细菌分类-课件.ppt

1、考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Faculty:Dr.Alvin FoxSuggested reading:Murray,Third edition Chapter 2,16-18 and 21.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Isolation(culture)Agar plate/coloniesLiquid media test tube-bulkId

2、entification&taxonomyFamilyGenusSpeciesTypeStrainqBiochemical(physiological)testsqMolecular testsqDNA-DNA homologyq16S rRNA sequencingqChemical profilingqNon culture based detection qPolymerase chain reaction-(PCR)qAgglutination(antigen detection)qStainqSerology(antibody detection).考评项目赋标准分，对照考评内容和考

3、评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分1.Isolation&identification aids treatment since infectious diseases caused by different bacteria have a variety of clinical courses and consequences.Susceptibility testing of isolates helps in selection of antibiotics for therapy.The identif

4、ication is based on taxonomic principles applied tothe clinical microbiological situation.4.Tests must be easily learned,low in cost and rapidly performed.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Family:a group of related genera.Genus:a group of related species.Spe

5、cies:a group of related strains.Type:sets of strain within a species(e.g.biotypes,serotypes).Strain:one line or a single isolate of a particular species.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Samples of body fluids are streaked on culture plates and isolated col

6、onies of bacteria appear after incubation.Observation of these colonies for size,texture,color,and(if grown on blood agar)hemolysis reactions,is highly important as a first step in bacterialidentification.Whether the organism requires oxygen for growth is another important differentiating characteri

7、stic.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Colonies are Gram stained and individual bacterial cells observed under the microscope.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项

8、目考评实际得分之和为该考评类目的考评实际得分 Stage1.Staining with crystal violet.Stage 2.Fixation with iodine stabilizes crystal violet staining.All bacteria remain purple or blue.Stage 3.Extraction with alcohol.Decolorizes some bacteria (Gram negative)and not others(Gram positive).Stage 4.Counterstaining with safranin.G

9、ram positive bacteria are stained with crystal violet and remain purple.Gram negative bacteria are stained pink.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Shape cocci(round)bacilli(rods)spi

10、ral or curved(e.g.spirochetes)Single or multiple cells clusters(e.g.streptococci)chains(e.g.streptococci)Gram positive or negative.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分.考评项目赋标准分，对照考评内容

11、和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 The bacteria are speciated using these isolated colonies.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Antibiotic susceptibility t

12、esting is performed.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Comparisons of species involve comparisons of multiple strains for each species.Comparisons are primarily based on chemical or molecular analysis.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评

13、实际得分之和为该考评类目的考评实际得分It would be ideal to compare sequences of entirebacterial chromosomal DNA.Alternatively,genomic similarity has been assessed by the guanine(G)+cytosine(C)content(%GC).This has been replaced by two alternatives:Hybridization 1.Sequencing specific genes.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评

14、，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分1.How well two strands of DNA from differentbacteria bind(hybridize)together.This technique is employed to compare the genetic relatedness of bacterial strains/species.If the DNA from two bacterial strains display a high degree of homology(i.e.they bind

15、 well)the strains are considered to be members of the same species.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Sequencing of 16S ribosomal RNA molecules(16S rRNA)The 16S rRNA is approximately 1600 nucleotides in length.The 16S rRNA provides genomic similarity above th

16、e species level allowing comparisons of relatedness across the entire bacterial kingdom.Closely related bacterial species often have identical rRNA sequences.5.The technique provides complementary information to DNA-DNA hybridization.The development of probes based on 16S data have improvedidentific

17、ation of some bacterial pathogens.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Sophisticated tools are available for studying the structural composition of bacteria(most commonly fatty acid,carbohydrate or ubiquinone profiling)of bacteria.Characterization of secreted m

18、etabolic products(e.g.volatile alcohols and short chain fattyacids)is also helpful.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分 Certain human pathogens either can not be isolated in the laboratory grow extremely poorly.Successful isolation can be slow and in some inst

19、ances impossible.3.Direct detection of bacteria without culture is possible for some organisms.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Antigen detectionUsed in many doctors offices for the group A streptococcus.The patients throat is swabbed and streptococcal anti

20、gen extracted directly from the swab(without prior bacteriological culture).Thebacterial antigen is detected by aggregation(agglutination)of antibody coated latex beads.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分The polymerase chain reaction(PCR)can be used toamplify

21、 large amounts of specific genes or portions of genes.Great success has been achieved in rapid diagnosis of tuberculosis.考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Certain clinical samples such as sputum can be directly assessed for the presence of bacteria can be helpful(e.g.detection of M.tuberculosis in sputum).考评项目赋标准分，对照考评内容和考评办法对考评项目进行考评，评出各考评项目的考评实际得分，考评类目下各考评项目考评实际得分之和为该考评类目的考评实际得分Serologic identification of an antibody response(in patients serum)to the infecting agent can only be successful several weeks after an infection hasoccurred.