Impact of locking solutions on conditioning biofilm formation in tunnelled haemodialysis catheters and inflammatory response activation

INTRODUCTION

The surface of tunnelled cuffed catheters provides an optimal environment for the development of biofilms, which have recently been described as conditioning films because of the presence of adherent biological materials. These biofilms are associated with infection and thrombosis and potentially increase patients' inflammatory response. These complications could be reduced by the use of locking solutions.

OBJECTIVE

To analyse biofilm formation, using confocal and electron microscopy, in tunnelled cuffed catheters locked with three different solutions and to determine the relationship between these solutions and inflammatory response.

STUDY DESIGN

This prospective study included 35 haemodialysis patients with tunnelled cuffed catheter removal for non-infection-related reasons. The participants were divided into three groups according to the lock solution used: (1) heparin 1: 5000 IU; (2) citrate 4%; and (3) taurolidine 1.35%, citrate 4% and heparin 500 IU (taurolock); in the latter group, 25,000 IU taurolidine-urokinase was used in the last weekly session. All tunnelled cuffed catheters were cultured, and the inner surface was evaluated with confocal and electron microscopy. The inflammatory profile of included patients was determined at tunnelled cuffed catheter removal.

RESULTS

There were no differences in clinical or demographic variables between the three subgroups. Biofilm thickness was lower in the taurolidine group than in the citrate 4% and heparin groups (28.85 ± 6.86 vs 49.99 ± 16.56 vs 56.2 ± 15.67 µm, respectively; p < 0.001), as was biofilm volume (1.01 ±1.18 vs 3.7 ± 2.15 vs 5.55 ±2.44, µm³, respectively; p < 0.001). The mean interleukin-6 value was 39%, which was 50% lower than in the citrate and heparin groups, but without significance differences.

CONCLUSION

Our results show that biofilms were found in all tunnelled cuffed catheters, but the thickness and volume were significantly lower in tunnelled cuffed catheters locked with taurolidine solution. Therefore, the type of locking solution used in tunnelled cuffed catheters should maintain tunnelled cuffed catheter sterility and prevent catheter-related bloodstream infections. No significant difference was observed in the inflammatory profile according to the type of locking solution.

P661 Relationship between streptococcal infective endocarditis and preneoplastic colorectal lesions

Background

Colorectal cancer is associated with infective endocarditis (IE), due to specific gut pathogens like streptococcus Gallolyticus that use the tumor presence as a point of blood entry. However, the association between streptococcal IE and pre-cancerous lesions such as dysplastic adenomas is unknown.

Objectives

To determine the association with pre-neoplastic colorectal lesions and streptococcal IE.

Methods

Two hundred eighty consecutive patients with IE were included in a protocol of clinical, microbiological and imaging follow-up, between January 2008 and December 2018. Precancerous lesions were divided as high and low-grade dysplasia based on World Health Organization criteria. Colorectal cancer was defined as the presence of malignant cell beyond the muscularis mucosa.

Results

A colonoscopy was performed in 81 patients (29%) and 26 of them (32%) presented colorectal lesions: 10 (38%) colorectal cancer and 16 (62%) precancerous lesions (12% high degree (n = 2); 88% low degree (n = 14)). Both, colorectal cancer (20% vs 11%; p = 0.02) and preneoplastic lesions (44% vs 8%; p &lt; 0.001) were associated with higher incidence of streptococcus Gallolyticus IE (Figure 1). Additionally, the subgroup of precancerous lesions with low degree also showed this association (43% vs 9%; p = 0.001).

Conclusions

Precancerous colorectal lesions are also associated with streptococcus Gallolyticus IE, even low-grade lesions. Hence, it is necessary to rule out occult neoplastic and preneoplastic colorectal lesions with colonoscopy in these patients.

Figure 1: Relationship between S. Gallolyticus IE and colorectal lesions.

a Statistical significance between colorectal cancer and S. Gallolyticus IE.

b Statistical significance between preneoplastic colorectal lesions and S. Gallolyticus IE.

Abstract P661 Figure.