Introduction: Prophylaxis with gentamicin locking of chronic tunnelled central venous catheter branches in chronic haemodialysis patients reduces bacterial infections and morbidity and mortality associated with catheter bacteraemia.
Aim: We undertook a 7-year, prospective, observational study involving 101 patients on chronic haemodialysis with catheters treated with prophylaxis to evaluate the appearance of bacterial resistance to the antibiotic in pathogens usually sensitive to its action.
Material and methods: A protocol of universal asepsis in catheter management. Postdialysis intraluminal locking of the branches with gentamicin at 5mg/branch + 1% heparin sodium, monitoring trough levels in the blood and modifying the dose according to the established protocol. The diagnosis of bacteraemia was based on usual criteria. The main study variables were: Diagnosis by the bacteriology department of bacterial resistance in pathogens sensitive to gentamicin. Diagnosis of clinical ototoxicity. Secondary variables were: Patients hospitalised/bacteraemia; number of bacteraemia/catheter/1000 days; infectious mortality; and catheter withdrawal/bacteraemia. Pathogens found in blood culture.
Main variables: We found no resistance of pathogens usually sensitive to the antibiotic or clinical ototoxicity. The mean number of months each patient remained in the study was 23 (1-84). Secondary variables: Three patients (3%) were hospitalised due to bacteraemia; number of bacteraemias: 8; number of bacteraemia/catheter/1000 days: 0.11; infectious mortality per bacteraemia: 1 patient (1%); catheter withdrawal due to bacteraemia: 2 (2%). No patients were diagnosed with endocarditis or spondylodiscitis. The mean trough level of gentamicin in each patient during the study was 0.17µg/ml (0.05-0.31); the mean intraluminal gentamicin locking dose per branch was 3mg (2-5), equivalent to 1.1-1.7mg/ml/branch.
Conclusions: This 7-year, prospective observational study of 101 patients on chronic haemodialysis with tunnelled central venous catheters showed: 1) Prophylaxis with intraluminal gentamicin locking of the catheter branches does not cause bacterial resistance in pathogens sensitive to its action. 2) No clinical ototoxicity was seen. 3) The lack of resistance and ototoxicity may be influenced by the gentamicin prophylaxis dose used, which was much lower than in other studies.