ANAEROBIC BACTERIAL CULTURE METHODS.pptx

presentation on anaerobic bacterial culture methods

1. ANAEROBIC CULTURE METHODS DR.K.AARATHI

2. Obligate anaerobic bacteria can grow only in the absence of oxygen. G rowth of such bacteria, anaerobic environment is needed. M ethods used to create anaerobiosis are- Evacuation and Replacement This involves evacuation of the air from jar and replacement with inert gas like hydrogen followed by removal of the residual oxygen by use of a catalyst. It is carried out either by:™™

3. Manual method by using McIntosh and Filde’s anaerobic jar . M ost popular method for creating anaerobiosis in the past,not using presently. ™™

4. Automated system ( Anoxomat ): It automatically E vacuates air and replaces by hydrogen gas from a cylinder. „„ The catalyst used to combust residual oxygen is a sachet containing aluminum pellets coated with palladium.

5. Absorption of Oxygen by Chemical Methods- GasPak system M ost commonly used method for anaerobiosis , especially for laboratories with less sample load. ™™ O xygen is removed by chemical reactions . ™™ It uses a sachet containing sodium bicarbonate and sodium borohydride which react chemically in presence of water, to produce hydrogen and CO2 gas. ™™ The traces of oxygen is removed by using the same catalyst used for Anoxomat placed below the jar lid . ™™

6. GENbag Place the plates in the airtight bag. Open the protective aluminium foil pouch. Remove the generator and immediately place it into the bag. Do not add water or a catalyst. Place the clip seal on the bag, immediately seal the pouch and incubate. GENbag enables the incubation of 1 or to 2 plates, identification or susceptibility testing strips, 1 microtitration plate. Bacterial growth can be observed without opening, through the transparent bag. .

7. GENbox Place the plates in the jar. For GENbox anaer , add the anaerobic indicator stick. Open the protective aluminium foil pouch. Remove the generator and immediately place 1 generator for GENbox jar 2.5L or 3 for GENbox 7.0 L. Do not add water or a catalyst. Immediately seal the jar and incubate. Rectangular GENbox jars are compact and easily stackable. The transparent cover and container enable direct observation of cultures .

8. Anaerobic Glove Box and Anaerobic Work Station: These systems provide facility for easy processing, incubation and examination of the specimens without exposure to oxygen . ANAEROBIC GLOVE BOX

9. Indicator of anaerobiosis : The effectiveness of anaerobiosis can be checked by: „„ Reduced methylene blue remains colorless in anaerobic conditions, but turns blue on exposure to oxygen. „„ Pseudomonas : Absence of its growth indicates that complete anaerobiosis has been achieved.It is used as biological indicator.