Johns Hopkins Researcher Explains Collaboration With UA on MTB, PTB

(From Spring 2011 edition of Center for Food Safety Newsletter)


Nicole Parrish


Just like it’s been said for a long time, traveling to national conferences actually does bring back tangible results. An encounter a few years ago over a poster session led to a collaboration that has proven effective against two tuberculosis strains that have been deadly to ruminants.
It began at the 2007 annual meeting of the American Society for Microbiology, where Vesela Chelova, who was then a post-doctoral associate at the Center for Food Safety in the University of Arkansas Division of Agriculture, met Nicole Parrish, associate director of clinical mycobacteriology at the Johns Hopkins Hospital and University.

Prompted by the poster before them, they began discussing tuberculosis strains. Chelova’s interest was from the standpoint of animals and Parrish’s interest was oriented toward humans, but they soon began to see there could be common solutions.
During a visit to the Center for Food Safety in February, Parrish explained the research progress that has resulted since that meeting at ASM.
After learning about the Arkansas food science research on citrus, Parrish contacted Phil Crandall, professor of food science at the U of A. She then collaborated in experiments on the effects of Valencia orange oil against aerobically-grown Mycobacterium tuberculosis (MTB). The Valencia treatments proved to be effective.
The research team also studied M. paratuberculosis (PTB), a related species of Mycobacterium.
MTB is one of the causative agents for the 2 billion cases of tuberculosis infections that were estimated to have arisen in 2009, Parrish said. Among those cases, MTB’s infections also causes Johne’s disease, a fatal gastrointestinal disease in cattle that causes chronic wasting of cattle and other ruminants which can lead to the need to kill a herd. Johne’s disease costs the United States about $1.5 billion a year.
Parrish explained that the antimicrobial effects of essential citrus oils have been found to be effective against MTB. Her collaboration with the Arkansas scientists went on to find that all strains of MTB and PTB were susceptible to the high concentrations of orange oil that were tested, with the Valencia orange oil providing the decisive results.
Additional studies are planned to further characterize the mechanism of action of these oils against the Mycobacteria in an effort to find new drugs and drug targets for these diseases in humans and animals, Parrish said.