Characteristics of biofilms formed on non-tunneled hemodialysis catheters

Background

Microbial biofilms are mechanisms used by microorganisms that cause chronic infections in humans. In hemodialysis patients with catheter-related bacteremia, Staphylococcus aureus is an independent risk factor for both infectious complications and failure of bacteremia treatment. We analyzed the characteristics of biofilms formed by these Staphylococcus species on non-tunneled hemodialysis catheters.

Patients and methods

A total of 50 adult patients with end-stage renal disease receiving hemodialysis through non-tunneled catheters, whose catheters were removed for catheter-related bacteremia, were studied.

Results

Catheter cultures were positive in only 32 patients and staphylococcal biofilm was found in 25 patients. All biofilm producers were S. aureus. In tissue culture plate method, 2 were strong biofilm producers, 15 were moderate biofilm producers and 5 isolates were considered as weak biofilm producers. In tube method, there were no strong biofilm producers, 12 were moderate biofilm producers and 13 were weak biofilm producers. In Congo red agar method there were no strong biofilm producers, 10 were moderate biofilm producers and 15 isolates were weak biofilm producers.

Conclusion

Our study shows that S. aureus is the most common bacteria isolated from patients with catheter-related bacteremia. S. aureus is the predominant microorganism responsible for biofilm formation in the non-tunneled HD catheters. Tissue culture plate method is more sensitive to detect biofilm formation by S. aureus.