Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Manual blood culture Techniques

4,581 views

Published on

The lecture is a simple one describing the various methods that could be applied in small microbiology laboratories where the automated systems are lacking.

Published in: Health & Medicine
  • Thank you Sir
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Eat This POTENT Vegetable To Melt Diabetic Fat. IMPORTANT: Be careful, only eat it twice a day or you will lose diabetic belly fat too fast... ●●● https://bit.ly/2n5cFHd
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Manual blood culture Techniques

  1. 1. MANUAL BLOOD CULTURE METHODOLOGY STILL IN USE. Dr Mostafa Mahmoud Ahmed, Ph D Consultant Microbiologist, GDHA, Riyadh, KSA. Associate Prof. of Microbiology & Immunology. Faculty of Medicine – Ain Shams University
  2. 2. BLOOD CULTURE METHODS  Many methods available; the choice of which depends mainly upon resources.  The cheapest one is the manual (conventional).  The expensive and sophisticated automated systems are now in hands.  Note that 90% of blood cultures (BC) are normally negative making comparison between different systems so difficult.  There is no blood system as absolute reference one so, sensitivities and specificities cannot be accurately calculated.
  3. 3. A . Manual System: 1. Conventional broth-based system  Simple  Labor-intensive.  Each bottle contains 50-100 ml of broth supplemented with 0.025-0.05% sodium polyanethol sulfonate (SPS) to prevent clotting.  Two bottles aerobic (vented) and anaerobic ones.  To be inspected daily for signs of growth.
  4. 4.  Signs of growth: turbidity, hemolysis, surface pellicle, or froth (gas production).  Another alternative is blind subculture daily.
  5. 5.  The main disadvantage of the conventional system is the highest rate of contamination during subculture techniques.  Prolonged incubation and subculture is needed to detect Brucella species.
  6. 6. 2-Biphasic systems - Conventional broth that can flood solid agar in a closed system. Different devices available:. i- Hemoline system  Castaneda medium is the principle of it.  Was developed in 1947 in France (Biomerieux).  Contains 40 ml broth and solid agar.  Originally described for aerobic culture, however, anaerobic culture bottles available.  Inoculation of agar is by flooding it by inversion of bottles.  Colonies easily detected on surface of agar by inspection daily for 7 days.
  7. 7. Hemoline system
  8. 8. Hemoline system
  9. 9. ii- Septi-Check system -was developed by Hofhann-La Roche, Switzerland in 1980s. - Now marketed by BD systems in USA. -It was based on the dip slide bacteriologic urine- culture kit. - modified to fit onto 100-ml blood-culture bottles, the paddles being coated with appropriate media (chocolate, MacConkey agar). - The bottles contain 70 ml of broth medium. -The paddle is inoculated by the blood in broth by simple inversion of the bottle.
  10. 10. - The agar surfaces and the broth should be visually inspected for microbial growth twice daily for the first 2 days of incubation, and thereafter once a day up to the seventh day of incubation. - For anaerobic blood cultures, conventional broth bottles that should not be vented are available for this system. - advantages: less contamination on subcultures of positive. - disadvantage: daily inspection. - other biphasic systems available but not popular as the previously described ones.
  11. 11. Septi-check system
  12. 12. 3-Gas capture or broth displacement (Signal) system: - Was developed in 1986 by Oxoid. - Based upon the principle that microbial metabolism produces positive pressure in a sealed bottle, which can be visualized in a secondary plastic cylinder (Signal device) attached to the broth tube via a needle. - Aerobic and anaerobic microorganisms causing sepsis can be isolated from one Signal bottle. - However the use of both aerobic and anaerobic bottles in other systems was superior to single bottle use.
  13. 13. Oxoid signal devices
  14. 14. 4- Lysis-centrifugation system (Isolator) -A single-tube blood-culture system based on lysis, centrifugation and subsequent direct plating on appropriate media was described in 1978. - it is now distributed by Oxoid Isolator System. - The Isolator 10 tubes contain the following reagents in 0.7 mL of aqueous solution: saponin (cell-lysing agent), propylene glycol (blocks the foaming tendency of saponin), and SPS (anticoagulant).
  15. 15. - At least 6 ml of blood should be inoculated into these tubes, which must be processed as soon as possible, or at most 8 h after the inoculation of blood. - Tubes are centrifuged in the laboratory, preferably at 3000 g for 30 min. The supernatant is discarded, and the pellet is inoculated on solid media. - The Isolator 1.5 used for pediatric patients inoculated with a maximum of 1.5 ml of blood, and is processed without centrifugation. - Easy manipulation and detect more pathogens.
  16. 16. Isolator Blood Culture System
  17. 17. Some characters of commercial BC systems:
  18. 18. Thank you Alsharjah UAE 2014

×