Streptococci Flashcards by Caleb hansen

Gram positive cocci arranged in

Pairs

chains

Mostly facultative anaerobes, but range from strictly anaerobic to capnophilic

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Gram positive cocci have … requirements, require … or …. in the medium

Catalase….

growth

blood or serum

negative

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Haemolytic patterns

None =

Incomplete =

Complete =

None = gamma

Incomplete = Alpha

Complete = Beta

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Has …. properties

Biochemical

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Streptococcus Pneumoniae

Gram positive coccus are ….. in diameter

often …. or …. in shape

0.5 to 1.um

oval or lancelate

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Streptococcus Pneumoniae only grows in

enriched media such as blood

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Streptococcus Pneumoniae is catalase …. and requires ….

negative

blood

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Streptococcus Pneumoniae are ….. organisms from large …. colonies

capsulated

mucoid

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Non capsulated Streptococcus Pneumoniae are

short and fat

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Streptococcus Pneumoniae

All colonies …. with age

autolyse

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Streptococcus Pneumoniae

Alpha … when grown aerobically

haemolytic

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Streptococcus Pneumoniae

Virulent strains are covered with

complex polysaccharide capsule

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Streptococcus Pneumoniae

Over 90 strains recognised by typing these ….

POLYSACCARIDES ]

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Streptococcus Pneumoniae

Purified antigens used as

polyvalent vaccine

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Streptococcus Pneumoniae

Cell wall contains

choline which is important for regulation of cell wall hydrolsis

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Streptococcus Pneumoniae

Cell wall contains

choline which is important for regulation of cell wall hydrolysis

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Choline must be present for the activity of the

autolysin amidase during cell division

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Some techoic acid is exposed which is called

Percipitates … reactive substance protein in the presence of calcium

C substance https://www.brainscape.com/decks/9736283/cards/quick?pack_id=17277361#

Calcium

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Virulence factors

… componets

enzymes and ….

carried …

Has the ability to spread to

Structural components

enzymes and toxin

Carried asymptomatically:
- upper respiratory tract of 10-15% of adults

lungs
sinuses
Middle ear
To other sites via blood

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Virulence factors

Colonisation mediated by

A secretory …. protease disrupts clearance from

binding to epithelial cells via a protein adhesion

IgA

Mucous

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Pneumolysin is a

binds too

creates pores too

cytotoxin

cholesterol in the host membrane

Creates pores to destroy the ciliated epithelial cells

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Tissue destruction is characteristic of pneumococcal infection caused by

teichoic acid
peptidoglycan
Pneumolysin

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Penumococcal infection activates with pathways and produces what

activates classical and alternative complement pathway, producing C3a, C5a and also IL1 and TNF alpha

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Virulence factors results in

inflammatory response

Fever

Tissue damage

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Production of hydrogen peroxide by the bacteria causes

further tissue damage

Peumococci enter a variety of cells by binding to

receptors for platelet activating factor

Virulence factors facilitates spread through

blood and CNS

Capsule give protection from Pneumolysin suppresses Non capsulated (rough) strains are

phagocytosis oxidative burst avirulent

Clinical syndromes from Streptococcus

Bacterial pneumonia Otitis media Sinusitis

Bacteriaemia occurs in

20-30% of pneumonia cases | up to 80% of meningitis cases

Pneumonia has rapid onset: symptoms morality rate higher with type ...

Fever 39-41 localised to lower lobes Generalised bronchopneumonia 3

Virulence factors are sensitive to:

Penicillin Erthrymocyin Tetracycline

Control by vaccine of capsular .... for at risk patients

polysaccharide

2 effective vaccines

Pneumovax - Contains 23 serotypes - known to cause 90% of disease Prevenar - Contains 13 serotypes

B haemolytic streptocci Is classified by .... based on cell wall polysaccharides.

lancefield grouping system - Groups A, B, C, F and G

Lipteichoic acid group D and

enterococci

Not all groups demonstrate

beta haemolysis

Group A streptococcus Colonies may appear ...

Capsulated | Non capsulated

Group A streptococcus capsule of hyaluronic acid is lost during

the stationary phase

Hyaluronic acid is found in ,,,, therefore in non immunogenic -....

connective tissue - antiphagocytic

Virulence proteins M protein has ... different types and degrades ....

80 C3b

what does 29 M types produce

Opacity factor

M like proteins bind the Fc portion of ,,,, and ,,,, and ..... which is a protease inhibitor

IgG and IgA and alpha2macroglobulin F protein has a receptor for fibronectin Important for attachment to epithelial cells of: - Pharynx - skin

what are the pryrogenic exotoxins and what do they act as

SpeA, SpeB and SpeC they act as superantigens

s and o are

Streptolysins

what are the 5 things that streptolysin S does

- cell bound haemolysin - lyses erythrocytes, leukocytes and platelets - destroys phagocytes - Oxygen stable - non immunogenic

what are the 3 things that streptolysin 0 does

- Haemolysin activity - Inactivated by oxygen reversibly and irreversibly by cholestral - stimulates anitbody response

What are the 2 streptokinases and what do they do

A and B Lyse blood clots

what does Dnase do

depolymerises cell free DNA in purulent material

what are all the virulence factors

Pyrogenic exotoxins Streptolysins o Streptolysin S Streptokinases. a and b Dnase C5a peptidase Hyaluronidase ‘spreading factor Diphosphopyridine nucleotidase.

Epidemiology Clonosises .... of childrena and young adults transient and .... on ... of production of antibodies to the particular ,,,, protein spread by

oropharynx depend on speed M spready by droplet infection and skin colonisation

Suppurative clinical syndromes Pharyngitits is a 2-4 days after exposure the 5 symptoms are what appears on tonsils what are the complications lysogenised with a temperate stimulates production of

sore throat ``` fever sore throat headache malaise abdominal pain ``` grey white exudate scarlet fever bactriophage pyrogenic exotoxin

Suppurative clinical syndromes Soft tissue infections (3) cellulitis involves deeper... Infected wounds Pyoderma

- Erysipelas - skin rash face or legs - Preceded by respiratory tract or skin infections tissue ulcers insect bites etc Impetigo

-suppurative clinical syndromes Necrotising fasciitis becomes... spreads.... What spec involved.... Follows entry of bacteria to... high

infection becomes established in the fascial tissue below the skin spreads rapidly causing tissue necrosis skin and wound, cellulitis mortality

suppurative clinical syndromes treatment involves surgical removal of .... and .... therapy

dead tissue and antibiotic therapy

streptococcal toxic shock syndrome may follow .... and .... tissue infection severe ..... organ symptoms what spec implicated

throat and soft tissue multi organ Spec A.B.C

Soft tissue inflammation at the site of infection with non specific symptoms increased pain as disease progresses to multi organ ,,,, and ,,,,,

fever chill nausea shock and failure

Bacteriaemic and often have Predisposing factors,

necrotising fasciitis HIV , cancer, diabetics , alcohol and drug abuse

Non suppurative disease often a complication of rheumatic fever is associated with Inflammation involves can cause chronic damage to caused by specific M groups - ... formed to cell wall .... cross react with the... of the heart Rhenumatic heart disease - repeated attacks with different ,, types can lead to ..... disease cu

initial streptococcal infection pharyngeal infection 2-5 weeks after initial infection Heart valves, joints and blood vessels heart valves antibodies formed to cell wall antigens cross react with the sarcolemma of the heart different m types can lead to heart valve disease

diagnosis and treatment ... stain and ... characteristics .... grouping sensitive to treatment - sensitive to ..... prompt treatment prevents ... does not influence progression of prophylaxis necessary in some cases

gram stain and growth characteristics lancefield grouping sensitive to bacitracin sensitive to penicillin prevents rheumatic fever. does not influence progression to glomerulonephritis prophylaxis necessary in some cases

Group B streptococci. S.agalactiae. grow as .... appearing colonies on ...... small zone of group specific polysaccharide .... what are the 6 enzymes Useful for identification rather than ... colonisies of lower gas...... and g,,, tract

buttery nutritionally enriched medium. beta haemolysis cell wall antigen ``` Dnases, hyaluronidase, neuraminidase, proteases, Hippurase Hemolysins. ``` pathogenesis gastrointestinal and genitourinary tract

Group B streptococci Cause: 5 causes Risk factors 4 risks All serotypes but .... mostly due to type .... <5% mortality, 15-30% of those with meningitis have neurological ...

- Neonatal disease, - Urinary tract infection - wound infections - Occasionally bacteraemia - 29.5% of reported neonatal bacterial meningitis - heavily colonised mother lacking specific antibody - Premature rupture of membranes - Pre term delivery - Prolonged labour and obstetric complications meningitis mostly due to type 111 sequelae

Group C and G streptococci S.equisimilis and S. anginosus associated with

human disease

Cause of Group C and G streptococci:

- Pharyngitits | - found in wound infections

S.anginosus also has what antigens for what group

polysaccharide antigens for group G

Group G: is part of can cause

part of normal flora can cause wound and throat infections

Cases of bacteraemia reported for both

C and G

Group F. streptococci what group what are the growth conditions what odour normal what of vaginal area involved in deep ....

Milleri group - co2 - minute colonies of blood agar characteristic caramel odour normal flora of vaginal area involved in deep infections e,g abscesses

Group D and the enterococci how many species most common species E..... responsible for 80-90% human infections E. 10-15% Part of normal .... Facultatively anaerobic cocci - Growing optimally at .... range .... Grow as non haemolytic ...] - Tolerate 6.5% ... and 40%

18 - E.faecalis - E. Facecium E. faecalis responsible for 80-90% human infections Part of normal flora of bowelecium 10-15%. Facultatively anaerobic cocci Growing optimally at 35oc. Range 10-45oc. Grow as non haemolytic colonies - Tolerate 6.5% salt and 40% bile salts

Enterococci - Few virulence factors but can cause life... Virulence factors include: - aggre... - carb.... - Bacte... - Gel... ``` Most important is antibiotic resistance -amino... beta.. vanc... A,van..... ```

threatening disease Aggregation susbstance Carbohydrate adhesins Bacteriocin Gelatinase. Aminoglycosides Beta-lactams Vancomycin (mediated by Van A,Van B and Van c genes).