Escherichia coli Bacteremia Trends over Five Years: Progressively Rising Incidence and Decreasing Antibiotic Resistance

Abstract

Monitoring the microbiology of positive blood cultures (BCs) revealed a rising proportion of E. colibacteremia (ECB). We examined the trend, causes and antibiotic resistance over 5 years. Retrospective review of BC in a 772-bed teaching hospital in Detroit, Michigan from adult (≥18 years) inpatients and the emergency center (1/1/2012–12/31/2016). All BCs with E. coli(identified by Vitek® 2, bioMerieux, 2012–15 and MALDI-TOF MS, Bruker, 2016) were selected and patient medical records were reviewed. Each patient was counted once. The number of ECB, the source and antibiotic susceptibility (determined using Vitek® 2 AST-XN06 and GN69 cards) were recorded. The yearly rate of ECB, patient characteristics and antibiotic susceptibility were compared. E. coliwas encountered in 1336 BCs among 767 patients. The rate (per 1000 discharges) steadily increased (table). Patient age, the use of indwelling urinary catheters (IUC) and the source of ECB did not change overtime but diabetes frequency decreased. Quinolone, trimethoprim/sulfa, aminoglycosides, cephalosporin resistance and the frequency of isolates with extended-spectrum b lactamases decreased. Trends (%) of E. coli bacteremia in adults over a 5 year period. a: Extended Mantel–Haenszel test for linear trends; b: per 1000 discharges. Trends (%) of E. coli bacteremia in adults over a 5 year period. a: Extended Mantel–Haenszel test for linear trends; b: per 1000 discharges. ECB is steadily rising while the frequency of antibiotic resistance and patients with diabetes is decreasing. The reason for ECB rise is uncertain. The decline in antibiotic resistance may be a reflection of improved antibiotic stewardship. Prospective study is warranted to identify the reasons for increased ECB and to institute control measures. All authors: No reported disclosures.