Dr. Katharine Field, Professor
Director, Bioresource Research Program
RESEARCH INTERESTS: Novel applications of molecular techniques to water quality problems caused by microbial contamination. Host-specific and geographic distribution of fecal bacteria. Persistence and fate of microbiological contaminants in water, including anaerobes, indicators, antibiotic resistance genes and pathogens.
COURSES TAUGHT: MB 385 Emerging Infectious Diseases; MB 490 Capstone Experience; BRR 200 Developing a Research Proposal: Theory and Practice, and BRR 403 Thesis.
My laboratory addresses fundamental questions in environmental microbiology and microbial evolution. Projects are all related to examining the effects of microbial contamination in water, and range from marker and technology development and validation to studying antibiotic resistant genes and host-fecal bacteria coevolution.
|Rapid detection of molecular markers for fecal bacteria and pathogens is the new paradigm for monitoring water quality.
To date, investigators have concentrated on identifying human and agricultural contamination. In many areas, however, significant contamination may come from overlooked sources: wild animals and birds. To investigate this problem and provide new tools, we developed and published two new avian assays: GFC, based on Catellicoccus, which targets fecal bacteria found in gulls, and GFD, based on Helicobacter, which targets avian fecal bacteria found in gulls, ducks, geese, and chickens. A focus of the lab is identifying other frequently overlooked sources of contamination such as rodents, and estimating their impact and associated health risk.
Occurrence and persistence of fecal bacteria markers in hosts and water: Another research focus is on understanding the occurrence, survival, spread, and correlation among fecal pathogens, molecular markers, and public health indicators in natural waters. For qPCR of markers to be used quantitatively across environments, both the temporal and geographic frequency and the relative persistence and decay of the markers must be understood. Our past work used mesocosms to compare decay of human and ruminant markers under varying environmental conditions. We are currently focusing on markers from different bacterial groups that occur in the same host species.
Sample interference in environmental QPCR: Sample interference in environmental applications of quantitative PCR prevents rapid, accurate estimations of genes and transcripts. We developed a spike-and-recovery approach using a mutant strain of Escherichia coli that contains a chromosomal insertion of a mutant GFP gene. This approach, coupled with previously developed kinetic outlier detection (KOD) methods, allowed sensitive detection of PCR inhibition at much lower inhibitor concentrations than alternative approaches using Cq values or amplification efficiencies. We are currently testing the approach in environmental water studies. These methods will be useful in a wide variety of environmental “omics”.
|Sewage treatment plants, wildlife, and agriculture are potential sources of microbial contamination in water. They can contribute different pathogens and can be identified by molecular detection of source-specific bacteria.
Importance of Research: Microbial contamination in water is extremely widespread throughout the United States. For example, the year 2010 saw a 29% increase in the number of beach closures from contamination in the US, resulting in massive economic and recreational losses. Microbial contamination not only poses a health risk, but also threatens drinking water sources and causes environmental degradation. Our techniques have been successfully applied for rapid assessment of microbial water quality, and for microbial source tracking, in the United States and elsewhere. Since the US EPA is currently testing qPCR methods of monitoring aquatic fecal contamination, our findings on marker persistence and sample interference will play an important role in new water quality policy.
BioResource Research: I direct the BioResource Research program, an interdisciplinary undergraduate biosciences major based on research. BRR fits well with the Microbiology major (and many others) and allows students to earn credit for their research and gain additional experience and professional contacts.
Bioenergy Education Project: I direct OSU’s $4.4 million Bioenergy project. Along with a pre-college program and a Professional Science Master’s Degree, we are establishing a new interdisciplinary Bioenergy minor. Providing students with bioenergy core concepts, research experience, professional development, and scholarships, the Bioenergy Minor is available to students in any OSU major.
Brooks, L.E. and Field, K.G. 2017. Global model fitting to compare survival curves for fecal indicator bacteria and ruminant-associated genetic markers. J. Appl Microbiol. 2017 Mar 27. doi: 10.1111/jam.13454. PMID:28345274
Brooks, L. and Field, K.G. 2016. Bayesian meta-analysis to synthesize decay rate estimates for common fecal indicator bacteria. Water Research 104:262-271.
Shanks, O., Kelty, R., Oshiro, R., Haugland, T.M., Brooks, L., Field, K.G., and Sivaganesan, M. 2016. Data acceptance criteria for standardized human-associated fecal source identification quantitative real-time PCR methods. Appl. Environ. Microbiol. 82:2773-2782.
Green, H.C., Haugland, R.A., Varma, M., Millen, H.T., Borchardt, M.A., Field, K.G., Walters, W.A., Knight, R., Sivaganesan, M., Kelty, C.A., and Shanks, O.C. 2014. Improved HF 183 quantitative real-time PCR assay for characterization of human fecal pollution in ambient surface water samples. Appl Environ Microbiol 80(10):3086-94.
Wang, D., Famleitner, A.H., Field, K.G., Green, H.C., Shanks, O.C. and Boehm, A.B. 2013. Enterococcus and Escherichia coli fecal source apportionment with microbial source tracking genetic markers--is it feasible? Water Research 47(18):6849-61.
Green, H.C. and Field, K.G. 2012. Sensitive detection of sample interference in environmental qPCR. Water Research 46(10):3251-60.
Green, H.C., Dick, L. K., Gilpin, B., Samadpour, M., and Field, K.G. 2012. Genetic markers for rapid PCR-based Identification of gull, Canada goose, duck, and chicken fecal contamination in water. Appl Environ Microbiol. 78: 503-510.
Green, H.C., Shanks, O.C., Sivaganesan, M., Haugland, R.A., and Field, K.G. 2011. Extended survival of human fecal Baceroides in Marine Water. Environ Microbiol 13: 3235-3249.
Walters, S.P. and Field, K.G. 2009. Survival and persistence of human and ruminant-specific fecal Bacteroidales in freshwater mesocosms. Environ Microbiol 11:1410-21.
Field, K. G., and Samadpour, M. 2007. Fecal source tracking, the indicator paradigm, and managing water quality. Water Research 41: 3517-3538.
Walters, S.P., V.P. Gannon, and Field, K.G. 2007. Detection of Bacteroidales fecal indicators and the zoonotic pathogens E. coli O157:H7, Salmonella, and Campylobacter in river water. Environ Sci Technol 41: 1856-1852.
Shanks, O.C., C. Nietch, M.T. Simonich, M. Younger, D. Reynolds and Field, K.G. 2006. Basin-wide analysis of the dynamics of fecal contamination and fecal source idenfication in Tillamook Bay, Oregon. Appl Environ Microbiol 72: 5537-5546.
Walters, S.P. and Field, K.G. 2006. Persistence and growth of fecal Bacteroidales assessed by bromodeoxyuridine immunocapture. Appl Environ Microbiol 72:4532-4539.
Book Chapters (selected)
Shanks, O.C., Green, H., Korajkic, A. and Field, K.G. 2016. Overview of microbial source tracking methods targeting human fecal pollution sources. In "Manual of Environmental Microbiology," M.V. Yates, C.H. Nakatsu, R.V. Miller, and S.D. Pillai. Fourth Edition, ASM Press, Washington D.C.
Kinzelman, J., K.G. Field, H. Green, V.J. Harwood and McPhail, C. 2012. Indicators, sanitary surveys, and source attribution techniques. In "Animal Waste, Water Quality, and Human Health," A. Dufour and J. Bartram, eds. WHO/US EPA. World Health Organization, IWA Publishing Alliance House, London.
Devereux, R., P. Rublee, J.H. Paul, K.G. Field and Santo Domingo, J.W. 2006. Development and Applications of Microbial Ecogenomic Indicators for Monitoring Water Quality. Environ Monitor Assess 116: 459-479.