Is More Always Better? Effect of a Combination Pseudomonas Antibiogram on Levofloxacin Use and Patient Outcomes for Pneumonia in a Large Community Hospital

BACKGROUND: Evidence suggests that combination therapy for Pseudomonas pneumonia only provides mortality benefit in critically ill patients. In November 2015, the Antimicrobial Stewardship Subcommittee at Baptist Memorial Hospital-Memphis (BMH-Memphis) developed a combination Pseudomonasantibiogram and guideline, based on local susceptibilities, for critically ill patients with Hospital Acquired Pneumonia (HAP), Health Care Associated Pneumonia (HCAP), or Ventilator Associated Pneumonia (VAP). METHODS: This is a single center, retrospective study evaluating patients admitted to the BMH-Memphis medical intensive care unit (MICU) and surgical intensive care unit (SICU) with a diagnosis-related group (DRG) code for HAP, HCAP, or VAP.The primary objective of this study was to compare levofloxacin days of therapy per 1000 patient-days (DOT/1000 patient-days) before and after implementation of the combination Pseudomonas antibiogram guideline at BMH-Memphis. Secondary objectives included a comparison of individual levofloxacin orders, 30-day mortality, hospital length of stay (LOS), ICU LOS, 90-day incidence of extended spectrum β-lactamases (ESBLs), and 30-day readmission rates and incidence of Clostridium difficile. Adverse events including acute kidney injury and QTc prolongation were also evaluated pre- and post-implementation of the guideline. RESULTS: A total 150 patients were included in this study to meet power for the primary objective. Levofloxacin DOT/1000 patient-days was reduced by 3.4 days in the post-implementation period (P < 0.001) with a 63% reduction in individual levofloxacin orders (P < 0.001). Furthermore, there were significantly lower 30-day mortality rates in the post-implementation period, which persisted in a multivariate logistic regression analysis (P = 0.01). There was no difference in hospital or ICU LOS, 30 day readmission rates or incidence of Clostridium difficile,or 90-day incidence of ESBLs. There was also no difference in adverse events between the two study periods. CONCLUSION: This study demonstrates that the implementation of a combination anti-pseudomonal guideline can decrease levofloxacin use while reducing 30-day mortality rates without increasing hospital or ICU LOS. DISCLOSURES: All authors: No reported disclosures.