(X.-F. Wan, L. Dong, Y. Shu, et al. Indications that live poultry markets are a major source of human H5N1 influenza virus infection in China. J. Virol. 85:13432-13438.)
Compound in Apples Inhibits E. coli O157:H7
A compound that is abundant in apples and strawberries inhibits the highly pathogenic E. coli O157:H7 biofilms while sparing a beneficial strain of E. coli that also forms biofilms in the human gut, according to a paper in the December 2011 issue of the journal Infection and Immunology.
Transcriptome analysis revealed that the compound, called phloretin, suppresses toxin and other genes involved in O157:H7 pathology and biofilm formation. And in a rat model of colitis, phloretin, reduced colon inflammation and body weight loss. "Phloretin has a triple biological activity as an antioxidant compound, a biofilm inhibitor, and an anti-inflammatory agent," says corresponding author Jintae Lee of Yeungnam University, Gyeongsan, Korea.
E. coli O157:H7 causes hemorrhages in the intestine. To date, no effective therapy for O157:H7 biofilms has been found. Biofilms generally are notoriously resistant to antimicrobial therapy. So in the study, Lee screened a dozen flavonoids, including phloretin, for their ability to inhibit these biofilms. "We found that phloretin markedly reduced E. coli O157:H7 biofilm formation on abiotic surface and human colon epithelial cells, while phloretin did not harm commensal E. coli K-12 biofilms," says Lee. Commensal E. coli can actually fortify the human immune system, he says.
In addition to its anti- E. coli O157:H7 biofilm activity, phloretin "accounts in part for the antioxidant capacity of apples, and it also shows anti-inflammatory activity," says Lee. "This study suggests that phloretin in apples could reduce the risk of E. coli
|Contact: Jim Sliwa|
American Society for Microbiology