Epidemiology of Escherichia coli Sequence Type 131 in a Veterans Affairs Medical Center
Escherichia coli sequence type 131 (ST131), characterized by fluoroquinolone (FQ) resistance and extended-spectrum β-lactamase production, has emerged as a major health threat. We assessed ST131's prevalence in a Veterans Affairs Medical Center (VAMC), and examined epidemiological and clinical associations.
From 10/12/2010-4/25/2011, consecutive E. coli isolates from the Minneapolis VAMC clinical microbiology laboratory were characterized for antimicrobial susceptibility and ST131 status. Epidemiological, clinical, and outcomes data from medical record review were assessed for associations with ST131.
Of 311 unique isolates, 61 (19.6%) were ST131. Overall, most isolates were from urine (84%), followed by wounds (13%), respiratory samples (3%), and others (1%). The sole ST131-associated epidemiological factor was long-term care facility (LTCF) exposure (33% for ST131, vs. 14% for others; P = .001). Clinically, ST131 was not significantly associated with indicators of severe infection, including SIRS, fever, sepsis, or intensive care unit admission, and was significantly negatively associated with dysuria (10% vs. 26%; P = .01). Compared with non-ST131 isolates, ST131 isolates were more likely to be resistant to FQs (85% vs. 8%; P < .001), ampicillin (77% vs. 34%; P < .001), ampicillin/sulbactam (69% vs. 26%; P < .001), gentamicin (36% vs. 3%; P < .001), and trimethoprim/sulfamethoxazole (31% vs. 17%; P = .02). ST131 also was significantly associated with discordant initial treatment, both overall (63% vs. 5%; P < .001) and among patients with evidence of infection (52% vs. 5%; P < .001). Despite this, recurrence (clinical and microbiological) and mortality (in hospital and all-cause) were similar between groups.
E. coli ST131, which accounted for nearly 20% of unique (by patient) E. coli isolates at our VA, was significantly associated with LTCF exposure, extensive antimicrobial resistance, and discordant therapy, but not with more severe infections or worse outcomes. Our findings support that ST131 is a LTCF-associated pathogen, but they challenge the notion that ST131 causes more severe or complicated disease, at least among veterans.
D. M. Drekonja,
S. Porter, None
C. Clabots, None
R. Amway, None
M. A. Kuskowski, None
J. R. Johnson, None
See more of: Poster Abstract Session