DOD: Methicillin Resistant Staphylococcus aureus (MRSA)

Staphylococcus aureus

30 different species

Spherical, Gram +, Form irregular clusters like grapes

Facultative anaerobe

Nonmotile, non spore-forming

Staphylococcus aureus

Normal microbiota of skin and nose of healthy people

~30% of individuals colonized

Staphylococcus aureus primary infections

local cutaneous (folliciltis)

Staphylococcus aureus systemic infections

Osteomyelitis – bone infection

Pneumonia – lung infection

Endocarditis – heart infection

virulence factor of Staphylococcus aureus: coagulase

enzyme that coagulates blood plasma

virulence factor of Staphylococcus aureus: Hemolysins

toxin that kills (lyse) RBC

diaginosis of mersa

lab test- coagulase, ferment, etc

prevention of mersa in community

Wash hands

Keep cuts/scrapes covered/clean

Avoid contact with other people’s wounds or bandages

Avoid sharing personal items such as towels or razors

prevention of mersa in healthcare

Wash hands constantly

Glove use and proper use

Masks when needed

Gowns when needed

Appropriate device handling

Correct handling of laundry

in the us how many carriers of mrsa is there

2.3 million carries (2 percent of pop)

people in ICU because of mrsa in 1974 and 2004

1974 – 2% Staph. infections were MRSA

2004 – 64% Staph. Infections were MRSA

how many serious mrsa infections are there per year

80,000 people with 11,285 deaths in 2011 (~84% HA-MRSA, ~16% CA-MRSA)

treatment of mrsa

Drain boil/abscess – by healthcare provider

Vancomycin or teicoplanin

new antibiotics approved by fda

Vancomycin or teicoplanin

Now strains of MRSA showing resistance to these antibiotics

Vancomycin intermediate-resistant Staphylococcus aureus (VISA) - 1997

New antibiotics approved by FDA

Linezolid (Zyvox)

Daptomycin (Cubicin)

CA-MRSA

Rise in Community-associated MRSA

Rise in Community-associated MRSA people who are affected

People who have been recently hospitalized or had a medical procedure

Young and healthy

Prisoners, athletes, children, military recruits

• ppl in tight corders

usually CA-MRSA is susceptible to

more types of antibiotics

HA-MRSA main reservoirs

infected or colonized patients

what else can be a reservoir for HA MRSA

personnel but are mostly links for transmission between patients

main mode of transmission of mrsa

hands

Healthcare-associated MRSA (HA-MRSA)

Frequent MRSA infections among persons in hospitals and healthcare facilities

Healthcare-associated MRSA (HA-MRSA) has

Have weakened immune systems

Have wounds and open sores

Repeated exposure to antibiotics

methicillin 1959

was first semisynthetic penicillin designed against penicillinases

timeline for mrsa

Staphylococcus aureus developed resistance – first problem in UK in 1961

Outbreaks in U.S. in late 1960’s

So prevalent that methicillin use is discontinued in the U.S.

what is methicillin resistant to

other antibiotics – oxacillin, penicillin, amoxicillin, cephalosporins