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The species name aeruginosa is a Latin word meaning verdigris ("copper rust"), referring to the blue-green color of laboratory cultures of the species. This blue-green pigment is a combination of two secondary metabolites of P. aeruginosa , pyocyanin (blue) and pyoverdine (green), which impart the blue-green characteristic color of cultures. [ 7 ]
MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate gram-negative and enteric (normally found in the intestinal tract) bacteria and differentiate them based on lactose fermentation. [1] Lactose fermenters turn red or pink on MacConkey agar, and nonfermenters do not change color.
The laboratory procedure involves making serial dilutions of the sample (1:10, 1:100, 1:1000, etc.) in sterile water and cultivating these on nutrient agar in a dish that is sealed and incubated. Typical media include plate count agar for a general count or MacConkey agar to count Gram-negative bacteria such as E. coli. Typically one set of ...
Pseudomonas aeruginosa is highly contagious and has displayed resistance to antibiotic treatments, making it difficult to manage effectively. Some strains of Pseudomonas are known to target white blood cells in various mammal species , posing risks to humans, cattle, sheep, and dogs alike.
Cetrimide also enhances the production of Pseudomonas pigments such as pyocyanin and pyoverdine, which show a characteristic blue-green and yellow-green colour, respectively. [3] [4] Cetrimide agar is widely used in the examination of cosmetics, pharmaceuticals and clinical specimens to test for the presence of Pseudomonas aeruginosa. [1]
MacConkey agar is a selective and differential medium used to differentiate between gram-negative bacteria while inhibiting the growth of gram-positive bacteria. Adding bile salts and crystal violet to the agar inhibits the growth of most gram-positive bacteria, making MacConkey agar selective.
Most strains of Acinetobacter, except some of the A. lwoffii strain, grow well on MacConkey agar (without salt). Although officially classified as not lactose-fermenting, they are often partially lactose-fermenting when grown on MacConkey agar. They are oxidase-negative, catalase-positive, indole-negative, nonmotile, and usually nitrate-negative.
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagnostic methods used as research tools in molecular biology .