The effect of growth temperature on the pathogenicity of Campylobacter.

Control of Campylobacter in the food chain requires a better understanding of the behaviour of the bacteria in relevant environments. Campylobacter species are largely non-pathogenic in poultry, the body temperature of which is 42 °C. However, the bacteria are highly pathogenic in humans whose body temperature is 37 °C. The aim of this study was to examine if switching from commensal to pathogenic behaviour was related to temperature. We examined the growth, motility and invasion of T84 cells by three species of Campylobacter: C. jejuni 81116, C. jejuni M1, C. coli 1669, C. coli RM2228 and C. fetus fetus NC10842 grown at 37 and 42 °C. Our results suggest that C. jejuni isolates grow similarly at both temperatures but some are more motile at 42 °C and some are more invasive at 37 °C, which may account for its rapid spread in poultry flocks and for infection in humans, respectively. C. coli, which are infrequent causes of Campylobacter infections in humans, is less able to grow and move at 37 °C compared to 42 °C but was significantly more invasive at the lower temperature. C. fetus fetus, which is infrequently found in poultry, is less able to grow and invade at 42 °C.

Susceptibility of Campylobacter jejuni and Yersinia enterocolitica to UV radiation.

Two enteric pathogens, Campylobacter jejuni and Yersinia enterocolitica serogroup O:3, together with Escherichia coli, were investigated for susceptibility to UV radiation at 254 nm. The UV dose required for a 3-log reduction (99.9% inactivation) of C. jejuni, Y. enterocolitica, and E. coli was 1.8, 2.7, and 5.0 mWs/cm2, respectively. Using E. coli as the basis for comparison, it appears that C. jejuni and Y. enterocolitica serogroup O:3 are more sensitive to UV than many of the pathogens associated with waterborne disease outbreaks and can be easily inactivated in most commercially available UV reactors. No association was found between the sensitivity of Y. enterocolitica to UV and the presence of a 40- to 50-megadalton virulence plasmid.

Decontamination of Campylobacter jejuni on chicken drumsticks using chemicals and radiation.

A trial was conducted to compare the efficacy of four disinfectants and radiation to reduce the level of C. jejuni contamination on poultry meat. Two levels of each treatment were applied to chicken drumsticks inoculated with a known concentration of a strain of Campylobacter jejuni, biotype 1, isolated from a human patient with diarrhea. Radiation using a cobalt-60 source at a level of 0.5 KGy effected a 99% surface reduction in C. jejuni. With a mean initial surface contamination level of 1.1 X 10(3) Colony Forming Units/cm2, 1 KGy completely eliminated C. jejuni. Glutaraldehyde at 0.5% concentration for 30 minutes had an efficacy similar to the lower dose of radiation. Chlorine showed a negligible effect on C. jejuni. Succinic acid and Poly (hexamethylenebiguanide hydrochloride) were statistically similar in their effectiveness, ranking between glutaraldehyde and chlorine. These results strongly indicate that, of the alternatives tested, low-dose radiation is the method of choice for reducing Campylobacter contamination of poultry products.