Bacillus anthracis Sterne produced a catecholate siderophore named anthrachelin that was based on 3,4-dihydroxybenzoic acid (3,4-DHB, or protocatechuic acid), a catechol moiety previously unreported as a siderophore component. During iron restriction, both anthrachelin and free 3,4-DHB were excreted. Growth at 37 degrees C (as compared with 23 degrees C) decreased excretion of anthrachelin but not its precursor 3,4-DHB, suggesting that anthrachelin assembly is temperature regulated. A plasmidless strain also produced anthrachelin in an iron- and temperature-regulated fashion, indicating that anthrachelin genes are chromosomal. In addition to anthrachelin-mediated iron delivery, B. anthracis also used heme, hemoproteins, iron-transferrin, and certain heterologous siderophores (xenosiderophores) produced by other microorganisms as iron sources. Downregulation of anthrachelin production at the temperature of the mammalian host (which triggers toxin production in this pathogen) may focus the B. anthracis iron acquisition systems to exploit the iron sources prevailing in the infected host.

Protocatechuic acid, or 3,4-dihydroxybenzoic acid, is produced by both soil and marine bacteria in the free form and as the iron binding component of the siderophore petrobactin. The soil bacterium, Bacillus thuringiensis kurstaki ATCC 33679, contains the asb operon, but does not produce petrobactin. Iron restriction resulted in diminished B. thuringiensis kurstaki ATCC 33679 growth and the production of catechol(s). The gene product responsible for protocatechuic acid (asbF) and its receptor (fatB) were expressed during stationary phase growth. Gene expression varied with growth temperature, with optimum levels occurring well below the Bacillus anthracis virulence temperature of 37 °C. Regulation of protocatechuic acid suggests a possible role for this compound during soil growth cycles.

Mannnose-binding lectin (MBL) binds oligosaccharides on the surface of microorganisms to form complexes that activate the complement cascade and facilitate phagocytosis. Teicoplanin and dalbavancin glycopeptide antibiotics possess N-acetyl glucosamine and mannose oligosaccharides that may bind MBL. Pharmaceuticals capable of binding to MBL may decrease clearance of significant pathogens such as yeast. An invasive candidemia murine model was utilized to evaluate differences in survival between mannose- and teicoplanin-treated groups compared to a control group administered normal saline. Three groups of BALB/c mice were injected with Candida albicans ATCC 44858 (1.4 x 10(6) CFU). Pharmaceutical agents were administered 2 h pre-infection and 8 h post-infection. In vivo cumulative survival at 52 h revealed 10%, 30% and 90% survival rates for mice administered mannose, teicoplanin, and saline, respectively. There was 0% survival for mice given mannose or teicoplanin at 56 h, compared with 70% for the normal saline treated mice at the same time point (P < 0.05). This in vivo study shows 'accelerated progression of infection' for Candida-inoculated mice exposed to mannose or teicoplanin compared to those given normal saline. Further, protein polyacrylamide gel electrophoresis studies suggested a potential MBL-drug interaction which may attenuate complement activation, opsonization and phagocytosis.