Muellner, U., G. Fournie, P. Muellner, C. A. Ahlstrom, and D. U. Pfeiffer. 2018. Epidemix - an Interactive Multi-Model Application for Teaching and Visualizing Infectious Disease Transmission. Epidemics 23:49-54. doi:10.1016/j.epidem.2017.12.003.
Christina Ahlstrom, Ph.D.
Biography
Education and/or Training
Ph.D. 2015 University of Calgary, Calgary, Alberta, CanadaVeterinary Medical Sciences
M.S. 2011 Colorado State University, Fort Collins, COAnimal Science
B.S. 2008 University at Buffalo, Buffalo, NYBiology
Areas of Specialization and/or Research Interests
Antibiotic resistant bacteria
Bacterial genomics
Molecular epidemiology
Wildlife health and disease
Professional Experience
2017 - Present Geneticist, USGS Alaska Science Center, Anchorage, Alaska
2015 - 2017 Consultant Epidemiologist & Data Analyst, Epi-interactive, Wellington, New Zealand
2017 Molecular Epidemiology Consultant, Food and Agriculture Organisation, Rome, Italy
2016 Molecular Epidemiology Consultant, Food and Agriculture Organisation, Rome, Italy
2005 - 2008 Seasonal Research Assistant, Quality Milk Production Services, Cornell University, Ithaca, NY
Science and Products
Date published: August 21, 2018
Status: Active Antibiotic Resistant Bacteria in Migratory Birds
Migratory birds, and particularly those using habitats close to human settlements, may be infected with antibiotic resistant bacteria. The USGS is working with public health professionals to understand the role of birds in the maintenance and dispersal of antibiotic resistant bacteria. Additionally, the USGS is investigating how antibiotic resistant bacteria in birds may relate to public and...
Contacts: Andy Ramey, Ph.D., Christina Ahlstrom, Ph.D.
Date published: July 13, 2017
Status: Active Avian Influenza Research
Since 2006, the USGS Alaska Science Center has been part of the State and Federal interagency team for the detection and response to highly pathogenic (HPAI) viruses in North America. Avian influenza or "bird flu" is a viral disease that primarily infects domestic poultry and wild birds. Avian influenza viruses are naturally occurring in wild birds such as ducks, geese, swans, and gulls. These...
Year Published: 2021
Genomic comparison of carbapenem-resistant Enterobacteriaceae from humans and gulls in Alaska
ObjectivesWildlife may harbor clinically important antimicrobial resistant (AMR) bacteria, but the role of wildlife in the epidemiology of AMR bacterial infections in humans is largely unknown. In this study, we aimed to assess dissemination of theblaKPC carbapenemase gene among humans and gulls in Alaska.MethodsWe performed whole genome...
Ahlstrom, Christina; Frick, Anna; Pongratz, Catherine; Spink, Kimberly; Xavier, Catherine; Bonnedahl, Jonas; Ramey, Andrew M.
Year Published: 2021
Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls
Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal...
Ahlstrom, Christina; van Toor, Mariëlle L.; Woksepp, Hanna; Chandler, Jeffrey C; Reed, John; Reeves, Andrew B.; Waldenström, Jonas; Franklin, Alan B.; Douglas, David C.; Bonnedahl, Jonas; Ramey, Andrew M.
Year Published: 2020
Comparative genomics and genomic epidemiology of mycobacterium avium subsp. paratuberculosis strains
Two phenotypically distinct strains of Mycobacterium avium subsp. paratuberculosis (MAP) were recognized in the 1930s but it was not until the introduction of restriction endonuclease analysis (REA) in the mid-1980s that these two strains, MAP-C and MAP-S, could be distinguished genetically. Since then, a plethora of molecular typing techniques...
Stevenson, Karen; Ahlstrom, Christina
Year Published: 2020
Validation of a screening method for the detection of colistin-resistant E. coli containing mcr-1 in feral swine feces
A method was developed and validated for the detection of colistin-resistant Escherichia coli containing mcr-1 in the feces of feral swine. Following optimization of an enrichment method using EC broth supplemented with colistin (1 µg/mL) and vancomycin (8 µg/mL), aliquots derived from 100 feral swine fecal samples were spiked with of one of five...
Chandler, Jeffrey C; Franklin, Alan B.; Bevins, Sarah N.; Bentler, Kevin T; Bonnedahl, Jonas; Ahlstrom, Christina; Bisha, Bledar; Shriner, Susan A.
Year Published: 2020
Gulls as sources of environmental contamination by colistin-resistant bacteria
In 2015, the mcr-1 gene was discovered in Escherichia coli in domestic swine in China that conferred resistance to colistin, an antibiotic of last resort used in treating multi-drug resistant bacterial infections in humans. Since then, mcr-1 was found in other human and animal populations, including wild gulls. Because gulls could disseminate the...
Franklin, Alan B.; Ramey, Andrew M.; Bentler, Kevin T; Barret, Nicole L; McCurdy, Loredana M; Ahlstrom, Christina; Bonnedahl, Jonas; Shriner, Susan A.; Chandler, Jeffrey C
Year Published: 2020
Antibiotic resistant bacteria in wildlife: Perspectives on trends, acquisitions and dissemination, data gaps, and future directions
The proliferation of antibiotic resistant bacteria in the environment has potential negative economic and health consequences. Thus, previous investigations have targeted wild animals to understand the occurrence of antibiotic resistance in diverse environmental sources. In this critical review and synthesis, we summarize important concepts...
Ramey, Andrew M.; Ahlstrom, Christina
Year Published: 2019
Early emergence of mcr-1-positive Enterobacteriaceae in gulls from Spain and Portugal
We tested extended‐spectrum β‐lactamase producing bacteria from wild gulls (Larusspp.) sampled in 2009 for the presence of mcr‐1. We report the detection of mcr‐1 and describe genome characteristics of four Escherichia coli and one Klebsiella pneumoniaeisolate from Spain and Portugal that also exhibited colistin resistance...
Ahlstrom, Christina; Ramey, Andrew M.; Woksepp, Hanna; Bonnedahl, Jonas
Year Published: 2019
Repeated detection of carbapenemase-producing Escherichia coli in gulls inhabiting Alaska, USA
We report the first detection of carbapenemase-producing Escherichia coli in Alaska and in wildlife in the United States. Wild bird (gull) feces sampled at three locations in Southcentral Alaska yielded isolates that harbored plasmid-encoded blaKPC-2 or chromosomally-encoded blaOXA-48, and genes associated with...
Ahlstrom, Christina; Ramey, Andrew M.; Woksepp, Hanna; Bonnedahl, Jonas
Year Published: 2019
Satellite tracking of gulls and genomic characterization of fecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial resistant Escherichia coli on the Kenai Peninsula, Alaska
Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well-described. We equipped 17 landfill-foraging gulls with satellite transmitters and collected gull fecal samples longitudinally from...
Ahlstrom, Christina; Bonnedahl, Jonas; Woksepp, Hanna; Hernandez, Jorge; Reed, John; Tibbitts, Lee; Olsen, Björn; Douglas, David C.; Ramey, Andrew M.
Year Published: 2018
Acquisition and dissemination of cephalosporin-resistant E. coli in migratory birds sampled at an Alaska landfill as inferred through genomic analysis
Antimicrobial resistance (AMR) in bacterial pathogens threatens global health, though the spread of AMR bacteria and AMR genes between humans, animals, and the environment is still largely unknown. Here, we investigated the role of wild birds in the epidemiology of AMR Escherichia coli. Using next-generation sequencing, we characterized...
Ahlstrom, Christina Ann; Bonnedahl, Jonas; Woksepp, Hanna; Hernandez, Jorge; Bjorn, Olsen; Ramey, Andrew M.Pre-USGS Publications
Ahlstrom, C. A., P. Muellner, G. Lammers, M. Jones, S. Octavia, R. Lan, and J. Heller. 2017. Shiga-toxin producing E. coli O157 shedding dynamics in an Australian beef herd. Frontiers in Veterinary Science 4:200. doi:10.3389/fvets.2017.00200.
Ahlstrom, C. A., C. S. Manuel, H. C. Den Bakker, M. Wiedmann, and K. K. Nightingale. 2017. Molecular Ecology of Listeria spp., Salmonella, Escherichia coli O157:H7, and non-O157 Shiga Toxin Producing Escherichia coli in Pristine Natural Environments in Northern Colorado. Journal of Applied Microbiology. doi:10.1111/jam.13657.
Ahlstrom, C. A., P. Muellner, S. Spencer, S. Hong, A. Saupe, A. Rovira, C. Hedberg, A. Perez, and J. Alvarez. 2017. Inferring source attribution from a multi-year multi-source dataset of Salmonella in Minnesota. Zoonoses and Public Health 64(8):589-598. doi:10.1111/zph.12351.
Bauman, C. A., A. Jones-Bitton, C. A. Ahlstrom, L. Mutharia, J. De Buck, J. Jansen, D. F. Kelton, and P. Menzies. 2017. Identification of Mycobacterium avium ssp. paratuberculosis strains isolated from dairy goats and dairy sheep in Ontario, Canada. Canadian Journal of Veterinary Research 81(4):304-307.
Hong, S., A. Rovira, P. Davies, C. A. Ahlstrom, P. Muellner, A. Rendahl, K. Olsen, J. B. Bender, S. Wells, A. Perez, and J. Alvarez. 2016. Serotypes and antimicrobial resistance in Salmonella enterica recovered from clinical samples from cattle and swine in Minnesota, 2006 to 2015. International Journal of Parasitology: Parasites and Wildlife 11(12):e0168016. doi:10.1371/journal.pone.0168016.
Muellner, P., U. Muellner, M. C. Gates, T. Pearce, C. A. Ahlstrom, D. O'Neill, D. Brodbelt, and N. J. Cave. 2016. Evidence in Practice – A Pilot Study Leveraging Companion Animal and Equine Health Data from Primary Care Veterinary Clinics in New Zealand. Frontiers in Veterinary Science 3:116. doi:10.3389/fvets.2016.00116.
Davidson, F., C. A. Ahlstrom, J. De Buck, H. G. Whitney, and K. Tahlan. 2016. Examination of Mycobacterium avium subspecies paratuberculosis mixed genotype infections in dairy animals using a whole genome sequencing approach. PeerJ 4:e2793. doi:10.7717/peerj.2793.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2016. Relative frequency of 4 major strain types of Mycobacterium avium ssp. paratuberculosis in Canadian dairy herds using a novel single nucleotide polymorphism-based polymerase chain reaction. Journal of Dairy Science 99(10):8297-8303. doi:10.3168/jds.2016-11397.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, K. Tahlan, and J. De Buck. 2016. Genome-wide diversity and phylogeography of Mycobacterium avium subsp. paratuberculosis in Canadian dairy cattle. PLoS One 11:e0149017. doi:10.1371/journal.pone.0149017.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, S. Hendrick, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, and J. De Buck. 2015. Limitations of variable number of tandem repeat typing identified through whole genome sequencing of Mycobacterium avium subsp. paratuberculosis on a national and herd level. BMC Genomics 16:161. doi:10.1186/s12864-015-1387-6.
Den Bakker, H. C., S. Warchocki, E. M. Wright, A. F. Allred, C. A. Ahlstrom, C. S. Manuel, M. J. Stasiewicz, A. Burrell, S. Roof, L. Strawn, E. D. Fortes, K. K. Nightingale, D. Kephart, and M. Wiedmann. 2014. Listeria floridensis sp. nov., Listeria aquatica sp. nov., Listeria cornellensis sp. nov., Listeria riparia sp. nov., and Listeria grandensis sp. nov., from agricultural and natural environments. International Journal of Systematic and Evolutionary Microbiology 64:1882-1889. doi:10.1099/ijs.0.052720-0.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2014. Improved Short-Sequence-Repeat Genotyping of Mycobacterium avium subsp. paratuberculosis by Using Matrix-Assisted Laser Desorption Ionization—Time of Flight Mass Spectrometry. Applied and Environmental Microbiology 80:534-539. doi:10.1128/AEM.03212-13.
Zadoks, R. N., H. M. Griffiths, M. A. Munoz, C. A. Ahlstrom, G. J. Bennett, E. Thomas, and Y. H. Schukken. 2011. Sources of Klebsiella and Raoultella species on dairy farms: be careful where you walk. Journal of Dairy Science 94(2):1045-1051. doi:10.3168/jds.2010-3603.
Munoz, M. A., G. J. Bennett, C. A. Ahlstrom, H. M. Griffiths, Y. H. Schukken, and R. N. Zadoks. 2008. Cleanliness Scores as Indicator of Klebsiella Exposure in Dairy Cows. Journal of Dairy Science 91(10):3908-3916. doi:10.3168/jds.2008-1090.
Munoz, M. A., C. A. Ahlstrom, B. J. Rauch, and R. N. Zadoks. 2006. Fecal Shedding of Klebsiella pneumoniae by Dairy Cows. Journal of Dairy Science 89(9):3425-3430. doi:10.3168/jds.S0022-0302(06)72379-7.
Muellner, P., D. Hodges, C. A. Ahlstrom, M. Newman, R. Davidson, D. U. Pfeiffer, J. Marshall, and C. Morley. 2018. Creating a framework for the prioritization of biosecurity risks to the New Zealand dairy industry. Transboundary and Emerging Diseases 65(4):1067-1077. doi:10.1111/tbed.12848.