Category: Professional Posters
Purpose: Antibiotic therapy is essential for the treatment of cystic fibrosis (CF) lung infections. However, CF-specific airway pathophysiology and frequent antimicrobial exposure increase the risk of developing resistant infections. Antibiotic selection is generally based on previous culture information, if available, or institution-specific antibiograms. Most institutional antibiograms, including Children’s Mercy Kansas City (CMKC) exclude CF patient cultures. Hence, it can be a challenge to assess the appropriateness of empiric antibiotic selection and changes in susceptibility patterns. We report three-year data from a planned 10-year CF-specific antibiogram implemented at CMKC in 2016.
Methods: CF patient culture data collection started in 2016 and will continue until 2026. All CF patient cultures, sputum or throat swab, obtained at CMKC will be included in the CF antibiogram. Patients were identified via a microbiology report and the following data were collected for 2016-2018: demographics, microorganism isolates, and susceptibility information. Susceptibility information was reported for methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (PA), Achromobacter, Stenotrophomonas maltophila, and Burkholderia species.
Results: Comparing the 2016-2018 CF antibiogram to the hospital antibiogram, gram-positive and gram-negative microorganisms tested were less susceptible. CF isolates from sputum cultures were less susceptible than those from throat swabs. Both MSSA and MRSA had significantly lower susceptibility for clindamycin compared to hospital-wide rates (MSSA 70% vs 81%, MRSA 39% vs 84%, p<0.0001). MSSA and MRSA susceptibility rates for other antimicrobials tested in the CF antibiogram were similar to the hospital antibiogram. Over the three-year period, the hospital-wide prevalence of MRSA was higher than among the CF population (32-34% vs 27-28%). The most common gram-negative isolate for CF cultures was PA. For every antimicrobial tested, including aminoglycosides, PA isolates from CF patients were less susceptible than hospital-wide PA isolates. Over the three-year period, there did not appear to be any significant changes in susceptibility pattern for CF microorganisms tested.
Conclusion: The CF-specific antibiogram demonstrated significantly increased rates of clindamycin resistance for MRSA and MSSA isolates and more resistant PA isolates among CF patients. This has important clinical implications for empiric antimicrobial selection and will allow monitoring of resistance trends over time.