Transcript PTS - University of California, Irvine

Staphylococcal Infections
Godwin Tse
LA-TRAP
Summer 2011
Staphylococcus
• from Greek word staphlye
and kokkos, “bunches of
grapes”
• Gram positive bacteria
• Round (coccus), found in
clusters
• Genus can be divided the
ability to produce coagulase
• Coagulase positive
▫ S. aureus
▫ S. hyicus-intermedius group (5 other strains)
• S. aureus
▫ Part of normal flora, can be
found in nose and skin
▫ 80% of population in the
US are colonized at some
point, 20-30% persistently
Pathophysiology
• Tissue invasion
▫ Transmission
▫ Formation of abscess
▫ Transport via blood
• Toxin-mediated disease
▫ Consumption of contaminated food
▫ Caused by enterotoxins
Skin infection
• impetigo
• cellulitis
• bacteremia/sepsis
• staphyococcal
pneumonia
• endocarditis
• osteomyelitis
Food poisoning
• toxic shock syndrome
• gastroenteritis
• Scalded skin syndrome
Signs and Symptoms
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Abscess, boils
Redness, swelling, lesions
Pus
High fevers, chills, low BP
• Food poisoning: nausea, vomiting, diarrhea,
dehydration withing 1-6 hrs
Risk factors
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Newborn infants
Breastfeeding women
Weakened immune systems
Skin injuries/disorders
Chronic conditions such as diabetes, cancer,
vascular disease, lung disease
• Presence of intravenous catheters or surgical
incisions
Tests
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Blood culture
Culture from the infected site
Gram stain and culture of the fluid
Sputum culture
Urine culture
Treatment
• Drainage of infection
• Antibiotics
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▫
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Pencillins
Cephalosporins
Clindamycin
Vancomycin
MRSA
• Methicillin resistent Staphylococcus aureus
• HA-MRSA
▫ Affects the very sick, elderly, and those with an
open wound such as a bedsore or catheter
• CA-MRSA
▫ Associated with recent antibiotic use, active skin
diseases/injuries, poor hygiene, crowded settings
▫ Accounts for 12% of MRSA infections (from CDC)
• Coagulase negative staphylococci
▫ S. epidermidis
 Creates biofilms
 Occurs on intravenous catheters or
surgical implants
▫ Antibiotics not as effective due to
impaired diffusion caused by
surface proteins
▫ Most effective treatment is to
replace catheter or implant
Prevention
• Proper hygiene when attending to skin wounds
• Avoid skin contact with infected individuals
• Safe food practices
Source
References
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http://www.medicinenet.com/staph_infection/
http://emedicine.medscape.com/article/971358
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004520/
http://en.wikipedia.org/wiki/Staphylococcal_infection
http://www.cedars-sinai.edu/Patients/QualityMeasures/Preventing-Hospital-Acquired-Infections/PreventingBloodstream-Infections-by-Methicillin-Resistant-Staphylococcusaureus-MRSA.aspx
• http://www.cdc.gov/