Early Clinical Failure Criteria for Gram-Negative Bloodstream Infections

According to data published in Clinical Microbiology and Infection, the risk for 28-day mortality or prolonged hospitalization can be estimated between 72 and 96 hours after detecting a Gram-negative bloodstream infection (GN-BSI), using early clinical failure criteria.

To develop an early clinical failure criteria, investigators identified 766 adults with community-onset GN-BSI who survived hospitalization for ≥72 hours. Of these, 225 had the unfavorable outcomes of 28-day mortality (n=53) or hospital length of stay >14 days from GN-BSI onset (n=156), or both (n=16). Multivariable logistic regression was then used to investigate the associations between clinical variables occurring 72 to 96 hours after GN-BSI and these unfavorable outcomes.

The factors identified as predictors of unfavorable outcomes after adjusting for Charlson Comorbidity Index and appropriateness of empirical antimicrobial therapy were: systolic blood pressure <100 mm Hg or vasopressor use (adjusted odds ratio [aOR], 1.8; 95% CI, 1.2-2.9), heart rate >100 beats/minute (aOR, 1.7; 95% CI, 1.1-2.5), respiratory rate ≥22 breaths/minute or mechanical ventilation (aOR, 2.1; 95% CI, 1.4-3.3), altered mental status (aOR, 4.5; 95% CI, 2.8-7.1), and white blood cell count >12,000/mm³ (aOR, 2.7; 95% CI, 1.8-4.1). The area under receiver operating characteristic curve of the early clinical failure criteria model in predicting unfavorable outcomes was 0.77: 0.84 in predicting 28-day morality and 0.71 for prolonged hospitalization.

The study suffered from common limitations found in retrospective studies, such as potential missing variables. Further, this work was conducted in 2 hospitals within the same healthcare system; including more centers would expand the diversity of the population and microbiology. In keeping with this, validation of the early clinical failure criteria in other geographical and healthcare settings would provide reassurances of its precision. Investigators also note that because these criteria were derived in hospitalized adults with community-onset GN-BSI, the results should not be extrapolated to children, and using prediction scores based on baseline variables remains more applicable in ambulatory settings.

The investigators concluded that, “these criteria may have clinical utility in the management of GN-BSI.” Specifically, in assisting the drive for short- vs long-course antimicrobials, the early clinical failure criteria might also improve the design of future clinical investigations examining the efficacy of empirical or definitive antimicrobial regimes.

Reference

Rac H, Gould AP, Bookstaver PB, Justo JA, Kohn J, Al-Hasan MN. Evaluation of early clinical failure criteria for Gram-negative bloodstream infections [published online May 31, 2019]. Clin Microbiol Infect. doi:10.1016/j.cmi.2019.05.017