Affiliation:
1. Biology Department, New Mexico State University, Las Cruces, New Mexico 88003
Abstract
ABSTRACT
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.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Reference27 articles.
1. Immunomagnetic Separation of
Cryptosporidium parvum
from Source Water Samples of Various Turbidities
2. Bullock, W. O., J. M. Fernandez, and J. M. Short. 1987. XL1-Blue: a high efficiency plasmid transforming recA Escherichia coli strain with beta-galactosidase selection. BioTechniques.5:376-378.
3. Connel K. J. Scheller K. Miller and C. C. Rodgers. 2000. Performance of methods 1622/23 in the ICR supplemental surveys. In Proceedings of the Water Quality Technology Conference 2000. American Water Works Association Denver Colo. [CD-ROM.]
4. Eaton A. D. L. S. Clesceri and A. E. Greenberg (ed.). 1995. Standard methods for the examination of water and wastewater. American Public Health Association Washington D.C.
5. Concentration of enteroviruses from large volumes of tap water, treated sewage, and seawater
Cited by
120 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献