兽医专业英语(扬州大学)l.ppt

Lesson FifteenSalmonella Testing New words and phrasesSalmonellaBacteriologicalImmunologicalEnzymicChromogenicImmunochromatographicListeriaFloraAgarPeptoneMagnetic Streak LuminescentReagentGiardiaCryptosporidiumProtozoa(zoon)StreptavidinImmunosorbentBrothImmobilizeInoculationTextThe food market continues to grow with the introduction of new products and novel methods of presentation.The increase in sample numbers has provided impetus(推动力)for the development of new tests which are designed to streamline the test methods and provide reliable and economical results to ensure both the bacteriological safety and long-term stability of the food products.Immunological,enzymic and molecular biological techniques are now appearing as test methods in addition to the routine agar plate detection methods.Although providing great sensitivity and specificity,many methods still require significant capital investment in equipment and skilled personnel in order to attain best test performance.For Salmonella testing the ability to provide quick,sensitive and accurate test results is important to ensure that this diverse and commonly encountered group of pathogens is not distributed into the human food chain.For quality control of raw materials the key problem is often the detection of low numbers of viable pathogens in the presence of much greater numbers of background flora.This is a significant problem if the final product is not required to receive further cooking.In cases where food products are partially cooked,then chilled prior to sale,the problem becomes one of detection requiring a test method with high sensitivity to the target organism.Conventional tests require a period of nonselective enrichment followed by a further period of enrichment in a selective growth medium,where conditions favour growth of the target organism,which can subsequently be cultured by plating onto a selective agar plate.The search for low numbers of target organisms has also been significantly improved by the use of immuno-linked magnetic beads,which can be used to“select”specific target organisms from a mixed culture.The magnetic beads are linked with an antibody which is specific for the target organism.These beads do not possess any native magnetism but exhibit magnetic properties only when introduced into a magnetic field.Now the immuno-linked magnetic beads can be used to capture target organisms,and the beads can then be separated from the mixture by application of a strong magnetic field and the unwanted mixture discarded.The bead preparation can then be washed and used for further analysis,either by streaking onto selective agar plates or by combination with luminescent reagents in order to rapidly detect low levels of the target organism.Magnetic beads are available for detection of Salmonella,and E.coli O157:H7.Similar preparations are also available for detection of Giardia and Cryptosporidium,protozoa which pose significant problems for the water industry.Use of Streptavidin linked beads provides an opportunity to coat magnetic beads with specific antibodies of interest,thus opening the way for new method development and detection of less common microorganisms.Alternative immunosorbent technology forms the basis of a quick and simple test designed to screen enrichment broth samples for the presence of Salmonella organisms(antigen).Specific antibodies are immobilized on a permeable support and used to capture Salmonella antigens which may be present in the test sample.All the necessary test reagents are present in the test device and the test carried out simply by introduction of a few drops of the sample enrichment broth into the test well.The sample diffuses through the reaction track to give a test and control result-visible as a coloured line in the viewing window.Tests can be carried out on enrichment broth samples after only 24 hours with a visible result 1015 minutes after inoculation of the device.鸡沙门氏菌的分离鉴定及药物敏感试验Separation Identification and Drug Susceptibility Test of Avian Salmonella摘要：从新疆南疆地区某鸡场采集到的14 份具有沙门氏菌病病变特征的病料中分离出沙门氏菌10 株.Abstract:14 samples with avian salmonellosis were collected from southern area of Xinjiang，and 10 strains of chicken Salmonella were separated标题标题通过形态观察、生化试验、血清学鉴定及动物致病性试验，结果表明，10 株沙门氏菌的血清型为O2、O9，这两种血清型沙门氏菌对5 日龄雏鸡具有很强的致病作用.The results of morphological observation，biochemical tests，serotype identification and pathogenicity tests showed that O2 and O9 were the dominant serogroups and both serogroups were high pathogenic for chickens 5 days old 药敏试验结果表明，沙门氏菌对硫酸庆大霉素最敏感，其次是头孢唑啉钠，敏感率分别为100 和90，其对乙酰螺旋霉素和罗红霉素产生耐药性.The drug susceptibility test indicated that the sensitivities of the 10 strains to gentamycin sulfate and cefazolin sodium were 100 and 90，respectivelyAnd they were high resistance to acetylspiramycin and roxithromycin关键词：鸡；沙门氏菌；分离；鉴定；药物敏感试验Key words:chicken；Salmonella；separation；identification；drug susceptibility testRapid Hygiene Testing TechnologyRapid hygiene testing technologies,such as those of the market leader Biotrace,are mostly based on the measurement of adenosine triphosphate(ATP).ATP is chemical found in a living cells.So,if ATP is present on a surface that appears to be clean to the human eye,some food residues or other cellular material must be present creating a potential breeding ground for bacteria.Harnessing this principle,the ATP based rapid hygiene tests seek to measure the amount of ATP present on the critical points of a production line,and this can either be measured on surfaces or in rinse waters for Clean In Place(CIP)systems.Rapid hygiene testing technology is also an excellent training tool enabling personnel to see a clear and immediate link between good hygiene practice and the hygiene test result.Some companies have even used the technology to modify their production lines,by identifying production areas which are difficult to clean and feeding that information back to suppliers of their production line equipment.