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when they are transferred from rearing farms to production facilities at 15-18 weeks of age (McWhorter and Chousalkar, unpublished).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.
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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
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Journals
Year Citation 2024 Khan, S., McWhorter, A. R., Andrews, D. M., Underwood, G. J., Moore, R. J., Van, T. T. H., . . . Chousalkar, K. K. (2024). A live attenuated Salmonella Typhimurium vaccine dose and diluent have minimal effects on the caecal microbiota of layer chickens. Frontiers in Veterinary Science, 11, 1364731-1-1364731-11.
2024 Khan, S., McWhorter, A. R., Andrews, D. M., Underwood, G. J., Moore, R. J., Van, T. T. H., . . . Chousalkar, K. K. (2024). Dust sprinkling as an effective method for infecting layer chickens with wild-type Salmonella Typhimurium and changes in host gut microbiota. Environmental Microbiology Reports, 16(3), e13265-1-e13265-13.
Europe PMC12024 Trott, D. J., McWhorter, A., Hewson, K., Abraham, R., & Abraham, S. (2024). Antimicrobial resistance in production animals. Microbiology Australia, 45(2), 59-62.
Scopus12024 Trott, D. J., & McWhorter, A. (2024). One Health AMR: past, present and future. Microbiology Australia, 45(2), 46-47.
2023 Jia, S., McWhorter, A. R., Khan, S., Andrews, D. M., Underwood, G. J., & Chousalkar, K. K. (2023). Investigation of a gel-based delivery method for the administration of a live, attenuated Salmonella Typhimurium vaccine.. Veterinary microbiology, 280, 109721.
Scopus3 Europe PMC12023 McWhorter, A. R., Weerasooriya, G., Kumar, S., & Chousalkar, K. K. (2023). Comparison of peroxyacetic acid and acidified sodium chlorite at reducing natural microbial contamination on chicken meat pieces. Poultry Science, 102(11), 1-9.
Scopus2 WoS1 Europe PMC12023 Abdo, A., McWhorter, A., Hasse, D., Schmitt-John, T., & Richter, K. (2023). Efficacy of Plasma-Treated Water against Salmonella Typhimurium: Antibacterial Activity, Inhibition of Invasion, and Biofilm Disruption. Antibiotics, 12(9), 1-13.
Scopus32022 Weerasooriya, G., Khan, S., Chousalkar, K. K., & McWhorter, A. R. (2022). Invasive potential of sub-lethally injured Campylobacter jejuni and Salmonella Typhimurium during storage in chicken meat juice. Food Control, 135, 108823-1-108823-13.
Scopus9 WoS72022 McWhorter, A. R., Weerasooriya, G., Willson, N. L., & Chousalkar, K. K. (2022). Peroxyacetic acid and acidified sodium chlorite reduce microbial contamination on whole chicken carcasses obtained from two processing points. Food Microbiology, 106, 1-12.
Scopus6 WoS1 Europe PMC42022 Weerasooriya, G., McWhorter, A. R., Khan, S., & Chousalkar, K. K. (2022). Effects of Sublethally Injured Campylobacter jejuni in Mice. MICROBIOLOGY SPECTRUM, 10(4), 1-16.
2021 McWhorter, A. R., Khan, S., Sexton, M., Moyle, T. S., & Chousalkar, K. K. (2021). Acidification and extended storage at room temperature of mayonnaise reduce Salmonella Typhimurium virulence and viability. Food Research International, 141, 110117-1-110117-9.
Scopus7 WoS5 Europe PMC12021 Lin, Q., Chousalkar, K. K., McWhorter, A. R., & Khan, S. (2021). Salmonella Hessarek: An emerging food borne pathogen and its role in egg safety. Food Control, 125, 107996-1-107996-10.
Scopus14 WoS112021 McWhorter, A., Owens, J., Valcanis, M., Olds, L., Myers, C., Smith, I., . . . McLelland, D. (2021). In vitro invasiveness and antimicrobial resistance of Salmonella enterica subspecies isolated from wild and captive reptiles. Zoonoses and Public Health, 68(5), 402-412.
Scopus13 WoS7 Europe PMC102021 Weerasooriya, G., McWhorter, A. R., Khan, S., & Chousalkar, K. K. (2021). Transcriptomic response of Campylobacter jejuni following exposure to acidified sodium chlorite.. NPJ science of food, 5(1), 9 pages.
Scopus12 WoS7 Europe PMC62021 Khan, S., McWhorter, A. R., Moyle, T. S., & Chousalkar, K. K. (2021). Refrigeration of eggs influences the virulence of Salmonella Typhimurium.. Sci Rep, 11(1), 1-12.
Scopus12 WoS6 Europe PMC42020 Jia, S., McWhorter, A. R., Andrews, D. M., Underwood, G. J., & Chousalkar, K. K. (2020). Challenges in vaccinating layer hens against salmonella typhimurium. Vaccines, 8(4), 696.
Scopus26 WoS11 Europe PMC142020 McWhorter, A. R., & Chousalkar, K. K. (2020). Salmonella on Australian cage egg farms: Observations from hatching to end of lay. Food Microbiology, 87, 12 pages.
Scopus12 WoS10 Europe PMC42020 Kuriyawe Muhandiramlage, S., McWhorter, A. R., & Chousalkar, K. K. (2020). Chlorine Induces Physiological and Morphological Changes on Chicken Meat Campylobacter Isolates.. Front Microbiol, 11, 503.
Scopus12 WoS9 Europe PMC62020 McWhorter, A. R., Sexton, M., & Chousalkar, K. K. (2020). The effects of varied food acid ratios and egg components on Salmonella Typhimurium culturability from raw egg-based sauces. Food Microbiology, 92, 7 pages.
Scopus32020 Chousalkar, K. K., Khan, S., & McWhorter, A. R. (2020). Microbial quality, safety and storage of eggs. Current Opinion in Food Science, 38, 91-95.
Scopus23 WoS142019 McWhorter, A. R., & Chousalkar, K. K. (2019). From hatch to egg grading: monitoring of Salmonella shedding in free-range egg production systems. Veterinary Research, 50(1), 58.
Scopus17 WoS13 Europe PMC92019 McWhorter, A. R., Tearle, R., Moyle, T. S., & Chousalkar, K. K. (2019). In vivo passage of Salmonella Typhimurium results in minor mutations in the bacterial genome and increases in vitro invasiveness.. Vet Res, 50(1), 1-10.
Scopus5 WoS2 Europe PMC12019 Chousalkar, K., Sims, S., McWhorter, A., Khan, S., & Sexton, M. (2019). The Effect of Sanitizers on Microbial Levels of Chicken Meat Collected from Commercial Processing Plants.. International journal of environmental research and public health, 16(23), 11 pages.
Scopus20 WoS13 Europe PMC92018 Pande, V., McWhorter, A., & Chousalkar, K. (2018). Anti-bacterial and anti-biofilm activity of commercial organic acid products against Salmonella enterica isolates recovered from an egg farm environment. Avian Pathology, 47(2), 189-196.
Scopus9 WoS7 Europe PMC22018 McWhorter, A., Phan, G., Hocking, H., & Chousalkar, K. (2018). In vitro invasion capacity of Salmonella Typhimurium DT9 isolates sourced from humans and layer hen environments. Zoonoses and Public Health, 65(1), e259-e264.
Scopus1 WoS1 Europe PMC12018 Howard, A. J., Chousalkar, K. K., & McWhorter, A. R. (2018). In vitro and in vivo efficacy of a live attenuated Salmonella Typhimurium vaccine at preventing intestinal colonization in chicks. Zoonoses and public health, 65(6), 736-741.
Scopus4 WoS4 Europe PMC32018 McWhorter, A., & Chousalkar, K. (2018). A long-term efficacy trial of a live, attenuated Salmonella Typhimurium vaccine in layer hens. Frontiers in Microbiology, 9(JUN), 1380-1-1380-13.
Scopus20 WoS13 Europe PMC132018 Sharma, P., Caraguel, C., Sexton, M., McWhorter, A., Underwood, G., Holden, K., & Chousalkar, K. (2018). Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: A randomised controlled trial. BMC Microbiology, 18(1), 9 pages.
Scopus13 WoS8 Europe PMC62017 Sharma, P., Pande, V., Moyle, T., McWhorter, A., & Chousalkar, K. (2017). Correlating bacterial shedding with fecal corticosterone levels and serological responses from layer hens experimentally infected with Salmonella Typhimurium. Veterinary Research, 48(1), 5-1-5-11.
Scopus16 WoS15 Europe PMC102017 Chousalkar, K., Sexton, M., McWhorter, A., Hewson, K., Martin, G., Shadbolt, C., & Goldsmith, P. (2017). Salmonella Typhimurium in the Australian egg industry: multidisciplinary approach to addressing the public health challenge and future directions. Critical Reviews in Food Science and Nutrition, 57(12), 2706-2711.
Scopus22 WoS19 Europe PMC92016 Pande, V., Devon, R., Sharma, P., McWhorter, A., & Chousalkar, K. (2016). Study of Salmonella typhimurium infection in laying hens. Frontiers in Microbiology, 7(FEB), 10 pages.
Scopus49 WoS39 Europe PMC272016 Pande, V., McWhorter, A., & Chousalkar, K. (2016). Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces. Biofouling, 32(7), 699-710.
Scopus27 WoS25 Europe PMC162016 McWhorter, A., & Chousalkar, K. (2016). In vitro invasive capacity of Salmonella strains into sections of the layer hen oviduct. Veterinary Microbiology, 192, 135-144.
Scopus5 WoS4 Europe PMC32015 McWhorter, A., Davos, D., & Chousalkar, K. (2015). Pathogenicity of Salmonella strains isolated from egg shells and the layer farm environment in Australia. Applied and Environmental Microbiology, 81(1), 405-414.
Scopus29 WoS24 Europe PMC142015 McWhorter, A. R., Smith, L. M., Shellam, G. R., & Redwood, A. J. (2015). Murine cytomegalovirus strains co-replicate at multiple tissue sites and establish co-persistence in salivary glands in the absence of Ly49H-mediated competition. Journal of General Virology, 96(5), 1127-1137.
Scopus2 WoS2 Europe PMC12015 McWhorter, A., & Chousalkar, K. (2015). Comparative phenotypic and genotypic virulence of Salmonella strains isolated from Australian layer farms. Frontiers in Microbiology, 6(Jan), 12-1-12-14.
Scopus26 WoS25 Europe PMC192015 Hemmatzadeh, F., Keyvanfar, H., Hasan, N., Niap, F., Bani Hassan, E., Hematzade, A., . . . Ignjatovic, J. (2015). Interaction between Bovine leukemia virus (BLV) infection and age on telomerase misregulation. Veterinary Research Communications, 39(2), 97-103.
Scopus7 WoS5 Europe PMC52015 Pande, V., Gole, V., McWhorter, A., Abraham, S., & Chousalkar, K. (2015). Antimicrobial resistance of non-typhoidal Salmonella isolates from egg layer flocks and egg shells. International Journal of Food Microbiology, 203, 23-26.
Scopus35 WoS30 Europe PMC192014 Hadifar, F., Ignjatovic, J., Tarigan, S., Indriani, R., Ebrahimie, E., Haliza Hasan, N., . . . Hemmatzadeh, F. (2014). Multimeric recombinant M2e protein-based ELISA: A significant improvement in differentiating avian influenza infected chickens from vaccinated ones. PLoS One, 9(10), e108420-1-e108420-8.
Scopus13 WoS17 Europe PMC92013 McWhorter, A., Smith, L., Masters, L., Chan, B., Shellam, G., & Redwood, A. (2013). Natural killer cell dependent within-host competition arises during multiple MCMV infection: consequences for viral transmission and evolution. PLoS Pathogens, 9(1), e1003111-1-e1003111-13.
Scopus26 WoS22 Europe PMC212013 Smith, L., McWhorter, A., Shellam, G., & Redwood, A. (2013). The genome of murine cytomegalovirus is shaped by purifying selection and extensive recombination. Virology, 435(2), 258-268.
Scopus31 WoS25 Europe PMC272009 Beauvais, D., Ell, B., McWhorter, A., & Rapraeger, A. (2009). Syndecan-1 regulates αvβ₃ and αvβ₅ integrin activation during angiogenesis and is blocked by synstatin, a novel peptide inhibitor. Journal of Experimental Medicine, 206(3), 691-705.
Scopus229 WoS215 Europe PMC1862008 Gorman, S., Lloyd, M., Smith, L., McWhorter, A., Lawson, M., Redwood, A., & Shellam, G. (2008). Prior infection with murine cytomegalovirus (MCMV) limits the immunocontraceptive effects of an MCMV vector expressing the mouse zona-pellucida-3 protein. Vaccine, 26(31), 3860-3869.
Scopus12 WoS9 Europe PMC72008 Smith, L., McWhorter, A., Masters, L., Shellam, G., & Redwood, A. (2008). Laboratory strains of murine cytomegalovirus are genetically similar to but phenotypically distinct from wild strains of virus. Journal of Virology, 82(13), 6689-6696.
Scopus59 WoS58 Europe PMC522004 Simon, A. M., McWhorter, A. R., Chen, H. D. R., Jackson, C. L., & Ouellette, Y. (2004). Decreased intercellular communication and connexin expression in mouse aortic endothelium during lipopolysaccharide-induced inflammation. Journal of Vascular Research, 41(4), 323-333.
Scopus43 WoS39 Europe PMC292004 Simon, A. M., McWhorter, A. R., Dones, J. A., Jackson, C. L., & Chen, H. D. R. (2004). Heart and head defects in mice lacking pairs of connexins. Developmental Biology, 265(2), 369-383.
Scopus32 WoS32 Europe PMC232004 Simon, A. M., McWhorter, A. R., Dones, J. A., Jackson, C. L., & Chen, H. D. R. (2004). Erratum: Heart and head defects in mice lacking pairs of connexins (Developmental Biology (2004) 265 (369-383) DOI: 10.1016/j.ydbio.2003.09.036). Developmental Biology, 271(2), 517-518.
2003 Simon, A. M., & McWhorter, A. R. (2003). Role of connexin37 and connexin40 in vascular development. Cell Communication and Adhesion, 10(4-6), 379-385.
Scopus29 WoS27 Europe PMC152003 Simon, A. M., & McWhorter, A. R. (2003). Decreased intercellular dye-transfer and downregulation of non-ablated connexins in aortic endothelium deficient in connexin37 or connexin40. Journal of Cell Science, 116(11), 2223-2236.
Scopus125 WoS118 Europe PMC922002 Simon, A. M., & McWhorter, A. R. (2002). Vascular abnormalities in mice lacking the endothelial gap junction proteins connexin37 and connexin40. Developmental Biology, 251(2), 206-220.
Scopus172 WoS155 Europe PMC1192000 Simon, A. M., McWhorter, A. R., Sellitto, C., Goodenough, D. A., & Paul, D. L. (2000). Generation of vascular connexin double knockout mice.. FASEB JOURNAL, 14(4), A541. 2000 Simon, A. M., & McWhorter, A. R. (2000). Developmental defects in Cx40-/-Cx43-/- mice. MOLECULAR BIOLOGY OF THE CELL, 11, 227A. -
Book Chapters
Year Citation 2017 Chousalkar, K., & McWhorter, A. (2017). Egg Production Systems and Salmonella in Australia. In S. Ricke, & R. Gast (Eds.), Producing Safe Eggs: Microbial Ecology of Salmonella (pp. 71-85). United Kingdom: Academic Press.
DOI Scopus3 -
Conference Papers
Year Citation 2019 Khan, S., Chousalkar, K., & McWhorter, A. (2019). Salmonella interventions and their limitations. In Australian Veterinary Poultry Association Scientific Meeting. Sydney. 2006 Beauvais, D. M., McWhorter, A. R., Ell, B. J., & Rapraeger, A. C. (2006). Syndecan-1 regulates β3 and β5 integrin tumor-promoting activity. In MATRIX BIOLOGY Vol. 25 (pp. S42). Nashville, TN: ELSEVIER SCIENCE BV.
DOI2003 Ouellette, Y., McWhorter, A. R., & Simon, A. M. (2003). Decreased intercellular communication and connexin 40 expression in mouse aortic endothelium during lipopolysaccharide-induced inflammation. In CRITICAL CARE MEDICINE Vol. 31 (pp. A42). ORLANDO, FLORIDA: LIPPINCOTT WILLIAMS & WILKINS.
- 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"
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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
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