Evaluation and optimization of a reusable hollow fiber ultrafilter as a first step in concentrating cryptosporidium parvum oocysts from water

Kuhn, Ryan C; Oshima, Kevin H.

doi:10.1016/s0043-1354(00)00560-1

Cited by 30 publications

(20 citation statements)

References 8 publications

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“…Consistent with previous work (8,9,26), the washing procedures were effective in completely removing protozoa and viruses. When bacterial growth was observed, additional cycles of sanitization were done until the plate counts were zero.…”

Section: Resultssupporting

confidence: 87%

“…When we introduced representative viruses, bacteria, and protozoa simultaneously into water with higher turbidity, specifically, the Rio Grande surface water samples, bacterial recoveries remained greater than 90%, while the recoveries of viruses (46 to 59%) and C. parvum (54%) were consistent with recoveries observed previously (8,9,26). Other studies have examined the use of ultrafiltration to concentrate a single type of microorganism from water (7,8,19).…”

Section: Discussionsupporting

confidence: 65%

“…coveries from the other surface waters with a history of poor oocyst recovery ranged from 19.0 to 44.5%. Interestingly, the worst oocyst recoveries (19%) were from the two water sources having the lowest turbidities, and oocyst recoveries from both of these samples were also poor in other studies (3,8,9). In contrast to the variable recoveries of C. parvum, recoveries of bacteria (92%) and viruses (59 and 63%) from these water sources remained high and consistent with recoveries from the Rio Grande samples.…”

Section: Discussionsupporting

confidence: 57%

“…Other studies have examined the use of ultrafiltration to concentrate a single type of microorganism from water (7,8,19). However, there are few studies that describe the successful recovery of multiple organisms from a single water sample.…”

Section: Discussionmentioning

confidence: 99%

“…The ultrafiltration setup consisted of a filter, a tubing system, two reservoirs, and a pump that were connected as described previously (8).…”

Section: Methodsmentioning

confidence: 99%

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Optimization of a Reusable Hollow-Fiber Ultrafilter for Simultaneous Concentration of Enteric Bacteria, Protozoa, and Viruses from Water

Morales-Morales

Vidal

Olszewski

et al. 2003

Appl Environ Microbiol

122

102

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The detection and identification of pathogens from water samples remain challenging due to variations in recovery rates and the cost of procedures. Ultrafiltration offers the possibility to concentrate viral, bacterial, and protozoan organisms in a single process by using size-exclusion-based filtration. In this study, two hollow-fiber ultrafilters with 50,000-molecular-weight cutoffs were evaluated to concentrate microorganisms from 2-and 10-liter water samples. When known quantities (10 5 to 10 6 CFU/liter) of two species of enteric bacteria were introduced and concentrated from 2 liters of sterile water, the addition of 0.1% Tween 80 increased Escherichia coli strain K-12 recoveries from 70 to 84% and Salmonella enterica serovar Enteritidis recoveries from 36 to 72%. An E. coli antibiotic-resistant strain, XL1-Blue, was recovered at a level (87%) similar to that for strain K-12 (96%) from 10 liters of sterile water. When E. coli XL1-Blue was introduced into 10 liters of nonsterile Rio Grande water with higher turbidity levels (23 to 29 nephelometric turbidity units) at two inoculum levels (9 ؋ 10 5 and 2.4 ؋ 10 3 per liter), the recovery efficiencies were 89 and 92%, respectively. The simultaneous addition of E. coli XL1-Blue (9 ؋ 10 5 CFU/liter), Cryptosporidium parvum oocysts (10 oocysts/liter), phage T1 (10 5 PFU/liter), and phage PP7 (10 5 PFU/liter) to 10 liters of Rio Grande surface water resulted in mean recoveries of 96, 54, 59, and 46%, respectively. Using a variety of surface waters from around the United States, we obtained recovery efficiencies for bacteria and viruses that were similar to those observed with the Rio Grande samples, but recovery of Cryptosporidium oocysts was decreased, averaging 32% (the site of collection of these samples had previously been identified as problematic for oocyst recovery). Results indicate that the use of ultrafiltration for simultaneous recovery of bacterial, viral, and protozoan pathogens from variable surface waters is ready for field deployment.

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Section: Resultssupporting

confidence: 87%