Abstract. Tunneled catheters are widely used for the provision of hemodialysis. Long-term catheter survival is limited by tunneled catheter-related infections (CRI). This study assesses the efficacy of catheter-restricted filling with gentamicin and citrate in preventing CRI in hemodialysis patients. A doubleblind randomized study was conducted to compare heparin (5000 U/ml) with gentamicin/citrate (40 mg/ml and 3.13% citrate; ratio 2:1) as catheter-lock solutions. A total of 112 tunneled catheters in 83 patients were enrolled at the time of catheter insertion for commencement or maintenance of hemodialysis. The primary end point was CRI. Catheter malfunction, defined as blood flow rate of Ͻ200 ml/min for three consecutive dialyses and/or the use of urokinase, was also assessed as a secondary end point. Infection rates per 100 catheter-days were 0.03 in the gentamicin group versus 0.42 in the heparin group (P ϭ 0.003). Kaplan-Meier survival analyses showed mean infection-free catheter survival of 282 d (95% CI, 272 to 293 d) in the gentamicin group versus 181 d (95% CI, 124 to 237 d) in the heparin group (log rank, 9.58; P ϭ 0.002). Cox regression analyses showed a relative risk for infection-free catheter survival of 0.10 (95% CI, 0.01 to 0.92) in the gentamicin group when adjusted for gender, race, diabetes mellitus, catheter malfunction, and hemoglobin (P ϭ 0.042). The incidence of catheter malfunction was not significantly different between groups. Predialysis gentamicin levels were significantly higher in patients randomized to gentamicin (gentamicin/citrate: median 2.8 mg/L [range, 0.6 to 3.5 mg/L], n ϭ 5; heparin: median Ͻ0.2 mg/L [range Ͻ0.2 to 0.2 mg/L], n ϭ 5; P ϭ 0.008). Tunneled hemodialysis catheter-restricted filling with gentamicin and citrate is a highly effective strategy for prevention of CRI. Although citrate as a catheter-lock solution provides adequate anticoagulation for the interdialytic period, gentamicin levels suggest significant risk for chronic aminoglycoside exposure and associated ototoxicity. Before this technique is adopted, these preliminary observations warrant replication in future studies that will examine the efficacy and safety of lower doses of gentamicin or alternative agents with a reduced potential for toxicity.In the absence of a functioning arteriovenous fistula or synthetic graft, tunneled hemodialysis catheters are essential for the provision of hemodialysis. Approximately 19% of new hemodialysis patients in the United States rely on tunneled catheters for the initiation of hemodialysis, and nearly 70% of these patients are still using tunneled catheters after 60 d (1). The most important factors limiting long-term survival of tunneled catheters are poor blood flow and catheter-related infections, each of which can predispose to the other (2). The infection rate for tunneled catheters averages 0.08 to 0.7 per 100 catheter-days (1,3,4). Catheter-related infections (CRI) are associated with a substantial morbidity, mortality, and additional cost per infective episode. ...

Clostridium difficile is an important nosocomial pathogen and the most frequently diagnosed cause of infectious hospital-acquired diarrhoea. Toxigenic strains usually produce toxin A and toxin B, which are the primary virulence factors of C. difficile. Some recently described strains produce an additional toxin, an adenosine-diphosphate ribosyltransferase known as binary toxin, the role of which in pathogenicity is unknown. There has been concern about the emergence of a hypervirulent fluoroquinolone-resistant strain of C. difficile in North America and Europe. The use of fluoroquinolone antimicrobials appears to be acting as a selective pressure in the emergence of this strain. In this review, we describe the current state of knowledge about C. difficile as a cause of diarrhoeal illness.

SUMMARYBetween 1966 and 1991, melioidosis, a disease caused byPseudomonas pseudomalleithat is mostly confined to tropical regions, occurred in farm animals and a farmer in temperate south-west Western Australia. Using anEscherichia coliprobe containing a ribosomal RNA operon,P. pseudomalleiDNA from isolates from 8 animals, a soil sample and the human case showed an identical ribotype on Southern blotting. The ribotype was different from the 3 commonest ribotypes seen in tropical Australia. This molecular typing supports the theory of clonal introduction ofP. pseudomalleiinto a non-endemic region, with environmental contamination, local dissemination and persistence over 25 years. As melioidosis is often fatal in humans, such persistence in a temperate region is cause for concern.

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