1 / 24

ENTEROBACTERIACEAE ENTERIC GRAM NEGATIVE RODS

ENTEROBACTERIACEAE ENTERIC GRAM NEGATIVE RODS. Dr.Indumathi Gokula Metropolis Clinical laboratory. FEATURES. LARGE HETEROGENOUS GROUP : NATURAL HABITAT : HUMAN/ANIMAL INTESTINE MORE THAN 25 GENERA AND 110 SPECIES; 20-25 CLINICALLY SIGNIFICANT SPECIES

zarola
Download Presentation

ENTEROBACTERIACEAE ENTERIC GRAM NEGATIVE RODS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ENTEROBACTERIACEAEENTERIC GRAM NEGATIVE RODS Dr.Indumathi Gokula Metropolis Clinical laboratory

  2. FEATURES • LARGE HETEROGENOUS GROUP : • NATURAL HABITAT : HUMAN/ANIMAL INTESTINE • MORE THAN 25 GENERA AND 110 SPECIES; • 20-25 CLINICALLY SIGNIFICANT SPECIES • FACULTATIVE ANAEROBES, FERMENT CARBOHYDRATES, COMPLEX ANTIGENIC STRUCTURE • PRODUCE TOXINS AND VIRULENCE FACTORS

  3. CHARACTERISTICS • GRAM NEGATIVE BACILLI • NON SPORING • MOTILE(PERITRICHOUS FLAGELLA)/NON MOTILE • CAPSULATED/NON CAPSULATED • NON FASTIDIOUS • FERMENT GLUCOSE WITH ACID/GAS • REDUCE NITRATES TO NITRITES • OXIDASE NEGATIVE/CATALASE POSITIVE • BIOCHEMICAL TESTS DONE TO DIFFERENTIATE THE VARIOUS SPECIES

  4. CLASSIFICATION • COMPLEX • CHANGING TAXONOMY

  5. ANTIGENIC STRUCTURE • COMPLEX • 3 ANTIGENS • O (SOMATIC) • H(FLAGELLAR) • K(CAPSULAR)

  6. O ANTIGEN (SOMATIC) • MOST EXTERNAL PART OF CELL WALL LPS • REPEAT POLYSACCHARIDE UNITS • HEAT AND ALCOHOL RESISTANT • DETECTED BY AGGLUTINATION • ANTIBODIES TO ‘O’ ARE IgM • GENUS SPECIFIC • CROSS SHARING • ASSOCIATED WITH DISEASE (UTI OR DIARRHOEA CAUSING E.COLI) • MORE THAN 150 TYPES

  7. H ANTIGENS(FLAGELLAR) • LOCATED ON FLAGELLA • HEAT AND ALCOHOL LABILE • ANTIBODIES FLUFFY CLUMPS MAINLY IgG TYPE • MORE THAN 50 TYPES

  8. K ANTIGENS (CAPSULAR) • EXTERNAL TO O ANTIGEN • MORE THAN 100 TYPES • PRESENT IN SOME GENERA • POLYSACCHARIDE/PROTEINS • ASSOCIATED WITH VIRULENCE • E.G.K1 OF E.COLI MENINGITIS, UTI • KLEBSIELLA : UTI 8,9,10,24 • Vi ANTIGENS IN SALMONELLA • INHIBITS PHAGOCYTOSIS • ANTIGENIC FORMULA : E.COLI 055:K5:H21

  9. ESCHERICHIA COLI • NORMAL INTESTINAL FLORA • DETECTION IN WATER INDICATES RECENT FECAL CONTAMINATION • ONLY ONE SPECIES • SEVERAL SEROTYPES AND BIOTYPES • MA : LF • IMVIC ++--

  10. PATHOGENICITY • URINARY TRACT INFECTION • DIARRHOEA • PYOGENIC INFECTION • SEPTICAEMIA

  11. UTI • COMMON CAUSE OF ASCENDING INFECTION • PREGNANCY, SEXUALLY ACTIVE FEMALES, OTHER PREDISPOSING FACTORS LIKE OBSTRUCTION • PYELONEPHRITIS • UROPATHOGENIC STRAIN • VIRULENCE FACTOR : HAEMOLYSIN • P PILUS • K ANTIGEN • O1,2,4,6,7,75; K SEROTYPES K1,2,3,5,12,13

  12. E.COLI DIARRHOEA • 5 STRAINS • ENTEROPATHOGENIC(EPEC) • ENTEROTOXIGENIC(ETEC) • ENTEROINVASIVE(EIEC) • ENTEROHAEMORRHAGIC(EHEC) • ENTEROAGGREGATIVE(EAEC)/ • DIFFUSE AGGREGATIVE

  13. DIARRHOEA • WATERY STOOLS • ABDOMENAL CRAMPS • VOMITING • WITH OR WITHOUT FEVER • WITH OR WITHOUT BLOOD AND MUCUS • SELF LIMITING 5-10 DAYS

  14. EPEC • INFANTILE DIARRHOEA : SPORADIC CASES/INSTITUTIONAL OUTBREAK • INCUBATION 1-2 DAYS • O26B6,055B5 STRAINS • VIRULENCE FACTOR: PILI (Bfp) ; intimin(adhesin); Tir ( translocated intimin receptor) • BACTERIAL ATTACHMENT TO MICROVILLI; AND EFFACING (DISTRUPTION) MECHANISM

  15. ENTEROPATHOGENIC E.COLI

  16. EPEC DIAGNOSIS • ISOLATION • SEROTYPING WITH POLYVALENT SERA • TISSUE CULTURE ADHESION : FLUORESCENT ACTIN STAIN • DNA BASED DETECTION FOR VIRULENCE GENES

  17. ETEC • TRAVELLERS’ DIARRHOEA • BOTH ADULTS AND CHILDREN • CONSUMPTION OF WATER CONTAMINATED WITH SEWAGE • IP 1-7 DAYS NO FEVER • SELF LIMITING 2-6 DAYS • O6, 08, 025, 027

  18. ETEC • VIRULENCE FACTOR • ENTEROTOXIN : LT AND ST: GENETIC CONTROL • PILI OR K PROTEINS • LT : CHOLERA LIKE TOXIN, ACTIVATES CYCLIC AMP PATHWAY : FLUID HYPERSECRETION INTENSE & PROLONGED ST : ACTIVATES CYCLIC GMP PATHWAY: SHORT ONSET OF ACTION

  19. ETEC • DIAGNOSIS • CULTURE FAECES • DETECT LT/ST TOXIN • LT TOXIN BY : IN VIVO • IN VITRO • IN VIVO : LIGATED RABBIT ILEAL LOOP (6-18HRS) • ADULT RABBIT SKIN TEST • IN VITRO : ELISA • RIA • TISSUE CULTURE (CHO CELL LINES)

  20. EIEC • DYSENTRY/FEVER • OLDER CHILDREN AND ADULTS • O124, 136, 144 • IP 3 DAYS ; DURATION 7-10DAYS • VIRULENCE FACTOR: PLASMID CODED OMP • INVASIVE: ENDOCYTOSIS→INFLAMMATION→ NECROSIS→ULCERATION DETECTION : SERENY TEST HeLA CELL INVASION

  21. EHEC • DEVELOPED COUNTRIES • CONTAMINATED BEEF AND UNPASTEURIZED MILK • HAEMORRHAGIC COLITIS/HUS • IP 3-4 DAYS • DURATION : 5-10 DAYS • O157H7 • VEROTOXIN :CYTOTOXIN:SHIGA LIKE TOXIN • DETECTION OF VERO TOXIN BY GENETIC PROBES • GROWTH ON MA SORBITOL AGAR

  22. EAEC ACUTE OR CHRONIC DIARRHOEA >14DAYS DURATION DEVELOPING COUNTRIES FOOD BORNE CHARACTERISTIC ATTACHMENT TO CELLS : STACKED BRICK FORMATION VIRULENCE : FIMBRIA, HEAT LABILE ENTEROTOXIN AND CYTOTOXIN

  23. EAEC

  24. SEPSIS/MENINGITIS • INADEQUATE NORMAL DEFENSES • SUSCEPTIBLE : NEW BORN • UROSEPSIS • MENINGITIS : K1 ANTIGEN IN NEONATES

More Related