chloramine-t and troclosene

Although active chlorine compounds are well-known antimicrobial agents in human medicine, their initial steps of action have not been completely clarified. Using N-chlorotaurine (NCT), an endogenous mild representative, we observed persisting oxidation capacity affixed to bacteria. It was the aim of this study to investigate this 'chlorine cover'.. Pathogens were incubated in NCT, which was subsequently washed off. The oxidation capacity on the bacterial surface was measured photometrically.. Superficial chlorination in the form of covalent N-Cl bonds to Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans could be attached before killing took place. For S. aureus, 3 min incubation with NCT produced a cover of 3.3 x 10(-16) mol Cl(+)/cfu, while the cfu count was reduced by only 26%. The kind of microorganism, coating time, pH, buffer system and, basically, the chlorine compound, influenced the cover strength. The relative cover strength on S. aureus by NCT, chloramine T, sodium dichloro-isocyanurate or N,N-dichlorotaurine was 1:15.7:38.7:0.24. Chlorine covers were surprisingly stable and could be detected for 3 h at 20 degrees C (>8 h at 1 degrees C), even without a reduction of cfu. However, addition of 5% ammonium chloride caused a rapid loss of viability, explained by formation of highly bactericidal NH(2)Cl, an effect that resembles the ignition of a time-bomb.. The chlorine cover can be regarded as the first sign of interaction between chlorinating agent and microorganism, and may explain the non-lethal features of postantibiotic effect and attenuation of bacterial virulence. Furthermore, it may be a decisive step in bacterial inactivation by the myeloperoxidase-hypochlorite system in innate immunity.

Topics: Bacteria; Chloramines; Chlorine; Chlorine Compounds; Disinfectants; Models, Molecular; Molecular Structure; Oxidation-Reduction; Surface Properties; Taurine; Time Factors; Tosyl Compounds; Triazines

Solutions of chlorine-releasing agents (CRAs) show varying activity against Bacillus subtilis spores; sodium hypochlorite (NaOCl) shows higher activity than sodium dichloroisocyanurate (NaDCC) which is more active than chloramine-T. Investigations with coat- and cortex-extracted spores indicate that resistance to CRAs depends not only on the spore coat but also the cortex. Whereas extraction of alkali-soluble coat protein increased sensitivity to NaOCl and NaDCC, degradation of coat and cortex material was required to achieve significant activity with chloramine-T. NaOCl (in the presence and absence of NaOH) and NaDCC (in the presence of NaOH only) produced degradation of spore coat and cortex material which may be related to their rapid sporicidal action at low concentrations under these conditions. By contrast, chloramine-T produced no degradation of cortex peptidoglycan and was only effective against normal and alkali-treated spores at high concentrations, requiring extraction of peptidoglycan with urea/dithiothreitol/sodium lauryl sulphate (UDS) or UDS/lysozyme to achieve significant activity at low concentrations. Results suggest that the sporicidal action of CRAs is associated with spore coat and cortex degradation causing rehydration of the protoplast allowing diffusion to the site of action on the underlying protoplast.

Topics: Bacillus subtilis; Chloramines; Disinfectants; Dithiothreitol; Muramidase; Peptidoglycan; Picolinic Acids; Sodium Dodecyl Sulfate; Sodium Hydroxide; Sodium Hypochlorite; Spores, Bacterial; Tosyl Compounds; Triazines; Urea