WISCONSIN STATE LABORATORY OF HYGIENEWISCONSIN STATE LABORATORY OF HYGIENE 1

Analysis and Comparison Analysis and Comparison of Cumulative Statewide of Cumulative Statewide Antibiograms for Antibiograms for Wisconsin, 2006 and 2008Wisconsin, 2006 and 2008

Christina M. Carlson1, Tam T. Van2, Steve A. Marshall2, David M. Warshauer2, and Peter A. Shult2

1MPH Program, University of Wisconsin - Madison2Wisconsin State Laboratory of Hygiene, Communicable Diseases Division

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Antimicrobial Resistance: An Antimicrobial Resistance: An ever-increasing public health ever-increasing public health problemproblem• U.S. Healthcare-associated infections:

-1.7 million infections (1 in 10 patients)

-99,000 associated deaths/yr-6.7 billion annual economic burden (2002)

• Staphylococcus aureus->95% of penicillin resistant

-60% methicillin resistant

• >20% of all Enterococcus infections resistant to Vancomycin

Source: CDC. 2009. Antimicrobial resistance in healthcare settings fact sheet.

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Antimimicrobial Resistance: Antimimicrobial Resistance: TrendsTrends

0

10

20

30

40

50

60

70

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Year

Per

cen

t R

esis

tan

ce

Methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA) Among ICU Patients, 1995-2004

0

5

10

15

20

25

30

35

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Year

Per

cen

t R

esis

tan

ce

Vancomycin-resistant EnterocociAmong ICU Patients,

1995-2004

0

5

10

15

20

25

30

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Year

Per

cen

t R

esis

tan

ce

3rd generation cephalosporin-resistant Klebsiella pneumoniae Among ICU

Patients,1995-2004

05

101520

2530

3540

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

Year

Per

cen

t R

esis

tan

ce

Fluoroquinolone-resistant Pseudomonas aeruginosa Among ICU

Patients,1995-2004

Source: CDC: National Nosocomial Infections Surveillance System. 2009.

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Antibiogram:Antibiogram:

An overall profile of the antibiotic susceptibility of an organism to a collection of antimicrobial agents routinely tested and used

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

• Monitor resistance trends• Reveal emergence of potential novel resistance • Aid clinicians in empiric treatment of infections• Problem: Lack of standardized data• Clinical Laboratory Standards Institute

guidelines for preparation of antibiograms

WISCONSIN STATE LABORATORY OF HYGIENEWISCONSIN STATE LABORATORY OF HYGIENE 5

A Cumulative Statewide A Cumulative Statewide Antibiogram for WisconsinAntibiogram for Wisconsin

• Compare WI’s antimicrobial susceptibility status in 2006 and 2008

• Assess current challenges and needs regarding antimicrobial susceptibility testing (AST) in WI

Study Goals:

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MethodsMethods

• Preparation of cumulative antibiogram

-requested 2008 antibiograms from 135 clinical/ reference laboratories in WI

-calculated average % susceptibility for selected antimicrobial agent-organism combinations

-2008 cumulative susceptibility patterns compared with 2006

• Evaluation of antibiograms

-CLSI M39-A2 and M100-S19 documents

-WI adherence to CLSI guidelines compared with adherence nationally

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Local & regional anti-biograms received Local & regional anti-biograms received from WI healthcare facilities performing ASTfrom WI healthcare facilities performing AST

• 47 of the 87 (54%) healthcare facilities performing AST contributed antibiograms in 2006 and 2008

• 28 common sites provided antibiograms in 2006 and 2008

Provided an antibiogram in 2008

Provided an antibiogram in 2006

Provided an antibiogram in both 2006 & 2008

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Comparison of local/regional antibiograms in WI and nationwide meeting CLSI recommendations

• WI antibiograms showed at least 70% compliance to 4 of the 6 CLSI elements analyzed

• Adherence to CLSI guidelines in 2008 WI antibiograms, as compared to 2006, improved in all elements analyzed, except 1) reporting verified susceptibility results and 2) indicating the use of duplicates

0

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verifiedreports

collectionperiod

(MM/YY)

reportpercent

susceptibile

speciesorganized

bymorphology

duplicatehandled

less than 10isolates

Pe

rce

nt

(%)

Nationwide

Wisconsin 2006

Wisconsin 2008

Nationwide data is from: Zapantis et. al. 2005 JCM, 43:2629. It includes antibiograms from 2000 – 2002.

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WI cumulative statewide antibiogram for 2008Indicates a ≥10% decrease in susceptibility as compared

to 2006Indicates a ≥10% increase in susceptibility as compared to 2006

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WI cumulative statewide antibiogram for 2008Indicates a ≥10% decrease in susceptibility as compared

to 2006Indicates a ≥10% increase in susceptibility as compared to 2006

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Conclusions

• WI healthcare facilities can improve on current antibiograms by: 1) excluding duplicates from their data and indicating so 2) excluding susceptibility data for organisms with <10

isolates

• WI susceptibility data for 2008 is largely comparable to that of 2006, and overall susceptibility patterns in WI show less resistance compared to the nation

• Susceptibility patterns among multiple organism-agent combinations between 2006 & 2008 statewide antibiograms suggest the need for increased adherence to CLSI practice guidelines in WI

• Statewide antibiograms should only be used for surveillance purposes and not to guide empiric therapy for individual patients YET…

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Future Directions

• Develop a standardized & sustainable strategy to the development of an annual statewide antibiogram for WI

-survey a subset of high capacity laboratories in each public health region

-a more precise and accurate statewide antibiogram useful to facilities that cannot/do not

compile their own

• Continued development of WSLH-sponsored surveys, workshops, teleconferences, webinars aimed at monitoring & improving AST practices in WI healthcare facilities

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Acknowledgements

Capstone CommitteeCapstone Committee Steve Marshall, MS David Warshauer, PhD Christopher Olsen, DVM, PhD

WI State Laboratory of HygieneWI State Laboratory of Hygiene Charles Brokopp, DrPH Peter Shult, PhD Tam Van, PhD (CDC EID Fellow)

UW MPH ProgramUW MPH Program Patrick Remington Barbara Duerst Heather Cote