Methods: Retrospective study evaluating MINO use in adults at NewYork-Presbyterian Hospital from 2012-2017. Patients included received MINO ≥ 2 days for a culture-positive gram-negative infection (CDC/NHSN criteria) susceptible to MINO. Patients with MINO started > 5 days after positive culture or with untreated polymicrobial infections were excluded. The primary outcome was clinical failure at the end of therapy. Secondary outcomes included 30-day mortality, development of resistance or recurrence within 90 days.
Results: 114 pts were included: majority were male (51%) with median age 57 yrs. Median duration was 12 days with 8 pts receiving high-dose MINO (≥ 150 mg q12H). S. maltophilia was the most prevalent pathogen (72%) followed by Klebsiella pneumoniae (16%) with a median MINO MIC of 1 mg/L. 68% of pts received combination therapy. Treatment success was observed in 71 pts (63%). Pts with treatment failure had higher median Charlson Comorbidity Index (5 vs. 3; p=0.026), SOFA score (7 vs. 5; p=0.028), and were more likely to have underlying leukemia or lymphoma (39% vs. 7%; p<0.001). No differences were seen in primary or secondary outcomes between combination and monotherapy regimens. MICs had no impact on failure outcome, 30-day mortality or 90-day recurrence (all p>0.05); however, MICs ≤ 2 mg/L were associated with increased development of resistance (34% vs. 12%; p=0.021). In a multivariable analysis, vasopressor use (OR 2.79; 95%CI 1.05,7.41; p = 0.04) and underlying leukemia/lymphoma (OR 4.49; 95%CI 1.26,15.95; p = 0.02) were associated with increased risk of treatment failure.
Conclusion: MINO MIC impacted resistance, but did not correlate with treatment failure, mortality or recurrence. Severity of illness and comorbidities but not choice of MINO may be associated with clinical failures.