Clinical Characteristics Associated with Bacterial Bloodstream Coinfection in COVID-19

Inappropriate antibiotic use in COVID-19 is often due to treatment of presumed bacterial coinfection. Predictive factors to distinguish COVID-19 from COVID-19 with bacterial coinfection or bloodstream infection are limited.

We conducted a retrospective cohort study of 595 COVID-19 patients admitted between March 8, 2020, and April 4, 2020, to describe factors associated with a bacterial bloodstream coinfection (BSI). The primary outcome was any characteristic associated with BSI in COVID-19, with secondary outcomes including 30-day mortality and days of antibiotic therapy (DOT) by antibiotic consumption (DOT/1000 patient-days). Variables of interest were compared between true BSI (n = 25) and all other COVID-19 cases (n = 570). A secondary comparison was performed between positive blood cultures with true BSI (n = 25) and contaminants (n = 33) on antibiotic use.

Fever (> 38 °C) (as a COVID-19 symptom) was not different between true BSI (n = 25) and all other COVID-19 patients (n = 570) (p = 0.93), although it was different as a reason for emergency department (ED) admission (p = 0.01). Neurological symptoms (ED reason or COVID-19 symptom) were significantly higher in the true BSI group (p < 0.01, p < 0.01) and were independently associated with true BSI (ED reason: OR = 3.27, p < 0.01; COVID-19 symptom: OR = 2.69, p = 0.03) on multivariate logistic regression. High (15-19.9 × 10⁹/L) white blood cell (WBC) count at admission was also higher in the true BSI group (p < 0.01) and was independently associated with true BSI (OR = 2.56, p = 0.06) though was not statistically significant. Thirty-day mortality was higher among true BSI (p < 0.01). Antibiotic consumption (DOT/1000 patient-days) between true BSI and contaminants was not different (p = 0.34). True bloodstream coinfection was 4.2% (25/595) over the 28-day period.

True BSI in COVID-19 was associated with neurological symptoms and nonsignificant higher WBC, and led to overall higher 30-day mortality and worse patient outcomes.