Between Community and Hospital: Healthcare-Associated Gram-Negative Bacteremia among Hospitalized Patients

Abstract

Objective.: Healthcare-associated, community-acquired bacteremia is a subcategory of community-acquired bacteremia distinguished by recent exposure of the patient to the healthcare system before hospital admission. Our objective was to apply this category to a prospective cohort of hospitalized patients with gram-negative bacteremia to determine differences in the epidemiological characteristics, treatment, and outcome of community-acquired bacteremia; healthcare-associated, community-acquired bacteremia; and hospital-acquired bacteremia.Design.: A 6-month prospective cohort study.Setting.: A 1,250-bed tertiary care hospital.Patients.: Adults hospitalized with gram-negative bacteremia.Results.: Among 250 patients, 160 (64.0%) had bacteremia within 48 hours after admission; 132 (82.5%) of these were considered to have healthcare-associated, community-acquired bacteremia, according to previously published criteria. For patients with healthcare-associated, community-acquired bacteremia, compared with patients with community-acquired bacteremia, malignancies (59 [44.7%] of 132 patients vs 3 [10.7%] of 28 patients; P = .001), open wounds at admission (42 [31.8%] vs 3 [10.7%]; P = .02), and intravascular catheter-related infections (26 [19.7%] vs 0; P = .009) were more frequent and Escherichia coli as a causative agent was less frequent (16 [57.1%] vs 33 [25.0%]; P = .001). There was no difference between these 2 groups in inadequate empirical antibiotic treatment (36 [27.3%] vs 6 [21.4%]; P = .5) and hospital mortality (18 [13.6%] vs 2 [[7.1%]; P = .5). Compared with 90 patients with hospital-acquired bacteremia, patients with healthcare-associated, community-acquired bacteremia had a higher Charlson score (odds ratio [OR], 1.31 [95% confidence interval (CI), 1.14–1.49]) but were less likely to have lymphoma (OR, 0.07 [95% CI, 0.01–0.51]), neutropenia (OR, 0.21 [95% CI, 0.07–0.61]), a removable foreign body (OR, 0.08 [95% CI, 0.03–0.20]), or Klebsiella pneumoniae infection (OR, 0.26 [95% CI, 0.11–0.62]).Conclusions.: Many cases of gram-negative bacteremia that occurred in hospitalized patients were healthcare associated. The patients differed in some aspects from patients with community-acquired bacteremia and from those with hospital-acquired bacteremia, but not in mortality.