This document discusses Streptococcal infections and diseases. It begins by introducing the different types of Streptococcus bacteria and how they cause both infectious and non-infectious conditions. It then focuses on Group A Streptococcus (Streptococcus pyogenes), describing its virulence factors and how it commonly causes respiratory infections, skin infections, scarlet fever, and non-suppurative diseases like rheumatic fever. It also discusses Streptococcus pneumoniae and how it causes pneumonia and other infections. The document provides details on pathogenesis, clinical presentations, diagnosis, and treatment of these important Streptococcal infections.

1. STREPTOCOCCAL
NFECTIONS & DISEASES
Presenting to Dr.Rusudan Qarseladze
Presenting by Tushar Rajput,Suhail Raes,Aditya Shashikant Gaikwad
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2. INTRODUCTION
• Streptococcus is Gram-positive bacteria classified as
ß, α and γ according to complete, partial and no
haemolysis on blood agar.
• Streptococci are among the most common causes of
bacterial infection in infancy and childhood.
• Streptococci cause both suppurative and non-
suppurative conditions.
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3. GROUP A STREPTOCOCCUS
(STREPTOCOCCUS PYOGENES)
• This is the most important streptococcal
species clinically causing both
suppurative and non-suppurative
diseases. Causes ß-haemolysis.
• It has > 80 immunologically distinct types
based on differences in the M protein in
the outer layer of the cell wall.
• The M antigen and lipoteichnoic acid are
major virulence factors of the organism.
Others are erythrogenic (pyrogenic)
exotoxins, hyaluronidase, streptokinase,
proteinase, streptolysin O and
streptolysin S.
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4. INCIDENCE
• 10 – 20% of normal school children are
colonized by this organism in their
throat.
• The incidence of Group A Streptococcal
disease is lowest in infancy (they are
protected by transplacentally acquired
antibodies and the lack of pharyngeal
receptors for the antigens of the
organism).
• Spread occurs by direct body contact and
by air droplets.
• Overcrowding and skin damage
encourage streptococcal skin infections.
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5. CLINICAL PRESENTATIONS
• RESPIRATORY
Presents similar to coryza in infants younger
than 6 months
Nasopharyngitis, cervical adenopathy, purulent
nasal discharge, otitis media and sinusitis among
children aged 6 months to 3 years.
Tonsillitis, pharyngitis, meningism, peritonsillar
and retropharyngeal abscesses occur in children
aged more than 3 years.
Pneumonia due to Strep pyogenes is usually very
severe and rapidly progressive.
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6. CLINICAL PRESENTATIONS
• SKIN – Most of these commonly follow
insect bites and scabetic infestation.
Pyoderma (impetigo)
Erysipelas usually of the face and
extremities
Cellulitis
Necrotizing fasciitis
Myositis
Sometimes, abscesses may be formed.
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7. CLINICAL PRESENTATIONS
• SCARLET FEVER – No longer common in the
antibiotic era. Used to be associated with
significant mortality. It is due to the
erythrogenic exotoxins. Incubates between 1
day and 1 week. Presents with
tonsillopharyngitis, erythematous rash, fever
and oedematous tongue. The rash is followed by
extensive and severe desquamation.
• BACTERAEMIA – follow localized lesions usually
in debilitated patients. May thereafter lead to
osteomyelitis, arthritis, pyelonephritis and
meningitis.
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8. CLINICAL PRESENTATIONS
• VULVOVAGINITIS – usually among pre-pubertal girls.
Presents with purulent vaginal discharge, pain and
pruritus vulvae.
• RHEUMATIC FEVER – This is a non-suppurative
complication of Upper Respiratory Streptococcal
infection affecting the heart, joints, skin and brain. It
results in Rheumatic Heart Disease - the commonest
acquired heart disease in most developing countries.
• ACUTE GLOMERULONEPHRITIS – Another non-
suppurative renal disease resulting from Strep.
pyogenes infection of the skin (M49, 2, 55, 57) and
throat (M12, 1,2,3). In the tropics, AGN commonly
follows Streptococcal skin infections.
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9. STREPTOCOCCUS PNEUMONIAE
• This organism is encapsulated α-
haemolytic diplococci.
• Many healthy children carry the organism
in their upper respiratory tract between
6 months and 4 years. The isolation
peaks in the first 2 years of life and
thereafter declines.
• Males more affected than females. Blacks
more affected than whites.
• Majority of invasive diseases are due to
serotypes 4, 6B, 9V, 14, 18C, 19F and
23F.
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10. PATHOGENESIS
• Pneumococcus does not cause surface
infections.
• Host defence mechanisms include
epiglottic reflex which prevent aspiration
of secretions containing the organisms,
ciliary action which moves secretions
towards the pharynx and secretions from
the middle ear and sinuses which flow
into the pharynx and not vice-versa.
• When these are disturbed by viral
infection and irritants like smoke,
colonization by pneumococcus and
disease occur.
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11. PATHOGENESIS
• The organisms multiply and spread via the
lymphatics and blood to distant areas. It also
spreads locally to contiguous sites.
• Sickle cell disease, nephrotic syndrome,
post-splenectomy state, HIV, congenital and
acquired immune defects are predisposing
factors.
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12. CLINICAL FEATURES
• These are related to the sites of infection
Pneumonia
Otitis media
Sinusitis
Orbital and peri-orbital cellulitis
Pharyngitis
Parotitis.
• Local spread may produce empyema,
pericarditis, mastoiditis and meningitis.
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13. • GROUP B ß-HAEMOLYTIC
STREPTOCOCCUS
• This is a commensal of the vagina hence
causes diseases in the newborns:
septicaemia, pneumonia, otitis media,
osteomyelitis and meningitis.
• STREPTOCOCCUS VIRIDANS
• A cause of bacterial endocarditis
especially of non-native (prosthetic)
valves.
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14. DIAGNOSIS
• Blood culture.
• FBC – leucocytosis.
• Throat swab for m/c/s.
• Latex particle agglutination.
• Anti-Streptolysin O (ASO) titire > 166 Todds
Unit is highly suggestive of recent
streptococcal invasive infection.
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15. TREATMENT
• The goal of treatment is to minimise the severity
of symptoms and prevent suppurative and non-
suppurative complications.
• Penicillins are the drugs of choice. Oral Penicillin
V 250 – 500mg bid for 5 days; intravenous
Penicillin G 200, 000units/kg in 4 divided doses;
long-acting benzathine penicillin 600, 000 – 1,
200, 000 units per dose.
• Erythromycin (40mg/kg/day in 4 divided doses)
and Cephalexin (100mg/kg/day in 2 divided
doses) may also be used.
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16. PREVENTION
• Prophylactic Penicillins is indicated only for
patients with specific predisposing factors like
SCD, post-splenectomy, Nephrotic Syndrome, HIV
and congenital immune defects.
• Prophylactic Penicillin is also used in patients
with Rheumatic Heart Disease.
• No vaccine against Streptococcus pyogenes yet.
• The polyvalent pneumococcal vaccine has poor
immunogenicity in children younger than 2
years.
• The conjugate polypeptide pneumococcal
vaccine is newer and better because it has good
immunogenicity in children as young as 2 months
old.
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17. References
• https://www.msdmanuals.com/professional/infectious-
diseases/gram-positive-cocci/streptococcal-infections
https://www.cdc.gov/groupastrep/diseases-
public/index.html
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18. THANK YOU
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