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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?