Delftia acidovorans pseudo outbreak in portable reverse osmosis machines: Interventions to ensure safe and cost-effective hemodialysis.

INTRODUCTION: Reverse osmosis (RO), a major advance in hemodialysis (HD) safety, effectively clears most water organisms. Delftia acidovorans is an environmental water-borne pathogen that is rarely reported to cause human infections. We report a pseudo outbreak caused by colonization of RO machines with D acidovorans with no reported human infections and interventions to improve HD safety. METHODS: Repeated positive RO product water cultures triggered our hospital to initiate an investigation, RO machines were examined for mechanical integrity by biomedical engineers. Cultures of product water as well as RO parts were done. Testing for bacterial relatedness after identification was performed. An investigation was conducted in a systematic fashion to determine the cause and the extent of the problem. RESULTS: Upon formal review of policies and procedures, there were minor deficiencies. Rectifying these deviations from policies did not stop the repeated positive water cultures. A 7-step investigation and correction was successfully conducted. City water testing with filtration and concentration methods was positive for D acidovorans. Major renovation of the HD unit with replacement of all RO machines and a 2-step water filtration resulted in elimination of the pseudo outbreak. CONCLUSION: City water was the source of biofilm formation of D acidovorans in RO machines that was not possible to eradicate. Application of incoming water filters was an effective preventive strategy. Replacement of RO machines after 4 failed disinfection attempts is the most cost-effective strategy as well for persistent positive water cultures. The HD remains RO water culture negative 2 years after changes.

A method for chronic membrane plasmapheresis in the rat.

Therapeutic apheresis as applied to humans may encompass a single treatment or numerous treatments for disorders ranging from acute poisoning to severe chronic autoimmune disease. However, the mechanisms of beneficial effects of apheresis are not well characterized. Utilizing a miniaturized hollow-fiber membrane system, we have developed a reliable technique for long-term vascular access in the rat that permits repetitive plasmapheresis. We established vascular access in 14 animals, with 8 and 6 rats randomized to 3- and 7-wk experimental periods, respectively. Immunoglobulin levels of blood samples obtained immediately before and after each plasmapheresis were measured to examine membrane filtration characteristics. Overall, 100% of the animals survived and 93% successfully completed their assigned experimental periods. Mean decrease of immunoglobulin G and M levels for 28 plasmapheresis treatments in five rats was 66.9 +/- 8.1 and 61.0 +/- 7.3% (SD), respectively, indicating effective membrane filtration. This model of apheresis can be applied to several disorders in the rat, including, but not limited to, spontaneous insulin-dependent diabetes mellitus and experimental inflammatory bowel disease.

Erythropoietin therapy in patients with chronic renal failure.

Symptomatic anemia is a common complication of chronic renal failure. Treatment is now possible with the availability of recombinant human erythropoietin (epoetin alfa). Previous experimental studies have suggested that correcting the anemia of chronic renal failure may be harmful in that renal failure may be accelerated. Although experience with this drug has been primarily restricted to its use in patients with end-stage renal disease, several recent trials have been reported in patients with varying degrees of chronic renal failure. We review these studies with particular reference to the progression of renal failure and the drug's reported side effects. We conclude that the use of epoetin is beneficial and well tolerated and that there is no compelling evidence for the acceleration of renal failure associated with its use in patients.

Normal renal blood flow measurement using phase-contrast cine magnetic resonance imaging.

RATIONALE AND OBJECTIVES: This study assesses the ability of a cardiac-gated phase-contrast magnetic resonance imaging (MRI) technique to measure renal blood flow (RBF) noninvasively in humans. METHODS: In nine normal volunteers, total RBF in the renal arteries and in the left renal vein was estimated by MRI and correlated with RBF determined by the clearance of para-aminohippuric acid (CPAH) and the hematocrit level. RESULTS: Correlation of RBF estimated from left renal vein flow, with RBF by CPAH-hematocrit, yielded r = .86 (P less than .003). Repeated measurement of RBF by MRI demonstrated a high degree of reproducibility, with coefficients of variation ranging from 4.8% to 8.9%. However, the MRI measurements of arterial flow did not significantly correlate with the standard measurements. CONCLUSIONS: Reproducible noninvasive measurement of normal RBF is possible with the phase-contrast MRI technique used to measure renal venous blood flow.