Microbiology Microbiology lab. Skills Bacteriology 1 & 2 1435 - 2014 Dr. Ibrahim Hassan, Microbiology PhD.

MicrobiologyMicrobiology lab. Skills

Bacteriology 1 & 21435 - 2014

Dr. Ibrahim Hassan, Microbiology PhD

G +ve cocci in groups and chains(staphylpcocci & streptococci)

Gram +ve bacilli (Lactobacilli)

Bacterial Spores

G +ve bacilli in chains, - Bacillus anthracis- Clostridium tetani.

G -ve diplococci (Neisseria gonorrhoeae)

G -ve bacilli (E.coli)

Acid Fast Bacilli (Z.N.Stain)Mycobacterium tuberculosis

Culture media

Culture media

Bacteria are cultivated in the laboratory for:1- Isolation and identification of bacteria2- Preparation of antigens, toxins, and vaccines.3- Studying their properties.

Culture mediaTypes of media …….continue

1. Simple (Basic) Media.2. Deferential Media.3. Enriched Media.4. Selective Media.5. Special Media.

1. Simple (Ordinary) media:A. Liquid (broth ) media: without Agar.i- Peptone water: Peptone (1%), and NaCl (0.5%). It is used as a base medium.

ii- Nutrient broth: (Meat extract with peptone water). It forms the basis of most media. It is a clear yellowish fluid which becomes turbid when bacteria grown on it.

Culture mediaTypes of media …….continue

B-Solid (ordinary) media:i-Nutrient agar:This type of media is prepared by addition of agar(Derived from seaweeds)to the broth and sterilized by autoclaving It is the base of different types of media. It is used in the form of plates (For isolation of pure colonies), slope(For preservation of cultures), or deep agar tube(For anaerobic cultivation)ii- Gelatin media:This media consists of gelatin instead of agar.

Culture mediaTypes of media …….continue

2- Differential mediai- CLED (Cystine lactose electrolyte deficient): - Simple medium (peptone), lactose, bromothymol blue and agar. - It differentiates between lactose fermenter organisms. - produce yellow colonies and non lactose fermenter which produce blue, gray or green colonies.ii- MacConkey’s agar medium: - Simple medium (peptone), lactose, neutral red as an indicator and bile salts and agar. - Differential media because it differentiates between lactose fermenter organisms which give pink color and non lactose fermenter which give pale colonies.

Culture mediaTypes of media …….continue

CLED Agar

MacConkey Agar

Lactose FermenterLactose Non-Fermenter

3- Enriched media:This type of media contains highly nutrient substancee.g. blood, serum, egg,…..It is used for fastidious organisms which not grow on simple media.i- Blood agar:Simple medium in addition to blood.It differentiates between organisms according to types of hemolysis alpha (α) Beta (β) and Gamma (γ).ii. Chocolate Agar:Simple medium in addition to heated blood.

Culture mediaTypes of media …….continue

Blood Agar

Chocolate Agar