الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The quality of the dialysate used for HD is of paramount importance in assuring patient safety. The extremely thin dialyzer membrane is the only barrier between a patient and any harmful contaminants in the large volume of dialysate to which that patient is exposed during dialysis. Furthermore, since the water and concentrates used to formulate dialysate are usually prepared centrally, all patients being treated at the time will be exposed to harm if any of those components become contaminated.
Microbiological contamination of DF is a matter of serious concern in HD centers and improvement of microbiological quality, through assessment of water quality parameters is a permanent challenge for professionals at these units. For microbiological contaminants, the key metrics are the colony count and endotoxin concentration in the dialysate.
Standards have been developed for the quality of the dialysate and the water, concentrates and devices used in its preparation. UPDF is defined in international guidelines as containing < 0.1 CFU/mlusing HPC and < 0.03 EU/ml using the LAL assay. The definition is widely accepted and used for UPDF determination in international guidelines.
The present study aimed to assess the microbiological quality of DF in a HD center in Alexandria. It was carried out on 100 DF samples (10 dialysis water, 10 dialysate and 80 infusate samples). All samples were analyzed for enumeration of HPC, TC and fungi using the MF method and determination of endotoxin using LAL test.
The results of this study can be summarized as follows:
1. Overall, out of the total 100 examined DF samples, 83.0% and 37.0% were acceptable in relation to HPC and LAL assay respectively, according to EBPG of HD fluids.
2. The highest percentage of acceptable samples was for TC and fungi parameters (100% each), followed by HPC parameter (83.0%) while the least percentage of acceptable samples was for LAL parameter (37.0%).
3. As regards indicator organisms, no TC were revealed.
4. More than three quarters (78.8%) of infusate samples were acceptable for HPC while only 35.0% were acceptable for the LAL test.
5. HPC mean count of infusate samples was lower than those of dialysate and dialysis water samples (0.09, 16.8 and 23.0 CFU/ml respectively) witha significantdifference. Fungal mean counts were (0.05, 0.04 and 0.05 CFU/ml respectively).
6. HPC mean count of infusate samples from Bellco machines was higher than that from Fresenius (0.09 and 0.02 CFU/ml respectively) with a significant difference. Fungal mean counts were (0.05 and 0.02 CFU/ml respectively).
7. The percentage of acceptable infusate samples by LAL test from Fresenius machine was significantly higher than that from Bellco machines (100.0% and 25.7% respectively).
8. A significant higher percentage of acceptable LAL infusate samples at room 1 (closer to WTS) than room 2 (far away from WTS) (53.3% and 5.0% respectively). In addition, HPC mean counts of infusate samples collected from dialysis machines at room 2 were higher than those at room 1 (0.11 and 0.08 CFU/ml respectively) , although did not reach a significant level.
9. The agreement between HPC and LAL parameters was poor (44.0%).
10. About 80% of samples from Bellco machines with a total working hours <5000 or 5000-10000 were acceptable for HPC compared to 66.7% of samples from machines with >10000 hours.
11. When examined by LAL, the percentages of acceptability for the machines with total working hours <5000 and 5000-10000 was significantly higher than for those with >10000 hours.
12. Out of 80 infusate samples, 63 samples (78.8%) were acceptable when examined for HPC, decreased to 35.0% acceptability when examined by LAL and to 28.8% acceptability if evaluated by both HPC and LAL together.
It can be concluded from this study that:
1. Most of samples examined by LAL had unacceptable endotoxin levels.
2. Poor agreement between LAL and HPC parameters was detected as LAL assay decreased acceptability of infusate samples from 78.8% to 35.0%.
3. Much higher percentage of acceptable infusate samples were revealed from dialysis machines at room 1 due to the shortness of the tubes distributing water from a circulating system to the machines.
4. The increasing working hours of dialysis machines is inversely relatedto the quality of dialysate.
5. A significant difference between Bellco and Fresenius machines in the mean counts of HPC and in LAL test results of infusate samples. This might be related to the fact that Fresenius machine is of newer generation which incorporates recent technology.