Lecture 4: Bacterial Infections Part 1 (Incomplete) Flashcards
What are the 3 main G+ Cocci that cause infection?
Staphylcoccus
Streptococcus
Enterococcus
What is the most pathogenic staphylococcus?
S. aureus
Is S. aureus coagulase positive or negative? What does that tell us?
Coagulase +
Produces an enzyme that has the ability to clot blood.
What species of Staph are Coagulase negative?
S. epidermis
S. saprophyticus
S. lugdunesis
Where is staph usually found?
On the skin and anterior nares of healthy individuals.
What is the most common way staph infects someone?
Direct tissue invasion:
Skin and soft tissue infections
Osteomyelitis
Septic arthritis
Pneumonia
Endocarditis
What is the indirect way staph infects someone/causes disease?
Exotoxin production:
Staph food poisoning
Toxic shock syndrome
Scalded skin syndrome
What is the common clinical presentation of a staph infection?
Erythema + purulent drainage of an abscess.
MRSA will look more severe.
What kind of infections typically attract staph?
Open wound
Open burn
What is the first step in treating a staph infection on skin?
Draining the abscess.
What would prompt us to culture post abscess drainage and what kind of culture?
Blood cultures if there are also systemic signs of infection like a fever.
There is a patient with a staphylococcal skin infection. They are being treated outpatient. If the patient is at low risk for MRSA, what tx would I give?
Cephalexin - Keflex
Dicloxacillin
There is a patient with a staphylococcal skin infection. They are being treated outpatient. If the patient is at high risk for MRSA, what tx would I give?
Clindamycin
Doxycycline/Minocycline
sulfamethoxazole/trimethoprim (Bactrim)
What is safe to give in kids if they are at high risk for MRSA?
Bactrim
a patient has a staphylococcal skin infection. If the patient is being admitted for MRSA, what tx would I give?
What could be some other Treatment options if this first line med was not available
Vanco IV
Other options: clindamycin, cefazolin, naf/oxacillin, linezolid (this one is super expensive)
What percentage of osteomyelitis cases are caused by S. aureus?
60%!!!
How is osteomyelitis confirmed?
XRAY
What is the most confirmatory scan for osteomyelitis?
Bone Scan
What is the first step once osteomyelitis is confirmed?
Culturing the bacteria!!
What is the initial tx for osteomyelitis?
broad spectrum Empiric ABX:
Vanco + 3/4th gen cephalosporin (ex: ceftriaxone)
What are the specialized treatments for osteomyelitis?
Once a C&S is done, prolonged therapy for 4-6 may be required:
MSSA: Nafcillin IV/oxacillin/cefazoline
MRSA: Vanco IV
Surgery may be required.
What are the primary ways Toxic Shock Syndrome occurs?
Tampon use
Nasopharynx packing
Diret inoculation via wound or abscess.
What causes toxic shock syndrome specifically?
A focal concentration of toxin-producing S. aureus.
How does toxic shock syndrome typically present?
Sudden onset high fever
Hypotension
Myalgia
Diffuse erythematous rash, specifically on palms and soles of feet. Usually will desquamate as well.