Dr Andrea McWhorter

Grant-Funded Researcher (B)

School of Animal and Veterinary Science

Faculty of Sciences, Engineering and Technology

Eligible to supervise Masters and PhD - email supervisor to discuss availability.

 In 2012, I started a post-doctoral fellowship studying the comparative virulence of Salmonella serovars. Salmonella is a diverse bacterial genus with well over 2600 distinct serovars having been described. In our work, we have found that Salmonella serovars have significant variation in their in vitro and in vivo virulence capacities. This work has been published in both Frontiers in Microbiology and Applied and Environmental Microbiology. We have analysed whole genome sequences of selected Salmonella serovars and compared the variation that occurs amongst genes controlling bacterial invasion, intracellular replication and other disease processes. We have found substantial variation in the amino acid sequences between the selected serovars and are now in the process of characterising how this amino acid variability translates to functional variability.

I recently completed an epidemiology project tracking where Salmonella enters the egg laying production system. Egg laying hens typically become infected with Salmonella when they are transferred from rearing farms to production facilities at 15-18 weeks of age (McWhorter and Chousalkar, unpublished). Infection with Salmonella at this point typically does not cause disease symptoms in the birds because the dose is generally low and chickens, in general, are more resistance to non-species specific Salmonella than other vertebrates. My work has shown that the bacteria establish persistent infection and can be shed intermittently over the 80 week production lifespan of a layer hen. This leads to increased contamination of the farm environment and can then be a risk for egg contamination.

On farm Salmonella control programs are multifaceted involving strict biosecurity, cleaning and disinfecting. The use of a live, attenuated strain of Salmonella Typhimurium as a vaccine has been adopted in certain parts of the poultry industry. The vaccine has been shown to have efficacy in chicken meat birds but because of the extended productive lifespan of a layer hen, it was not known how effective the vaccine is over an extended period. We conducted both controlled experimental and on farm trials which demonstrated that the vaccine was not able to prevent infection or reduce the total amount of Salmonella shed in faeces or the rate of egg contamination. This outcome has led the further collaboration with the vaccine manufacturer, Bioproperties.

Most recently, I have commenced a project testing the efficacy of several commercial sanitizers used in the chicken meat industry to control Campylobacter and Salmonella. I am also working on studying the behaviour of Salmonella in raw egg-based foods. In artificially contaminated aioli, the number of culturable bacteria decreases over time. I established, however, that while the bacteria were non-culturable, they remained viable (viable-but-nonculturable, VBNC). This part of my research program is now aimed at understanding the risk that VBNC Salmonella in food represents for human disease.

  • Appointments

    Date Position Institution name
    2013 - ongoing Associate Lecturer University of Adelaide
    2012 - ongoing Post-doctoral Research Fellow University of Adelaide
  • Education

    Date Institution name Country Title
    2011 University of Western Australia Australia PhD
    1998 University of Wyoming United States Masters of Science
  • 2020 CIB on ARC-Linkage Grant in Collaboration with Bioproperties, "Salmonella in poultry: improving vaccine efficacy and understanding of host-pathogen interactions"
  • 2020 Co-investigator on Urgent COVID-19 Research Funding Scheme, "Are Poultry Workers Our 21st Century’s Milkmaids? Chicken coronavirus vaccine: Efficacy against SARS-CoV-2 (COVID-19)"
  • 2019 Co-investigator on Agrifutures Poultry Meat Scheme, "Sanitisers for commercial use in chicken meat production"
  • 2016 Co-investigator on Poultry CRC grant, "Field trial to study the efficacy of a Salmonella Typhimurium live vaccine in egg layers"
  • 2014 Co-investigator on Australian Eggs Grant, "Workshops for future development of Salmonella control strategies in egg industry"
  • Current Higher Degree by Research Supervision (University of Adelaide)

    Date Role Research Topic Program Degree Type Student Load Student Name
    2023 Principal Supervisor Epidemiology of avian Hepatitis E in layer hens Doctor of Philosophy Doctorate Full Time Mrs Stephanie Jane Hewitt
    2023 Principal Supervisor Mechanisms of Salmonella survival on eggs and in raw egg-based foods. Doctor of Philosophy Doctorate Full Time Ms Lingyun Li
    2022 Co-Supervisor Study of gut microbiota in hens Doctor of Philosophy Doctorate Full Time Mr Jiawei Zhang
    2020 Co-Supervisor iPhD with Bioproperties Pty Ltd: Improving the efficacy of Salmonella Typhimurium vaccination Doctor of Philosophy Doctorate Full Time Mr Siyuan Jia
  • Past Higher Degree by Research Supervision (University of Adelaide)

    Date Role Research Topic Program Degree Type Student Load Student Name
    2019 - 2022 Co-Supervisor Study of Foodborne Pathogens in Poultry Doctor of Philosophy Doctorate Full Time Dr Gayani Kuriyawe Muhandiramlage
    2019 - 2020 Co-Supervisor A study of non-typhoidal Salmonella virulence Master of Philosophy Master Full Time Miss Talia Sheryli Moyle
    2014 - 2018 Co-Supervisor Study of Salmonella Typhimurium Infection in Laying Hens and Vaccination Doctor of Philosophy Doctorate Full Time Dr Pardeep Sharma
    2013 - 2016 Co-Supervisor Studies on Salmonella enterica spp Isolated from Egg Farm Environment Doctor of Philosophy Doctorate Full Time Mr Vivek Pande
  • Position: Grant-Funded Researcher (B)
  • Phone: 83137907
  • Email: andrea.mcwhorter@adelaide.edu.au
  • Campus: Roseworthy
  • Building: Leske, floor G
  • Org Unit: School of Animal and Veterinary Science

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