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Journal of Bacteriology, August 2001, p. 4609-4613, Vol. 183, No. 15
Department of General and Environmental
Hygiene, Hygiene-Institute,1 and
Institute of Microbial Genetics,3
University of Tübingen, Tübingen, Germany;
Department of Microbiology, Molecular Genetics and
Immunology, University of Kansas Medical Center, Kansas City,
Kansas2; and Unité du
Choléra et des Vibrions, Institut Pasteur, Paris,
France4
Received 12 November 2000/Accepted 18 April 2001
Staphylococcus aureus expression of capsular
polysaccharide type 5 (CP5) has been shown to be downregulated by
CO2. Here we show that CO2 reduces CP5
expression at the transcriptional level and that CO2
regulates CP8 expression depending on the genetic background of the
strains. Growth in the presence of air supplemented with 5%
CO2 caused a significant decrease in CP8 expression in four
S. aureus strains, a marginal effect in four strains, and higher CP8 expression in strain Becker. Absolute CP8 expression in the
nine S. aureus strains differed largely from strain to strain. Four groups of strains were established due to sequence variations in the promoter region of cap5 and
cap8. To test whether these sequence variations are
responsible for the different responses to CO2, promoter
regions from selected strains were fused to the reporter gene
xylE in pLC4, and the plasmids were electrotransformed into
strains Becker and Newman. XylE activity was negatively regulated by
CO2 in all derivatives of strain Newman and was always
positively regulated by CO2 in all derivatives of strain
Becker. Differences in promoter sequences did not influence the pattern
of CP8 expression. Therefore, the genetic background of the strains
rather than differences in the promoter sequence determines the
CO2 response. trans-acting regulatory molecules
may be differentially expressed in strain Becker versus strain Newman.
The strain dependency of the CP8 expression established in vitro was
also seen in lung tissue sections of patients with cystic fibrosis
infected with CP8-positive S. aureus strains.
0021-9193/01/$04.00+0 DOI: 10.1128/JB.183.15.4609-4613.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Regulation of Staphylococcus aureus Type
5 and Type 8 Capsular Polysaccharides by CO2

*
Corresponding author. Mailing address: Department of
General and Environmental Hygiene, Hygiene-Institute, University of
Tübingen, Wilhelmstrasße 31, D-72074 Tübingen, Germany.
Phone: 49-7071-2982069. Fax: 49-7071-2983011. E-mail:
gerd.doering{at}uni-tuebingen.de.
Present address: Naval Medical Center, San Diego, CA 92134.
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