Clinically significant Enterobacteriaceae Escherichia Lactose fermented rapidly Shigella Lactose not fermented Salmonella Klebsiella ● roteus Citrobacter Serratia Mac conkey’ s agar
Clinically Significant Enterobacteriaceae • Escherichia • Shigella • Salmonella • Klebsiella • Proteus • Citrobacter • Serratia • …… Lactose NOT fermented Lactose fermented rapidly MacConkey's agar
Differential media Triple Sugar Iron(TSD slant Ingredients glucose sucrose, lactose, Slant, lactose, FeSO4 ferrous sulfate, and pH indicator phenol red (phenol red); Bacteria that ferment any of the three Butt, glucose, phenol red sugars in the medium will produce byproducts. These byproducts are usually acids, which will change the color of the ph indicator from red to yellow; Some bacteria utilize thiosulfate anion as a terminal electron acceptor, reducing it to hydrogen sulfide. The byproduct H2s reacts with ferrous sulfate in the medium to form black precipitate. E Coli Samonella Shigella
Differential media Triple Sugar Iron (TSI) slant • Ingredients : glucose ,sucrose , lactose , ferrous sulfate, and pH indicator (phenol red); • Bacteria that ferment any of the three sugars in the medium will produce byproducts. These byproducts are usually acids, which will change the color of the pH indicator from red to yellow; • Some bacteria utilize thiosulfate anion as a terminal electron acceptor, reducing it to hydrogen sulfide. The byproduct H2S reacts with ferrous sulfate in the medium to form black precipitate. Slant, lactose,FeSO4, phenol red Butt, glucose, phenol red E.Coli Samonella Shigella
Glucose Lactose motivity H,S Ecoli 十 Samonella+ 十 Shigella API 10s systems ONPG GLU ARA LDC ODC CIT H2S URE TDA IND
Shigella + - - - Samonella + - + + E.coli + + + - Glucose Lactose motivity H2S API 10s systems
3. Possess a complex antigenic structure Immulogic test for“sero” classification Flagella(H antigen Capsule(K or Vi antigen Lipopolysaccharide( LPS)or n O polysaccharid Polysaccharide lipid a U7P点CF就E ooplasmIc sp proprotein UPOPEOTEH Peptidogly PEPTDOCUCAH Inner membrane Cytopl
3. Possess a complex antigenic structure Immulogic test for “sero” classification
4. Easy to variation Plasmids and transfer of genetic information Original organisms Conjugation transduction Old donor New Donor transformation Drug resistant variation New type organism To oXinogeny variation Biochemical test variation
4. Easy to variation transformation transduction Original organisms Conjugation New type organism Drug resistant variation Toxinogeny variation Biochemical test variation