Researchers from Auburn University have developed a strategy that may lead to an effective vaccine against a common cause of ulcers. They report their findings in the January 2003 issue of the journal Infection and Immunity.
Helicobacter pylori bacteria were first isolated in the early 1980s and have since been shown to be a common cause of peptic ulcers and are also associated with some types of stomach cancer. Once identified, infections can be treated with antibiotics. There is currently no vaccine.
In the study the researchers developed a nasal vaccine that completely protected mice from infection with Helicobacter felis, a relative of H. pylori. H. felis infection in mice is currently accepted by researchers as a standard model for H. pylori vaccine development.
While the results are promising, more studies still need to be done, say the researchers.
(W. Jiang, H.J. Baker and B.F. Smith. 2003. Mucosal immunization with Helicobacter, CpG DNA, and cholera toxin is protective. Infection and Immunity, 71: 40-46.)
Sourdough compound delays mold growth
Bacteria isolated from sourdough bread produce a compound that inhibits the growth of molds. Researchers from the Institute of Sciences of Food Production in Bari, Italy, report their findings in the January 2003 issue of the journal Applied and Environmental Microbiology.
Sourdough bakery products have long been known to have longer shelf lives. In the study, the researchers identified an antifungal compound, known as phenyllactic acid (PLA), that is produced by a strain of the sourdough lactic acid bacterium Lactobacillus plantarum. When tested against a variety of fungi found in baked goods, the compound was able to delay growth by more than 2 days in some cases.
"The ability of PLA to act as a fungicide and delay growth a of a variety of fungal contaminants provides new perspectives for possibly using this natural antimicrobial compound to control fungal contaminants and extend the shelf lives of foods," say the researchers.
(P. Lavermicocca, F. Valerio and A. Visconti. 2003. Antifungal activity of phenyllactic acid against molds isolated from bakery products. Applied and Environmental Microbiology, 69: 634-640.)
Microbes harmful to inner ear potentially normal in outer ear canal
Organisms commonly associated with middle ear infections may exist as normal microbes in a healthy outer ear canal say researchers at the University of Colorado, University of British Columbia and the Molecular Sciences Institute. Their findings appear in the January 2003 issue of the Journal of Clinical Microbiology.
In the study, swab samples were taken from the outer ear of twenty-four individuals. The results showed the presence of Alloiococcus otitis and Corynebacterium otitidis, bacteria commonly associated with middle ear infections, in the outer ear canals of many healthy individuals. The findings also suggest that microbial populations of the human outer ear, believed to be random in their makeup, may be more consistent than previously thought.
"In any case, the identification of A. otitis and C. otitidis as prevalent commensals of the healthy human outer ear canal indicates a wider niche for these microbes than was previously thought," say the researchers. "Consequently, reevaluation of the roles of these two species in the pathogenesis of the middle ear is warranted."
(D. N. Frank, G. B. Spiegelman, W. Davis, E. Wagner, E. Lyons, N. R. Pace. 2003. Culture-independent molecular analysis of microbial constituents of the healthy human outer ear. Journal of Clinical Microbiology, 41. 1: 295-303.)