Comparative analysis of cultural isolation and PCR based assay for detection of Campylobacter jejuni in food and faecal samples

ABSTRACT

In the present study, the efficacy of polymerase chain reaction (PCR) based on mapA gene of C. jejuni was tested for detection of Campylobacter jejuni in naturally infected as well as spiked faecal and food samples of human and animal origin. Simultaneously, all the samples were subjected to the cultural isolation of organism and biochemical characterization. The positive samples resulted in the amplification of a DNA fragment of size ~589 bp in PCR assay whereas the absence of such amplicon in DNA extracted from E. coli, Listeria, Salmonella and Staphylococcus confirmed the specificity of the primers. Of randomly collected 143 faecal samples comprising human diarrheic stools (43), cattle diarrheic faeces (48) and poultry faecal swabs (52) only 4, 3 and 8, respectively, could be detected by isolation whereas 6, 3 and 10, respectively, were found positive by PCR. However, among food samples viz. beef (30), milk (35), cheese (30), only one beef sample was detected both by culture as well as PCR. Additionally, PCR was found to be more sensitive for C. jejuni detection in spiked faecal and food samples (96.1 percent each) as relative to culture isolation which could detect the organism in 86.7 percent and 80 percent samples, respectively. The results depicted the superior efficacy of PCR for rapid screening of samples owing to its high sensitivity, specificity and automation potential.