Establishment And Preliminary Application Of Campylobacter Jejuni Campylobacter Coli And Salmonella

In most industrialized countries ,Campylobacter jejuni is the commonest cause of infectious diarrhea, and as a result it causes high morbidity and economic lose. It is also an important diarrhea pathogen in China.Salmonella is one of commonest pathogens of infective diarrhea in developing countries. They are also most important cause of outbreaks of food-borne enteritis. Based on unique sequence characteristics of 165 rDNA, We have been developing a rapid and sensitive method for detecting Campy/aba cter jejuni, Campy/aba cter co/i and salmonella. We have searched the 1 6s rRNA genes of the three target bacteria and other relevent bacteria of intestines. Three species specific probes and a common probe and a pair of common primer were designed. The 1 6S rDNA was fist amplified by polymerase chain reaction,then the amplified products were hybridized to specific probe bound to Nylon Membranes. Hybrid products were detected by Dig Nucleic Acid Detection System. By laborious experiments, a perfect scheme of polymerase chain reaction and reverse dot blot have established. It has high specificty (95.38%) ,good reproducibility( 100%) and high sensitivity (1 00%)validated by application of real value (McNemar test P0.25 0). We also carried it into application in a field. The positive rate of PCR- RDB was 90%,that is , it could detect 23 strains of Campy/aba cter jejuni out of 25G. jejuni and 4 Salmonella out of 5 identified by bio-chemical method. -3- We skillfully combinated PCR and reverse dot blot, using the high specificity of reverse dot blot overconming the deficiency of high false positive rate of PCR as well as making use of the characteristic of high specificity of PCR. We could make correct etiological diagnosis within 5--6 hours by PCR-RDB. Our study provides some useful essential information about detecting many familiar diarrher pathogens at one time.