Streptococcal infections

Streptococcal infections, Refrence Harrison's 18th
عفونت های استرپتوکوکی، مناسب جهت تدریس دانشجویان رشته پزشکی

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Qom University of Medical Sciences And Health Services
Medical School
Supervisor: Dr. JavadKhodadadi
Provisioner: Mohammad Mahdi Shater
Streptococcal Infections

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Streptococcus
Streptos(like chain)+ coccus(like Sphere)

5. •Many varieties of them are normal flora
•GAS , S.pyogenes:
one of the most common bacterial infections of
school-age children, post infectious syndromes of ARF
and PSGN.
•GBS, S. agalactiae:
cause of bacterial sepsis and meningitis in newborns
•Viridansstreptococci:
are the most common cause of bacterial endocarditis
•Enterococci:
E. faecalis,E. faecium
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Streptococcus

6. •Gram positive
•Most are facultative anaerobes, although some
are strict anaerobes
•fastidious
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Streptococcus

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8. Lancefield Classification
•a serologic grouping based on the reaction of
specific antisera with bacterial cell-wall
carbohydrate antigens
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A,B,C,G/β
D/γ
variable/α

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A,B,C,G/β D/γvariable/α
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10. Group A Streptococci
•S.pyogenes
•500,000 deaths per year
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11. Group A Streptococci
•Virulence factor:
M-protein
Hyaluronic acid capsule
StreptolysinsS and O
pyrogenic exotoxins(erythrogenictoxins)
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12. CLINICAL
MANIFESTATIONS
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13. Pharyngitis
Seen in patients of all ages
Respiratory droplets are the usual mechanism
of spread, other routes, including food-borne
outbreaks
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A culture positive case of
streptococcal pharyngitis
with typical tonsillar
exudate in a 16 year old.

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Pharyngitis
The incubation period is 1–4 days
Symptoms include:
sore throat
fever and chills
malaise
sometimes abdominal complaints and
vomiting, particularly in children
Symptoms are mild to severe

15. sore throat fever and chills
malaise, fever and chills abdominal complaints & vomiting
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the large tonsils with white
exudate.
the petechiae, or small red
spots, on the soft palate.
large tonsils in the back of the
throat covered in white
exudate.

20. Differential Diagnosis
•Viral infections is more probable if we see:
•conjunctivitis
•Coryza
•Cough
•hoarseness
•discrete ulcerative lesions of the buccalor
pharyngeal mucosa
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23. Diagnose
•The throat cultureremains the diagnostic gold standard
•Vigorous rubbing of a sterile swab over both tonsillarpillars
•Rapid diagnostic kits generally are >95% specific
•A negative result should be confirmed by throat culture
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24. Complications
•uncommonwith the widespread use of antibiotics
•spread of infection from the pharyngeal mucosa to deeper
tissues by direct extension or by the hematogenousor
lymphatic route
•Cervical lymphadenitis
•Peritonsillaror retropharyngeal abscess,
•Sinusitis
•Otitis media
•Meningitis
•Bacteremia
•Endocarditis
•Pneumonia
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•ARF
•PSGN

25. The Asymptomatic Carrier State
•No symptoms with positive culture
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Scarlet Fever
consists of streptococcal infection, usually
pharyngitis, accompanied by rash
streptococcal pyrogenic exotoxins A, B, and C
Susceptibility to scarlet fever was correlated
with results of the Dick test
scarlet fever rash may reflect a hypersensitivity
reaction

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Scarlet Fever
Symptoms of pharyngitis
On the first or second day of illness over the
upper trunk

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Scarlet Fever
Then involve back and abdomen

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Scarlet Fever
spreading to involve the extremities but
sparing the palms and soles

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Scarlet Fever
The rash is made up of minute papules(sandpaper)
Finely punctate erythema has become confluent
Circumoralpallor & strawberry tongue

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Scarlet Fever
Pastia’sline

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Scarlet Fever
Subsidence of the rash in 6–9 days is followed after
several days by desquamation of the palms and soles

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Differential Diagnosis
•Other causes of fever and generalized rash:
•Measles and other viral exanthems
•Kawasaki disease
•Toxic shock syndrome
•Systemic allergic reactions (e.g., drug eruptions).

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Skin and Soft Tissue Infections
Impetigo(Pyoderma)
Cellulitis

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Impetigo(Pyoderma)
a superficial infection of the skin
caused by GAS and or Staphylococcus aureus
most often in young children (poor hygiene)
Minor trauma, such as a scratch or an insect bite
usual sites of involvement are the face(particularly
around the nose and mouth) and the legs

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Impetigo(Pyoderma)
Begin as red papules, which evolve quickly into
vesicular and then pustularlesions
Honeycomb-like crusts
Generally not painful, and patients do not appear ill
Fever is not a feature

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Differential Diagnosis
•Bullous impetigo due to S. aureus
more extensive & paper-like crusts
•herpetic lesions
more discrete, grouped vesicles
positive Tzancktest
•culture In difficult cases

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Cellulitis
Inoculationof organisms into the skin may lead to
cellulitis
infection involving the skin and subcutaneous
tissues
may also be associated with lymphangitis
One form of streptococcal cellulitis, erysipelas

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Erysipelas
a bright red swollen appearance of the involved skin
lesion is warmto the touch & may be tender
peaud'orangetexture(involvement of superficial lymphatics)
superficial blebs(usually 2–3 days after onset)
Fever and chills
Most occur on the malar area of the face

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Deep Soft-Tissue Infections
streptococcal myositis
Necrotizing fasciitis (hemolytic streptococcal
gangrene) involves the superficial and/or deep fascia
investing the muscles of an extremity or the trunk.
The source of the infection is the skin & bowel flora
Usually quite acute
Severe pain at the site of involvement
Malaise, fever, chills
Toxic appearance
the severity and extent of symptoms worsen
skin appearance(erythema and edema)

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Pneumonia and Empyema
GAS is an occasional cause of pneumonia
Pleuriticchest pain
Fever & chills
Dyspnea
Cough is usually present
Pleural effusion(≈ one-half of patients and always infected )
Empyema fluid is usually visible by chest radiography

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Bacteremia, Puerperal Sepsis
Bacteremia occurs rarely with otherwise
uncomplicated pharyngitis, occasionally with
cellulitis or pneumonia, and relatively frequently
with necrotizing fasciitis.
raises the possibility of endocarditis, an occult
abscess, or osteomyelitis

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Streptococcal Toxic Shock Syndrome
Shock with multisystem organ failure

50. Prevention
•No vaccine against GAS is commercially available
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51. Streptococci of Groups C and G
•occasionally cause human infections similar to those
caused by GAS
•S. dysgalactiae
•Pharyngitis
•Pneumonia
•Bacteremia
•Endocarditis
•Septic arthritis
•Puerperal sepsis
•Cellulitis and soft-tissue infections
•Some of species of group C Lancefield are zoonotic and
acquired from contact with animals or unpasteurized milk
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•Meningitis
•Epidural abscess
•Intraabdominalabscess
•Urinary tract infection
•Aneonatalsepsis

52. Group B Streptococci
•GBS major cause of sepsis and meningitis in human
neonates
•frequent cause of peripartumfever in women and an
occasional cause of serious infection in nonpregnant
adults
•S. agalactiae
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53. Infection in Neonates
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Early-onset infections
Late-onset infections

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Occur within the first week of life
Acquired from the colonized maternal genital tract
Prematurityand maternal risk factors (prolonged labor,
obstetric complications, and maternal fever)
Presentation of neonatal sepsis
Pneumonia respiratory distress
Lethargy
Hypotension
Bacteremic
Meningitis
Early-onset infections

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occur in infants 1 week to 3 monthsold
acquired during delivery or during later contact with a
colonized mother, nursery personnel, or another source
Meningitisis the most common manifestation
fever, lethargy or irritability, poor feeding, and seizures
Bacteremia, osteomyelitis, septic arthritis, and facial
cellulitis, submandibular or preauricularadenitis
Late-onset infections

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Identification of high-risk carrier mothers and treatment
with antibiotic or immunoprophylaxis
Screening for anogenitalcolonization at 35–37 weeks of
pregnancy by a swab culture of the lower vagina and
anorectum
Risk factors: preterm delivery, early rupture of
membranes (>24 h before delivery), prolonged labor,
fever, or chorioamnionitis
Vaccine may be for future
Prevention

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Peripartumfever, the most common manifestation
Related to symptoms of endometritisor chorioamnionitis
transitory bacteremia, meningitis or endocarditis
In old or chronic illness(diabetesmellitusor a malignancy):
Cellulitis and soft tissue infection , UTI, pneumonia,
endocarditis, and septic arthritis meningitis, osteomyelitis,
and intraabdominalor pelvic abscesses
Infection in Adults

58. NonenterococcalGroup D Streptococci
•S.bovis(S.gallolyticus, S.infantarius, S.pasteurianus,
S.letetiensis)
•S. bovisendocarditis is often associated with
neoplasms of the GIT-most frequently, a colon
carcinoma or polyp-but is also reported in association
with other bowel lesions.
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59. ViridansStreptococci
•S. salivarius, S. mitis, S. sanguis, and S. mutans
Normal flora of the mouth
Endocarditis
frequently in neutropenicpatients, particularly after bone
marrow transplantation or high-dose chemotherapy for
cancer
sepsis syndrome with high fever and shock
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ViridansStreptococci
•S. intermedius, S. anginosus, and S. constellatus
abscesses of brain and abdominal viscera
infections of oral cavity or respiratory tract

61. Other Streptococci
Abiotrophia& GranulicatellaSpecies (Nutritionally
Variant Streptococci)
They cause infections like viridansStreptococci
S.suiscause meningitisin humans people that exposure
to pigs
S.iniaeinfected humans who have handled live or freshly
killed fish(Cellulitis, bacteremia, endocarditis)
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