Mortality and Length of Stay Associated With Community-Acquired Escherichia coli and Staphylococcus aureus...

Antimicrobial resistance disproportionally affects low- and middle-income countries. We calculated the burden of resistant and susceptible Escherichia coli and Staphylococcus aureus bloodstream infections (BSIs) in ACORN2, a prospective clinical surveillance study in adults and children.

Patients with culture-confirmed community-acquired susceptible and resistant E. coli (third-generation cephalosporin susceptible [3GC-S] and resistant [3GC-R]) and S. aureus (methicillin-resistant [MRSA] and methicillin-susceptible [MSSA]) BSIs were compared against blood culture-negative patients (controls). Cause-specific hazard ratios (HRs) were calculated for competing events of in-hospital mortality and discharge alive. Length of hospital stay (LOS) was calculated.

From 22 802 blood cultures taken, there were 329 E. coli (177 [53.8%] 3GC-R) and 363 S. aureus (132 [36.4%] MRSA) BSIs. In-hospital mortality was 8.4% for controls, 20.1% for E. coli (20.3% 3GC-R; 19.7% 3GC-S), and 13.1% for S. aureus (12.2% MRSA; 13.7% MSSA). 3GC-S but not 3GC-R E. coli BSI cases had higher adjusted hazard of death than controls (HRs, 1.73 [95% confidence interval {CI}, 1.20-2.49] and 1.38 [95% CI, .99-1.94]); risk of dying was the same for 3GC-S compared with 3GC-R infections (P = .882). Neither MSSA nor MRSA BSI patients were more likely to die than controls (HRs, 1.33 [95% CI, .91-1.93] and 1.00 [95% CI, .61-1.66]) nor MSSA versus MRSA (P = .891). The hazard of discharge alive for both resistant and susceptible S. aureus and E. coli decreased significantly when compared with controls. LOS was 2 (95% CI, 0-3) days and 1 (95% CI, -1 to 3) day longer for resistant compared with susceptible infections, for E. coli and S. aureus.

Antimicrobial-resistant infections were not associated with increased mortality in ACORN2. Drug-resistant BSI had longer LOS compared with susceptible infections, but CIs encompassed 0 days.