Methicillin Resistant Staphylococcus aureus (MRSA) in the Community: Epidemiology and Management

1. Methicillin ResistantStaphylococcus aureus (MRSA)in the Community:Epidemiology and Management Rachel Gorwitz, MD, MPH Division of Healthcare Quality Promotion Centers for Disease Control and Prevention

2. 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

3. MRSA Strain Characteristics Were Initially Distinct

4. National Database of MRSA Pulsed-Field Types (Highlighted PFTs: historically community-associated) PFT MLST SCCmec 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

5. 100% 100% 100% 100% 80% 80% 80% 80% 60% 60% 60% 60% Pneumonia (AL, AR, IL, MD, TX, WA) Pneumonia (AL, AR, IL, MD, TX, WA) Pneumonia (AL, AR, IL, MD, TX, WA) Pneumonia (AL, AR, IL, MD, TX, WA) Missouri Missouri Missouri Missouri California California California California Athletes Athletes Athletes Athletes Pennsylvania Pennsylvania Pennsylvania Pennsylvania Colorado Colorado Colorado Colorado Mississippi Mississippi Mississippi Mississippi Texas Texas Texas Texas Prisoners Prisoners Prisoners Prisoners Georgia Georgia Georgia Georgia Tennessee Tennessee Tennessee Tennessee Texas Texas Texas Texas Children Children Children Children Missouri Missouri Missouri Missouri California California California California USA300-114 USA300-114 USA300-114 USA300-114 Community Community Community Community USA100 USA100 USA100 USA100 Hospital Strain Hospital Strain Hospital Strain Hospital Strain Hospital Strain Hospital Strain Hospital Strain Hospital Strain USA200 USA200 USA200 USA200 A Single Pulsed-Field Type (USA300) has Accounted for Most Community-Associated MRSA Infections in the U.S. 100% 100% 80% 80% 60% 60% Pneumonia (AL, AR, IL, MD, TX, WA) Pneumonia (AL, AR, IL, MD, TX, WA) Missouri Missouri California California Athletes Athletes Pennsylvania Pennsylvania Colorado Colorado Mississippi Mississippi Texas Texas Prisoners Prisoners Georgia Georgia Tennessee Tennessee Texas Texas Children Children Missouri Missouri California California USA300-114 USA300-114 Community Community USA100 USA100 Hospital Strain Hospital Strain Hospital Strain Hospital Strain USA200 USA200

6. 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

7. 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

10. Crowding Factors that Facilitate Transmission

11. Frequent Contact Defense Offense Crowding Factors that Facilitate Transmission

12. Frequent Contact Defense Offense Crowding Compromised Skin Factors that Facilitate Transmission

13. Frequent Contact Defense Offense Crowding Contaminated Surfaces and Shared Items Compromised Skin Factors that Facilitate Transmission

14. Frequent Contact Defense Offense Cleanliness Crowding Contaminated Surfaces and Shared Items Compromised Skin Factors that Facilitate Transmission

15. Frequent Contact Crowding Defense Offense Cleanliness Antimicrobial Use Contaminated Surfaces and Shared Items Compromised Skin Factors that Facilitate Transmission

16. 2004/2005 ABCs MRSA Surveillance Areas Minnesota New York Oregon Connecticut California Maryland Colorado Tennessee Georgia Total Population: ~ 16.3 million

17. 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

18. Black White Black White Incidence, Cases per 100,000 CA-MRSA Incidence Varies by Age and Race Atlanta, 2001-2002 Baltimore, 2002 26 per 100,000 18 per 100,000 Age Group (yr) Age Group (yr) • Fridkin et al NEJM 2005;352:1436-44

19. Healthcare-Associated Community-Associated Most Invasive MRSA Infections Are Healthcare-Associated 86% 14% Klevens et al JAMA 2007;298:1763-71

20. Incidence of Invasive CA-MRSA Infections and Deaths by AgeActive Bacterial Core surveillance (ABCS), 2005 Incidence per 100,000 persons Overall Incidence (all ages): Infections: 4.6 per 100,000 Deaths: 0.5 per 100,000 Klevens et al JAMA 2007;298:1763-71

21. 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

22. MRSA Was the Most Commonly Identified Cause of Purulent SSTIs Among Adult ED Patients (EMERGEncy ID Net), August 2004 59% (97% USA300) 54% 39% 15% 55% 74% 51% 68% 60% 60% 72% 67% Moran et al NEJM 2006;355:666-674

23. S. aureus Nasal ColonizationNational Health and Nutrition Examination Survey 2001-02 S. aureus: 32.4% = 89.4 M people MRSA: 0.8% = 2.3 M people MRSA colonization associated with age >= 60 years & being female

24. Clindamycin Resistance Among MRSA Isolates, Texas Children’s Hospital, Houston Texas,2001-2004 n=181 n=163 n=915 n=1192 n=198 n=551 Source: Hulten et al. PIDJ 2006;25:349-53, and Kaplan et al. Clin Infect Dis 2005;40:1785-91

25. 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.

26. 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

27. Strategies for Clinical Management of MRSA in the Community http:www.cdc.gov/ncidod/dhqp/ar_mrsa_ca.html

28. 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?

29. 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

30. Management of Skin Infections in the Era of CA-MRSA • I&D should be routine for purulent skin lesions

31. Management of Skin Infections in the Era of CA-MRSA • I&D should be routine for purulent skin lesions • Obtain material for culture

32. 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

33. 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

34. 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

35. 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

36. 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!

37. 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

38. 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

39. Clinical Considerations - Management Antimicrobial Selection (SSTIs) • Not optimal for MRSA (High prevalence of resistance or potential for rapid development of resistance): • Macrolides • Fluoroquinolones

40. D-zone test for Inducible Clindamycin Resistance E CC • 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

41. 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

42. 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.

43. 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

44. 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

45. 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

46. 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.

47. DHQP Posters and Patient Tear Sheet http://www.cdc.gov/mrsa

48. CA-MRSA Working Group Meeting Participants, July 2004 Gordon L. Archer Carol L. Baker Elizabeth Bancroft Henry F. Chambers Robert S. Daum Jeffrey S. Duchin Monica Farley James Hadler Jim Jorgensen Sheldon K. Kaplan Newton E. Kendig Kathleen Harriman Franklin D. Lowy Ruth Lynfield J. Kathryn MacDonald Loren Miller Gregory Moran Olga Nuno John H. Powers L. Barth Reller Nalini Singh Marcus Zervos Craig Zinderman CDC Daniel B. Jernigan* John Jernigan* Jay C. Butler Denise Cardo Roberta Carey Rachel Gorwitz Jeffrey C. Hageman Thomas Hennessy James M. Hughes Jean Patel Fred Tenover J. Todd Weber *Meeting Co-Chair

49. Questions? DHQP Inquiries hip@cdc.gov