Analysis of the interaction of Aeromonas caviae, A. hydrophila and A. sobria with mucins

Abstract

Aeromonas species are known to be involved in human gastrointestinal diseases. These organisms colonize the gastrointestinal tract. Aeromonas hydrophila, A. caviae, and A. sobria have been demonstrated microscopically to adhere to animal cell lines that express mucous receptors, but quantitative studies of adherence to mucosal components such as mucin have not been published to date. Purified bovine submaxillary gland, hog gastric mucin, and fish skin mucin were used as a model to study mucin-binding activity among A. caviae, A. hydrophila, and A. sobria strains. Our findings revealed that binding of radiolabeled and enzyme-conjugated mucins to Aeromonas cells varied depending on the labeling procedure. The highest binding was observed when the three mucin preparations were labeled with horseradish peroxidase. Binding of the various horseradish peroxidase-labeled mucins by A. caviae, A. hydrophila, and A. sobria cells is a common property among Aeromonas species isolated from human infections, diseased fish, and from environmental sources. The proportion of Aeromonas strains which bind the various horseradish peroxidase-labeled mucins was significantly higher for A. hydrophila than for A. caviae and A. sobria. Bacterial cell-surface extracts containing active mucin-binding components recognized the horseradish peroxidase-labeled mucins. The molecular masses of the mucin-binding proteins were estimated by SDS-PAGE and Western blot as follows: A. caviae strain A4812 (95 and 44 kDa); A. hydrophila strain 48748 (97, 45, 33 and 22 kDa); and A. sobria strain 48739 (95 and 43 kDa). Mucin interaction with Aeromonas cells was also studied in terms of growth in mucin-rich media. The culture conditions greatly influence the expression of A. hydrophila mucin-binding activity.

The importance of Aeromonas hydrophila in food safety

“…A. hydrophila strains localized in the large intestine and appeared not to be cell associated. Ascencio, Martinez-Arias, Romero, and Wadstrom (1998) studied adherence of A. hydrophila to mucosal components such as mucin. A. hydrophila strains had high ability to bind with various horseradish peroxidase-labeled mucins.…”

Stopping Bacterial Adhesion: A Novel Approach to Treating Infections

“…A number of studies have demonstratedin vitrothe mucin-binding activity of a variety of bacteria and parasites [90, 91]. In some cases, mucins have been shown to inhibit [92,93,94] and promote [94,95,96,97] bacterial adhesion. Pseudomonas aeruginosa adhesion molecules and surface structures that bind surface mucin have also been identified [44, 98, 99].…”

Host Immune Responses to Aeromonas Virulence Factors

“…In addition to type IV pili, A. hydrophila also possesses numerous type I pili [166], although there is no clear evidence to support a role for these pili in virulence. Besides pilus adhesions, A. hydrophila (and to a lesser degree A. caviae and A. sobria) also produces various lectins and adhesions that allow the bacteria to adhere to specific glycoconjugates on epithelial surfaces, erythrocytes, or mucin in the gut mucosa [167]. The various flagella, pili, and adhesions produced by Aeromonas spp.…”