Culture and detection of Campylobacter jejuni within mixed microbial populations of biofilms on stainless steel

Abstract

Campylobacter jejuni is the most frequently reported cause of foodborne illness in the United States, but its survival outside the host is poor. The objective of this research was to examine the formation and composition of biofilms by C. jejuni alone and within mixed bacterial populations from the poultry-processing environment. C. jejuni growth was assessed with four media, two temperatures, and two atmospheric conditions to develop culture methods for liquid media that would allow growth within the biofilms. Growth kinetics was followed at four cell densities to determine temporal compatibility within biofilm mixtures. Analysis of the biofilms by confocal laser scanning microscopy showed that C. jejuni formed a biofilm when incubated without other bacteria. The average surface area of stainless steel covered by C. jejuni increased by 50% from 24 to 48 h, remained level to 96 h, and then decreased by 88% by 168 h. C. jejuni and mixed bacterial populations formed biofilms during incubation periods of up to 7 days. The area of the mixture was significantly greater than for C. jejuni alone at 24 h, was approximately the same at 48 h, and was significantly less by 168 h. When incubated with either of two initial inoculum densities of other bacteria, the number of C. jejuni was enhanced after 24 h. The intensity of fluorescence and cell viability were monitored by epifluorescence microscopy. This study provides the basis for studying interactions of Campylobacter spp. with other bacteria in the environment, which will aid in the design of effective intervention strategies.