Parents might one day give
their children a weekly treatment with a nasal spray of virus enzymes to
prevent them from getting a severe middle ear infection, based on results
of a study done in mice by investigators from St. Jude Children's Research
Hospital and The Rockefeller University, in New York. Such a treatment
would avoid the use of antibiotics, thus eliminating the problem of
antibiotic resistance. A report on this study appears in the March issue of
the online journal "PLoS Pathogens."
Middle ear infection, also called acute otitis media, is an
inflammation of the middle ear space. About half of all children carry
Streptococcus pneumoniae, the bacteria that cause acute otitis media. These
bacteria migrate from the nose and throat to the middle ear after an
initial influenza virus infection paves the way.
The investigators based their treatment on the ability of viruses
called phages to break out of bacteria they infect by using a special
enzyme to destroy the cell walls.
The success of the new treatment, which uses a phage enzyme called
lysin to kill S. pneumonia, suggests that the strategy could significantly
reduce the incidence of acute otitis media in the United States. More than
24 million cases are now diagnosed each year, despite the use of vaccines
against S. pneumoniae.
"Lysin also appears to hold promise for preventing the secondary
pneumonia caused when a person infected with S. pneumoniae is subsequently
infected with the influenza virus, said Jonathan McCullers, M.D., associate
member in the Infectious Diseases department at St. Jude. McCullers is
first author of the "PLoS" paper.
The investigators demonstrated that lysin can eliminate these bacteria
from the ear using mice developed at St. Jude that represented the first
such model in which acute otitis media develops in a similar way that it
develops the disease in children. The mice were treated by purified lysin
that was prepared in the laboratory of Vincent A. Fischetti, Ph.D., a
professor and co- head of the Laboratory of Bacterial Pathogenesis and
Immunology at The Rockefeller University. He was assisted by Jutta M.
Loeffler, postdoctoral associate. Fischetti is senior author of the "PLoS"
paper.
"The nasal spray may eventually be used weekly during flu season to
keep a person free of Streptococcus pneumoniae or after infection with the
flu virus," said Fischetti. "This might truly be a case in which an ounce
of prevention would be worth a pound of cure."
Other St. Jude authors of this paper include Asa Karlstrom and Amy R.
Iverson (St. Jude).
This work was supported in part by the United States Public Health
Service and ALSAC.
St. Jude Children's Research Hospital
St. Jude Children's Research Hospital is internationally recognized for
its pioneering work in finding cures and saving children with cancer and
other catastrophic diseases. Founded by late entertainer Danny Thomas and
based in Memphis, Tenn., St. Jude freely shares its discoveries with
scientific and medical communities around the world. No family ever pays
for treatments not covered by insurance, and families without insurance are
never asked to pay. St. Jude is financially supported by ALSAC, its
fundraising organization. For more information, please visit
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