Download - Methicillin Resistant Staphylococcus aureus (MRSA) in the Community: Epidemiology and Management
Methicillin ResistantStaphylococcus aureus (MRSA)
in the Community:Epidemiology and Management
Rachel Gorwitz, MD, MPHDivision of Healthcare Quality Promotion
Centers for Disease Control and Prevention
Staphylococcus aureus Staphylococcus aureus: common cause of
infection in the community
Methicillin-resistant Staphylococcus aureus (MRSA):– Increasingly important cause of healthcare-
associated infections since 1970s– In 1990s, emerged as cause of infection in
the community
MRSA Strain Characteristics Were Initially Distinct
MRSA in Healthcare
MRSA in the Community
Prevalent genotypes (U.S.) USA100, USA200
USA300, USA400
Antimicrobial resistance Multiple agents
Few agents
SCCmec (genetic element carrying mecA resistance gene)
Types I-III Types IV, V
PVL toxin gene Rare Common
Dice (Opt:0.50%) (Tol 1.3%-1.3%) (H>0.0% S>0.0%) [0.0%-100.0%]
100
9080706050
PFT SCCmecMLST pvl
USA300 8 IV POS
USA700 72 IV NEG
USA100 5 I I NEG
USA800 5 IV NEG
USA400 1 IV POS
USA500 8 IV, I I NEG
USA1000 59 IV NEG/POS
USA900 15 MSSA NEG
USA600 45 I I NEG
USA200 36 I I NEG
USA1100 30 IV POS
USA1200 MSSA POS
McDougal et al J Clin Micro 2003;41:5113-5120
National Database of MRSA Pulsed-Field Types (Highlighted PFTs: historically community-associated)
100
%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA) 1
00%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA) 1
00%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA) 1
00%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA) 1
00%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA) 1
00%
80%
60%
Athletes
Prisoners
Children
Hospital StrainHospital Strain
MissouriCalifornia
Texas
Pennsylvania
Texas
MississippiColorado
Georgia
Missouri
Tennessee
USA300-114USA100USA200
CommunityCalifornia
Pneumonia (AL, AR, IL, MD, TX, WA)
A Single Pulsed-Field Type (USA300) has Accounted for Most Community-Associated MRSA Infections in the U.S.
Community-Associated MRSA:CDC Population-Based Surveillance Definition
MRSA culture in outpatient setting or 1st 48 hours of hospitalization AND patient lacks risk factors for healthcare-associated MRSA:– Hospitalization– Surgery– Long-term care– Dialysis– Indwelling devices– History of MRSA
Outbreaks of MRSA in the Community
Often first detected as clusters of abscesses or “spider bites”
Various settings– Sports participants– Inmates in correctional facilities– Military recruits– Daycare attendees– Native Americans / Alaskan Natives– Men who have sex with men– Tattoo recipients– Hurricane evacuees in shelters
Factors that Facilitate Transmission
Crowding
Frequent ContactCrowding
Factors that Facilitate Transmission
Frequent ContactCrowding
Compromised Skin
Factors that Facilitate Transmission
Frequent Contact
Contaminated Surfacesand Shared Items
Crowding
Factors that Facilitate Transmission
Compromised Skin
Frequent Contact
Cleanliness
Crowding
Contaminated Surfacesand Shared ItemsCompromised Skin
Factors that Facilitate Transmission
Contaminated Surfacesand Shared Items
Frequent Contact
Cleanliness
Crowding
Compromised Skin
Factors that Facilitate Transmission
Antimicrobial Use
2004/2005 ABCs MRSA Surveillance Areas
Total Population: ~ 16.3 million
Oregon
CaliforniaColorado
Tennessee
Georgia
Maryland
Connecticut
New YorkMinnesota
CA-MRSA Infections are Mainly Skin Infections
Disease Syndrome (%)
Skin/soft tissue 1,266 (77%)Wound (Traumatic) 157 (10%)Urinary Tract Infection 64 (4%)Sinusitis 61 (4%)Bacteremia 43 (3%)Pneumonia 31 (2%)
Fridkin et al NEJM 2005;352:1436-44
Age Group (yr)
Atlanta, 2001-2002 Baltimore, 2002
0
10
20
30
40
50
60
70
80
<2 2-18 19-64 >64
01020304050607080
<2 2-18 19-64 >64
Incidence, Cases per 100,000
Age Group (yr)
BlackWhite
BlackWhite
CA-MRSA Incidence Varies by Age and Race
26 per 100,000 18 per 100,000
•Fridkin et al NEJM 2005;352:1436-44
Most Invasive MRSA Infections Are Healthcare-Associated
Healthcare-Associated
Community-Associated
Klevens et al JAMA 2007;298:1763-71
14% 86%
Incidence of Invasive CA-MRSA Infections and Deaths by Age
Active Bacterial Core surveillance (ABCS), 2005
0
2
4
6
8
10
<1 1 2-4 5-17 18-34 35-49 50-64 >64
Age in years
Infections DeathsIncidence per 100,000 persons
Klevens et al JAMA 2007;298:1763-71
Overall Incidence (all ages):Infections: 4.6 per 100,000Deaths: 0.5 per 100,000
S. aureus-Associated Skin and Soft Tissue Infections in Ambulatory Care
11.6 million ambulatory care visits per year in 2001-03 for skin infections typical of S. aureus
Increase in hospital outpatient and ED visits (2001-03 versus 1992-94)
McCaig et al Emerg Infect Dis 2006;12:1715-1723
54%
51%
60%60%
67%
74%
39%
15%
55%
68%
72%
59%(97% USA300)
MRSA Was the Most Commonly Identified Cause of Purulent SSTIs Among Adult ED
Patients (EMERGEncy ID Net), August 2004
Moran et al NEJM 2006;355:666-674
S. aureus Nasal ColonizationNational Health and Nutrition Examination Survey 2001-02
0
5
10
15
20
25
30
35
40
45
50
1--5 6--11 12--19 20--29 30--39 40--49 50--59 60--69 70+
Age (years)
Pre
va
len
ce
(%
)
Male
Female
S. aureus: 32.4% = 89.4 M people
MRSA: 0.8% = 2.3 M people
MRSA colonization associated with age >= 60 years & being female
0
5
10
15
20
Year 1 Year 2 Year 3
% C
linda
myc
in R
esis
tant
Community Onset, Healthcare-associated MRSA
Community-associated MRSA
Clindamycin Resistance Among MRSA Isolates, Texas Children’s Hospital, Houston Texas,2001-2004
n=551
n=915 n=1192n=198
n=163
n=181
Source: Hulten et al. PIDJ 2006;25:349-53, and Kaplan et al. Clin Infect Dis 2005;40:1785-91
Emerging Multi-Drug Resistance in USA300?
Clusters of USA300 isolates with multiple resistance to erythromycin, clindamycin, tetracycline, ciprofloxacin, and mupirocin1
Resistance to ≤ one class of antibiotics other than beta-lactams is still the most common resistance pattern in MRSA USA300
TMP/SMX resistance rare in MRSA USA300
1Diep et al Lancet 2006. Han et al J Clin Micro 2007.
PFGE type
No. (%) of
nosocomial
cases(n = 49)
USA300 10 (20)
USA100 21 (43)
USA500 18 (37)
USA800 0 (0)
Distribution of PFGE types among MRSA isolates from nosocomial
bloodstream infectionsGrady Memorial Hospital, 2004
Seybold U, et al. Clin Infect Dis 2006;42:647-656
Strategies for Clinical Management of MRSA in the Community
http:www.cdc.gov/ncidod/dhqp/ar_mrsa_ca.html
Clinical Considerations - Evaluation
MRSA belongs in the differential diagnosis of skin and soft tissue infections (SSTI’s) compatible with S. aureus infection:
Abscesses, pustular lesions, “boils”
“Spider bites”
Cellulitis?
Clinical Considerations - Evaluation MRSA should also be considered in differential
diagnosis of severe disease compatible with S. aureus infection:
– Osteomyelitis
– Empyema
– Necrotizing pneumonia
– Septic arthritis
– Endocarditis
– Sepsis syndrome
– Necrotizing fasciitis
– Purpura fulminans
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or
toxin-testing should guide management
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or
toxin-testing should guide management Empiric antimicrobial therapy may be
needed
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or
toxin-testing should guide management Empiric antimicrobial therapy may be
needed Alternative agents have +’s and –’s: More
data needed to identify optimal strategies
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or toxin-
testing should guide management Empiric antimicrobial therapy may be needed Alternative agents have +’s and –’s: More
data needed to identify optimal strategies Use local data for treatment
0%10%20%30%40%50%60%70%80%
CenterA
CenterB
CenterC
CenterD
Total
Pe
rce
nta
ge
CA
-MR
SA
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or
toxin-testing should guide management Empiric antimicrobial therapy may be
needed Alternative agents have +’s and –’s: More
data needed to identify optimal strategies Use local data for treatment Patient education is critical!
Management of Skin Infections in the Era of CA-MRSA
I&D should be routine for purulent skin lesions
Obtain material for culture No data to suggest molecular typing or
toxin-testing should guide management Empiric antimicrobial therapy may be
needed Alternative agents have +’s and –’s: More
data needed to identify optimal strategies Use local data for treatment Patient education is critical! Maintain adequate follow-up
Clinical Considerations - Management
Antimicrobial Selection (SSTIs)
Alternative agents (More data needed to establish effectiveness!):– Clindamycin – Potential for inducible resistance,
Relatively higher risk of C. difficile associated disease?
– TMP/SMX – Group A strep isolates commonly resistant
– Tetracyclines – Not recommended for <8yo
– Rifampin – Not as a single agent
– Linezolid – Expensive, Potential for resistance with inappropriate use
Clinical Considerations - Management
Antimicrobial Selection (SSTIs)
Not optimal for MRSA (High prevalence of resistance or potential for rapid development of resistance):
– Macrolides
– Fluoroquinolones
D-zone test for Inducible Clindamycin Resistance
CCE
-Perform on erythromycin-resistant, clindamycin-susceptible S. aureus isolates-Clinical implications unclear, but treatment failures have occurred-Does not require pre-treatment or co-treatment with erythromycin in vivo
Management of Severe / Invasive Infections
Vancomycin remains a 1st-line therapy for severe infections possibly caused by MRSA
Other IV agents may be appropriate Consult an infectious disease specialist.
Final therapy decisions should be based on results of culture and susceptibility testing
Severe community-acquired pneumonia: Vancomycin or linezolid if MRSA is a consideration*
*IDSA/ATS Guidelines for treatment of CAP in adults: Mandell et al. CID 2007;44:S27-72
Screening and Decolonization In general, colonization cultures of infected or
exposed persons in community settings are not recommended. (May have a role in public health investigations).
Decolonization regimens:– May have a role in preventing recurrent infections
(more data needed to establish efficacy and optimal regimens for use in community settings).
– After treating active infections and reinforcing hygiene and appropriate wound care, consider consultation with an infectious disease specialist regarding use of decolonization when there are recurrent infections in an individual patient or members of a household.
Preventing Transmission Persons with skin infections should keep
wounds covered, wash hands frequently (always after touching infected skin or changing dressings), dispose of used bandages in trash, avoid sharing personal items.
Uninfected persons can minimize risk of infection by keeping cuts and scrapes clean and covered, avoiding contact with other persons’ infected skin, washing hands frequently, avoiding sharing personal items.
www.cdc.gov
Preventing Transmission Exclusion of patients from school, work, sports
activities, etc should be reserved for those that are unable to keep the infected skin covered with a clean, dry bandage and maintain good personal hygiene.
In general, it is not necessary to close schools to “disinfect” them when MRSA infections occur.
In ambulatory care settings, use standard precautions for all patients (hand hygiene before and after contact, barriers such as gloves, gowns as appropriate for contact with wound drainage and other body fluids).
www.cdc.gov
Role of Pets Greatest risk of Staph aureus / MRSA exposure in
most humans is other humans When household pet animals carry MRSA, likely
acquired from a human Transmission of MRSA from an infected or
colonized pet to a human is possible, but likely accounts for a very small proportion of human infections
Reasonable to consider pet as a source if transmission continues in a household despite optimizing other control strategies
Little evidence that antimicrobial-based eradication therapy is effective in pets; however, colonization tends to be short-term*
Barton et al 2006;Can J Infect Dis Med Microbiol
Conclusions
New strains of MRSA have emerged in the community, with implications for management of skin infections and other staphylococcal infections.
Incision and drainage remains a primary therapy for purulent skin infections.
Oral treatment options are available for patients with skin infections that require ancillary antibiotic therapy.
Patient education on proper wound care is a critical component of case management for patients with skin infections.
Strategies focusing on increased awareness, early detection and appropriate management, enhanced hygiene, and maintenance of a clean environment have been successful in controlling clusters / outbreaks of infection.
DHQP Posters and Patient Tear Sheet
http://www.cdc.gov/mrsa
CA-MRSA Working Group Meeting Participants, July 2004
Gordon L. ArcherCarol L. BakerElizabeth BancroftHenry F. ChambersRobert S. DaumJeffrey S. DuchinMonica FarleyJames HadlerJim JorgensenSheldon K. KaplanNewton E. KendigKathleen HarrimanFranklin D. LowyRuth LynfieldJ. Kathryn MacDonaldLoren Miller
Gregory MoranOlga NunoJohn H. PowersL. Barth RellerNalini SinghMarcus ZervosCraig Zinderman
CDCDaniel B. Jernigan*John Jernigan*Jay C. ButlerDenise CardoRoberta CareyRachel GorwitzJeffrey C. HagemanThomas HennessyJames M. HughesJean PatelFred TenoverJ. Todd Weber
*Meeting Co-Chair