171. Rising Rates of Gram-Negative Bacilli Blood Stream (GNB-BSI) Infection in Adults

Abstract Background Monitoring bloodstream infections provides updates of the microbiology and antibiotic susceptibility trends. We elected to examine GNB-BSI. Methods We retrospectively studied adults (≥18 years old) inpatients with gram-negative bacilli (GNB) bloodstream infection (BSI; January 1, 2010–December 31, 2017), determined the demographics, onset place, microbiology and source. The results were stratified to study year and evaluated by the extended Mantel–Haenszel chi square for linear trends. Results GNB were encountered in 4520/14314 (31.6%) positive blood culture (BC) accounting for 2811 BSI episodes (2291 patients) with a steadily increasing rate (table). The 3 most common organisms were Escherichia coli (EC; 44.4%), Klebsiella pneumoniae (KP; 19.2%) and Pseudomonas aeruginosa (PA; 9.6%). GNB-BSI rate increase was mainly in EC-BSI (P = 0.01). The rate of other GNB-BSI did not change. Source distribution of EC-BSI did not change and antibiotic resistance did not change. Conclusion GNB-BSI is rising, primarily due to EC, without changes in source distribution or antibiotic susceptibility. Prospective studies to look at EC lineage and virulence factors are needed to determine the reason for EC-BSI rise. Disclosures All authors: No reported disclosures.