Listeria Oxford Agar Principle, Composition, Preparation and Colonies Characteristics

Oxford_Agar MLTGEEKS

Listeria monocytogenes is responsible for an estimated 1,600 illnesses and 260 deaths in the United States (U.S.) annually and is ranks third in total number of deaths among food borne bacterial pathogens, with fatality rates exceeding even that of Clostridium botulinum and Salmonella. Listeria monocytogenes…

LACTOBACILLI MRS AGAR Principle, Composition, Preparation and Colonies Characteristics

lactobacillus casei on Lactobacilli agar MLT GEEKS

De Man, Rogosa & Sharpe, originally developed M.R.S in 1960; It is an alternative non-selective suitable media for most fastidious lactic acid bacteria and is a substitute for Tomato Juice Agar. Lactobacillus MRS is a growth medium recommended for the growth of all Lactobacillus species….

Motility Indole Urea Principle, Composition, Preparation and Colony Characteristics

Motility indole urea test MLTGEEKS

Abbreviated (MIU), Motility Indole Urea Medium base is used for the differentiation of Enterobacteriaceae. This medium is based on motility, urease and indole production. This medium contains peptones that provide carbon and nitrogen required for growth of bacteria. Urea provides a source of nitrogen for…

Acetate differential Agar principle and interpretation of test

Acetate utilization test MLTGEEKS

Trabulsi and Ewing first formulated acetate Differential Agar. Tatum, Ewing and Weaver later on modified the medium by replacing sodium citrate by sodium acetate, which enables the differentiation of Shigella species from Escherichia coli. Organic acids have been used widely as an aid in the…

Xylose Lysine Deoxycholate (XLD) Agar- Principle, Composition, Preparation and Colony Characteristics

Salmonella-Typhimurium on XLD agar MLTGEEKS

Abbreviated XLD agar, Xylose Lysine Deoxycholate agar is another selective  and differential growth  medium mostly used in the isolation of Salmonella  and Shigella species from clinical and non clinical samples. It has a pH of approximately 7.4 that gives it a bright pink or red appearance due to the indicator phenol red It is…

Mannitol Salt Agar (Selective and different culture media) for Halophilic bacteria

Mannitol salt agar MLTGEEKS

Abbreviate MSA, Mannitol salt agar  is a selective and differential culture medium used in microbiology for the growth and isolation of Gram positive Staphylococci species such as Staphylococcus aureus. It was described by Chapman and has been adopted by many official organisations. Several modifications of it have been developed, all formulations…

Thiosulfate Citrate Bile Sucrose Agar ideal for vibrio species

Abbreviated TCBS, Thiosulfate-Citrate-Bile-Sucrose Agar was original developed by Nakanishi but was subsequently modified by Kobayashy et al. TCBS is frequently used for the selective isolation of Vibrio cholerae and other enteropathogenic like Vibrios parahaemolyticus from suspected specimen. TCBS agar is both selective and differential culture…

BACTERIA IDENTIFICATION BY KOH STRING TEST

KOH-Test-for-Gram-stain-confirmation

The Gram staining reaction is not always effective in the indications of the organism’s cell wall structure. Poorly controlled decolorizing, wrong solution dilution and negligence of the technician can obviously be a source of errors resulting during gram staining, but even with adequate technique, some…

CLED Agar Composition, Preparation and Colony growth Characteristics

cled agar MLTGEEKS

Cystine Lactose Electrolyte-Deficient Agar(CLED Agar)  is a type of differential culture media in microbiology recommended for the diagnosis of urinary tract infections. The medium supports the growth of all urinary potential pathogens and provides distinct colony morphology.It also supports the growth of a number of contaminants…

MacConkey Agar Principles, Composition, Preparation, colony characteristics

MacConkey Agar principle and interpretation MLTGEEKS

The culture media MacConkey agar was developed in 20th century by Alfred Theodore MacConkey. MacConkey agar was the first formulated solid differential media but now known as   a selective and differential culture media commonly used for the isolation of enteric Gram-negative bacteria.Based on the…