Loeffler Medium, a modified version of the 1887 Loeffler formula, is now called Loeffler Medium. Loeffler medium is a modified formula that Loeffler developed in 1887. It enhances primary and secondary isolation, and cultivates fastidious pathogenic microorganisms. After prolonged subculturing or prolonged incubation, Loeffler medium restores virulence as well as other identifying properties (microscopic/colonial). High serum levels are useful in determining organisms’ proteolytic activity. It can also be used to demonstrate pigmentation and ascospores.
Campylobacter blood agar (CVA), is a selective medium that allows for the primary isolation from stool specimens of Campylobacter Jejuni. Dekeyser et al. Dekeyser et al. reported that Campylobacter jejuni was isolated from patients suffering from diarrhea and acute gastroenteritis using a filtration method and a selective media with antimicrobials. Skirrow, however, reported that a select medium containing three antimicrobics was used for isolation. Blaser and colleagues reported that they were able to isolate C. jejuni from feces using a selective medium that contained four antimicrobials: amphotericin (vancomycin), polymyxin B and trimethoprim. Reller et al. in 1983 also introduced a better selective medium containing cefoperazone and Vancomycin. This combination of antimicrobials allowed for better suppression of normal fecal bacteria, thereby allowing for better isolation of C.jejuni from the fecal specimen.
Rosenow developed a medium that could be used to cultivate streptococci using a dextrose broth and brain tissue in 1919. Hayden modified Rosenow’s formula and found that crushed marble promoted the growth of dental pathogens. The current formulation uses infusions from calf brain instead of brain tissue, and disodiumphosphate has been replaced by calcium carbonate.
In 1979, Dr. A. Rambach invented and patented the first chromogenic medium for E.coli detection. This technology uses a color-based differentiation technique. It uses soluble colorless molecules, also known as chromogens. They are composed of a substrate that targets a specific enzyme activity and a chromophore. The chromophore can be released when the enzyme of the target organism cleaves the colorless, chromogenic conjugate.
Peptone Yeast Extract Broth Based Media are enriched nonselective media which include hemin and vitamin K to aid in the recovery of aggressive organisms like Prevotella Spp., Porphyromonas species, as well as the Bacteroides fragileis group.
MacConkey Sorbitol Agar is an adaptation of the formulation that was described by Rappaport and Henigh. It is selective and differential media for the detection of sorbitol-nonfermenting Escherichia coli serotype O157:H7 associated with hemorrhagic colitis. E. coli serotype O157:H7 is a human pathogen that is associated with hemorrhagic colitis which is caused by the actions of a Shiga-like toxins (SLT).
Thayer and Martin have reported improvement of the Chocolate Agar formulation that contained antimicrobics vancomycin and colistin, Nystatin. These ingredients were added to limit the growth of contaminants, inhibit the development of the saprophytic Neisseria sp. and to enhance the development of the pathogenic Neisseria. Martin and Lester have added an antibiotic, trimethoprim, which made them more selective. They also demonstrated to be effective in the fight against Proteus spp. Trimethoprim lactate refrains Proteus swarming. The resultant medium is known as Modified Thayer Martin. It’s a suitable and rich medium to isolate as well as cultivation of the Neisseria species. from mixed flora and suppression of other Gram-negative diplococci and gram-negative bacilli yeast and other gram-positive organisms.
Roantree et al introduced a medium for the isolation of streptococci from group A beta-hemolytic. The medium was enriched with yeast nucleic acids and maltose boosted the size of colonies and improved the clarity, sharpness and precision of the hemolytic zones created by these organisms.
MRS Broth was developed by deMan, and co. in order to facilitate the most abundant growth of lactobacilli derived from feces, oral and other samples. Lactobacilli MRS Broth is a better media for lactobacilli. It allows for healthy growth and is especially suitable for several very discerning strains that grow poorly in other media.
Cystine tryptic agar (CTA) which is also referred to as cystine trypticase agar was created by Vera as an semi-solid growth medium to identify and maintain the health of microorganisms for long time period of time when stored at suitable temperatures. It’s used for determination of the motility of bacteria and, when combined with carbohydrate, is involved in the fermentation process and the differentiation of microorganisms that are fastidious, such as Neisseria and streptococci, as well as pneumococci and non-spore-forming anaerobes.
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