Antipseudomonal Drug Exposure Associated with MDR Organisms in the Liver and Lung Transplant Population

BACKGROUND: Multi-drug resistant (MDR) Gram-negative bacteria (GNB) are an emerging complication in transplant recipients. This study describes the prevalence of and risk factors for MDR-GNB infection/colonization in the liver and lung transplant population. METHODS: Cross-sectional study with nested case-case–control included adult liver or lung transplant candidates/recipients from 1/10-7/16. Patients with a positive GNB culture were classified as MDR- or Susceptible (S)-cases; MDR was defined as in vitro resistance to ≥ 3 antibiotic classes. Patients without a positive GNB culture were controls. Primary variable of interest: antibiotic days of therapy (DOT) during time at risk. Patient and isolate characteristics were collected and compared. RESULTS: We included 150 patients: 110 (73%) liver, 40 (27%) lung. Median (IQR) patient age and Charlson comorbidity index were 59 years (52–63) and 5 points (3–6). Isolated organisms: 31 (34%) E. coli, 28 (31%) K. pneumoniae, 33 (36%) others. Resistance to cefepime, piperacillin/tazobactam, and ertapenem: 38%, 27%, and 14%. 61 (41%) MDR-GNB, 21 (14%) S-GNB, 68 (45%) controls. Median (IQR) cumulative antibiotic DOT was: MDR-case – 24.5 days (6–46.5), S-case – 5 days (2–24, P = 0.017 vs. MDR), controls – 0 days (0–10, P < 0.001 vs. MDR). Median (IQR) antipseudomonal (AP) DOT was: MDR-case – 7 days (1–16), S-case – 1 day (0–8, P = 0.055 vs. MDR), controls – 0 days (0–1, P < 0.001 vs. MDR); AP exposure was independently associated with MDR-GNB infection/colonization after correcting for severity of disease pre-transplant (adjOR: 2.9, 95% CI: 1.6–5.3) (Table 1). CONCLUSION: MDR-GNB represent a significant burden to the liver and lung transplant population. A detailed antibiotic history, including AP DOT, may help with risk assessment to guide empiric therapy selection. DISCLOSURES: S. L. Davis, Allergan: Grant Investigator and Scientific Advisor, Consulting fee and Research grant; Merck: Grant Investigator and Scientific Advisor, Consulting fee and Research grant