The three extra-cellular zinc metalloproteinases of Streptococcus pneumoniae have a different impact on virulence in mice.
BACKGROUND
Streptococcus pneumoniae possesses large zinc metalloproteinases on its surface. To analyse the importance in virulence of three of these metalloproteinases, intranasal challenge of MF1 outbred mice was carried out using a range of infecting doses of wild type and knock-out pneumococcal mutant strains, in order to compare mice survival.


RESULTS
Observation of survival percentages over time and detection of LD50s of knock out mutants in the proteinase genes in comparison to the type 4 TIGR4 wild type strain revealed two major aspects: i) Iga and ZmpB, present in all strains of S. pneumoniae, strongly contribute to virulence in mice; (ii) ZmpC, only present in about 25% of pneumococcal strains, has a lower influence on virulence in mice.


CONCLUSIONS
These data suggest Iga, ZmpB and ZmpC as candidate surface proteins responsible for pneumococcal infection and potentially involved in distinct stages of pneumococcal disease.
Chiavolini
Damiana
D
Dipartimento di Biologia Molecolare, Laboratorio di Microbiologia Molecolare e Biotecnologia, Università di Siena, Siena, Italy. chiavolini@unisi.it
Memmi
Guido
G
Maggi
Tiziana
T
Iannelli
Francesco
F
Pozzi
Gianni
G
Oggioni
Marco R
MR
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D008666:Metalloendopeptidases / Q000502:physiology; D045726:Metalloproteases / Q000302:isolation & purification / Q000502:physiology*; D051379:Mice; D011008:Pneumococcal Infections; D012697:Serine Endopeptidases / Q000502:physiology; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000472:pathogenicity; D014774:Virulence / Q000502:physiology; D015032:Zinc / Q000378:metabolism*
C412019:ZmpB enzyme; D045726:Metalloproteases; D012697:Serine Endopeptidases; C021433:IgA-specific serine endopeptidase; D008666:Metalloendopeptidases; C478168:ZmpC protein, Streptococcus pneumoniae; D015032:Zinc