Staphylococcus aureus Resistance Patterns in Wisconsin: 2018 Surveillance of Wisconsin Organisms for Trends in Antimicrobial Resistance and Epidemiology (SWOTARE) Program Report.
Clin Med Res. 2019 Oct 03;:
Authors: Schulte RH, Munson E
OBJECTIVE: Surveillance of antimicrobial resistance patterns on a local level can reveal paradigms not obvious on a regional or national scale. Data collection from this perspective may potentially impact local prescription patterns and empiric treatment guidelines. The objective of this study was to establish a baseline Wisconsin Staphylococcus aureus antibiogram and to elucidate potential geographic and demographic factors associated with antimicrobial resistance.
DESIGN: Multi-center laboratory surveillance, with testing at a single site utilizing standardized media and susceptibility testing protocols METHODS: 309 isolates of clinically-significant Staphylococcus aureus were collected from hospital microbiology laboratories across Wisconsin in 2018, with distribution across seven geographic regions. Each isolate was tested using reference broth microdilution methods against a panel of 15 antimicrobial agents. Percentage susceptibility data, as well as median and 90th percentile minimum inhibitory concentration (MIC) values, were computed for each antimicrobial agent as a function of geographic region or demographic category.
RESULTS: Increased resistance to penicillin (≥ 86.0% of isolates), erythromycin (≥ 56.8%), cefoxitin (≥ 45.5%), levofloxacin (≥ 25.0%) and clindamycin (≥ 20.5%), was observed in the Southcentral, Lake Winnebago, and Southeast regions of Wisconsin. In addition, isolates phenotypically classified as methicillin-resistant S. aureus (MRSA) were found to have increased rates of resistance to clindamycin, erythromycin, and levofloxacin when compared S. aureus isolates susceptible to cefoxitin. S. aureus isolates demonstrated nearly 100% in vitro susceptibility to ceftaroline, dalbavancin, and telavancin. Statewide S. aureus isolates exhibited a vancomycin MIC90 of 1 μg/mL. S. aureus isolates from patients aged 20-39 years were more likely to demonstrate cefoxitin resistance when compared to other age groups (P ≤ 0.03), while isolates from patients ≥ 80 years were more likely to exhibit resistance to levofloxacin and clindamycin (P ≤ 0.046).
CONCLUSIONS: Several antimicrobial agents continue to demonstrate in vitro efficacy against clinical isolates of S. aureus (including MRSA) throughout Wisconsin, including three agents with recently-published susceptibility testing guidelines. However, continued surveillance efforts may be necessary in the Lake Winnebago, Southeast, and Southcentral regions to further assess higher rates of resistance to a number of antimicrobial agents.
PMID: 31582419 [PubMed - as supplied by publisher]