A RAPID DNA ISOLATION PROCEDURE FOR THE IDENTIFICATION OF CAMPYLOBACTER JEJUNI BY THE POLYMERASE CHAIN REACTION

Authors: Englen, Mark; Kelley, Lynda

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2000
Publication Date: 10/22/2000
Citation: Englen, M.D., Kelley, L.C. 2000. A rapid dna isolation procedure for the identification of campylobacter jejuni by the polymerase chain reaction. Letters in Applied Microbiology. 31: 421-426.

Interpretive Summary: In recent years, Federal and State health agencies have greatly increased their efforts to find better ways to control the microorganisms that can spoil the fresh food that we buy in the supermarket or eat in restaurants. Bacteria that cause food poisoning such as Campylobacter and Salmonella, can contaminate chicken and turkey products, and can multiply rapidly if the food is improperly handled or undercooked. Traditional methods for identifying these organisms rely on sample enrichment and growth on selective culture media, processes that may take days to complete and which do not positively identify the bacteria. We have developed a process to directly isolate DNA from bacteria in poultry processing samples, allowing rapid detection of these organisms by identification of unique genes. Using this method, we were able to directly detect Campylobacter in poultry carcass rinses without sample enrichment. Our method should be useful for a wide range of other sample types, and is adaptable to detection of other bacteria by simple modifications to target species specific genes. As food safety concerns continue to grow, food producers, processors and inspectors need more rapid and efficient methods to detect contamination of food products by bacterial pathogens. Our research offers the potential for direct dectection of bacteria in food and food processing samples, saving time and money compared to traditional detection methods.

Technical Abstract: We have developed an efficient process for rapidly isolating Campylobacter DNA using mechanical disruption combined with the guanidine based reagent DNAzol. Template DNA was isolated by this method from cultures of C. jejuni resistant to lysis by boiling or enzymes, and identified following polymerase chain reaction (PCR) amplification using primers specific for the hippuricase gene (hipO). Direct detection of Campylobacter in poultry processing samples by PCR is demonstrated in chicken carcass rinses spiked with lysis resistant C. jejuni. Our results indicate this method of DNA isolation may be ideal for direct PCR detection of pathogenic bacteria in complex samples of widely varied origin, especially when the target organisms are difficult to lyse by other means.