Transcript Final Case Study - Cal State LA

Case Study
Pathogenic Bacteriology
2009
Case #64
Hien Dang
Note: Embedded in your PowerPoint, you must address all questions in the case!
Case Summary

30-year-old male exposed to chicken pox

Fluid filled lesions on upper trunk
– Chicken pox caused skin lesions that opened up the
following week, crusted over, and healed

allowed pathogen to enter

Septic Shock
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Unresponsive to antibiotics, treated with
vancomysin, Cardiopulmonary arrest.
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Death.
Key Information Pointing to
Diagnosis

3 weeks prior to admission:
– Exposure to daughter infected with chicken pox


Treated with acyclovir
8 days prior to admission:
– Developed abdominal pain
– Fluid filled lesions that opened up, crusted over, healed
– Large, red Vesicle appeared on buttock


Treated with hydrocortisone cream
1 day prior to admission:
– Shortness of breath, pain and swelling in leg, vomiting
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Admission to local hospital:
– Treated with antibiotics
– Low Respiratory rate, decreased systolic blood pressure
– Unresponsive and Intubated
The Diagnosis for Case #

Admission to a new hospital
– Treated with Acyclovir and Vancomysin
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Lab Results:
– Liver failure, kidney failure, muscle breakdown
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Operating Room:
– Gross purulence in calf towards tracking up to thigh
– Ischemic dead muscle with viable muscle tissue in thigh
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Post Surgery:
– Cardiopulmonary arrest
– Could not be resuscitated
Classification Gram Stain Results, and
Microscopic Appearance
 Family:
Streptococcaceae
 Genus: Streptococcus
 Species: pyogenes
–
–
–
–
Gram (+)
Cocci arranged in chains
Carbohydrate Capsule
Facultative anaerobe
 Pathogen
pyogenes
identified as Streptococcus
Streptococcus pyogenes Diseases
and Pathogenesis
 Pharyngitis
 Wound
Infections
 Erysipelas
 Scarlet
Fever
Streptococcus pyogenes Diseases
and Pathogenesis
 Acute
glomerulonephritis
 Rheumatic
 Necrotizing
Fever
fasciitis
Streptococcus pyogenes
Pathogenesis
 Virulence
factors:
– Capsule
 Hyaluronidase
– M protein
 Major
virulence factor, protects S. pyogenes
from opsonization and phagocytosis
 Adherence
 Superantigen, causes shock in the affected
patient
– Patient experienced liver and kidney failure, fever,
and Sepsis
Streptococcus pyogenes
Pathogenesis

Virulence Factors
– Erythrogenic Toxins
 Produces
a toxic shock like syndrome similar to that
caused by Staphylococcus aureus
 Superantigen:
– Superantigen causes non-specific stimulation of T cells,
rendering the immune response useless.
– Scarlet Fever is associated with superantigen
production.
– DNAse
– Streptolysin S
– Streptolysin O
Diagnosis/Isolation/Identification/ of
Pathogen X

Media
– Sheep Blood Agar at 37°C
 With
Bacitracin antibiotic disk
 Biochemical
–
–
–
–
–
Testing
β-Hemolysis
Catalase (-)
Oxidase (-)
SXT Resistant
Taxo A Sensitive (susceptible to Bacitracin)
Therapy, Prevention and Prognosis

Antimicrobial Therapy:
– Penicillin
– Erythromycin (if allergic to Penicillin)
– Hydrocortisone cream is NOT effective
 Applied
at red vesicle, alleviated symptoms, but did
not directly treat the bacteria, allowed it to remain

Vaccine:
– Difficult to develop, poorly immunogenic
– Antibodies are protective against a specific
type of M protein
Primary Research Article Contributing to the
Understanding of the Disease caused by
Streptococcus pyogenes
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
O’Loughlin, RE, Roberson, A, et al. 2007. The Epidemiology of
Invasive Group A Streptococcal Infection and Potential Vaccine
Implications: United States, 2000-2004, Clinical Infectious
Diseases 2007;45:853–862.
Purpose:
– To estimate the potential impact of a multivalent GAS vaccine.

Methods:
– Collected data from Jan 2000 to Dec 2004 via CDC at 10 US
sites.
– Invasive GAS disease determined from patient with necrotizing
fasciitis or streptococcal toxic shock syndrome.
– All isolates were emm typed.
– Used US census data to calculate rates and to make age and
race-adjusted national projections.
Primary Research Article Contributing to the
Understanding of the Disease caused by
Streptococcus pyogenes

Results:
– Development of GAS vaccine is challenging because of the vast
number of emm types (>100)
– Also difficult due to potential cross-reactivity between epitopes
in the organism’s M protein and human tissue
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Conclusion:
– Introducing a vaccine could
significantly reduce morbidity
and mortality

This supports my case that
a vaccine is difficult to develop.
Take Home Message


Sepsis  Septic Shock
Typical symptoms
– Pus formation
– Liver failure
– Kidney failure

Pathogen
– Streptococcus pyogenes
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Diagnostics
– Antimicrobial testing involving Bacitracin
– Hemolysis test (Beta-hemolytic)
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Therapy
– based on Penicillin treatment for ten days immediately following
infection.
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Prevention
– Maintain proper hygiene to avoid mild superficial skin infections
– Ensure that open wounds heal properly without contact with
unsanitary or infectious persons
References
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O’Loughlin, RE, Roberson, A, et al. 2007. The Epidemiology
of Invasive Group A Streptococcal Infection and Potential
Vaccine Implications: United States, 2000-2004, Clinical
Infectious Diseases 2007;45:853–862.
McQueen, Nancy. 2009. Streptococcus Lecture. California
State University Los Angeles.
Smoot, LM, McCormick JK, et al. 2002. Characterization of
Two novel pyrogenic toxin superantigens made by an acute
rheumatic fever clone of Streptococcus pyogenes
associated with multiple disease outbreaks. Infection and
Immunity, 70:7095-7104.
Norrby-Teglund, A, Thulin, P, et al. 2001. Evidence for
superantigen involvement in severe group A streptococcal
tissue infections. Jour Infec. Disease 184:853-60.