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Involvement of NADH Oxidase in Competition and Endocarditis Virulence in Streptococcus sanguinis.

Ge X, Yu Y, Zhang M, Chen L, Chen W, Elrami F, Kong F, Kitten T, Xu P - Infect. Immun. (2016)

Bottom Line: An S. sanguinis nox mutant was found to fail to inhibit the growth of Streptococcus mutans under microaerobic conditions.The nox mutant exhibited decreased levels of extracellular H2O2; however, the intracellular level of H2O2 in the mutant was increased.The nox mutant also was shown to be more sensitive to blood killing, oxidative and acid stresses, and reduced growth in serum.

View Article: PubMed Central - PubMed

Affiliation: Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, USA.

No MeSH data available.


Related in: MedlinePlus

Attenuation in competitive index in vivo but not in vitro in the nox mutant. Vegetation, bacteria obtained from rabbit heart vegetation postinoculation; BHI, bacteria cultured in BHI broth. Data were obtained at least in biological triplicate.
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Figure 5: Attenuation in competitive index in vivo but not in vitro in the nox mutant. Vegetation, bacteria obtained from rabbit heart vegetation postinoculation; BHI, bacteria cultured in BHI broth. Data were obtained at least in biological triplicate.

Mentions: S. sanguinis is one of most common causes of bacterial endocarditis. A number of virulence factors for endocarditis have been identified in S. sanguinis (26–29). After the inoculation of precatheterized rabbits with a 1:1 mixture of the nox mutant and the wild type, followed by overnight incubation, the CI of the nox mutant relative to that of the wild type in the infected vegetation was measured. As shown in Fig. 5, the CI in the vegetation was 0.016, which was significantly less than 1 (P = 0.0003), indicating the reduced fitness of the mutant. To confirm the reduced fitness of the mutant was not due to a general growth deficiency, we also performed competitions with the mutant and the wild type in BHI medium (i.e., in vitro). The CI of the nox mutant compared to that of the wild type was not significantly different from 1 after the incubation of the mixed inoculum in BHI medium overnight (Fig. 5). This suggested that there was no growth difference between the mutant and the wild type. These data indicated that the virulence of the nox mutant was impaired and that the nox gene played a role in IE.


Involvement of NADH Oxidase in Competition and Endocarditis Virulence in Streptococcus sanguinis.

Ge X, Yu Y, Zhang M, Chen L, Chen W, Elrami F, Kong F, Kitten T, Xu P - Infect. Immun. (2016)

Attenuation in competitive index in vivo but not in vitro in the nox mutant. Vegetation, bacteria obtained from rabbit heart vegetation postinoculation; BHI, bacteria cultured in BHI broth. Data were obtained at least in biological triplicate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862721&req=5

Figure 5: Attenuation in competitive index in vivo but not in vitro in the nox mutant. Vegetation, bacteria obtained from rabbit heart vegetation postinoculation; BHI, bacteria cultured in BHI broth. Data were obtained at least in biological triplicate.
Mentions: S. sanguinis is one of most common causes of bacterial endocarditis. A number of virulence factors for endocarditis have been identified in S. sanguinis (26–29). After the inoculation of precatheterized rabbits with a 1:1 mixture of the nox mutant and the wild type, followed by overnight incubation, the CI of the nox mutant relative to that of the wild type in the infected vegetation was measured. As shown in Fig. 5, the CI in the vegetation was 0.016, which was significantly less than 1 (P = 0.0003), indicating the reduced fitness of the mutant. To confirm the reduced fitness of the mutant was not due to a general growth deficiency, we also performed competitions with the mutant and the wild type in BHI medium (i.e., in vitro). The CI of the nox mutant compared to that of the wild type was not significantly different from 1 after the incubation of the mixed inoculum in BHI medium overnight (Fig. 5). This suggested that there was no growth difference between the mutant and the wild type. These data indicated that the virulence of the nox mutant was impaired and that the nox gene played a role in IE.

Bottom Line: An S. sanguinis nox mutant was found to fail to inhibit the growth of Streptococcus mutans under microaerobic conditions.The nox mutant exhibited decreased levels of extracellular H2O2; however, the intracellular level of H2O2 in the mutant was increased.The nox mutant also was shown to be more sensitive to blood killing, oxidative and acid stresses, and reduced growth in serum.

View Article: PubMed Central - PubMed

Affiliation: Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, USA.

No MeSH data available.


Related in: MedlinePlus