Visible light as an inhibitor of Campylobacter jejuni.

Introduction: 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.

Methods: 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 Jcm for each wavelength. Inoculated plates were placed into a traditional Campy jar in order to mimic a 5% O 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.

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

Conclusion: Blue light effectively inhibits Campylobacter jejuni.