Sensitivity of Helicobacter pylori to an innate defence mechanism, the lactoperoxidase system, in buffer and in human whole saliva.
Helicobacter pylori has frequently been isolated from human dental plaque, and oral spread via saliva is thought to be one of its principal modes of transmission. Among other innate defence systems human saliva contains peroxidase enzymes and lysozyme. The sensitivity of H. pylori to physiological concentrations of lactoperoxidase and its salivary substrate thiocyanate, and different amounts of hydrogen peroxide (H(2)O(2)) was investigated in buffer and in human whole saliva. The effect of lysozyme was also studied in saliva. All tested H. pylori strains, ATCC 43504(T) and five clinical isolates, were efficiently inhibited by the peroxidase system with high concentrations of H(2)O(2) in buffer. The inhibition was stronger at lower pH. However, in human saliva these high concentrations of H(2)O(2) generated less hypothiocyanite, the antibacterial product of the peroxidase system and the effects of the peroxidase system were weaker. Physiological concentration of lysozyme was not bacteriocidal against H. pylori, nor did it enhance the effect of the peroxidase system in saliva. Thus, further studies are needed to enhance the efficacy of peroxidase systems in human saliva to make it more beneficial not only against dental but also against gastric pathogens.
Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland 2Department of Medical Biochemistry, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland 3Kårkulla samkommun, Kårkullavägen 142, FIN-21610 Kirjala, Finland.
Anna
A
Haukioja
Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland 2Department of Medical Biochemistry, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland 3Kårkulla samkommun, Kårkullavägen 142, FIN-21610 Kirjala, Finland.
Riikka
R
Ihalin
Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland 2Department of Medical Biochemistry, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland 3Kårkulla samkommun, Kårkullavägen 142, FIN-21610 Kirjala, Finland.
Vuokko
V
Loimaranta
Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland 2Department of Medical Biochemistry, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland 3Kårkulla samkommun, Kårkullavägen 142, FIN-21610 Kirjala, Finland.
Marianne
M
Lenander
Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland 2Department of Medical Biochemistry, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland 3Kårkulla samkommun, Kårkullavägen 142, FIN-21610 Kirjala, Finland.
Jorma
J
Tenovuo
D002021:Buffers; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000254:growth & development* / Q000472:pathogenicity*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007784:Lactoperoxidase / Q000378:metabolism*; D009113:Muramidase / Q000378:metabolism; D012463:Saliva / Q000201:enzymology / Q000382:microbiology*; D013861:Thiocyanates / Q000378:metabolism
D002021:Buffers; D013861:Thiocyanates; D006861:Hydrogen Peroxide; D007784:Lactoperoxidase; D009113:Muramidase; C031760:thiocyanate