Analysis and Comparison of
Cumulative Statewide
Antibiograms for Wisconsin,
2006 and 2008
Christina M. Carlson1, Tam T. Van2, Steve A. Marshall2, David
M. Warshauer2, and Peter A. Shult2
1MPH
Program, University of Wisconsin - Madison
2Wisconsin State Laboratory of Hygiene, Communicable
Diseases Division
WISCONSIN STATE
LABORATORY OF HYGIENE
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Antimicrobial Resistance: An everincreasing public health problem
• 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.
WISCONSIN STATE
LABORATORY OF HYGIENE
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Antimimicrobial Resistance: Trends
Methicillin (oxacillin)-resistant
Staphylococcus aureus (MRSA)
Among ICU Patients, 1995-2004
35
Percent Resistance
60
50
40
30
20
10
25
20
15
10
5
04
20
03
20
02
20
01
20
00
20
99
19
98
19
97
19
19
95
19
04
20
03
20
02
20
01
20
00
20
99
19
98
19
97
19
96
19
95
19
96
0
0
Year
Year
Year
WISCONSIN STATE
LABORATORY OF HYGIENE
Source: CDC: National Nosocomial Infections Surveillance
System. 2009.
04
20
03
20
02
20
01
20
00
20
99
19
04
20
03
20
02
20
01
20
00
20
99
19
98
19
97
19
96
19
95
0
98
5
19
10
19
15
19
20
97
35
30
25
20
15
10
5
0
96
25
95
Fluoroquinolone-resistant
Pseudomonas aeruginosa Among ICU
40
Patients,1995-2004
Percent Resistance
3rd generation cephalosporin-resistant
Klebsiella pneumoniae Among ICU
30
Patients,1995-2004
19
Percent Resistance
30
19
Percent Resistance
70
Vancomycin-resistant Enterococi
Among ICU Patients,
1995-2004
Year
3
Antibiogram:
An overall profile of the antibiotic susceptibility of an
organism to a collection of antimicrobial agents
routinely tested and used
•
•
•
•
•
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 HYGIENE
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
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A Cumulative Statewide Antibiogram
for Wisconsin
Study Goals:
• Compare WI’s antimicrobial
susceptibility status in 2006 and 2008
• Assess current challenges and needs
regarding antimicrobial susceptibility
testing (AST) in WI
WISCONSIN STATE
LABORATORY OF HYGIENE
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Methods
• 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
WISCONSIN STATE
LABORATORY OF HYGIENE
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Local & regional anti-biograms received from 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 2006
Provided an antibiogram in 2008
Provided an antibiogram in both 2006 & 2008
WISCONSIN STATE
LABORATORY OF HYGIENE
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Comparison of local/regional antibiograms in WI
and nationwide meeting CLSI recommendations
100
Percent (%)
90
80
Nationwide
70
Wisconsin 2006
Wisconsin 2008
60
50
40
30
20
10
0
verified
reports
•
•
collection
period
(MM/YY)
report
percent
susceptibile
species
organized
by
morphology
duplicate
handled
less than 10
isolates
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
WISCONSIN STATE
LABORATORY OF HYGIENE
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
Indicates a ≥10% decrease in susceptibility as compared to 2006
for 2008
Indicates a ≥10% increase in susceptibility as compared to 2006
WISCONSIN STATE
LABORATORY OF HYGIENE
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WI cumulative statewide antibiogram
Indicates a ≥10% decrease in susceptibility as compared to 2006
for 2008
Indicates a ≥10% increase in susceptibility as compared to 2006
WISCONSIN STATE
LABORATORY OF HYGIENE
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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…
WISCONSIN STATE
LABORATORY OF HYGIENE
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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
WISCONSIN STATE
LABORATORY OF HYGIENE
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Acknowledgements
Capstone Committee
UW MPH Program
 Steve Marshall, MS
 Patrick Remington
 David Warshauer, PhD
 Barbara Duerst
 Christopher Olsen, DVM, PhD  Heather Cote
WI State Laboratory of Hygiene
 Charles Brokopp, DrPH
 Peter Shult, PhD
 Tam Van, PhD (CDC EID Fellow)
WISCONSIN STATE
LABORATORY OF HYGIENE
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