Approaches to the detection of enteric pathogens, including Campylobacter, using nucleic acid hybridization

A previous study of the detection of Campylobacter jejuni in fecal samples spotted directly onto nitrocellulose filters before hybridization revealed a relatively low sensitivity and some false-positive results. We have investigated two factors that interfere with the detection of Campylobacter jejuni in fecal samples: interfering substances that create false-positive background signals and nonspecificity of the probe. Heterologous deoxyribonucleic acid probes bound nonspecifically to partially extracted fecal samples, indicating that the major basis for false-positive background was not due to homologous sequences. The problem of false-positive results could be reduced, but not eliminated, by extensive deoxyribonucleic acid extraction procedures applied to the clinical sample. The relative concentration of protein in each sample may be an important contributor to nonspecific binding. Other measures, such as sonication, glass bead fragmentation, and column separation, were not helpful. Development of a species-specific deoxyribonucleic acid probe derived from sequences encoding 16S ribonucleic acid is underway.