(M) Lesson 7.3: Gram Positive and Gram Negative Cocci Flashcards by Kchianna Lauren Coronel

Gram-positive cocci in chains
Non-motile and non-sporeforming
Negative for catalase
Facultative anaerobe
Pinpoint colony

Streptococcus

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Laboratory diagnosis basis for suspected Streptococcus?

Hemolytic pattern in the BAP

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Also called Taxo A
Uses 0.04 units of Bacitracin
Done for beta-hemolytic Streptococcus
Confirms Streptococcus pyogenes
More important than PYR

Bacitracin Susceptibility Test (Taxo A)

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Bacitracin Susceptibility Test (Taxo A)

This species results in a susceptible result for Streptococcus pyogenes.

Note: Means highly susceptible to bacitracin and there is no ZOI requirement.

Streptococcus pyogenes

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Bacitracin Susceptibility Test (Taxo A)

These species results in resistance.

Note: Positive for PYR test

Enterococcus faecalis and other Streptococci

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Identifies Streptococcus pyogenes
Follow-up confirmatory test for Bacitracin test

PYR Test (L-pyrrolidonyl B-napthylamide)

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What is the principle of the PYR Test?

Streptococcus pyogenes reacts with PYR because of the added D-dimethylaminocinnamaldehyde

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PYR Test

These species test positive (red) for this test.

Streptococcus pyogenes
Enterococcus faecalis

Other Streptococci test negative.

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Principle: Streptococcus agalactiae reacts with CAMP factor that it releases an arrowhead zone of hemolysis upon interaction with the hemolysin of another

CAMP Test

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CAMP Test

Streptococcus agalactiae releases what type of zone of hemolysis?

Arrowhead

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CAMP Test

This bacteria is the only one that tests positive for CAMP test denoted by a unique arrowhead zone of hemolysis.

Streptococcus agalactiae

Other beta-hemolytic Streptococci test negative.

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Differentiates Streptococcus agalactiae from other beta-hemolytic cocci

Hippurate Hydrolysis Test

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Hippurate Hydrolysis Test

Streptococcus agalactiae releases ____ that hydrolyzes hippurate, resulting in a purple-colored cotton upon reaction with ninhydrin.

Hippurase

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Hippurate Hydrolysis Test

This is the only bacteria that tests positive for this test denoted by a purple complex.

Streptococcus agalactiae

Other beta-hemolytic Streptococci test negative.

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For alpha-hemolysis, green growth in BAP
Utilizes optochin

Optochin Test

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An antimicrobial agent
Specifically Taxo P

Optochin

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Optochin Test

P on antibiotic disk indicates?

Optochin

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Optochin Test

P10 on antibiotic disk indicates?

Penicillin

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Principle of Optochin Test?

Ethyldrocuprein hydrochloride (optochin) inhibits the growth of Streptococcus pneumoniae

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Optochin test

Zone of Inhibition must measure ____ or ____ depending on which Taxo P is used by the laboratory for it to be called susceptible.

greater than 16 mm or 14 mm

Other alpha-hemolytic Streptococci tests negative.

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Principle: Under the influence of bile salt (sodium deoxycholate) or detergent, the organism’s cell wall lyses during cell division
Streptococcus pneumoniae is bile-soluble

Bile Solubility Test

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Positive indicator for Bile Solubility Test?

A suspension of Streptococcus pneumoniae in a solution of sodium deoxycholate (lyses and the solution becomes clear)

Other alpha-hemolytic Streptococci test negative.

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For Group D Streptococci
Uses bile esculin agar
Principle: Group D streptococci and Enterococcus

Bile Esculin Hydrolysis Test

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These species can grow in the presence of bile and hydrolyzes esculin to esculetin and glucose.

Group D Strep and Enterococcus

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* **Principle:** Enterococcus, Aerococcus, and some species of Pediococcus and leuconostoc can withstand a higher salt concentration than other gram-positive cocci. * Differentiates enterococcus from non-enterococcus

Salt Tolerance Test

# Salt Tolerance Test Enterococcus, Aerococcus, and some species of Pediococcus and Leuconostoc are halo-tolerant until?

6.5% NaCl

* Identification of Pediococcus species and Leuconostoc species ## Footnote They disturb biochemical tests because they have similar reactions to Group D enterococcus.

Vancomycin Resistant

* Incubated at room temperature for 5 minutes * Enterococcus faecalis and Pediococcus test **positive (red)** * Leuconostoc species test **negative (yellow)**

Leucine Aminopeptidase Test (LAP Test)

* Incubated at 35°C for 48 hours * Enterococcus faecalis tests **positive (yellow)** * Enterococcus faecium tests **negative (green)**

Pyruvate Broth

* Leuconostoc tests **positive (gas formation)** * Pediococcus tests **negative (no gas)**

MRS Broth Test

____, ____, ____, and ____ tests for beta-hemolytic Streptococcus.

Bacitracin, PYR, CAMP, and Hippurate Hydrolysis Test

What are the six important Streptococci?

1. Streptococcus pyogenes 2. Streptococcus agalactiae 3. Enterococcus faecalis 4. Streptococcus bovis 5. Streptococcus pneomoniae 6. Viridans group

Classification based on hemolytic pattern or hemolysis

Smith and Brown's

# Identify the classification type based on the information provided. * **Bacteria:** Streptococcus pyogenes, Streptococcus agalactiate, Groups C, F, and G * **Tests:** Bacitracin, PYR, CAMP, Hippurate Hydrolysis

Beta-Streptococci

# Identify the classification type based on the information provided. * **Bacteria:** Streptococcus pneumoniae, Viridans group * **Tests:** Optochin, Bile Solubility

Alpha-Streptococci

# Identify the classification type based on the information provided. * **Bacteria:** Enterococcus faecalis, Enterococcus faecium, Streptococcus bovis * **Tests:** Bile Esculin Hydrolysis, Salt Tolerance

Gamma-Streptococci

# Identify the classification type based on the information provided. * Small alpha zone surrounded by beta zone

Alpha-prime

# Type of Classification * Confirmatory * Based on carbohydrates present on the cell wall of Strep unique to each one * Also used for serology

Lancefield Classification

What are the different classifications for Lancefield Classification?

* A: Rhamnose-N-acetylglucosamine *(S. pyogenes)* * B: Rhamnose-glucosamine polysaccharide *(S. galactiae)* * C: Rhamnose-N-acetylgalactosamine * D: Glycelor teichoic acid *(Entero and non-enterococcus)* * F: Glucopyranosyl-N-acetylgalactosamine

GABS mean?

Group A Beta Streptococcus

* Beta-hemolytic because of its carbohydrate * Colonies inhibited by Bacitracin on BAP * Bacitracin-susceptible * Gram positive cocci in chains * Catalase-negative * Positive for PYR

Group A Streptococcus

# Group A Streptococcus Resides in either ____ or ____

Human throat or skin

Infection here is transmitted via **direct contact**

Skin

# Group A Streptococcus If it resides here, it is spread via **droplets.**

Human throat

# If it resides here, it is spread via droplets What are the two cell-associated factors?

1. Hyaluronic Acid 2. M Protein

# Cell-Associated Factors * A polysaccharide * non-immunogenic, making it not medically important * Inhibits phagocytic uptake * Easily destroyed once bacteria is released to the environment

Hyaluronic Acid

# Cell-Associated Factors * Are hair-like projections * Major virulence factor * Anti-phagocytic * Antigenic * Used to type Group A strep

M Protein

# Cell-Associated Factors What are the two hemolysin toxins?

1. Streptolysin O 2. Streptolysin S

# Group A Streptococcus * Used in serology * Immunogenic * For RBC lysis * Oxygen-labile

Streptolysin O

# Group A Streptococcus * Non-immunogenic * Oxygen-stable * For RBC lysis

Streptolysin S

# Group A Streptococcus What are three exotoxins?

1. Pyrogenic/Erythrogenic 2. Phage-coded 3. Superantigen

# Group A Streptococcus * Allows it to produce fever during infection

Pyrogenic/Erythrogenic

# Group A Streptococcus * Cells are lysed by a phage

Phage-coded

* Causes fever and rash of scarlet fever * Inhibits liver clearance of endotoxin, creating shock-like conditions

Exotoxins A-C

# Group A Streptococcus * Activates many helper T-cells by bridging T-cell receptors and MHC class II markers without processed Ag

Superantigen

# Group A Streptococcus What are the three spreading factors?

1. Streptokinase (fibrinolysin) 2. Streptococcal DNAse (streptodornase) 3. Hyaluronidase

# Group A Streptococcus (Spreading Factors) * Breaks down fibrin clot

Streptokinase (fibrinolysin)

# Group A Streptococcus (Spreading Factors) * Liquefies pus, extension of lesion

Streptococcal DNAse (streptodornase)

# Group A Streptococcus (Spreading Factors) * Hydrolyzes the ground substances of the connective tissues * Important to spread in cellulitis

Hyaluronidase

____ indicates presence of lesions and pus formation

Suppurative

* Pharyngitis * Scarlet fever * Pyoderma/Impetigo * Cellulitis, necrotizing fasciitis (flesh-eating bacteria), puerperal fever, lymphangitis, pneumonia, toxic shock-like syndrome

Acute (Suppurative) Infection

Most common cause of Acute (Suppurative) Infection

Streptococcus pyogenes

This means "no bacteria present, only its Ag"

Non-suppurative

This means "there is a prior infection"

Sequelae

* Diagnosed through serology, specifically Anti-streptolysin O (ASO)

Non-suppurative Sequelae to Group A Streptococcal Infections

* Medical term for sore throat * Abrupt onset of sore throat * Fever * Malaise * Headache * Tonsillar abscesses * Tender anterior cervical lymph nodes * **Detection:** Serological or rapid antigen test, hard to culture

Pharyngitis

* Pus-forming skin infection *(honey-crusted lesions)* * Can be caused by **Staphylococcus aureus** or **Streptococcus pyogenes**

Pyoderma/Impetigo

* Brawny edema * Advancing margin of erro

Erysipelas (Infection)

* Initially starts with a deep wound that is not treated properly * It also contains S. aureus, Pseudomonas, and anaerobes, but predominantly S. pyogenes (flesh-eating bacteria)

Necrotizing Fascilitis

* Has signs and symptoms similar to the pharyngitis (except it has rashes observed on the lower extremities) * Pastia lines (darkening of groin and armpit area) * Triad *(highly diagnostic to scarlet fever: rash, pastia lines, strawberry tongue)*

Scarlet Fever

* **Sequelae to:** pharyngitis with group A Strep (not Group C) * **Mechanism:** in genetically susceptible individuals, the infection results in production of Ab that crossreact with cardiac antigen * Symptoms usually occur 2-3 weeks after pharyngeal infection

Rheumatic Fever

# Determine the test for rheumatic fever. * J → joints (Migratory arthritis) * <3 carditis * N → subcutaneous nodules * E → erythma marginatum * S → sydenham chorea

Jones Criteria (J<3NES)

# Determine the test for rheumatic fever. * Fever * Arthralgias * Elevated acute phase reactants

Minor Jones Criteria

What must be needed for the diagnosis of rheumatic fever?

* 2 major or 1 major * 2 minor Jones criteria

* **Sequelae** to pharyngitis or cutaneous streptococcal infection * **Mechanism:** immune complexes bound to glomeruli * Kidneys are affected

Acute Glumerolonephritis

# Group A Streptococcus What are the three treatments?

* Penicillin G → drug of choice *(also prevents recurrent Streptococcus pyogenes)* * Beta-lactam drugs * Erythromycin

# Group A Streptococcus What is the diagnosis?

Taxo A

What are the two species under Group B Streptococcus?

1. Streptococcus agalactiae 2. GBS

* Beta-hemolytic * Bacitracin-resistant in BAP * Gram-positive cocci in chains * Catalase-negative * Camp test-positive (CAMP)

Group B Streptococcus

* Colonizes the ____ in 15-20% of women

Human vagina

# Group B Streptococcus What are the two manners of transmission?

1. Newborn infected during birth 2. Increased with prom

# Group B Streptococcus Serve as the main virulence factor

Beta-hemolysin

When should we treat a mother prior to delivery?

* She had a previous baby with GBS * Has documented GBS colonization * Prolonged rupture of membranes

* Alpha-hemolytic * Optochin-susceptible on BAP * Gram-positive lancet-shaped diplococci or in very short chains * Lysed by bile (bile-soluble)

Streptococcus pneomoniae

What are the diseases associated with Group B Streptococci?

1. Neonatal septicemia 2. Neonatal meningitis

Treatment for Group B Streptococci?

Ampicillin with Cefortaxime or Gentamicin

Reservoir for Streptococcus pneumoniae?

Human upper respiratory tract

Transmission of Streptococcus pneumoniae?

Respiratory droplets ## Footnote Often colonizes without causing disease

# Identify the pathogenesis (S. pneumoniae) For attachment

Teichoic acid

# Identify the pathogenesis (S. pneumoniae) Main major virulence

Polysaccharide capsule

# Identify the pathogenesis (S. pneumoniae) * Characteristic of its sputum * Due to the release of fluid and red and white cells stimulated by pneumococcus in alveoli

Rusty-colored sputum

# Identify the pathogenesis (S. pneumoniae) * Damages respiratory epithelium * It inhibits leukocyte respiratory burst and inhibits classical complement fixation

Pneumolysin O

# Identify the pathogenesis (S. pneumoniae) Highly inflammatory in CNS

Peptidoglycan/Teichoic acid

Most common cause especially in >65yrs, but also in infants

Streptococcus pneumoniae

* Prevented by pneumococcal vaccines that specifically target S. pneumoniae * **Symptoms:** Big shaking chills, sharp pleural pain, high fever (characteristic) * Lobar with productive blood-tinged sputum (rusty-colored)

Bacterial Pneumoniae

Makes an individual susceptible to pneumonia by S. pneumoniae

Predisposing conditions for Pneumonia

* Due to teichoic acid that can pass through the CNS * Most common cause among >40 y/o

Adult Meningitis

* Most common cause * Otitis media → infection of the ears

Otitis Media and Sinusitis in children

* In splenectomized patients

Septicemia

Treatment for Streptococcus Pneumoniae?

* Penicillin G * Resistance due to chromosomal alteration in penicillin-binding proteins *(treat with Vancomycin and Rifampin)* * Prevented with vaccination

The only streptococcus without Lancefield classification

Streptococcus pneumoniae

Three species under Viridans streptococci?

Streptococcus singuis Streptococcus mutans Streptococcus mitis

* Alpha-hemolytic * Optochin-resistant * G(+) in chains * Not bile-soluble

Viridans Streptococci

Reservoir for Viridans Streptococci?

Human oropharynx (as normal flora, more predominant in URT)

* Caused by S. mutans * Dextran-mediated adherence glues oral flora onto teeth, forming plaque and causing caries

Dental Carries

* Catalase-negative * PYR positive * Hydrolyzes esculin in 40% bile * Halo-tolerant (can grow under 6.5% NaCl)

Enterococcus (Group D Streptococcus)

* **Symptoms:** Malaise Fatigue Anorexia Night sweats Weight loss

Subacute infective endocarditis

What are the predisposing factors for Viridans streptococci?

* Makes an individual highly susceptible * Damage (or prosthetic) heart valve * Dental work w/o prophylactic antibiotics * Extremely poor oral hygiene

Pathogenesis for Viridans streptococci?

Dextran (biofilm)-mediated adherence

Treatment for Viridans Streptococci?

Penicillin G with aminoglycoside for endocarditis

Also called Streptococcus faecalis Group D, G(+) cocci in chains PYR (+) Catalase (-) Varied hemolysis Hydrolyzes esculin in 40% bile Grows in 6.5% NaCl

Enterococcus faecalis

Reservoir for Enterococcus faecalis?

* Human colon * Urethra * Female genital tract

Henlo, please look at the pathogenesis for Enterococcus faecalis <3

IDK HOW TO CARDS IT

What are the diseases associated with Enterococcus faecalis?

1. Urinary, biliary tract infection 2. Infective endocarditis (SBE)

T or F: Some vancomycin-resistant strains of Enterococcus faecium or E. faecalis have no reliable effective treatment

Familiarize yourself with the prevention for E. faecalis

Prophylactic use of beta-lactam drugs: penicillin and gentamicin in px w/ damaged heart valves prior to intestinal or urinary tract manipulation

What are the two important Non-Enterococci?

1. Streptococcus bovis 2. Streptococcus equinus

Hi, madaming table for Non-Enterococci, please just study them.

GOOOO (OR GO TO THE NEXT DECK IDK)

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(M) Lesson 7.3: Gram Positive and Gram Negative Cocci Flashcards

Streptococcus

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