MRSA Flashcards
What is MRSa
Methicillin resistant staph aureus, resistant to beta-lactam antibiotics and cephalosporins
Where is MRSA found on body?
Moist areas e.g. nose, perineum
How is MRSA resistant to B lactams?
MecA gene encodes a PBP with low affinity for methicillin, allowing resistance
Bacteria can continue to produce cell walls even in high drug concentrations
What are different types of MRSA?
Group A: more resistant, seen in hospitals
group B: seen in communitie
What does group B MRSA often contain?
PVL toxin, virulence factor associated with skin and soft tissue infections
What are risk factors for MRSA?
Chronic illness requiring frequent hospital visits
Crowded living conditions e.g. nursing homes
Abx use
Previous MRSA
Exposure to person with MRSA
Nasal colonisation with MRSA
HIV
Indwelling device/lines, wound
Older age
What kind of infections does MRSA cause?
Mostly skin and soft tissue, but can be
endocarditis
joint
pneumonia
urine
What are Sx of MRSA skin infectoin
Erythematous lesions with pustules
Can be abscess
Central ulceration may be present
Purulence (indicates staph); cellulitis without purulence indicates strep
What are DDx for MRSA skin/soft tissue
Insect bite
Folliculitis
Cellulitis
What Ix for MRSA?
Swab: nose and perineum indicates colonisation, needs to be done in context of Hx to diagnose infection
Bloods: raised WCC and CRP
Cultures: blood, sputum, urine, abscess fluid, aspirate from joint
Echo if IE suspected
CXR if pneumonia suspected
PCR for MecA gene
What Rx for MRSA/
If skin and soft tissue,
Debride and drain the abscess if needed
Antibiotics: if uncomplicated, give oral e.g. trimethoprim, doxycycline
If complicated (systemic Sx), give IV vancomycin
What infection control strategies can be done>
Hand washing, barrier nursing, avoid sharing items, keep wounds covered
How can decolonisation be done?
Chlorhexidine with nasal instillation of mupirocin
What are complications of MRSA?
Transmission to others, septic shock
