATION

More Reliable Classification than the Brown

Classification

Based on Antigenic Group Specific C Substance

BROWN CLASSIFICATION

Groups them according to their hemolytic pattern

produced in the blood agar medium

group A, group B, group C, group D

GROUPING OF LANCEFIELD CLASSIFICATION

According to the Letters of the alphabet

(Streptococcus pyogenes) (Streptococcus agalactiae) (Streptococcus equisimilis) (Enterococci) ()

GROUP A STREPTOCOCCI (GAS)
GROUP B STREPTOCOCCI
GROUP C STREPTOCOCCI Composed of several Streptococci, usually not pathogenic to man o source of Streptokinase

GROUP D STREPTOCOCCI Least studied Streptococcus

Microscopic morphology/

Morphology evaluation:

Gram staining

→ > 20 cocci in a chain

→ Result: Cocci in chains

(Catalase Test:) (TSA)

→ Screening test

→ Provides supporting data

→ Medium is (___)

→ Result: Negative (no gas bubbles)

→ Medium is Blood agar

→ Result: Beta-hemolytic

Streptococci

Bacitracin Disc Test

Only confirmatory test

→ Medium is Blood agar

→ Result: Bacitracin

sensitive/susceptible or Bacitracin

resistant

Bacitracin sensitive

Group A beta-hemolytic

streptococci Streptococcus

pyogenes

Result: Zone of Inhibition is present

Bacitracin resistant

Group B beta-hemolytic streptococci

Streptococcus agalactiae

Result: No Zone of inhibition

(Christie, Atkinson, Munch, Peterson)

CAMP TEST

(Christie,

Streptococcus agalactiae

presumptive test

Atkinson, Munch,

Peterson)

→ Result: Arrowhead hemolysis

(positive)

(Trypticase Soy Agar (TSA) (Hydrogen Peroxide)

Catalase test is performed in a (___________________)

Inoculate with the unknown sample

Incubate for 24 hrs

After 24hrs, there will be colonies in (1) (____________)

Add or treat it with (_____________)

BACITRACIN DISC / BACITRACIN SENSITIVITY TEST

The only confirmatory test

Medium used is Blood agar medium

(Streptolysin O) (same time) (24)

Why Stab the Blood Agar?

To demonstrate the surface and subsurface hemolysis

in a blood agar medium

To prevent the destruction of (____________) by the

oxygen trapped at the base of the petri dish

After the microscopic morphology evaluation,

inoculate TSA and Blood agar at the (________)

Incubate them together for (_________) hours

When the catalase test is in support to the

microscopic morphology, check the hemolytic pattern

in the blood agar medium

(Streptolysin O) (Streptolysin S)

Beta-hemolytic streptococci produce hemolysins

(hemo: RBC, lysins: lysis)

Streptococcus pyogenes produces two (2) Hemolysins:

o (___________)

• Oxygen-labile

• easily destroyed by oxygen

o (___________)

• Oxygen-stable

• never destroyed by oxygen

(trapped at the base) (human blood/ sheep blood) (surface and sub-surface)

In making the blood agar, just before the main content or base

content is poured into the plate, the petri-dish is opened wide.

When the TSA is poured into the plate, oxygen molecules will be

(___________) of the petri-dish

When (___________) is added to the petri dish, it

becomes red.

The oxygen is trapped in the entire base

When inoculated with beta-hemolytic streptococci, it cannot

demonstrate clearly the (_____________) hemolysis

The streptolysin O (produced by the organism) gets destroyed due

to the trapped oxygen at the base

(susceptibility or sensitivity) (Group A beta-hemolytic

streptococci Streptococcus

pyogenes)

Presence of Zone of Inhibition around the

Bacitracin disc

Any size of zone of inhibition

indicates (________________)

Bacitracin susceptible:

o (_________________________)

Group B beta-hemolytic

streptococci Streptococcus

agalactiae

Absence of Zone of Inhibition around the

bacitracin disc

Confluent lawn of growth

Bacitracin resistant:

o (___________)

CAMP TEST (Christie, Atkins, Munch-Peterson Test)

Streptococcus agalactiae has a presumptive test that

will presumptively identify the organism.

Medium is Blood agar

A test wherein the beta-hemolytic Staphylococcus

aureus is straight in perpendicular to the beta-hemolytic

Streptococcus agalactiae. When there is a double zone of

hemolysis, described as arrowhead hemolysis between

the streakings of Staphylococcus aureus and

Streptococcus agalactiae, the test is considered to be

positive and that result is a presumptive identification of

Streptococcus agalactiae.

Positive CAMP Test

Double zone of hemolysis

Described as Arrowhead

hemolysis

Arrowhead between the

streakings of Staphylococcus

aureus and Streptococcus

agalactiae