1
|
Plainvert C, Rosinski-Chupin I, Weckel A, Lambert C, Touak G, Sauvage E, Poyart C, Glaser P, Fouet A. A Novel CovS Variant Harbored by a Colonization Strain Reduces Streptococcus pyogenes Virulence. J Bacteriol 2023; 205:e0003923. [PMID: 36920220 PMCID: PMC10127592 DOI: 10.1128/jb.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 03/16/2023] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus, causes a wide variety of diseases ranging from mild noninvasive to severe invasive infections. To identify possible causes of colonization-to-invasive switches, we determined the genomic sequences of 10 isolates from five pairs each composed of an invasive strain and a carriage strain originating from five infectious clusters. Among them, one pair displayed a single-nucleotide difference in covS, encoding the sensor histidine kinase of the two-component CovRS system that controls the expression of 15% of the genome. In contrast to previously described cases where the invasive strains harbor nonfunctional CovS proteins, the carriage strain possessed the mutation covST115C, leading to the replacement of the tyrosine at position 39 by a histidine. The CovSY39H mutation affected the expression of the genes from the CovR regulon in a unique fashion. Genes usually overexpressed in covS mutant strains were underexpressed and vice versa. Furthermore, the covS mutant strain barely responded to the addition of the CovS-signaling compounds Mg2+ and LL-37. The variations in the accumulation of two virulence factors paralleled the transcription modifications. In addition, the covST115C mutant strain showed less survival than its wild-type counterpart in murine macrophages. Finally, in two murine models of infection, the covS mutant strain was less virulent than the wild-type strain. Our study suggests that the CovSY39H protein compromises CovS phosphatase activity and that this yields a noninvasive strain. IMPORTANCE Streptococcus pyogenes, also known as group A Streptococcus, causes a wide variety of diseases, leading to 517,000 deaths yearly. The two-component CovRS system, which responds to MgCl2 and the antimicrobial peptide LL-37, controls the expression of 15% of the genome. Invasive strains may harbor nonfunctional CovS sensor proteins that lead to the derepression of most virulence genes. We isolated a colonization strain that harbors a novel covS mutation. This mutant strain harbored a transcriptome profile opposite that of other covS mutant strains, barely responded to environmental signals, and was less virulent than the wild-type strain. This supports the importance of the derepression of the expression of most virulence genes, via mutations that impact the phosphorylation of the regulator CovR, for favoring S. pyogenes invasive infections.
Collapse
Affiliation(s)
- Céline Plainvert
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Isabelle Rosinski-Chupin
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Antonin Weckel
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Clara Lambert
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Gérald Touak
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Elisabeth Sauvage
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Claire Poyart
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| | - Philippe Glaser
- Institut Pasteur, Ecologie et Evolution de la Résistance aux Antibiotiques, UMR3525, Paris, France
| | - Agnès Fouet
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
- Service de Bactériologie, CNR des Streptocoques, Hôpitaux Universitaires Paris Centre, Paris, France
| |
Collapse
|