Background: The duration of colonization with CRE and its relevance for future infection remain unclear. We assessed risk factors for recurrent CRE culture in patients with a history of positive urine or sterile site culture, and evaluated time to new positive culture.
Methods: The Georgia Emerging Infections Program performs active population-based laboratory surveillance for CRE in Atlanta. We conducted a retrospective chart review of CRE cases in which a carbapenem-nonsusceptible E. coli, Klebsiella spp., or Enterobacter spp. was isolated from urine or a sterile site from 8/2011-12/2014. The first positive culture for a patient was considered an incident case, and isolation of the same organism >30 days later was considered recurrence. The mean number of recurrences, time to recurrence, and time from first to last positive culture were assessed. Logistic regression was performed to identify risk factors for recurrence.
Results: Of 454 patients with a positive CRE culture, 69 (15.2%) had recurrence (see figure), with a mean of 1.87 recurrent cases, a mean time to first recurrence of 4.4 months, and a mean time from first to last positive culture of 8.3 months (range 1-36 months). In univariate analysis, hospitalization in <=1 year (81.2% v 54.5%, p<0.0001), a central line (62.3% v 42.9%, p = 0.003), longer follow-up from positive culture to study end (792.4 days v 641.5 days, p=0.0002), ICU stay after culture (27.5% v 16.8%, p=0.04), and culture with Klebsiella pneumoniae (97.1% v 48.1%, p<0.0001) or a carbapenemase-producing organism (23.2% v 11%, p=0.006) were associated with recurrence, but culture site (17.1% from sterile site v 14.8% from urine) was not (p=0.62). In multivariable analysis, hospitalization in <=1 year (OR 3.04, 95% CI 1.58-5.85), central line (OR 2.46, 95% CI 1.39 - 4.34), and increased follow-up time (OR 1.001 per day, 95% CI 1.000-1.002) predicted recurrent positive culture.
Conclusion: We observed CRE recurrence over a prolonged time period, with length of follow-up time strongly associated with recurrence. This suggests that patients may remain colonized for years. Therefore, empiric antibiotic therapy may need to cover CRE and duration of contact isolation may need to be prolonged in patients with a history of colonization or infection.
M. E. Sexton,
J. T. Jacob, None