S. aureus and pathogenicity in terms of food

1. Staphylococcus aureus
Foodborne pathogen: Staphylococcal food-borne disease
Student name: Keerthana Kissanthomas
Student Id No. :A00280414

2. Introduction
• Gram positive bacteria (cocci shaped that
occur in clusters & member of Bacillota)
• Commensal bacteria in human microbiota.
• Opportunistic pathogen (common contributor
to skin diseases, sinusitis, and food poisoning)
Fig 1 – morphology of S. aureus under microscope
after gram staining (Ganguly, 2018)
Staphylococcal food-borne disease (SFP) results from the contamination of
food by S. aureus’s enterotoxins (SE). (Kadariya, Smith and Thapaliya, 2014)
Food intoxication (Staphyloenterotoxicosis)
• S. aureus bacteria is killed by cooking, but its toxins are resistant to heat
(withstand heat at 121°C for 10 min) and stomach enzymes
(proteases).
(M. Tallent, W. Bennett and M. Miller, 2022)

3. Symptoms and Incubation period
It is generally understood and accepted that S. aureus as a food
intoxicant presents a risk only when the growth to high numbers
occurs - >/= 100,000 CFU/g (>/= 1mg). (Rajkovic, 2016)
Primary symptoms: Vomiting, nausea, diarrhoea and
abdominal pain.
Secondary symptoms : dehydration, headache, myalgia and
fatigue
Incubation period: Symptoms generally occurs between 30
minutes to 8 hours (average of 3 hours) after ingestion.
Symptoms lasts 1-3 days. (CDC, 2018)
Images generated by (Bio render 2023

4. Food sources and transmissions
• Prefers to deposit their enterotoxins on poultry, meats, diary, bakery products and salads.
In raw foods, S. aureus does not compete effectively with indigenous bacteria. Source of contamination?
Air, dust, and food contact surfaces
can all act as carriers for S. aureus to
enter foods.
(Image by (WebstaurantStore, 2023)
.
Source: Argudín, Mendoza and Rodicio, 2010
Major source of contamination is poor
handling of cooked or processed foods
and followed by storage suitable.
(Image by blog.userve.com, 2022)
S. aureus is also found in dairy cattle
(cows), particularly those with
subclinical mastitis.
(Image by Webb, 2023)

5. Some Outbreaks
Table 1: some examples of outbreaks of Staphyloenterotoxicosis (Hennekinne, De Buyser and Dragacci, 2012)
Year Place, Country Food source Cases References

6. Pathogenesis/virulence & Mode of action (i)
Table 2: Main Staphylococcal enterotoxin (SE) of S. aureus involved in food (Pinchuk, Beswick and Reyes, 2010)
•After the consumption, enterotoxins are
absorbed in the abdomen and cause typical
gastroenteritis.
•Induces 5-hydroxytrytamine (5-HT) from mast
cells which stimulates the vomiting centre of the
brain
•Enterotoxins also cause damage to the
epithelial lining of the intestinal cells.
The genes for enterotoxin production are present in
pathogenicity islands in the chromosome (Arun K. Bhunia 2018)
Source: Dura, 2021
Fig 2: S. aureus enterotoxins in stomach
(Arun K. Bhunia 2018 citied in Dura, 2021)
Fig 3: S. aureus enterotoxins in intestinal
cells (Fisher E. L, et al. 2018)

7. Pathogenesis/virulence & Mode of action (ii)
• SEs are superantigens (SAgs) - stimulates many T-cells
• Enterotoxins form complex with MHC class II molecules on surface of antigen-
presenting cells
• Proliferates T-cells, producing a large amounts of inflammatory cytokines (IL-2, IFNγ,
IL-1, TNF-α).
• A high abundance of inflammatory cytokines stimulates the neuron receptors in the
intestinal tract and causes diarrhoea.
Source: Dura, 2021
Fig 4: SEs as superantigen (Fisher E. L, et al. 2018)
1. 15-year-old (healthy) boy presented with septic shock after eating meat from
a fast-food restaurant.
2. Developed food intoxication symptoms (diarrhoea) after 4 hours.
3. TSST-1 gene verified by real-time PCR analysis of the S.aureus strain.
Source: Goudsmit et al., 2021
• Food poising from S. aureus cause toxic shock syndrome, a SAgs called toxic
shock syndrome toxin 1 (TSST-1), is produced.

8. Detection
Source: Wu et al., 2016
Toxins not the bacterium itself

9. Prevention
• Prevent food from being held at an unsafe temperature
(between 4.4°C and 60°C) for more than 2 hours.
• Refrigerate as soon as possible (below 4 °C ).
• Food handlers practicing good hygiene.
• Avoid cross contamination (raw and cooked food).
• If reheating food, ensure the temperature reaches at least
74 °C .
Image by Evans, n.d shown in Pinterest n.d

10. References
• Argudín, M.Á., Mendoza, M.C. and Rodicio, M.R. (2010). Food Poisoning and Staphylococcus aureus Enterotoxins. Toxins, [online] 2(7), pp.1751–1773. doi:https://doi.org/10.3390/toxins2071751.
• blog.userve.com. (2022). Food Handler How-To: Handle Poultry Properly. [online] Available at: https://blog.userve.com/us/food-handler-how-to-handle-poultry-properly [Accessed 5 Nov. 2023].
• Centers for Disease Control and Prevention (2018). Staphylococcal (staph) food poisoning. [online] Centers for Disease Control and Prevention. Available at:
https://www.cdc.gov/foodsafety/diseases/staphylococcal.html.
• Ganguly, S. (2018). Photograph showing S. aureus grape cluster like morphology on Gram stain. 1000X. [Image] ResearchGate. Available at:
https://www.researchgate.net/publication/322243680_Molecular_Characterization_of_Staphylococcus_aureus_of_Camel_Camelus_dromedarius_Skin_Origin/figures?lo=1 [Accessed 30 Oct. 2023]
• Kadariya, J., Smith, T.C. and Thapaliya, D. (2014). Staphylococcus aureus and Staphylococcal food-borne disease: An ongoing challenge in public health. BioMed Research International, [online] 2014, pp.1–
9. doi:https://doi.org/10.1155/2014/827965
• Rajkovic, A. (2016). Staphylococcus: Food Poisoning. [online] , Ghent University, Ghent, Belgium & Belgrade University, Zemun-Belgrade, Serbia: Elsevier Ltd, pp.133–139. Available at:
https://elearning.unite.it/pluginfile.php/187875/mod_resource/content/0/rajkovic%2C2016-Staphylococcus-food%20poisoning.pdf [Accessed 2 Nov. 2023].
• Hennekinne, J.-A., De Buyser, M.-L. and Dragacci, S. (2012). Staphylococcus aureusand its food poisoning toxins: characterization and outbreak investigation. FEMS Microbiology Reviews, 36(4), pp.815–
836. doi:https://doi.org/10.1111/j.1574-6976.2011.00311.x.
• Pinchuk, I.V., Beswick, E.J. and Reyes, V.E. (2010). Staphylococcal Enterotoxins. Toxins, [online] 2(8), pp.2177–2197. doi:https://doi.org/10.3390/toxins2082177.
• Dura, S. (2021). Staphylococcal food poisoning (SFP)- Staphylococcus aureus enterotoxins. [online] Microbe Notes. Available at: https://microbenotes.com/staphylococcal-food-poisoning/ [Accessed 2 Nov.
2023].
• Fisher, E.L., Otto, M. and Cheung, G.Y.C. (2018). Basis of Virulence in Enterotoxin-Mediated Staphylococcal Food Poisoning. Frontiers in Microbiology, [online] 9(436), pp.1–18.
doi:https://doi.org/10.3389/fmicb.2018.00436.
• M. Tallent, S., W. Bennett , R. and M. Miller, W.B. (2023). BAM Chapter 13B - Staphylococcal Enterotoxins Detection Methods. FDA. [online] Available at: https://www.fda.gov/food/laboratory-methods-
food/bam-chapter-13b-staphylococcal-enterotoxins-detection-methods#:~:text=Staphylococcal%20enterotoxins%20(SEs)%20are%20pyrogenic [Accessed 3 Nov. 2023].
• Webb, B.H. (2023). Dairying. [online] Encyclopedia Britannica. Available at: https://www.britannica.com/topic/dairying.
• WebstaurantStore. (n.d.). WipesPlus 7" x 9" 100 Count No-Rinse Food Contact Surface Sanitizing Wipes. [online] Available at: https://www.webstaurantstore.com/wipesplus-7-x-9-food-contact-sanitizing-
wipes-canister/50033808.html [Accessed 5 Nov. 2023].
• Wu, S., Duan, N., Gu, H., Hao, L., Ye, H., Gong, W. and Wang, Z. (2016). A Review of the Methods for Detection of Staphylococcus aureus Enterotoxins. Toxins, [online] 8(7), p.176.
doi:https://doi.org/10.3390/toxins8070176.