Mueller-Hinton agar

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Colonies of Burkholderia pseudomallei on Muller-Hinton agar after 72 hours incubation. BpsMH.JPG
Colonies of Burkholderia pseudomallei on Müller-Hinton agar after 72 hours incubation.

Mueller-Hinton agar is a microbiological growth medium that is commonly used for antibiotic susceptibility testing, specifically disk diffusion tests. It is also used to isolate and maintain Neisseria and Moraxella species.

It typically contains:

Five percent sheep's blood and nicotinamide adenine dinucleotide may also be added when susceptibility testing is done on Streptococcus and Campylobacter species.

It has a few properties that make it excellent for antibiotic use. First of all, it is a nonselective, nondifferential medium. This means that almost all organisms plated on it will grow. Additionally, it contains starch. Starch is known to absorb toxins released from bacteria, so that they cannot interfere with the antibiotics. Second, it is a loose agar. This allows for better diffusion of the antibiotics than most other plates. A better diffusion leads to a truer zone of inhibition.

Mueller-Hinton agar was co-developed by a microbiologist John Howard Mueller and a veterinary scientist Jane Hinton at Harvard University as a culture for gonococcus and meningococcus. They co-published the method in 1941. [2]

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Diagnostic microbiology is the study of microbial identification. Since the discovery of the germ theory of disease, scientists have been finding ways to harvest specific organisms. Using methods such as differential media or genome sequencing, physicians and scientists can observe novel functions in organisms for more effective and accurate diagnosis of organisms. Methods used in diagnostic microbiology are often used to take advantage of a particular difference in organisms and attain information about what species it can be identified as, which is often through a reference of previous studies. New studies provide information that others can reference so that scientists can attain a basic understanding of the organism they are examining.

Jane Hinton

Jane Hinton (1919–2003) was a pioneer in the study of bacterial antibiotic resistance and one of the first two African-American women to gain the degree of Doctor of Veterinary Medicine (1949). Prior to her veterinary medicine studies at the University of Pennsylvania, she had been a laboratory technician at Harvard, co-developing the Mueller-Hinton agar, a culture medium that is now commonly used to test bacterial susceptibility to antibiotics. She later practiced as a small animal veterinarian in Massachusetts, and then as a federal government inspector. Hinton was the daughter of William Augustus Hinton, a microbiologist and the first African-American professor at Harvard University.

John Howard Mueller was an American biochemist, pathologist, and bacteriologist. He is known as the discoverer in 1921 of the amino acid methionine and as the co-developer, with Jane Hinton, of the eponymous Mueller-Hinton agar.

References

  1. "Susceptibility testing of Salmonella using disk diffusion" (PDF). World Health Organization. July 2002. p. 9. Retrieved 12 May 2016.
  2. Mueller, J. H.; Hinton, J. (1 October 1941). "A Protein-Free Medium for Primary Isolation of the Gonococcus and Meningococcus". Experimental Biology and Medicine. 48 (1): 330–333. doi:10.3181/00379727-48-13311.