When is coagulase-negative Staphylococcus bacteraemia clinically significant?

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Clinical Diagnostics

Background:

• Coagulase-negative staphylococci (CoNS) are frequent contaminants in blood cultures (BC).
• Distinguishing true CoNS bloodstream infections from contamination is crucial for appropriate patient management.

Purpose of the Study:

• To develop and validate an algorithm for determining the clinical significance of CoNS bacteremia.
• To reduce misclassification of nosocomial bloodstream infections and inappropriate antibiotic therapy.

Main Methods:

• A prospective study analyzed 269 cases of CoNS bacteremia.
• Medical records were reviewed, and clinical significance was determined using CDC/NHSN criteria.
• Multivariate analysis identified predictors of clinical significance, and algorithm performance was compared.

Main Results:

• Of 269 cases, 97 (36%) were clinically significant bloodstream infections (CSB).
• Key predictors of CSB included time to positivity < 16 hours, identification of Staphylococcus epidermidis, central venous catheter presence, multiple positive bottles, and high Charlson score.
• The developed algorithm demonstrated 62% sensitivity and 93% specificity for identifying CSB.

Conclusions:

• The developed algorithm can aid in accurately identifying clinically significant CoNS bacteremia.
• Implementation of this algorithm may lead to more appropriate antibiotic treatment and fewer misdiagnosed infections.