Microbiological analysis of tunneled hemodialysis catheters isolated from patients receiving hemodialysis in Saskatchewan.

ABSTRACT

Aim: To compare the microbial communities inside hemodialysis catheters from symptomatic and asymptomatic patients to determine their differences.Materials & methods: Catheters (n = 41) were removed from patients in the Saskatchewan Health Authority over an 18-month period. The catheter section inside the body was flushed and the contents were evaluated using culture-dependent and culture-independent analysis.Results: All catheters were colonized by bacteria, with considerable overlap between groups based on microbial communities and the individual species detected. More Gram-negative species were detected by sequencing, whereas predominantly Gram-positive strains were cultured. Antibiotic resistance and biofilm formation was widespread and not correlated with either catheter group.Conclusion: Common pathogens were detected in each set of catheters, therefore predicting infections based on the microbiology is difficult.

Many patients use catheters to help clean their blood, a process called hemodialysis. The use of catheters is also associated with complications, such as blood infections. We looked at the types of bacteria associated with catheters from patients who had infections (n = 21) and compared them to catheters from patients who had no signs of infection (n = 20). Once removed from the patient, we flushed out each catheter and tried to grow bacteria in different conditions. We also looked at DNA from within the catheter to identify bacterial species that were present. All 41 catheters had bacteria and there were many common species detected. We detected species known to cause illness such as Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas, Enterobacter, Morganella and Stenotrophomonas species. S. aureus was only grown from patients that had infections. Resistance to antibiotics was found to be common in bacteria grown from catheters. This did not seem to be influenced by whether patients were infected or not. Finally, we identified several catheters where two species, S. epidermidis and P. aeruginosa, were detected together. Our main conclusion was that bacteria are commonly present inside catheters that are used for hemodialysis, regardless of whether patients are infected or not.