Strep pg 1-6 200QS

Gram (+) cocci in chains

What is the Gram reaction and morphology of Streptococcus species?

Grayish pinpoint translucent colonies

What type of colonies do Streptococcus species form on Blood Agar Plate (BAP)?

Capsule

What structure is present in young colonies of Streptococcus?

Catalase (-)

What is the catalase reaction for Streptococcus species?

Non-motile (NM) and non-sporeforming (NS)

What are the motility and spore-forming characteristics of Streptococcus species?

Capnophilic (5-10% CO2)

What atmospheric condition promotes the growth of Streptococcus?

Oxidase (-)

What is the oxidase reaction for Streptococcus species?

Insoluble in bile

does not ferment inulin

Blood Agar Plate (BAP)

What is the medium of choice for growing Streptococcus?

Phenylethyl Alcohol Agar (PEA)

What is the selective medium used for isolating Streptococcus?

LAP Test (Leucine Aminopeptidase)

What test is used as a presumptive test for catalase-negative Gram-positive cocci?

Leucine-beta-naphthylamide

What substrate is used in the LAP test?

Cinnamaldehyde

What reagent is added in the LAP test?

Red

What color indicates a positive result in the LAP test?

Slight yellow/Colorless

What color indicates a negative result in the LAP test?

Lancefield Classification

What classification system serogroups Streptococcus using known antibodies to cell wall carbohydrates?

Rhamnose-N-acetylglucosamine

What is the specific cell wall carbohydrate for Lancefield Group A?

Rhamnose-glucosamine polysaccharide

What is the specific cell wall carbohydrate for Lancefield Group B?

Rhamnose-N-acetylgalactosamine

What is the specific cell wall carbohydrate for Lancefield Group C?

Glycerol teichoic acid

What is the specific cell wall carbohydrate for Lancefield Group D?

Glucopyranosyl-N-acetylgalactosamine

What is the specific cell wall carbohydrate for Lancefield Group F?

Peptidoglycan and Teichoic acid

What are the two main structural layers/components of the streptococcal cell wall?

Hyaluronic acid

What is the main component of the streptococcal capsule that prevents phagocytosis?

Pediococcus, Aerococcus, Gemella, Enterococcus, Globicatella, Alloiococcus, Leuconostoc, Lactococcus

What acronym represents the organisms that resemble streptococci (PAGE GALL)?

Group B Strep (Streptococcus agalactiae)

All streptococci and related organisms are negative for hippurate hydrolysis except which group?

Group C, G, and D

Which streptococcal groups are found as normal flora of the skin, nasopharynx, GIT, and genital tract?

Beta hemolysis

What type of hemolysis is exhibited by Streptococcus pyogenes?

Group A

What is the common term used for Streptococcus pyogenes?

Beta hemolysis

What type of hemolysis is exhibited by Streptococcus agalactiae?

Group B

What is the common term used for Streptococcus agalactiae?

Beta hemolysis

What type of hemolysis is exhibited by Streptococcus dysgalactiae and Streptococcus equi?

Group C

What common Lancefield group do S. dysgalactiae and S. equi belong to?

Alpha, gamma, or non-hemolytic

What hemolytic patterns can be shown by the Streptococcus bovis group?

Group D non-enterococcus

Is the Streptococcus bovis group classified as enterococcus or non-enterococcus?

Enterococcus faecalis and Enterococcus faecium

Name two species belonging to the Group D enterococcus classification.

Alpha, Beta, or gamma hemolysis

What hemolytic patterns can Enterococcus faecalis and faecium exhibit?

Alpha hemolysis

What type of hemolysis is produced by Streptococcus pneumoniae?

Pneumococcus

What is the common term for Streptococcus pneumoniae?

Viridans strep

What group of streptococci includes Anginosus, Mutans, Mitis, and Salivarius?

Smith & Brown Classification

What classification system categorizes streptococci based on their hemolytic pattern on blood agar?

Beta hemolysis

What type of hemolysis causes complete and clear zone of lysis?

Alpha hemolysis

What type of hemolysis causes partial lysis with a greenish discoloration?

Gamma hemolysis

What type of hemolysis shows no breakdown of red blood cells?

Alpha prime-alpha

What type of hemolysis displays an inner zone of intact red cells and an outer zone of complete beta hemolysis?

Hydrogen peroxide

Alpha hemolysis is caused by what substance produced by bacteria that oxidizes hemoglobin?

Green methemoglobin (biliverdin)

Oxidation of hemoglobin during alpha hemolysis turns it into what greenish pigment?

Leuconostoc

Name a vancomycin-resistant, LAP-negative organism that resembles streptococci.

Pediococcus

Name a vancomycin-resistant, LAP-positive organism that resembles streptococci.

Academic or Bergey's Classification

What classification system categorizes streptococci based on temperature requirements for growth?

Pyogenic group

Which temperature group of streptococci grows only at 37°C and produces pus?

Streptococcus pyogenes

Name the primary representative organism of the Pyogenic group.

45°C and 37°C

At what temperatures can members of the Viridans group grow?

S. mutans, S. salivarius, S. mitis, S. sanguis

Name four species belonging to the Viridans group of streptococci.

45°C, 10°C, and 37°C

At what temperatures can members of the Enterococci group grow?

Enterococcus faecalis

Which Enterococcus species is part of the normal flora of the human intestine and commonly causes opportunistic UTIs?

10°C and 37°C

At what temperatures can members of the Lactic group grow?

Streptococcus lactis

Which species belongs to the Lactic group and is often found in dairy products?

Streptococcus pyogenes (Group A Streptococcus)

What organism is considered the most serious streptococcal pathogen?

Sensitive

What is the susceptibility of Streptococcus pyogenes to 0.04 units of Bacitracin?

PYR (+)

What is the PYR test result for Streptococcus pyogenes?

Throat and skin

What are the primary reservoirs of Streptococcus pyogenes in humans?

Direct contact and respiratory droplets

What are the modes of transmission (MOT) for S. pyogenes?

M protein

What is the major antiphagocytic virulence factor of S. pyogenes attached to peptidoglycan?

Gene emm

What gene codes for the M protein in S. pyogenes?

Mucoid colonies

What type of colonies are formed by encapsulated/mucoid strains of S. pyogenes?

Rheumatogenic M protein

What type of M protein is associated with post-streptococcal rheumatic fever?

Nephritogenic M protein

What type of M protein is associated with acute glomerulonephritis?

Protein F (Fibronectin-Binding Protein)

What surface protein of S. pyogenes acts as an adhesion molecule that binds fibronectin?

Streptolysin O

What hemolysin of S. pyogenes is oxygen-labile and active only in its reduced form?

Streptolysin O

Which streptococcal hemolysin is highly antigenic and stimulates the production of ASO antibodies?

Streptolysin O

Which hemolysin is responsible for subsurface hemolysis on BAP?

Streptolysin S

What hemolysin of S. pyogenes is oxygen-stable and responsible for surface hemolysis in aerobic conditions?

Non-antigenic

Is Streptolysin S antigenic or non-antigenic?

Streptokinase

What enzyme produced by S. pyogenes dissolves or digests fibrin clots to promote the spread of infection?

Plasminogen

Streptokinase converts which plasma precursor into plasmin?

Streptococcal DNase (Streptodornase)

What enzyme degrades DNA, liquefies pus, and promotes lesion extension?

DNase B

What is the most common form of streptococcal DNase?

Pyogenic exotoxin A

What toxin increases sensitivity to endotoxin by 10^5-fold and causes uncontrollable secretion of cytokines?

Streptococcal toxic shock syndrome

What severe condition is caused by Pyogenic exotoxin A?

Erythrogenic / Pyrogenic Toxin B

What extracellular toxin (Exotoxin B) degrades proteins and acts as a cysteine protease in "flesh-eating" streptococci?

Hyaluronidase

What enzyme solubilizes hyaluronic acid and is known as the "spreading factor"?

SMASHED (Streptolysin O, M protein, Anti-C5a peptidase, Streptokinase, Hyaluronidase, Endotoxin, DNase)

What acronym summarizes the virulence factors of Streptococcus pyogenes?

Cleaves complement component C5a to inhibit neutrophil recruitment

What is the function of the anti-C5a peptidase virulence factor?

It masks Pathogen-Associated Molecular Patterns (PAMPs) so it remains unrecognized

Why does the hyaluronic acid capsule allow S. pyogenes to evade host immunity?

Hyaluronic acid

What is the binding substance in human connective tissue that hyaluronidase acts upon?

Strep throat / pharyngitis

What acute infection caused by S. pyogenes is common in children aged 5 to 15 and manifests with fever, headache, and lymphadenopathy?

Erysipelas

What inflammatory skin infection of the dermal layer is also known as "St. Anthony's Fire"?

Impetigo (Pyoderma)

What superficial skin disease begins as small vesicles, progresses to weeping lesions, and is commonly called "honey-crusted lesions"?

Young children aged 2 to 5 years old

What age group is most commonly affected by impetigo?

Cellulitis

What severe condition can develop following deeper tissue invasion by streptococci, potentially leading to gangrene in diabetic patients?

Scarlet fever

What disease is characterized by pharyngitis followed by a blanching, "sandpaper" rash and a "strawberry tongue"?

Redness (erythema) and rash (exanthem) on upper chest spreading to trunk/extremities

What are the two cardinal signs of Scarlet Fever rash?

Dick's Test

What diagnostic skin test measures susceptibility to Scarlet Fever by injecting 0.1 ml erythrogenic toxin?

Erythema / redness (> 1 cm) at the test site

What result in Dick's Test indicates susceptibility to Scarlet Fever?

Schultz-Charlton Reaction (Blanche Phenomenon)

What diagnostic test uses an injection of anti-erythrogenic toxin to determine if a rash is caused by Scarlet Fever?

Disappearance/blanching of the rash within 6-8 hours

What is a positive result in the Schultz-Charlton test?

Flesh-eating disease / Hospital gangrene / Suppurative fasciitis / Necrotizing erysipelas

What is another term for Type 2 Necrotizing Fasciitis caused by S. pyogenes?

Type 1 NF

What type of Necrotizing Fasciitis is polymicrobial and can be caused by Vibrio species in saltwater-contaminated wounds?

Gas gangrene / Clostridial myonecrosis (caused by Clostridium perfringens)

What condition is classified as Type 3 Necrotizing Fasciitis?

Rheumatic fever

What post-streptococcal sequela occurs specifically following Group A streptococcal pharyngitis?