ABSTRACT
We established a multiplex direct PCR for rapid detection of E.coli,Salmonella,Staphylococcus aureus,Listeria and Yersinia enterocolitica bacteria.Multiplex direct PCR primers were designed according to gene sequences of phoA (E.coli),inv A (Salmonella),nuc (S.aureus),hl y (Listeria),and ail (Y.enterocolitica).After the multiplex direct PCR were established,the specificity and sensitivity of primers were detected.Then,multiplex direct PCR was applied to examine 60 swine product samples,the detection specificity,accuracy and positive predictive value were calculated compared with the gold standard culture method.Results showed that multiplex direct PCR primers could be used for specific detection of E.coli,Salmonella,S.aureus,Listeria and Y.enterocolitica,with the minimal detectable limit of 10,1,100,1 and 1 CFU,respectively.For the examination of 60 swine product samples using multiplex direct PCR,15 were positive for E.coli,6 positive for Salmonella,21 positive for S.aureus,20 positive for Listeria,and 35 positive for Y.enterocolitica,with all positive detection rates higher than that of culture.The total detection sensitivity was 100％,accuracy was 94％,and positive predictive value was 81.44％.Multiplex direct PCR could be used for specific and sensitive detection of common food-borne pathogens,and the testing time was shorten to be 3 hours because of saving time for template extraction.Multiplex direct PCR might serve the detection of food-borne pathogens in food safety risk monitoring much better.
ABSTRACT
Taenia multiceps is a cestode parasite with its larval stage [metacestode], Coenurus cerebralis, mainly encysts in the central nervous system of sheep and other livestock causing cerebralis coenurosis. Since treatment of coenurosis with chemotherapy showed little effect and surgical removal of cysts is not advisable in field conditions, vaccination is useful to control coenurosis. Previous study indicated that immunization with T. multiceps metacestode antigens could induce protection in sheep against coenurosis, so the aim of this study was to identify T. multiceps metacestode antigens in order to find potential vaccine development candidates for further study. The protein extracts from the larval T. multiceps were analyzed by twodimensional electrophoresis [2-DE] and characterized by mass spectrometry. A total of 150 protein spots were detected with isoelectric point [pI] value from 4.97 to 9.65 and molecular weight from 14 to 98 kDa. Twenty-two protein identities were determined by mass spectrometry and 15 unique proteins were obtained. Functional annotation revealed that some of these proteins are involved in catalytic activity, binding, metabolic, cellular process and stress response. Among these molecules are antioxidant proteins [peroxiredoxin and glutathione-S-transferase], glycolytic enzymes [malate dehydrogenase and enolase], proteins with chaperone activity [heat shock protein 70 and small heat shock protein], and structural proteins [actin, actin modulator protein and paramyosin]. The identification of T. multiceps metacestode protein will provide valuable information to elucidate their specific roles in the parasitism and screen new targets for vaccine development