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Pseudomonas septicemia due to deficient disinfectant mixing during reuse
R Vanholder1, E Vanhaecke, S Ringoir
1Nephrology Department, University Hospital, Ghent, Belgium.
Abstract:
We describe a cluster of four septicemias with pseudomonas, that occurred in a unit performing formaldehyde reuse of capillary dialyzers. Samples of blood, heparin solutions, dialysate and effluent of reused dialyzers, were evaluated bacteriologically and upon the adequacy of the reuse procedure. Pseudomonas aeruginosa, vesicularis and/or xanthomonas maltophilia were found on the blood cultures obtained during the septicemic reactions, and in the effluent of two reprocessed dialyzers not yet used (greater than 10(4) CFU/ml). These two dialyzers had also extremely low formaldehyde concentrations (0.0014 and 0.005% versus the expected 4%). Membrane and antibiogram characteristics of a Pseudomonas aeruginosa strain, recovered from the blood cultures in one patient, and of a strain found in the effluent of one of the two contaminated reprocessed dialyzers, were the same. The problem was attributed to the inadequate mixing of the disinfectant with the tap water used in the automated reprocessing device, in the absence of an alarm disclosing this failure.
Insights
A cluster of four septicemia cases linked to Pseudomonas contamination in reused capillary dialyzers was identified. Inadequate formaldehyde disinfection, due to faulty mixing, was the primary cause of these serious infections.
Area of Science:
- Infectious Diseases
- Nephrology
- Microbiology
Background:
- Hemodialysis involves reusing dialyzers, a process that requires effective disinfection.
- Pseudomonas species are opportunistic pathogens, particularly concerning in immunocompromised patients undergoing dialysis.
Purpose of the Study:
- To investigate a cluster of septicemia cases associated with reused capillary dialyzers.
- To identify the causative agent and the source of contamination.
- To evaluate the effectiveness of the dialyzer reprocessing procedure.
Main Methods:
- Bacteriological analysis of blood cultures, heparin solutions, dialysate, and dialyzer effluent.
- Assessment of formaldehyde concentrations in reused dialyzers.
- Comparison of Pseudomonas aeruginosa strains from patients and dialyzers using membrane and antibiogram characteristics.
Main Results:
- Four cases of septicemia caused by Pseudomonas aeruginosa, vesicularis, and/or xanthomonas maltophilia were identified.
- Contaminated effluent (greater than 10(4) CFU/ml) was found in two reprocessed dialyzers.
- Severely low formaldehyde concentrations (0.0014% and 0.005%) were detected in the contaminated dialyzers.
- Identical Pseudomonas aeruginosa strains were isolated from a patient's blood and a reprocessed dialyzer.
Conclusions:
- The septicemia cluster was attributed to inadequate formaldehyde disinfection during automated dialyzer reprocessing.
- Failure in disinfectant mixing, undetected by the reprocessing device, led to insufficient sterilization.
- This highlights the critical need for reliable monitoring and alarm systems in automated reprocessing units to prevent patient infections.
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