Contents
Context
Campylobacter jejuni is a Gram-negative, microaerophilic, helical-shaped bacteria which has been implicated in as being one of the most common causes of human gastroenteritis worldwide. Infection with this bacteria causes common symptoms such as diarrhoea, abdominal pain, fever, headache, nausea and vomiting. [1] C. jejuni grows optimally between 37 and 42 degrees C and is most commonly found on undercooked poultry, though it has been reported in other undercooked meat and meat products, raw milk, and in untreated drinking water [1].
Treatment and Prevention
Treatment for Campylobacteriosis (Campylobacter-caused diarrhoeal disease) is generally only given in the most severe cases or when patients are vulnerable, and usually consists of giving more fluids and glucose-electrolyte solutions to ensure dehydration does not occur. https://emedicine.medscape.com/article/213720-treatment Erythromycin therapy can also be given but little clinical benefit is seen if the treatment is begun after four days of symptom onset. https://emedicine.medscape.com/article/176400-overview However, the use of antibiotics can be recommended in the case of patients who are immunocompromised, pregnant, or with very severe symptoms. https://emedicine.medscape.com/article/213720-treatment. Prevention of this infection is very easy, with several strategies from the farm to the consumer recommended by WHO: [1]
- Enhanced biosecurity to avoid transmission of Campylobacter from the environment to the flock of birds – only in closed housing conditions
- Good hygienic slaughtering practices carried out
- Prevention methods in domestic kitchens are similar to those specified for other foodborne bacterial infections – ensure meat is cooked through and that milk has been pasteurized before consumption
Current Detection Methods
Culture-based screening
Rapid detection methods
Our device
In an attempt to reduce incidences of food poisoning by Campylobacter jejuni we decided to create a biosensor that was able to detect the presence of Campylobacter jejuni quickly and accurately. To do this we aimed to create a two part biosensor that will detect both xylulose – a rare sugar that is present of the Campylobacter jejuni capsule – and autoinducer-2, a quorum sensing molecule used by campylobacter. For the detection of xylulose two possible avenues were explored: utilising the mannitol operon, that is known to detect xylulose but may have some off target affects; and mutagenesis of the arabinose operon with an aim to change its target sugar to xylulose. The detectors for both xylulose and autoinducer-2 will form the two components of an AND gate that will ensure only a signal is seen when both xylulose and untoinducer-2 are present. Regarding the application of our biosensor we designed a device that would house the biosensor to make the application simple and easy. In addition to this we also looked at producing xylulose in a cheap and efficient way as the cost of xylulose held us back with regards to thorough testing of the biosensor elements. All of the above were done with thought of the implications with regards to human practices and how a genetically engineered biosensor would be received by the public.
- Why xylulose/why autoinducer-2?
