Effects of incubation time and temperature on microbiologic sampling procedures for hemodialysis fluids (original) (raw)
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Comparison of different culture methods on bacterial recovery in hemodialysis fluids
2004
To examine the culture method that could provide the highest bacterial recovery, 143 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the temperature (20 C vs 37 C), the duration of incubation (48-hour vs 7day), and the culture technique (membrane filtration vs spread plate methods). The European Best Practice Guideline method, R2A at 20 C for 7-day incubation provided higher bacterial recovery than the Association for the Advancement of Medical Instrumentation (AAMI) method, TSA at 37 C for 48-hour incubation. The membrane filtration method gave better yield than the spread plate method. As such, the European Best Practice Guideline method in combination with the membrane filtration technique would be the culture method of choice for hemodialysis fluids.
Comparison of microbiologic assay methods for hemodialysis fluids
Journal of clinical microbiology, 1991
To help prevent pyrogenic reactions and bacteremia in hemodialysis patients, the Association for the Advancement of Medical Instrumentation and the Centers for Disease Control recommend microbiologic assay of hemodialysis fluids at least monthly. Five commercially available assay systems were evaluated by using the membrane filtration technique with standard methods agar and trypticase soy agar as the standards for comparison. Each assay system was challenged with dialysate and reverse-osmosis water from local dialysis centers, aqueous suspensions of eight laboratory strains of gram-negative bacilli and nontuberculous mycobacteria, and a mixed microbial flora inoculated into reverse-osmosis water and laboratory-prepared dialysate. Mean viable counts from triplicate samples were obtained after incubation at 37°C for up to 72 h. The efficiency of recovery varied with the specific type of microbial challenge. The SPC water sampler (Millipore Corp., Bedford, Mass.) was the most consistent in obtaining the highest viable counts. Other commercial systems were comparable to each other in overall performance. All assay systems tested provided an acceptable balance between microbial recovery and required sampling time, equipment, and expertise.
Comparison of techniques for culture of dialysis water and fluid
Introduction Microbiological culture of dialysis water and fluid is a routine safety measure. In the United States (U.S.), laboratories perform these cultures on trypticase soy agar at 35–378C for 48 h (TSA-48h), not on the tryptone glucose extract agar or Reasoner's 2A agar at 17–238C for 7 days (TGEA-7d and R2A-7d, respectively) recommended by international standards. We compared culture methods to identify samples exceeding the accepted action level of 50 CFU/mL. Methods Dialysis water and fluid samples collected from 41 U.S. dialysis programs between 2011 and 2014 were cultured at two U.S. laboratories. Each sample was cultured using (1) either TGEA-7d or R2A-7d and (2) TSA-48h. We compared proportions exceeding the action level by different methods and test characteristics of TSA-48h to those of TGEA-7d and R2A-7d. Findings The proportion of water samples yielding colony counts 50 CFU/mL by TGEA-7d was significantly different from the proportion by TSA-48h (P 5 0.001; difference in proportion 4.3% [95%CI 1.3–7.3%]). The proportions of dialysis fluid samples 50 CFU/mL by TGEA-7d and TSA-48h were not significantly different; there were no significant differences for comparisons of R2A-7d to TSA-48h. Discussion In dialysis fluid, TSA-48h was comparable to TGEA-7d and R2A-7d in identifying samples as having bacterial counts 50 CFU/mL. In dialysis water, TSA-48h was comparable to R2A-7d in identifying samples 50 CFU/mL, but TGEA-7d did yield significantly more results above 50 CFU/mL. Nonetheless, the negative predictive value of a TSA-48h result of <50 CFU/mL in dialysis water exceeded 95%.
Bacterial Recovery in Hemodialysis Fluids
emro.who.int
To examine the culture method that could provide the highest bacterial recovery, 150 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the ...
Therapeutic Apheresis and Dialysis, 2009
The Committee of Scientific Academy of the Japanese Society for Dialysis Therapy (JSDT) proposes a new standard on microbiological management of fluids for hemodialysis and related therapies. This standard is within the scope of the International Organization for Standardization (ISO), which is currently under revision. This standard is to be applied to the central dialysis fluid delivery systems (CDDS), which are widely used in Japan. In this standard, microbiological qualities for dialysis water and dialysis fluids are clearly defined by endotoxin level and bacterial count. The qualities of dialysis fluids were classi-fied into three levels: standard, ultrapure, and online prepared substitution fluid. In addition, the therapeutic application of each dialysis fluid is clarified. Since highperformance dialyzers are frequently used in Japan, the standard recommends that ultrapure dialysis fluid be used for all dialysis modalities at all dialysis facilities. It also recommends that the dialysis equipment safety management committee at each facility should validate the microbiological qualities of online prepared substitution fluid. Key Words: Bacteria, Central dialysis fluid delivery system, Endotoxin, Standard of fluid for hemodialysis.
Primary Culture Media for Routine Urine Processing
It has been recommended that routine microbiological processing of urine specimens include quantitative plating onto blood agar medium along with a selective and differential agar such as MacConkey agar for gram-negative organisms. Few data have been published to justify this combination. To evaluate the validity of this recommendation 2,553 midstream, clean-voided urine samples were quantitatively plated onto blood agar, MacConkey agar, and colistinnalidixic acid agar, which is a selective medium for gram-positive organisms. The amounts of growth on each of the three media were compared. Results indicated that the best medium combination was colistin-nalidixic acid agar and MacConkey agar. The use of colistin-nalidixic acid agar instead of blood agar increased the detection of significant growth of enterococci, lactobacilli, and Torutlopsis glabrata.
Applied microbiology, 1974
Representative strains of anaerobic bacteria from human infections were used to evaluate broth media, gas mixtures, and inocula for use in developing a procedure for performing minimal inhibitory concentration antimicrobic susceptibility tests. Nine commercially available media, including two that were chemically defined, were tested. Tests were performed in atmospheres with carbon dioxide concentrations between 2.5 and 10% and also in the GasPak system (BBL) that had a disposable hydrogen-carbon dioxide generator. Growth curves on each organism grown in schaedler broth and a 5% carbon dioxide atmosphere were used to determine growth characteristics, equate time of the particular growth phases to turbidity readings, and determine the numbers of viable organisms present in the culture. Schaedler broth proved to be most advantageous in combination with an atmosphere of 5% carbon dioxide, 10% hydrogen, and 85% nitrogen. The growth curve studies yielded valuable data on the rapidity and...
Journal of Clinical Microbiology, 2006
Manufacturers generally recommend that blood culture bottles be loaded into instruments within a short time of collection. However, in our experience, delays often occur prior to loading the bottles. We examined the effect of holding bottles under various temperatures (T)—room temperature (RT), 4°C, 37°C, and RT for 2 h following incubation at 37°C (to simulate transit [TR])—and for various holding times of 4, 12, and 24 h. We utilized the BacT/ALERT system with FA and FN bottles and the BACTEC system with Plus (PL) and Lytic 10 (LY) bottles. Standardized inocula and 5 ml of blood were added to each bottle. Fifteen organisms were evaluated based upon expected performance: aerobic (FA and PL), anaerobic (FN and LY 10), and facultative (all bottles). Based upon expected performance, the FA and FN bottles recovered 458 of 468 organisms and 282 of 288 organisms, respectively, whereas the PL and LY bottles recovered 453 of 468 organisms and 257 of 288 organisms, respectively ( P = <0....
Journal of Clinical Microbiology, 1990
Three systems that are available for the incubation of anaerobic organisms were evaluated to assess their ability to support the growth of 25 anaerobic stock strains and to successfully recover anaerobic bacteria from clinical specimens. These were the anaerobic chamber, the Anaerobic Pouch System Catalyst-Free (Difco Laboratories, Detroit, Mich.), and the Bio-Bag Environmental Chamber Type A (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.). Three study centers were involved, the Wadsworth Anaerobe Laboratory (Los Angeles, Calif.), the Good Samaritan Hospital (San Jose, Calif.), and the Massachusetts General Hospital (Boston). A total of 171 anaerobic organisms were isolated from 49 clinical specimens that were cultured at the three test centers. Of these, 169 (99%) were recovered from media that were incubated in the anaerobic chamber, 163 (95%) were recovered from the Anaerobic Pouch, and 147 (86%) were recovered from the Bio-Bag. A similar trend was seen with the stock strains, in which the anaerobic chamber often supported better growth of the organisms than did either of the bag systems.