An instant procedure to demonstrate catheter-tip colonization may help clinicians

Area of Science:

• Microbiology
• Infectious Diseases
• Medical Diagnostics

Background:

• Intravascular catheter use is associated with significant risks of colonization and bloodstream infections.
• Early and accurate detection of catheter colonization is crucial for patient management and preventing severe outcomes like catheter-related bloodstream infections (CRBSIs).
• Traditional culture methods for catheter-tip analysis require 24-48 hours for results.

Purpose of the Study:

• To compare the efficacy of acridine orange and Gram stains for external smear analysis of intravascular catheter tips.
• To evaluate whether performing staining before or after rolling the catheter tip on an agar plate influences diagnostic yield.
• To assess the predictive value of these staining methods for catheter colonization and CRBSIs.

Main Methods:

• A total of 425 intravascular catheter tips were processed.
• Staining techniques (acridine orange and Gram stain) were performed on external smears.
• Staining was randomly assigned to be performed either before (Group A) or after (Group B) rolling the catheter tip on an agar plate.
• Staining results were compared with subsequent culture results obtained 24-48 hours later.

Main Results:

• Catheter colonization was detected in 25.7% of tips, and CRBSIs were identified in 6.1% of patients.
• Group A (staining before culture) demonstrated superior sensitivity and negative predictive value for predicting colonization compared to Group B.
• For CRBSI prediction, Group A showed higher sensitivity and concordance than Group B, with both groups achieving 100% specificity in certain metrics.

Conclusions:

• Performing acridine orange or Gram staining on catheter tips before culture is a highly effective, rapid, and cost-efficient method.
• This pre-culture staining approach accurately anticipates catheter colonization and aids in ruling out CRBSIs.
• The procedure is simple to perform and significantly improves diagnostic yield compared to staining after initial culture plating.