Predictive scoring models for persistent gram-negative bacteremia that reduce the need for follow-up blood cultures: a retrospective observational cohort study

• Published in: BMC infectious diseases 2020-09, Vol.20 (1), p.1-680, Article 680
• Main Authors: Jung, Jongtak, Song, Kyoung-Ho, Jun, Kang Il, Kang, Chang Kyoung, Kim, Nak-Hyun, Choe, Pyoeng Gyun, Park, Wan Beom, Bang, Ji Hwan, Kim, Eu Suk, Park, Sang-Won, Kim, Nam Joong, Oh, Myoung-don, Kim, Hong Bin
• Format: Article
• Language: English
• Subjects: Abscesses; Analysis; Antibiotics; Bacteremia; Beta lactamases; Blood; Blood tests; Catheters; Chronic kidney failure; Cohort analysis; Confidence intervals; End-stage renal disease; Fever; Follow-up blood culture; Gram-negative bacteremia; Health aspects; Health services; Hemodialysis; Hospitals; Infection; Infections; Infectious diseases; Kidney diseases; Medical instruments; Medical treatment; Microorganisms; Multivariate analysis; Nosocomial infections; Observational studies; Persistent bacteremia; Predictive scoring model; Regression analysis; Risk analysis; Risk factor; Risk factors; Scoring models; Statistical analysis; β Lactamase
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-020-05395-8

Although the risk factors for positive follow-up blood cultures (FUBCs) in gram-negative bacteremia (GNB) have not been investigated extensively, FUBC has been routinely carried out in many acute care hospitals. We attempted to identify the risk factors and develop a predictive scoring model for positive FUBC in GNB cases. All adults with GNB in a tertiary care hospital were retrospectively identified during a 2-year period, and GNB cases were assigned to eradicable and non-eradicable groups based on whether removal of the source of infection was possible. We performed multivariate logistic analyses to identify risk factors for positive FUBC and built predictive scoring models accordingly. Out of 1473 GNB cases, FUBCs were carried out in 1268 cases, and the results were positive in 122 cases. In case of eradicable source of infection, we assigned points according to the coefficients from the multivariate logistic regression analysis: Extended spectrum beta-lactamase-producing microorganism (+ 1 point), catheter-related bloodstream infection (+ 1), unfavorable treatment response (+ 1), quick sequential organ failure assessment score of 2 points or more (+ 1), administration of effective antibiotics (- 1), and adequate source control (- 2). In case of non-eradicable source of infection, the assigned points were end-stage renal disease on hemodialysis (+ 1), unfavorable treatment response (+ 1), and the administration of effective antibiotics (- 2). The areas under the curves were 0.861 (95% confidence interval [95CI] 0.806-0.916) and 0.792 (95CI, 0.724-0.861), respectively. When we applied a cut-off of 0, the specificities and negative predictive values (NPVs) in the eradicable and non-eradicable sources of infection groups were 95.6/92.6% and 95.5/95.0%, respectively. FUBC is commonly carried out in GNB cases, but the rate of positive results is less than 10%. In our simple predictive scoring model, zero scores--which were easily achieved following the administration of effective antibiotics and/or adequate source control in both groups--had high NPVs. We expect that the model reported herein will reduce the necessity for FUBCs in GNB cases.