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1. MRSA in Our Community Tony Chang, MD
Primary Care Case Conference
August 2, 2006
2. Staphylococcus aureus
3. Objectives What kind of skin infections are associated with Staphylococcus aureus?
What is community-acquired methicillin-resistant Staphylococcus aureus (ca-MRSA)?
How much of a problem is ca-MRSA around the country?
How much of a problem is it in Madison?
4. Cellulitis
5. Clinical Case Mr. N is a 58 year old man who presents to with a nonhealing right lower leg skin infection beginning 1 month ago.
6. PMFS PMH
Hypertension
Hypothyroidism
Depression
Glaucoma
FH/SH
Parents deceased
Youngest of 12
4 sisters with diabetes
Married with 2 children
Quit smoking 1973
6-8 drinks per week
Enjoys curling
7. Meds NKDA
Cephalexin 500 mg 4 times daily
Atenolol 50 mg daily
Synthroid 100 mcg daily
Ranitidine 150 mg twice daily as needed
Xalatan, Betimol
8. Exam Afebrile, BP 134/66, HR 72, RR 16
Original scrape: 1 cm ulcer, dark base, partially covered by dry epithelial roof
Another 5 mm ulcer similar in appearance
17 satellite lesions 1-3 mm, some pustular
Pustule unroofed with #15 scalpel and cultured
9. Folliculitis Pustules that appeared after treatment with topical steroid and occlusion with plastic wrap.Pustules that appeared after treatment with topical steroid and occlusion with plastic wrap.
10. Culture Results Resistant to
Cefazolin
Erythromycin
Oxacillin Sensitive to
Vancomycin
Clindamycin
11. MRSA in Hospital vs. Community Hospital
multiresistant
clonal
catheter infections Community
pauciresistant
polyclonal (?)
skin diseases
pneumonia MRSA in patients at risk are likely to be of the multiresistant hospital type, whereas those in patients without risks are likely to be more susceptible but more invasive.MRSA in patients at risk are likely to be of the multiresistant hospital type, whereas those in patients without risks are likely to be more susceptible but more invasive.
12. Furuncle (boil) S. aureus is the most common pathogenS. aureus is the most common pathogen
13. MRSA around the country What is the incidence of ca-MRSA?
What type of infections are associated with ca- MRSA?
What portion of S. aureus skin infections are caused by ca-MRSA?
How serious are these skin infections?
How is ca-MRSA transmitted?
14. Baltimore, Atlanta, Minnesota Study Design:
Prospective population-based surveillance supplemented by patient interviews
11 Baltimore hospitals
Health District 3 in Greater Atlanta
Laboratory-based surveillance in Minnesota
12 Minnesota hospitals Methicillin-Resistant Staphylococcus aureus Disease in Three CommunitiesMethicillin-Resistant Staphylococcus aureus Disease in Three Communities
15. Baltimore, Atlanta, Minnesota Patients with MRSA: 194 patients excluded from the non-interviewed group for unclear reasons194 patients excluded from the non-interviewed group for unclear reasons
16. Baltimore, Atlanta, Minnesota
17. Baltimore, Atlanta, Minnesota
18. Baltimore, Atlanta, Minnesota
19. Baltimore, Atlanta, Minnesota
20. Baltimore, Atlanta, Minnesota Observations:
Annual disease incidence
25.7/100,000 in Atlanta
18.0/100,000 in Baltimore
6% were invasive
77% involved skin and soft tissue
23% of patients were then hospitalized
21. Erysipelas A superficial cellulitis with lymphatic involvement. Group A and Group G Strep. A superficial cellulitis with lymphatic involvement. Group A and Group G Strep.
22. Los Angeles Study Design:
Retrospective review of records of 843 patients
Wound cultures that grew MRSA
January 15, 2003 – April 15, 2004
14/843 (1.7%) had necrotizing fasciitis Necrotizing Fasciitis Caused by Community-Associated Methicillin-Resistant Staphylococcus aureus in Los Angeles.Necrotizing Fasciitis Caused by Community-Associated Methicillin-Resistant Staphylococcus aureus in Los Angeles.
23. Los Angeles Observations:
Risk factors: injection drug use, diabetes, chronic hepatitis C, cancer, HIV/AIDS
All isolates susceptible to clindamycin, TMP-SMX, rifampin
All isolates were the same genotype USA300
24. Necrotizing Fasciitis
25. Saint Louis Study Design:
Retrospective cohort study and nasal-swab survey of 84 St. Louis Rams football players and staff members
Investigation of an outbreak of MRSA abscesses A Clone of Methicillin-Resistant Staphylococcus aureus among Professional Football Players.A Clone of Methicillin-Resistant Staphylococcus aureus among Professional Football Players.
26. Saint Louis Observations:
During 2003 season, 8 MRSA infections occurred among 5/58 players
Infections occurred at turf-abrasion sites
Risk factors:
lineman or linebacker position, high BMI
All isolates were genotype USA300-0114
27. Saint Louis Observations:
No MRSA recovered from nasal or environmental samples
MSSA recovered from whirlpools and taping gel and from 35/84 nasal swabs (42%)
28. Nasal carriage
29. Atlanta Study Design:
Prospective laboratory surveillance to identify S. aureus recovered from skin and soft tissue
Determine the proportion of infections caused by community-acquired MRSA
Grady Health System in Atlanta
8/1/2003 – 11/15/2003 Emergence of Community-Acquired Methicillin-Resistant Staphylococcus aureus USA 300 Clone as the Predominant Cause of Skin and Soft-Tissue Infections.Emergence of Community-Acquired Methicillin-Resistant Staphylococcus aureus USA 300 Clone as the Predominant Cause of Skin and Soft-Tissue Infections.
30. Atlanta Observations: ca-MRSA: USA300 (99% )and USA400 (1%). Other MRSA: USA100 (25%), USA500 (63%), USA800 (12%)ca-MRSA: USA300 (99% )and USA400 (1%). Other MRSA: USA100 (25%), USA500 (63%), USA800 (12%)
31. Impetigo honey-yellow firmly adherent crust. Primarily a Staph disease, but Strep can also coexist/coinfect.honey-yellow firmly adherent crust. Primarily a Staph disease, but Strep can also coexist/coinfect.
32. S. aureus at UWHC
33. MRSA prevalence at UWHC
34. Brown Recluse Spider Bite
35. Brown Recluse Spider Bite
36. Cutaneous Anthrax
37. Recommendations Be aware that ca-MRSA is on the rise
Have a low threshold for obtaining culture
especially for “spider bites”
Recognize more invasive infections
necrotizing fasciitis
septic thrombophlebitis
pneumonia
38. Continuing Questions For common skin infections, what empiric antibiotic do I use?
What about nasal carriage?
Is it useful to obtain nasal cultures?
If positive, is attempted eradication recommended?
39. Special Thanks Carol Spiegel, PhD
Department of Pathology & Laboratory Medicine