MRSA in Our Community Tony Chang, MD Primary Care Case Conference August 2, 2006

MRSA in Our MRSA in Our CommunityCommunity

Tony Chang, MDTony Chang, MD

Primary Care Case ConferencePrimary Care Case Conference

August 2, 2006August 2, 2006

Staphylococcus aureusStaphylococcus aureus

Electron micrograph from Visuals Unlimited

ObjectivesObjectives

What kind of skin infections are associated What kind of skin infections are associated with with Staphylococcus aureusStaphylococcus aureus??

What is community-acquired methicillin-What is community-acquired methicillin-resistant resistant Staphylococcus aureusStaphylococcus aureus (ca-MRSA)? (ca-MRSA)?

How much of a problem is ca-MRSA around How much of a problem is ca-MRSA around the country?the country?

How much of a problem is it in Madison?How much of a problem is it in Madison?

CellulitisCellulitis

Clinical CaseClinical Case

Mr. N is a 58 year old man who presents to with Mr. N is a 58 year old man who presents to with a nonhealing right lower leg skin infection a nonhealing right lower leg skin infection beginning 1 month ago.beginning 1 month ago.

Works at Oscar Meyer engineeringWorks at Oscar Meyer engineering Scraped his right leg climbing around freight elevator Scraped his right leg climbing around freight elevator Seen at IMC 2 days later - Augmentin x 10 daysSeen at IMC 2 days later - Augmentin x 10 days Seen at employee health - Cephalexin (day #8)Seen at employee health - Cephalexin (day #8) Soaking in a hot tubSoaking in a hot tub

PMFSPMFS

PMHPMH HypertensionHypertension HypothyroidismHypothyroidism DepressionDepression GlaucomaGlaucoma

FH/SHFH/SH Parents deceasedParents deceased Youngest of 12Youngest of 12 4 sisters with diabetes4 sisters with diabetes Married with 2 childrenMarried with 2 children Quit smoking 1973Quit smoking 1973 6-8 drinks per week6-8 drinks per week Enjoys curlingEnjoys curling

MedsMeds

NKDANKDA

Cephalexin 500 mg 4 times dailyCephalexin 500 mg 4 times daily Atenolol 50 mg dailyAtenolol 50 mg daily Synthroid 100 mcg dailySynthroid 100 mcg daily Ranitidine 150 mg twice daily as neededRanitidine 150 mg twice daily as needed Xalatan, BetimolXalatan, Betimol

ExamExam

Afebrile, BP 134/66, HR 72, RR 16Afebrile, BP 134/66, HR 72, RR 16 Original scrape: 1 cm ulcer, dark base, Original scrape: 1 cm ulcer, dark base,

partially covered by dry epithelial roofpartially covered by dry epithelial roof Another 5 mm ulcer similar in appearanceAnother 5 mm ulcer similar in appearance 17 satellite lesions 1-3 mm, some pustular17 satellite lesions 1-3 mm, some pustular

Pustule unroofed with #15 scalpel and culturedPustule unroofed with #15 scalpel and cultured

FolliculitisFolliculitis

Culture ResultsCulture Results

Resistant to Resistant to CefazolinCefazolin ErythromycinErythromycin OxacillinOxacillin

Sensitive toSensitive to VancomycinVancomycin ClindamycinClindamycin

Light growth Light growth Staphylococcus aureusStaphylococcus aureus

MRSA in Hospital vs. CommunityMRSA in Hospital vs. Community

HospitalHospital multiresistantmultiresistant clonalclonal catheter infectionscatheter infections

CommunityCommunity pauciresistantpauciresistant polyclonal (?)polyclonal (?) skin diseasesskin diseases pneumoniapneumonia

Mandell, Bennett, & Dolin: Principles and Practice of Infectious Diseases, 6th ed

Furuncle (boil)Furuncle (boil)

MRSA around the countryMRSA around the country

What is the incidence of ca-MRSA?What is the incidence of ca-MRSA? What type of infections are associated with ca- What type of infections are associated with ca-

MRSA?MRSA? What portion of What portion of S. aureusS. aureus skin infections are skin infections are

caused by ca-MRSA?caused by ca-MRSA? How serious are these skin infections?How serious are these skin infections? How is ca-MRSA transmitted?How is ca-MRSA transmitted?

Baltimore, Atlanta, MinnesotaBaltimore, Atlanta, Minnesota

Study Design:Study Design: Prospective population-based surveillance Prospective population-based surveillance

supplemented by patient interviewssupplemented by patient interviews 11 Baltimore hospitals11 Baltimore hospitals Health District 3 in Greater AtlantaHealth District 3 in Greater Atlanta

Laboratory-based surveillance in MinnesotaLaboratory-based surveillance in Minnesota 12 Minnesota hospitals12 Minnesota hospitals

NEJM 2005;352:1436-44.


Patients with MRSA:Patients with MRSA:

NEJM 2005;352:1436-44.

12,553 9,972 health-care associated MRSA

2,581

280 also health-care associated

1,063 interviewed

1518 783

1324

?

2107 suspected cases of ca-MRSA

1647 associated with clinical illness


NEJM 2005;352:1436-44.

AtlantaAtlanta BaltimoreBaltimore MinnesotaMinnesota

BacteremiaBacteremia 3030 77 66

MeningitisMeningitis 1 1 11 00

OsteomyelitisOsteomyelitis 1111 66 77

BursitisBursitis 1212 00 77

ArthritisArthritis 1313 00 22

Invasive ca-MRSA Infections


NEJM 2005;352:1436-44.


BacteremiaBacteremia 2%2% 6%6% 3%3%

MeningitisMeningitis <1% <1% 1%1% <1%<1%

OsteomyelitisOsteomyelitis 1%1% 5%5% 1%1%

BursitisBursitis 1%1% 00 1%1%

ArthritisArthritis 1%1% 00 1%1%

Invasive ca-MRSA Infections


NEJM 2005;352:1436-44.


Skin & soft tissueSkin & soft tissue 973973 9595 198198

WoundWound 136136 88 1313

PneumoniaPneumonia 2323 44 44

Urinary tractUrinary tract 5757 44 33

SinusSinus 6060 00 11

Other ca-MRSA Infections


NEJM 2005;352:1436-44.


Skin & soft tissueSkin & soft tissue 77%77% 83%83% 77%77%

WoundWound 11%11% 7%7% 10%10%

PneumoniaPneumonia 2%2% 3%3% 2%2%

Urinary tractUrinary tract 4%4% 3%3% 1%1%

SinusSinus 5%5% 00 <1%<1%

Other ca-MRSA Infections


Observations:Observations: Annual disease incidenceAnnual disease incidence

25.7/100,000 in Atlanta25.7/100,000 in Atlanta 18.0/100,000 in Baltimore18.0/100,000 in Baltimore

6% were invasive6% were invasive 77% involved skin and soft tissue77% involved skin and soft tissue 23% of patients were then hospitalized23% of patients were then hospitalized

NEJM 2005;352:1436-44.

ErysipelasErysipelas

Los AngelesLos Angeles

Study Design:Study Design: Retrospective review of records of 843 Retrospective review of records of 843

patientspatients Wound cultures that grew MRSAWound cultures that grew MRSA January 15, 2003 – April 15, 2004January 15, 2003 – April 15, 2004 14/843 (1.7%) had necrotizing fasciitis14/843 (1.7%) had necrotizing fasciitis

NEJM 2005;352:1445-53.

Los AngelesLos Angeles

Observations:Observations: Risk factors: injection drug use, diabetes, Risk factors: injection drug use, diabetes,

chronic hepatitis C, cancer, HIV/AIDSchronic hepatitis C, cancer, HIV/AIDS All isolates susceptible to clindamycin, TMP-All isolates susceptible to clindamycin, TMP-

SMX, rifampinSMX, rifampin All isolates were the same genotype USA300All isolates were the same genotype USA300

NEJM 2005;352:1445-53.

Necrotizing FasciitisNecrotizing Fasciitis

Cohen & Powderly: Infectious Diseases, 2nd ed

Saint LouisSaint Louis

Study Design:Study Design: Retrospective cohort study and nasal-swab Retrospective cohort study and nasal-swab

survey of 84 St. Louis Rams football players survey of 84 St. Louis Rams football players and staff membersand staff members

Investigation of an outbreak of MRSA Investigation of an outbreak of MRSA abscessesabscesses

NEJM 2005;352:468-75.


Observations:Observations: During 2003 season, 8 MRSA infections During 2003 season, 8 MRSA infections

occurred among 5/58 playersoccurred among 5/58 players Infections occurred at turf-abrasion sitesInfections occurred at turf-abrasion sites Risk factors: Risk factors:

lineman or linebacker position, high BMIlineman or linebacker position, high BMI All isolates were genotype USA300-0114All isolates were genotype USA300-0114

NEJM 2005;352:468-75.


Observations:Observations: No MRSA recovered No MRSA recovered

from nasal or from nasal or environmental samples environmental samples

MSSA recovered from MSSA recovered from whirlpools and taping whirlpools and taping gel and from 35/84 gel and from 35/84 nasal swabs (42%)nasal swabs (42%)

NEJM 2005;352:468-75.

Chris Massey of the St. Louis Rams

Nasal carriageNasal carriage

AtlantaAtlanta

Study Design:Study Design: Prospective laboratory surveillance to identify Prospective laboratory surveillance to identify

S. aureusS. aureus recovered from skin and soft tissue recovered from skin and soft tissue Determine the proportion of infections caused Determine the proportion of infections caused

by community-acquired MRSAby community-acquired MRSA Grady Health System in AtlantaGrady Health System in Atlanta 8/1/2003 – 11/15/20038/1/2003 – 11/15/2003

Ann Intern Med. 2006;144:309-17.

AtlantaAtlanta

Observations:Observations:

Ann Intern Med. 2006;144:309-17.

389Episodes of community-onset S. aureus skin and soft tissue infections

279 (72%)MRSA

110 (28%)MSSA

244 (87%)ca-MRSA

35 (13%)Other MRSA

ImpetigoImpetigo

S. aureusS. aureus at UWHC at UWHC

0

20

40

60

80

100

120

140

160

2000 2001 2002 2003 2004 2005 2006

MRSA

MSSA

Outpatient isolates of S. aureus from any site

MRSA prevalence at UWHCMRSA prevalence at UWHC

0

5

10

15

20

25

30

35

40

2000 2001 2002 2003 2004 2005 2006

%MRSA

Brown Recluse Spider BiteBrown Recluse Spider Bite

Brown Recluse Spider BiteBrown Recluse Spider Bite

Cutaneous AnthraxCutaneous Anthrax

Cohen & Powderly: Infectious Diseases, 2nd ed

RecommendationsRecommendations

Be aware that ca-MRSA is on the riseBe aware that ca-MRSA is on the rise Have a low threshold for obtaining cultureHave a low threshold for obtaining culture

especially for “spider bites”especially for “spider bites” Recognize more invasive infectionsRecognize more invasive infections

necrotizing fasciitisnecrotizing fasciitis septic thrombophlebitisseptic thrombophlebitis pneumoniapneumonia

Ann Intern Med. 2006;144:368-70.

Continuing QuestionsContinuing Questions

For common skin infections, what empiric For common skin infections, what empiric antibiotic do I use?antibiotic do I use?

What about nasal carriage?What about nasal carriage? Is it useful to obtain nasal cultures?Is it useful to obtain nasal cultures? If positive, is attempted eradication recommended?If positive, is attempted eradication recommended?

Special ThanksSpecial Thanks

Carol Spiegel, PhDCarol Spiegel, PhD Department of Pathology & Laboratory MedicineDepartment of Pathology & Laboratory Medicine

Documents

MRSA in Our Community Tony Chang, MD Primary Care Case Conference August 2, 2006