Methicillin Resistant Staphylococcus aureus Exposure Assessment

in a Burn Center Environment

Cassandra Andrade, Space Grant Intern

Kelly Reynolds, Ph.D., Project Mentor

Overview• Staphylococcus aureus• Resistance• Transmission/infection risks• Need for Burn Center project• Project• Procedures• Results• Future Study

Staphylococcus aureus

• Gram positive organism • Opportunistic pathogen• Common on skin and in anterior of nose • ~2 billion people worldwide carry organism• Infections:

– Skin boils– Bacteremia (sepsis)– pneumonia

Antibiotic Resistance & MRSA

• Organism no longer susceptible to antibiotics due to overexposure to antibiotics & exchange of genetic information between organisms

• More than 700,000 people die/year in U.S. of nosocomial antibiotic resistant infections

• Organism harder to treat• Methicillin resistant S. aureus

– First identified in a British hospital 1961– 53 billion people worldwide carry it– Transferable to sensitive S. aureus

Transmission & Acquisition

• Surface survival- “fomites”– Towels (damp), porous surfaces– Survival from days to weeks

• Skin-skin contact– Razors, poor hand washing – ~ 10 organisms to cause infection

• Health care facilities (hospital-acquired)– staff hygiene – inadequate surface cleaning– Immunocompromised patients

Burn Center • Extremely immunocompromised

patients– Loss of #1 protection: skin– Co-morbid factors:

• Heavy steroids, immune suppressing therapies

• Other infections• Invasive devices

– Catheters– ventilators

Burn Center Project• Why?

– In the U.S. MRSA causes more deaths then AIDS– Patients dying from infections rather than injury– Present conflicts:

• staff hygiene vs. patients already have inactive infection vs. environment

• Treating patients that come in carrying the organism reduces infection vs. treatment doesn’t reduce infections

• Hypothesis:– Contaminated environmental surfaces are the major

contributing factor to the number of patient infections

Project

• Preliminary environmental swabs• 500 environmental surfaces

– Patient areas: bed rails, pillows etc– Staff areas: offices, nurses stations etc.– Visitor areas: waiting room etc.

• Assess numbers of organisms• Calculate exposure of patients and staff• Genetic characterization

Procedures• Surface samples collected with “Chem wipes”• 100µL of sample spread plated onto NC Blood

Agar• Beta-hemolysis colonies streaked on to

Trypticase Soy Agar• Biochemical tests carried out:

– Gram Stain– Catalase– Tube coagulase– Slide coagulase– Poly-B sensitivity– Oxicillin plate (final MRSA decipher)

Preliminary data & ResultsArea Oxycillin plateFamily Waiting area phoneFamily Waiting area Chair 1Family Waiting area Chair 2 resistant Nutrition Rm Counter/CabinetsVideo/Game consol cartNurses Station West center phoneNurses Station West Counter resistantNurses Station East CounterBreak Room Table Clean Bed rails17 Bed rails7 Bed rails resistant11 Bed rails (only 2 ) resistantClean Bathroom floor resistant11 Bathroom floor resistant17 Bathroom floor7 Bathroom floor resistant x2Clean Bedside Table resistant17 Bedside Table10 Beside Table resistant7 Bedside TableClean Linen Basket11 Linen Basket17 Linen Basket7 Linen BasketClean Family chair11 Family chair resistant10 Family chairTub Room curtain 1

-11 out of 30 samples test positive for MRSA

- identification of “hotspots” for next surface samples

Future Study

• Burn patient cultures and assessment of number of MRSA present

• Water testing of Burn center tub room water for presence of MRSA and top infectious pathogens

Questions??