urinary tract infections-Lab diagnosis (e.coli, klebsilla, proteus, pseudomonas)


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Urinary tract infections-Lab diagnosis

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urinary tract infections-Lab diagnosis (e.coli, klebsilla, proteus, pseudomonas)

  1. 1. UTI-lab diagnosis MGMC&H,Jaipur 1
  2. 2. UTI-lab diagnosis MGMC&H,Jaipur 2 • It is defined as a disease caused by microbial invasion of the genitourinary tract that extends from the renal cortex of the kidney to the urethral meatus. •Route of infection to reach the urinary tract can be either- Ascending route Haematogenous route
  3. 3. UTI-lab diagnosis MGMC&H,Jaipur 3 • E.coli • Klebsiella • Pseudomonas • Proteus Gram –ve Bacilli • Staphylococcus • EnterococciGram +ve Bacilli • M.tuberculosis • Citrobacter • Salmonella Miscellaneous • Candida albicans Fungus E.coli c.albicans Citrobacter Staphylococcus
  4. 4. UTI-lab diagnosis MGMC&H,Jaipur 4 UTI causing organisms E.coli (63%) Klebssiella(15%) Pseudomonas(5%) Proteus(5%) Other Gram -ve bacteria Staphylococcus Enterococcus
  5. 5. UTI-lab diagnosis MGMC&H,Jaipur 5 •Sterile pyuria is urine which contains white blood cells while appearing sterile by standard culturing techniques. • Sterile pyuria is listed as a side effect from some medications such as paracetamol (acetaminophen).
  6. 6. UTI-lab diagnosis MGMC&H,Jaipur 6 •An infection contracted outside of a health care setting or an infection present on admission. •E.Coli is the most common cause followed by stapylococcus saprophyticus s.saprophyticus
  7. 7. UTI-lab diagnosis MGMC&H,Jaipur 7 •Acquired by a patient during a hospital visit. •Most common organism causing it- Klebsiella
  8. 8. UTI-lab diagnosis MGMC&H,Jaipur 8 Patients with urinary catheters have a higher chance of getting UTI’s.This is because germs can travel along the tubing of the catheter and cause infection in the urinary system.This is then referred to as a “catheter associated” UTI. Complications – •Cystitis • pyelonephritis • bacteremia • prostatitis •Rarely, endocarditis, septic arthritis, and meningitis
  9. 9. UTI-lab diagnosis MGMC&H,Jaipur 9 Poor aseptic insertion of catheter: periurethral flora inserted into bladder. Migration of bacteria along outer surface of catheter. Open drainage. Breaks in the closed drainage system.
  10. 10. UTI-lab diagnosis MGMC&H,Jaipur 10 1. 2. 3.
  11. 11. UTI-lab diagnosis MGMC&H,Jaipur 11
  12. 12. UTI-lab diagnosis MGMC&H,Jaipur 12 •Collected PRIOR to antibiotics. •WASH hands properly. •Specimen is collected in a STERILE container BEFORE ANTIBIOTICS STERILE CONTAINER
  13. 13. UTI-lab diagnosis MGMC&H,Jaipur 13 First morning specimen should be taken. FEMALES- MALES- Clean the area with soap and water , hold the labia apart and discard few ml of urine and then collect the midstream sample directly into the sterile container. Clean the glans with soap and water, retract the foreskin, discard few ml of urine and the collect the mid stream sample directly into the sterile container . •Discard the rest of the urine. •The first portion of urine adequately flushes out the normal urethral flora.
  14. 14. UTI-lab diagnosis MGMC&H,Jaipur 14 •Urine should be collected directly from the catheter and not from the collection bag. •The catheter should not touch the container. •Catheterization to obtain urine is not done because of risk of introducing infection though it yields excellent results. A clean catch specimen after cleansing of genitalia. OR Supra pubic aspiration.
  15. 15. UTI-lab diagnosis MGMC&H,Jaipur 15
  16. 16. UTI-lab diagnosis MGMC&H,Jaipur 16 THE SPECIMEN SHOULD BE TRANSPORTED IMMEDIATELY. •Urine is a good medium for the growth of microorganisms, hence delay in processing will hamper the results. •If delay is unavoidable, the specimen can be refrigerated for up to four hours at 4˚c.
  17. 17. UTI-lab diagnosis MGMC&H,Jaipur 17 Urine transport tubes have shown to preserve bacteria without refrigeration. It consistes of- -Boric acid -Glycerol -Sodium formate
  19. 19. UTI-lab diagnosis MGMC&H,Jaipur 19 Urine is centrifuged and deposit is examined under the microscope. Following can be seen- •Pus cell( 0-5/hpf is the normal value for pus cells in the human body). •RBC •Epithelial cells •Bacteria Bacteria Pus cell
  20. 20. UTI-lab diagnosis MGMC&H,Jaipur 20 Most lab use a semi quantitative method (STANDARD LOOPTECHNIQUE) for culture. This technique involves a standard calibrated loop which transfers a fixed and small volume of urine. STANDARDCALIBRATED LOOP
  21. 21. UTI-lab diagnosis MGMC&H,Jaipur 21 Fixed and small amount of uncentrifuged urine is transferred to BLOOD and MacCONKEY’S AGAR. Incubate at 37˚c for 24 hours Next day, the number of colonies grown is counted and total count per ml is calculated. •BLOOD AGAR- gives a quantitative measurement of bacteriuria. •Mac CONKEY’SAGAR- gives presumptive diagnosis of the bacteria.
  22. 22. UTI-lab diagnosis MGMC&H,Jaipur 22 INTERPRETATION OF RESULTS •Bacteriological diagnosis of UTI is carried out by ‘SIGNIFICANT BACTERIURIA’ using quantitative cultures developed by KASS(1956). •This is based on the fact that normal urine is sterile but during voiding may become contaminated with genital commensals. SIGNIFICANT BACTERIURIA DOUBTFUL SIGNIFICANCE NO SIGNIFICANT GROWTH •When bacterial count is more than 105/ml of a single species. •It indicates ACTIVE UTI. •Between 104 to 105 bacteria per ml. •Specimen should be repeated for culture. • <103 bacteria per ml are regarded as contaminated. • Contamination is also considered when 3 or more bacteria are isolated.
  23. 23. UTI-lab diagnosis MGMC&H,Jaipur 23 The organisms are identified by-  colony characters  gram staining  motility  biochemical test  slide agglutination test  serological test
  24. 24. UTI-lab diagnosis MGMC&H,Jaipur 24 SIZE 1-2 mm COLONY CHARACTER Blood agar Mac Conkey agar Grey-white, moist, smooth, opaque, non mucoid Pink colony( due to lactose fermentation) GRAM STAINING Gram –ve bacteria BIOCHEMICALTEST Indole Methyl red Voges-Proskauer(VP) Citrate + + - - MOTILITY Motile
  25. 25. UTI-lab diagnosis MGMC&H,Jaipur 25 BLOOD AGAR MacCONKEY’S AGAR GRAM STAINING
  26. 26. UTI-lab diagnosis MGMC&H,Jaipur 26 SIZE 2-4 mm COLONY CHARACTER Blood agar Mac Conkey agar Grey-white, moist, smooth, opaque, mucoid Pink colony( due to lactose fermentation) GRAM STAINING Gram –ve bacteria BIOCHEMICALTEST Indole Methyl red Voges-Proskauer(VP) Citrate - - + + MOTILITY Non-Motile
  27. 27. UTI-lab diagnosis MGMC&H,Jaipur 27 BLOOD AGAR GRAM STAINING MacCONKEY’S AGAR
  28. 28. UTI-lab diagnosis MGMC&H,Jaipur 28 COLONY CHARACTER Blood agar Nutrient agar Mac Conkey agar Exhibits SWARMING(fishy odour) Exhibits SWARMING Smooth pale colonies GRAM STAINING Gram –ve bacteria BIOCHEMICALTEST Indole TSI PPA Urease Oxidase -(P.mirabilis) +(P.vulgaris) H2S production + + - MOTILITY Motile
  30. 30. UTI-lab diagnosis MGMC&H,Jaipur 30 SIZE 2-4mm COLONY CHARACTER Blood agar Nutrient agar Mac Conkey agar Smooth, large, convex, translucent(sweetish aromatic odour) Same as on blood agar Smooth pale colonies GRAM STAINING Gram –ve bacteria BIOCHEMICALTEST Indole TSI PPA Urease Oxidase Citrate - K/ no change (without H2S production) - +/- + - MOTILITY Motile
  32. 32. UTI-lab diagnosis MGMC&H,Jaipur 32 Dip slides Pour plate method Triphenyltetrazolium chloride (TTC) test Griess nitrite test Glucose test paper Polymorphonuclear neutrophils (PMNs) Catalase test Leucocyte esterase Detection of lipopolysaccharide (endotoxin)
  33. 33. UTI-lab diagnosis MGMC&H,Jaipur 33 In this test commercially available plastic slides coated with CLED agar (cysteine lactose electrolyte deficient) on one side and MacConkey’s agar on the other is dipped in urine then placed in a sterile container is incubated at 37˚c.
  34. 34. UTI-lab diagnosis MGMC&H,Jaipur 34 •It is a quantitative method •But, is cumbersome for routine diagnostic work
  35. 35. UTI-lab diagnosis MGMC&H,Jaipur 35 •It is based on nitrate reducing enzymes produced by bacteria present in urine. •Gram -ve bacteria- NITRATES NITRITES •The presence of nitrite detected by the test indicates UTI. •Normal urine does not contain nitrite.
  36. 36. UTI-lab diagnosis MGMC&H,Jaipur 36 (TTC TEST) TTC is reduced by several frequently encountered urinary tract pathogens and produce a pink red precipitate.
  37. 37. UTI-lab diagnosis MGMC&H,Jaipur 37 •Certain bacteria have an enzyme catalase which acts on hydrogen peroxide to release oxygen. H2O2 H2O + O [Nascent oxygen] •The presence of catalase is evident by formation of bubbles. •It indicates bacteriuria. (test present only in catalase +ve organisms.) catalase
  38. 38. UTI-lab diagnosis MGMC&H,Jaipur 38 It is based on utilisation of the minute amount of glucose present in normal urine, by bacteria causing the infection. Hence, it indicates bacteriuria.
  39. 39. UTI-lab diagnosis MGMC&H,Jaipur 39 (PMNs) •PMNs are counted in uncentrifuged urine specimen with the help of haemocytometer. 8 PMN/mm3 is indicative of infection.
  40. 40. UTI-lab diagnosis MGMC&H,Jaipur 40 Presence of the enzyme in urine indicates infection. This test helps in the detection of gram –ve bacteria in urine.
  41. 41. UTI-lab diagnosis MGMC&H,Jaipur 41 •Esch. coli and other common urinary pathogens develop multiple drug resistance and of the transferable variety. •Antibiotic sensitivity is necessary to administer proper antibiotic. •Done by STOKES DISC DIFFUSION method.
  42. 42. UTI-lab diagnosis MGMC&H,Jaipur 42