Visible light as an inhibitor of Campylobacter jejuni

Campylobacter jejuni is a Gram-negative, microaerophilic bacteria that is the leading cause of food-borne illnesses in the United States; it frequently causes severe diarrhoea. Campylobacter jejuni has recently demonstrated antibiotic resistance; therefore, alternative methods for treating these infections must be investigated. Visible light has proven to be an effective inhibitory agent for many medically significant species of bacteria and fungi.

Visible light in the blue range (405 nm and 464 nm) was administered to a suspension of Campylobacter jejuni. Brain-heart infusion agar was inoculated with the suspension of the organism following exposure to blue light at a dose of 24 Jcm² for each wavelength. Inoculated plates were placed into a traditional Campy jar in order to mimic a 5% O₂ atmosphere and incubated at 37 °C for 48 hours. Following incubation, colony forming units were counted and compared with controls to determine if the light energy had effectively inhibited the growth of the organism.

Both 405 nm and 464 nm light at a dose of 24 Jcm² were shown to be effective inhibitors of Campylobacter jejuni, with kill rates ranging from 82.4-98.9%.

Blue light effectively inhibits Campylobacter jejuni.