Potential of lactoferrin to prevent antibiotic-induced Clostridium difficile infection

Objectives: C. difficile infection (CDI) is a global healthcare problem. Recent evidence suggests that the availability of iron may be important for C. difficile growth. This study evaluated the comparative effects of iron-depleted (1% Fe3+ saturated) bovine apo-lactoferrin (apo-bLf) and iron-saturated (85% Fe3+ saturated) bovine holo-lactoferrin (holo-bLf) in a human in vitro gut model that simulates CDI. Methods: Two parallel triple-stage chemostat gut models were inoculated with pooled human faeces and spiked with C. difficile spores (strain 027 210, PCR ribotype 027). Holo- or apo-bLf was instilled (5mg/mL, once daily) for 35 days. After 7 days, clindamycin was instilled (33.9mg/L, four times daily) to induce simulated CDI. Indigenous microflora populations, C. difficile total counts and spores , cytotoxin titres, short-chain fatty acids, biometals, lactoferrin, and iron content of lactoferrin were monitored daily. Results: In the apo-bLf model, germination of C. difficile spores occurred 6 days post-clindamycin, followed by rapid vegetative cell proliferation and detectable toxin. By contrast, in the holo-bLf model, only a modest vegetative cell population was observed until 16 days post-antibiotic. Notably, no toxin was detected in this model. In separate batch culture experiments, holo-bLf prevented C. difficile vegetative cell growth and toxin production, whereas apo-bLf and iron alone did not. Conclusions: Holo-bLf but not apo-bLf delayed C. difficile growth and prevented toxin production in a human gut model of CDI. This inhibitory effect may be iron-independent. These observations suggest that bLf in its iron-saturated state could be used as a novel preventative or treatment strategy for CDI

Photochemistry of trans- and cis-[RuCl2(dmso)(4)] in aqueous and nonaqueous solutions

The photochemical behavior of the trans- and cis[RuCl2(dmso)(4)] complexes has been investigated in organic coordinating solvents (dmso, CH3CN) and aqueous solutions by means of electronic and H-1 NMR spectroscopy as well as chloride - selective electrode measurements. Excitation in the UVA and visible region of the cis-[RuCl2(dmso)(4)] complex in dmso leads to geometric isomerization with quantum yields Phi(313) = 0.41 and Phi(365) = 0.49 to give the photostable trans complex, whereas in acetonitrile and aqueous solutions, both isomerization and substitution processes occur. Moreover, in the latter two solvents, the trans isomer is photoactive and undergoes substitution reactions. In acetonitrile, for both trans- and cis-[RuCl2(dmso)(4)] isomers, selective photolabilization of the dimethylsulfoxide ligands results in the formation of the trans-[RuCl2(CH3CN)(4)] complex. In aqueous solutions, the dmso and Cl- ligands are gradually substituted by water molecules to give as a final product a mixture of (aqua)ruthenium(II) and (aqua) (chlorido)ruthenium(II) complexes. These species may prove to be useful in the binding of cellular components