[BIO 120.3] Q1: Gram Positive Cocci - Streptococci

Streptococci, Staphylococci

What are 2 groups of Gram (+) cocci?

catalase (+), Gram (+), cocci

GEN: Staphylococcus: catalase, Gram, shape

catalase (-), Gram (+), cocci

GEN: Streptococcus: catalase, gram, shape

Streptococcus are chained spheres, Staphylococcus are clustered spheres

In terms of general basic morphology, how can we differentiate Streptococcus and Staphylococcus?

Group A, Group B, Group D, Viridans Group, S. pneumoniae

What are 5 groups under streptococci?

S. aureus, S. epidermidis, S. saprophyticus

What are 3 groups under staphylococci?

Lancefield Classification

Classification scheme wherein streptococci are classified according to antigenic characteristics of the C carbohydrate (cell wall)

More than 18 groups (A-S)

The Lancefield Classification has how many groups?

TRUE

T/F: Aside from Lancefield classification, Streptococci may be divided based on Hemolysis, Biochemical Reactions, Growth Characteristics, Genetic Studies, and Other Antigenic Reactions

FALSE

T/F: Aside from Lancefield classification, Staphylococci may be divided based on Hemolysis, Biochemical Reactions, Growth Characteristics, Genetic Studies, and Other Antigenic Reactions

Antigenic characteristics of the C carbohydrate (cell wall)

What is the basis of the Lancefield classification?

Cocci arranged in chains

What is the cell structure morphology of Streptococcus spp.?

Hemolytic: B-hemolytic, A-hemolytic, G-'hemolytic'

What is the culture morphology (hemolysis) of Streptococcus spp. (general)?

Complete (clear zones)

Describe B-hemolytic cultures

Partial (greenish discoloration)

Describe A-hemolytic cultures

Non-hemolytic

Describe Gamma hemolytic cultures

S. pyogenes

What is the primary example of Group A streptococcus?

less than 3 months

The age range of neonates is?

S. agalactiae

What is the primary example of Group B streptococcus?

Enterococci

What is the primary example of Group D streptococcus?

S. mutans, S. intermedius

What are 2 examples of Streptococci under Viridans?

Catalase (-), Microaerophilic, B-hemolysis caused by Streptolysin O (oxygen-labile) and S (oxygen-stabile)

What is the culture characteristics of Group A: Streptococcus pyogenes? Based on:
- Catalase reaction
- Oxygen usage
- Hemolysis

Pus Production

What is the hallmark of S. pyogenes?

M-protein, Lipoteichoic acid, Streptolysin O and S, Streptokinase, Hyaluronidase, Exotoxins (Erythrogenic or Pyrogenic)

What are the pathogenesis/virulence factors of the Group A: S. pyogenes?

M-protein, Lipoteichoic acid

What virulence factor/s of S. pyogenes functions as an adherence factor?

Adherence factor, antiphagocytic, antigenic

What are three characteristics of the M-protein for S. pyogenes?

Erythrogenic or Pyrogenic Toxin

What toxin of S. pyogenes can cause scarlet fever and TSS?

Overproduction of cytokines

What do erythrogenic or pyrogenic toxin stimulate?

Superantigen

The erythrogenic or pyrogenic toxin produced by S. pyogenes is what kind of exotoxin?

Clue: Cytokine overproduction is an aspect of this kind of exotoxin.

Pharyngitis, Skin Infections, Scarlet Fever, Toxic Shock Syndrome

What are the 5 clinical findings for direct invasion of Group A: S. pyogenes?

Pharyngitis

Clinical finding in S. pyogenes: swollen tonsils with pus

High dose Penicillin with Clindamycin, Erythromycin (for allergic to penicillin)

What are the possible treatments for S. pyogenes-caused strep throat or pharyngitis?

Gram Stain, Culture, Throat Swab

What are three possible ways for diagnosis of Pharyngitis that is caused by S. pyogenes?

Impetigo, Pyoderma, Cellulitis, Necrotizing Fasciitis, Fournier's Gangrene

What are 6 skin infections caused by S. pyogenes?

Impetigo

S. pyogenes Clinical Finding: Initially starts as painful, bright rashes that eventually swell and break out; primarily affects children

Pyoderma

S. pyogenes Clinical Finding: Starts off as pustules and eventually becomes flaky and scab-like

Cellulitis

S. pyogenes Clinical Finding: Swelling of deep tissues, appear as blackish red, and hot to the touch

Necrotizing Fasciitis

S. pyogenes Clinical Finding: Flesh eating bacteria

Fournier's Gangrene

S. pyogenes Clinical Finding: Flesh eating bacteria that affects scrotum and anus

Children and young adults (5 - 15 years old)

Scarlet Fever primarily affects what age range?

Pharyngitis

Scarlet fever commonly starts as what disease?

Areas of body with folds

Rashes caused by Scarlet Fever are prominent in what areas of the body?

Strawberry tongue syndrome

Distinctive characteristic of the Scarlet Fever?

Penicillin (erythromycin), Amoxicillin, Clindamycin

What are the three treatments for Scarlet Fever?

Gram stain, culture, throat swab

What are the diagnostics for Scarlet fever?

FALSE

T/F: Between S. aureus and S. pyogenes, TSS is more associated with S. pyogenes.

TRUE

T/F: Between S. aureus and S. pyogenes, TSS is more associated with S. aureus.

Penicillin (erythromycin), Amoxicillin, Clindamycin

What are the three treatments for TSS caused by S. pyogenes?

Gram Stain, Culture

What are two diagnostic methods for TSS caused by S. pyogenes?

TRUE

T/F: Rheumatic fever is not a direct invasion type of clinical finding for S. pyogenes

FALSE

T/F: Rheumatic fever is a direct invasion type of clinical finding for S. pyogenes

Delayed antibody-mediated disease

Rheumatic fever is what kind of clinical finding?

heart

What organ does rheumatic fever affect?

Heart has antigens similar to S. pyogenes, so the immune system gets confused when attacking.

Why does rheumatic fever occur?

Fever, Heart Inflammation, Arthritis, Chorea or St. Vitus Dance

What are the four symptoms of Rheumatic Fever?

Chorea

Hallmark symptom of rheumatic fever characterized by uncontrolled dance like movements by patients

Catalase (-), Facultative Anaerobe, B-Hemolytic

What are the culture characteristics of Group B Streptococcus (S. agalactiae)?

Delivery

When do babies acquire Group B Strep infections?

Neonatal meningitis, Neonatal pneumonia, Neonatal sepsis

What are three clinical findings for Group B Strep (S. agalactiae)?

Penicillin

What is the treatment for diseases caused by S. agalactiae?

Gram stain of CSF or urine; Culture of CSF, urine, or blood

What are 2 diagnostic methods for Group B Strep (S. agalactiae)?

More general symptoms than adult meningitis

Why is neonatal meningitis more difficult to determine than adult meningitis?

S. agalactiae, E. Coli, L. Monocytogenes

What are the 3 microorganisms causing Neonatal meningitis?

Swab vaginally and rectally during 35th and 37th week of pregnancy, take antibiotics

How do we check if pregnant mothers have Group B strep infections? If they are positive, what is advised?

CSF

What is the best sample to be used for diagnosis of Group B (S. agalactiae) infections?

Enterococcus faecalis, E. faecium

Under Group D, what are 2 species that fall under enterococcus?

Streptococcus bovis, S. equinus

Under Group D, what are 2 species that fall under non-enterococci?

Catalase (-), Facultative anaerobe, Usually G-hemolytic but may be A-hemolytic

What is the culture characteristic of Group D Streptococci (Enterococcus and Non-enterococci)?

Can grow in 40% bile and 6.5% NaCl

What makes Enterococcus very unique in terms of the environment it can grow in?

Can grow in 40% bile but NOT in 6.5% NaCl

How are non-enterococci different from enterococcus?

Streptococcus bovis

What specific Streptococcus species is being currently studied for its relation to colon cancer?

2nd to 3rd

What is the rank of Enterococcus as a cause of nosocomial infections?

Extracellular dextran, adhesion to heart valves

What is the main pathogenesis / virulence factor of Group D Strep? What is the function of that virulence factor?

Subacute bacterial endocarditis, Biliary tract infections, UTI (especially enterococci)

What are 3 significant clinical findings for Group D strep?

Ampicillin + Aminoglycoside, Vancomycin; both have emerging resistance

The 2 treatment for Group D Strep are ? However, what is the problem with these treatments?

Gram Stain, Culture

What are two methods for diagnostics of Group D Strep?

Enterococci in 40% bile, 6.5% NaCl; Non-enterococci in bile only

How can we prepare the culture media for Group D Strep given that there are two groups within?

Vancomycin-Resistant Enterococci (VRE)

Previously resistant strains of Group D Strep Enterococci have evolved in terms of antibiotic resistance, leading to what is called as?

vanA

What is the gene found in VRE that confers their resistance to vancomycin

vanA can transfer from VRE to S. aureus, which by itself already has MRSA and VRSA

Why is VRE in general problematic not only for within VRE diseases?

Viridans

Streptococci that is a normal flora of oral cavity & nasopharynx

Oral Cavity, Nasopharynx

What are two locations wherein Viridans are considered to be normal flora in?

Mitis, Salivarius, Mutans, Anginosus

What groups do we have under Viridans?

More than 30% of culturable bacteria

Viridans groups comprise how many % of bacteria we find in mouth, saliva, tongue or gingival crevice?

Anginosus

Among the 4 groups within Viridans, what is the only group that is Beta-hemolytic?

Catalase (-), Facultative anaerobe and may be microaerophilic, A-hemolytic, may also also be G-hemolytic

What is the culture characteristics of Viridans group of Streptococci?

Mitral Valve

What valve of the heart is targeted by Viridans?

Rheumatic Fever

Viridans like to establish infections in people who have already experienced prior heart infections. This includes prior infection of what disease?

Extracellular dextran, adhesion to heart valves

What is the main pathogenesis / virulence factor of Streptococci: Viridans Group? What is the function of that virulence factor?

Subacute bacteria endocarditis (S. viridans), Dental caries (S. mutans), Brain or liver abscesses (S. intermedius)

What are three (3) clinical findings for Streptococci Viridans Group?

Penicillin

What is the treatment for Streptococci: Viridans group?

Gram Stain, Culture

What are the diagnostics for Streptococci Viridans group?

Slow progression of disease

What does "subacute" in subacute bacterial endocarditis mean?

S. intermedius

What specific species of Streptococci from the Viridans group are microaerophiles as we can deduce from their connected clinical findings?

Bacterial pneumonia and meningitis in adults, Otitis media in children

S. pneumoniae is the primary cause of what diseases?

Lancet-shaped, Arranged in pairs (diplococci)

Morphology of S. pneumoniae cells?

Catalase (-), Facultative anaerobe, A-hemolytic

Describe the culture characteristics of S. pneumoniae?

Capsules (antigenic), Pneumolysin

What are the two pathogenesis or virulence factors of S. pneumoniae?

Antigenic

A characteristic of the S. pneumoniae capsule wherein it can be recognized by macrophages for phagocytosis

There are 84 capsule serotypes for S. pneumoniae

What is the reason why even if we get infected by S. pneumoniae once, it does not automatically mean that our immune system will readily recognize S. pneumoniae in the next infections?