Surveillance of Wisconsin Antibacterial Susceptibility Patterns

Document Type


Format of Original

8 p.

Publication Date



Wisconsin Medical Society

Source Publication

Wisconsin Medical Journal

Source ISSN



Background: Antimicrobial resistance presents a threat to quality patient care. Knowledge of local antibacterial susceptibility patterns can guide clinicians in empiric antibacterial administration and assist pharmacists and infectious disease physicians in development of appropriate therapeutic pathways.

Methods: To characterize Wisconsin antibacterial susceptibility patterns and elucidate geographic or temporal variation in antibacterial resistance, a retrospective, observational analysis of antibiogram data was performed. Seventy-two members of the Wisconsin Clinical Laboratory Network (WCLN) submitted antibiograms describing clinically significant isolates tested in calendar year 2013 to the WCLN Laboratory Technical Advisory Group.

Results: In the context of commonly reported antibacterial agents, data were compiled for approximately 75,800 isolates of Escherichia coli; 13,300 Klebsiella pneumoniae; 6300 Proteus mirabilis; 2800 Enterobacter cloacae; 8400 Pseudomonas aeruginosa; 30,000 S aureus; 11,200 coagulasenegative Staphylococcus spp; and 13,800 Enterococcus spp. P mirabilis isolates from northern Wisconsin were more likely to demonstrate resistance than those in the southern region. In contrast, P aeruginosa isolates from southern Wisconsin had decreased susceptibility to a number of agents when compared to other regions. Temporal trending in decreased E coli and P mirabilis susceptibility to fluoroquinolones and trimethoprim-sulfamethoxazole was observed. Increased methicillin-resistant Staphylococcus aureus (MRSA) rates were observed in northwest and southeast Wisconsin. In general, northeast Wisconsin exhibited less frequency of antibacterial resistance.

Conclusions: Geographic variation exists with respect to antibacterial resistance, particularly in areas of Wisconsin adjacent to large population centers of neighboring states. Antibacterial surveillance in Wisconsin is indicated on a regular basis to assess emerging trends in antibacterial resistance. Existing WCLN infrastructure allows for such investigations.


Wisconsin Medical Journal, Vol. 15, No. 1 (February 2016): 29-36. Publisher link.