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MRSA - Mary Merkle Design

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					    MRSA

     Alana Arnold, PharmD
     Clinical Coordinator
     Infectious Disease Specialist
     Children's Hospital Boston




1
    Objectives

       Definition - CA vs HA MRSA
       Transmission
       Prevalence
       Risk Factors
       Diagnosis
       Treatment
       Decolonization
       Prevention

2
    Antimicrobial Resistance

       The adaptive potential of the microbial world
        is such that for each new antibiotic that is
        introduced, several escape mechanisms are
        soon devised.
       The action of antibiotics and resistance are
        linked like light and shadow: one does not
        exist without the other.


3                                       Waldevogel, NEJM, 1999
    MRSA
    Definition

      Methicillin-resistant Staphylococcus
     aureus (MRSA) is a bacterium responsible
     for difficult-to-treat infections in humans.
     MRSA is by definition a strain of
     Staphylococcus aureus that is resistant to a
     large group of antibiotics called the beta-
     lactams, which include the penicillins and the
     cephalosporins.

4
    HA–MRSA
    Characteristics

       Hospital–associated strains of S.                        Courtesy of the CDC
        aureus still cause about 85% of all        This electron micrograph depicts
                                                   large numbers of Staphylococcus
        MRSA cases.                                aureus bacteria, which were
                                                   found on the inside surface of a
       Hospital patients with S. aureus           catheter. The sticky-looking
                                                   substance woven between the
        infections are five times more likely to   round cocci bacteria is known as
                                                   a “biofilm”. Biofilms help to
        die in the hospital than are patients      protect the bacteria.
        without the infection.
       Multi-drug resistant (MDR)
       Vancomycin is one of the few
        remaining treatments for HA-MRSA,
        but it is no longer effective in every
5       case due to rising MICs.
        Evolution
        From HA and CA-MRSA

        1961 – MRSA first described
        Until recently, most MRSA infections started in
         hospitals, especially among surgery and
         immunocompromised patients. (HA-MRSA)
        In the 1990s, new strains of MRSA began to strike
         healthy people in community settings. (CA-MRSA)
        These two types of MRSA are now known as
         hospital-associated MRSA (HA–MRSA) and
         community-associated MRSA (CA–MRSA).

6
    CA–MRSA
    Characteristics

       Staphyloccal bacteria that have become                   Courtesy of the CDC
        resistant to beta-lactam antibiotics but NOT
        multi-drug resistant (MDR).
       Several antibiotics remain effective against
        CA–MRSA, but it is an aggressive and
        rapidly evolving form of S. aureus.
       Usually appears as a skin infection, but it    Cutaneous abscess
        can spread quickly to a bloodstream            caused by methicillin–
        infection or a very serious form of            resistant
        pneumonia.                                     Staphylococcus aureus
                                                       bacteria.




7
    MRSA
    Prevalence

       Prevalence is increasing!!
        HA-MRSA in ICU patients
               1989 = 27%
               2005 = 60%
        CA-MRSA
               18 in 100,000 (Baltimore)
               26 in 100,000 (Atlanta)
               Some areas report > 10% incidence in ER skin infection visits

       Review your antibiogram to assess prevalence in
        your community.
       Review patient’s risk factors for MRSA

8
    CA-MRSA
    Transmission

       Direct person to person contact
       Sharing of towels or personal hygiene items
       Athletic equipment
       Clothes
       Drug use equipment
       Contact sports
       Food-borne

9
     Transmission of Methicillin-Resistant
     Staphylococcus aureus (MRSA)


        Most MRSA infections occur through direct contact with
         people or surfaces that carry the bacteria.
        Staph bacteria enter the body through skin cuts or
         abrasions and spread easily.
        Approximately 25-30% of people carry S. aureus on
         their bodies without becoming sick, but they can pass
         the germ to others, who may become ill.



10
     CA-MRSA
     Risk Factors

     May occur in healthy persons without traditional HA-MRSA
       associated risk factors.

     CA–MRSA typically occurs in;
        – Places where people have close contact, including childcare
          centers, nursing homes, prisons.
        – Certain populations (Pacific Islanders, Native Americans)
        – Contact sports (football, rugby, wrestling)
        – Sharing of towels, athletic equipment, personal items
        – Poor personal hygiene




11
     CA-MRSA and HA-MRSA
     Differences

                      CA-MRSA                                   HA-MRSA
     Infection Site   Skin and soft tissue infections (SSTIs)   Nosocomial pneumonia,
                      (pulmonary, bloodstream, urinary          catheter-related, UTI,
                      infections much less common)              bloodstream, or SSTI

     Antimicrobial    Usually susceptible to Bactrim,           Vancomycin, Linezolid
                      doxycycline, clindamycin, rifampin        Synercid, Daptomycin
     Susceptibility
     Risk Factors     Places where people have close            Recent hospitalization or
                      contact-childcare centers, nursing        surgery, history of recurrent
                      homes, and prisons.                       abscesses or recurrent skin
                      Certain populations (Pacific Islanders,   infection, Long term care
                      Native Americans)                         facility resident, IV drug user,
                      Contact sports (football, wrestling)      indwelling catheters, medical
                                                                conditions such as diabetes,
                      Sharing of towels, athletic equipment,    HIV, renal failure
                      personal items
                      Poor personal hygiene
12
     CA-MRSA
     Diagnosis

        Commonly complain of infected pimples, spider
         bites, or sores.
        Usually minor carbuncles, furuncles, abscesses.
        Can be more extensive cellulitis, deep-seated
         abscesses, septic arthritis, pneumonia and sepsis.
        Should be considered in the DDX of all SSTIs.
        Aerobic cultures should be obtained on all open
         lesions/ draining abscesses.


13
     CA-MRSA
     Treatment

        Some S. aureus infections can be treated
         without antibiotics by surgically draining the
         wound. Local incision and drainage and hot          Cultured Staphylococcus
         packs are first-line therapy for skin infections.   aureus on agar plate.

        Before prescribing an antibiotic, a doctor must
         determine if MRSA bacteria are present.
        Using the wrong drug delays treatment and
         encourages the development of more resistant
         bacteria.




14
     CH-MRSA
     Antibiotic Susceptibility

        Resistant to beta-lactam antibiotics
        Retain susceptibility to many other classes of
         antimicrobials such as;
         –   Bactrim
         –   Clindamycin
         –   Tetracyclines (Doxycycline/Minocycline/Tigecycline)
        HA-MRSA = MDR and only treated with vancomycin,
         linezolid, daptomycin or Synercid
        Abx based on culture confirmation and sensitivity
        Close follow-up in 24-48 hrs

15
     CA-MRSA
     Antibiotic Susceptibility

      Bactrim 99-100%
      Clindamycin ~50% (in Boston area)
       Clindamycin resistance is inducible – do not
       use for empiric therapy
      Tetracyclines – ?
        Do not use if patients <8yrs of age
     Others:
         Vancomycin, linezolid, daptomycin and Synercid

16
     CA-MRSA
     Antibiotic Regimens

      Bactrim 12-20 mg/kg/day divided q8-12hr
      Clindamycin 30 mg/kg/day PO divided q8hr
      Doxycycline 4 mg/kg/day PO divided q12hr
        Duration = 4 weeks
     Others:
         Vancomycin, linezolid, daptomycin and Synercid



17
     Patient Case

        JR is a 5 yr old boy with sulfa allergy who
         presents to ER with skin lesion and fever
        Would drained, culture done
        Empiric therapy ?
        MSSA or MRSA?
        Treatment duration?


18
     MRSA
     Decolonization

        Insufficient evidence to support use of topical or
         systemic antimicrobial therapy for eradicating MRSA
         colonization.
         –   Cochrane review of 6 trials with 384 participants
         –   Insufficient evidence to support the use of either topical or
             systemic agents
         –   Potential for serious adverse events and development of
             antimicrobial resistance
        Per CDC and NEHC, it may be reasonable when pt
         has multiple documented recurrences.
        Per NEHC consider Hibiclens washes from neck
         down x 5 days.

19
     MRSA
     Prevention

        Isolation and Contact Precautions within health
         care facilities
        Wash hands frequently and thoroughly.
        Use a hand sanitizer when soap and water are
         not available.
        Keep skin cuts clean and covered.
        Don’t touch another person’s skin wound or
         bandage.
        Avoid sharing personal items, such as towels,
         washcloths, and razors.
        Routine cleaning of athletic equipment
        Routine disinfection of countertops, exam tables
         or other treatable surfaces.
        All open wounds should be covered.
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