Anaerobic Cultivation - Microbiology - Lecture Slides, Slides for Microbiology. Baddi University of Emerging Sciences and Technologies


Description: Anaerobic Cultivation, Anaerobic Infections, Anaerobic Environment, Anaerobic Culture Media, Sampling and Transport, Bacteria in Relation, Obligate Anaerobic, Microaerophilic are the important key points of lecture slides of Microbiology.
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Practical 7 ST anaerobic cultivation

Practical 7 ST anaerobic cultivation

• Bacteria in relation to oxygen • Anaerobic infections - sampling and transport • Cultivation

- establishing of anaerobic environment - anaerobic culture media, - procedure: inoculation, isolation

Bacteria in relation to oxygen

• Obligate aerobic -require gaseous oxygen, cannot grow without oxygen

Obligate anaerobic - oxygen is toxic for them. Methabolic pathway used for gaining energy is fermentatio with production of foul-smelling end products.

• Facultative anaerobic - able to adapt to aerobic or anaerobic

• Microaerophilic - require reduced oxygen tension

Anaerobic infections • Usually endogenous bacteria - disturbance of the

balance of normal flora (ATB and colon microflora) or unusual anatomic sites (perforation of colon - anaerobic peritonitis)

• Exogenous bacteria - wound contamination • Exudate, pus, abscess • Sampling and transport in anaerobic conditions -

aspirate in the syringe with the needle capped or protected with rubber. Surgical sampling can be required. Never use the dry swab!

Establishing of anaerobic conditions • Candle jar - microaerophilic, facultative anaerobic • Anaerobic jar with atmosphere generator (foil envelopes): release hydrogen

and carbon dioxide + catalyser (should be regenerated at regular interval) after addition of water. Anaerobiosis redox indicator strips

• Anaerostat - bottle with anaerobic athomosphere • Biological method - cocultivation with Serratia marcescens • Tubes of broth cultures (thioglycolate, cooked meat) - their formulations

contain reducing substances - anaerobic conditions at the lower part - fresh and screwed well - regeneration - 15 minutes in boiling water bathwith screw loosened to dissolve oxygen, screx tightened and cool

Culture media

• Blood agar • Blood agar based enriched with growths

factors and antibiotics (selective, kanamycin, neomycin, aminoglycosides - to inhibit most aerobic and facultative anaerobic bacteria)

• VL bouillon • Should be stored in refrigerator in plastic bag -

decrease the solution of oxygen in the agar - use freshly prepared media

Innoculation, isolation

• Innoculation without delay • Innoculation of anaerobic and aerobic culture

(anaerobic jar, canle jar or aerobic incubator) • 48hrs • Often mixed infection • Comparison of aerobic and anaerobic culture • Gram staining: principal is the presence of anaerobic

infection G+coccus, G+rod, G- coccus, G- rod, sporulation

Biological method

• Half of the surface of medium in the Petri dish is innoculated with the tested sample, the other with Serratia marcescens - bacteria able to produce anaerobic environment by the consumption of oxygen. Petri dishes is sealed with the wax or parafin and introduced to the not oxygen - free incubator


----------------------- Serratia marcescens

Biological sample

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