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Hernandez-Morfa M, Reinoso-Vizcaino NM, Zappia VE, Olivero NB, Cortes PR, Stempin CC, Perez DR, Echenique J. Intracellular Streptococcus pneumoniae develops enhanced fluoroquinolone persistence during influenza A coinfection. Front Microbiol 2024; 15:1423995. [PMID: 39035445 PMCID: PMC11258013 DOI: 10.3389/fmicb.2024.1423995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 06/18/2024] [Indexed: 07/23/2024] Open
Abstract
Streptococcus pneumoniae is a major pathogen responsible for severe complications in patients with prior influenza A virus (IAV) infection. We have previously demonstrated that S. pneumoniae exhibits increased intracellular survival within IAV-infected cells. Fluoroquinolones (FQs) are widely used to treat pneumococcal infections. However, our prior work has shown that S. pneumoniae can develop intracellular FQ persistence, a phenomenon triggered by oxidative stress within host cells. This persistence allows the bacteria to withstand high FQ concentrations. In this study, we show that IAV infection enhances pneumococcal FQ persistence during intracellular survival within pneumocytes, macrophages, and neutrophils. This enhancement is partly due to increased oxidative stress induced by the viral infection. We find that this phenotype is particularly pronounced in autophagy-proficient host cells, potentially resulting from IAV-induced blockage of autophagosome-lysosome fusion. Moreover, we identified several S. pneumoniae genes involved in oxidative stress response that contribute to FQ persistence, including sodA (superoxide dismutase), clpL (chaperone), nrdH (glutaredoxin), and psaB (Mn+2 transporter component). Our findings reveal a novel mechanism of antibiotic persistence promoted by viral infection within host cells. This underscores the importance of considering this phenomenon when using FQs to treat pneumococcal infections, especially in patients with concurrent influenza A infection.
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Affiliation(s)
- Mirelys Hernandez-Morfa
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicolas M. Reinoso-Vizcaino
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Victoria E. Zappia
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nadia B. Olivero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paulo R. Cortes
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Cinthia C. Stempin
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Daniel R. Perez
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Jose Echenique
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Yamamoto Y. Roles of flavoprotein oxidase and the exogenous heme- and quinone-dependent respiratory chain in lactic acid bacteria. BIOSCIENCE OF MICROBIOTA, FOOD AND HEALTH 2024; 43:183-191. [PMID: 38966056 PMCID: PMC11220326 DOI: 10.12938/bmfh.2024-002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/22/2024] [Indexed: 07/06/2024]
Abstract
Lactic acid bacteria (LAB) are a type of bacteria that convert carbohydrates into lactate through fermentation metabolism. While LAB mainly acquire energy through this anaerobic process, they also have oxygen-consuming systems, one of which is flavoprotein oxidase and the other is exogenous heme- or heme- and quinone-dependent respiratory metabolism. Over the past two decades, research has contributed to the understanding of the roles of these oxidase machineries, confirming their suspected roles and uncovering novel functions. This review presents the roles of these oxidase machineries, which are anticipated to be critical for the future applications of LAB in industry and comprehending the virulence of pathogenic streptococci.
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Affiliation(s)
- Yuji Yamamoto
- Laboratory of Cellular Microbiology, School of Veterinary Medicine, Kitasato University, 23-35-1 Higashi, Towada, Aomori 034-8628, Japan
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Hernandez-Morfa M, Olivero NB, Zappia VE, Piñas GE, Reinoso-Vizcaino NM, Cian MB, Nuñez-Fernandez M, Cortes PR, Echenique J. The oxidative stress response of Streptococcus pneumoniae: its contribution to both extracellular and intracellular survival. Front Microbiol 2023; 14:1269843. [PMID: 37789846 PMCID: PMC10543277 DOI: 10.3389/fmicb.2023.1269843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 08/28/2023] [Indexed: 10/05/2023] Open
Abstract
Streptococcus pneumoniae is a gram-positive, aerotolerant bacterium that naturally colonizes the human nasopharynx, but also causes invasive infections and is a major cause of morbidity and mortality worldwide. This pathogen produces high levels of H2O2 to eliminate other microorganisms that belong to the microbiota of the respiratory tract. However, it also induces an oxidative stress response to survive under this stressful condition. Furthermore, this self-defense mechanism is advantageous in tolerating oxidative stress imposed by the host's immune response. This review provides a comprehensive overview of the strategies employed by the pneumococcus to survive oxidative stress. These strategies encompass the utilization of H2O2 scavengers and thioredoxins, the adaptive response to antimicrobial host oxidants, the regulation of manganese and iron homeostasis, and the intricate regulatory networks that control the stress response. Here, we have also summarized less explored aspects such as the involvement of reparation systems and polyamine metabolism. A particular emphasis is put on the role of the oxidative stress response during the transient intracellular life of Streptococcus pneumoniae, including coinfection with influenza A and the induction of antibiotic persistence in host cells.
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Affiliation(s)
- Mirelys Hernandez-Morfa
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nadia B. Olivero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Victoria E. Zappia
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - German E. Piñas
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicolas M. Reinoso-Vizcaino
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Melina B. Cian
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mariana Nuñez-Fernandez
- Centro de Química Aplicada, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paulo R. Cortes
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Jose Echenique
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Hernandez-Morfa M, Reinoso-Vizcaíno NM, Olivero NB, Zappia VE, Cortes PR, Jaime A, Echenique J. Host Cell Oxidative Stress Promotes Intracellular Fluoroquinolone Persisters of Streptococcus pneumoniae. Microbiol Spectr 2022; 10:e0436422. [PMID: 36445159 PMCID: PMC9769771 DOI: 10.1128/spectrum.04364-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 12/02/2022] Open
Abstract
Bacterial persisters represent a small subpopulation that tolerates high antibiotic concentrations without acquiring heritable resistance, and it may be generated by environmental factors. Here, we report the first antibiotic persistence mechanism in Streptococcus pneumoniae, which is induced by oxidative stress conditions and allows the pneumococcus to survive in the presence of fluoroquinolones. We demonstrated that fluoroquinolone persistence is prompted by both the impact of growth arrest and the oxidative stress response induced by H2O2 in bacterial cells. This process protected pneumococci against the deleterious effects of high ROS levels induced by fluoroquinolones. Importantly, S. pneumoniae develops persistence during infection, and is dependent on the oxidative stress status of the host cells, indicating that its transient intracellular life contributes to this mechanism. Furthermore, our findings suggest persistence may influence the outcome of antibiotic therapy and be part of a multistep mechanism in the evolution of fluoroquinolone resistance. IMPORTANCE In S. pneumoniae, different mechanisms that counteract antibiotic effects have been described, such as vancomycin tolerance, heteroresistance to penicillin and fluoroquinolone resistance, which critically affect the therapeutic efficacy. Antibiotic persistence is a type of antibiotic tolerance that allows a bacterial subpopulation to survive lethal antimicrobial concentrations. In this work, we used a host-cell infection model to reveal fluoroquinolone persistence in S. pneumoniae. This mechanism is induced by oxidative stress that the pneumococcus must overcome to survive in host cells. Many fluoroquinolones, such as levofloxacin and moxifloxacin, have a broad spectrum of activity against bacterial pathogens of community-acquired pneumonia, and they are used to treat pneumococcal diseases. However, the emergence of fluoroquinolone-resistant strains complicates antibiotic treatment of invasive infections. Consequently, antibiotic persistence in S. pneumoniae is clinically relevant due to prolonged exposure to fluoroquinolones likely favors the acquisition of mutations that generate antibiotic resistance in persisters. In addition, this work contributes to the knowledge of antibiotic persistence mechanisms in bacteria.
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Affiliation(s)
- Mirelys Hernandez-Morfa
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicolás M. Reinoso-Vizcaíno
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nadia B. Olivero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Victoria E. Zappia
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paulo R. Cortes
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea Jaime
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - José Echenique
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Zarrella TM, Yang J, Metzger DW, Bai G. Bacterial Second Messenger Cyclic di-AMP Modulates the Competence State in Streptococcus pneumoniae. J Bacteriol 2020; 202:e00691-19. [PMID: 31767779 PMCID: PMC6989799 DOI: 10.1128/jb.00691-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/19/2019] [Indexed: 02/07/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a naturally competent organism that causes diseases such as pneumonia, otitis media, and bacteremia. The essential bacterial second messenger cyclic di-AMP (c-di-AMP) is an emerging player in the stress responses of many pathogens. In S. pneumoniae, c-di-AMP is produced by a diadenylate cyclase, CdaA, and cleaved by phosphodiesterases Pde1 and Pde2. c-di-AMP binds a transporter of K+ (Trk) family protein, CabP, which subsequently halts K+ uptake via the transporter TrkH. Recently, it was reported that Pde1 and Pde2 are essential for pneumococcal virulence in mouse models of disease. To elucidate c-di-AMP-mediated transcription that may lead to changes in pathogenesis, we compared the transcriptomes of wild-type (WT) and Δpde1 Δpde2 strains by transcriptome sequencing (RNA-Seq) analysis. Notably, we found that many competence-associated genes are significantly upregulated in the Δpde1 Δpde2 strain compared to the WT. These genes play a role in DNA uptake, recombination, and autolysis. Competence is induced by a quorum-sensing mechanism initiated by the secreted factor competence-stimulating peptide (CSP). Surprisingly, the Δpde1 Δpde2 strain exhibited reduced transformation efficiency compared to WT bacteria, which was c-di-AMP dependent. Transformation efficiency was also directly related to the [K+] in the medium, suggesting a link between c-di-AMP function and the pneumococcal competence state. We found that a strain that possesses a V76G variation in CdaA produced less c-di-AMP and was highly susceptible to CSP. Deletion of cabP and trkH restored the growth of these bacteria in medium with CSP. Overall, our study demonstrates a novel role for c-di-AMP in the competence program of S. pneumoniaeIMPORTANCE Genetic competence in bacteria leads to horizontal gene transfer, which can ultimately affect antibiotic resistance, adaptation to stress conditions, and virulence. While the mechanisms of pneumococcal competence signaling cascades have been well characterized, the molecular mechanism behind competence regulation is not fully understood. The bacterial second messenger c-di-AMP has previously been shown to play a role in bacterial physiology and pathogenesis. In this study, we provide compelling evidence for the interplay between c-di-AMP and the pneumococcal competence state. These findings not only attribute a new biological function to this dinucleotide as a regulator of competence, transformation, and survival under stress conditions in pneumococci but also provide new insights into how pneumococcal competence is modulated.
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Affiliation(s)
- Tiffany M Zarrella
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
| | - Jun Yang
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
| | - Dennis W Metzger
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
| | - Guangchun Bai
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
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The PhoU protein from Escherichia coli interacts with PhoR, PstB, and metals to form a phosphate-signaling complex at the membrane. J Bacteriol 2014; 196:1741-52. [PMID: 24563032 DOI: 10.1128/jb.00029-14] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Robust growth in many bacteria is dependent upon proper regulation of the adaptive response to phosphate (Pi) limitation. This response enables cells to acquire Pi with high affinity and utilize alternate phosphorous sources. The molecular mechanisms of Pi signal transduction are not completely understood. PhoU, along with the high-affinity, Pi-specific ATP-binding cassette transporter PstSCAB and the two-component proteins PhoR and PhoB, is absolutely required for Pi signaling in Escherichia coli. Little is known about the role of PhoU and its function in regulation. We have demonstrated using bacterial two-hybrid analysis and confirmatory coelution experiments that PhoU interacts with PhoR through its PAS (Per-ARNT-Sim) domain and that it also interacts with PstB, the cytoplasmic component of the transporter. We have also shown that the soluble form of PhoU is a dimer that binds manganese and magnesium. Alteration of highly conserved residues in PhoU by site-directed mutagenesis shows that these sites play a role in binding metals. Analysis of these phoU mutants suggests that metal binding may be important for PhoU membrane interactions. Taken together, these results support the hypothesis that PhoU is involved in the formation of a signaling complex at the cytoplasmic membrane that responds to environmental Pi levels.
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The StkP/PhpP signaling couple in Streptococcus pneumoniae: cellular organization and physiological characterization. J Bacteriol 2009; 191:4943-50. [PMID: 19502404 DOI: 10.1128/jb.00196-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Streptococcus pneumoniae, stkP and phpP, encoding the eukaryotic-type serine-threonine kinase and PP2C phosphatase, respectively, form an operon. PhpP has the features of a so-called "soluble" protein, whereas StkP protein is membrane associated. Here we provide the first genetic and physiological evidence that PhpP and StkP, with antagonist enzymatic activities, constitute a signaling couple. The StkP-PhpP couple signals competence upstream of the competence-specific histidine kinase ComD, receptor for the oligopeptide pheromone "competence stimulating peptide." We show that PhpP activity is essential in a stkP(+) genetic background, suggesting tight control of StkP activity by PhpP. Proteins PhpP and StkP colocalized to the cell membrane subcellular fraction and likely belong to the same complex, as revealed by coimmunoprecipitation in cellular extracts. Specific coimmunoprecipitation of the N-kinase domain of StkP and PhpP recombinant proteins by PhpP-specific antibodies demonstrates direct interaction between these proteins. Consistently, flow cytometry analysis allowed the determination of the cytoplasmic localization of PhpP and of the N-terminal kinase domain of StkP, in contrast to the periplasmic localization of the StkP C-terminal PASTA (penicillin-binding protein and serine-threonine kinase associated) domain. A signaling route involving interplay between serine, threonine, and histidine phosphorylation is thus described for the first time in this human pathogen.
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8
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The Streptococcus pneumoniae competence regulatory system influences respiratory tract colonization. Infect Immun 2008; 76:3131-40. [PMID: 18443092 DOI: 10.1128/iai.01696-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The Streptococcus pneumoniae ComDE two-component signaling system controls the development of genetic competence in the bacterium and affects virulence in models of pneumonia and bacteremia. We have investigated the impact of the competence pathway during colonization of the nasopharynx, the principal ecological niche of the pneumococcus. Previous work showed that deletion of the pneumococcal CiaRH signaling system inhibited colonization and increased expression of genes required for competence. We anticipated that signaling by the competence pathway might similarly reduce carriage. Consistent with this expectation, a comE deletion that blocked transformation increased colonization fitness such that the mutant outcompeted the wild type in an infant rat model of asymptomatic carriage. Deletion of comD-immediately upstream of comE and likewise required for competence-similarly increased colonization fitness if the orientation of the antibiotic resistance cassette inserted into the comD locus was such that it reduced transcription of comE. However, an alternative comD deletion mutation that caused an increase in comE transcription impaired colonization instead. Activation of the competence system through a comE(D143Y) mutation did not affect colonization, but an inability to secrete the competence-stimulating peptide due to deletion of comAB produced a density-dependent reduction in colonization fitness. These results suggest a model in which signaling by the unactivated form of ComE reduces colonization fitness compared to that of bacteria in which it is either activated or absent entirely, with the most substantial fitness gain accompanying deletion of comE. This observation demonstrates that the pneumococcus incurs a substantial fitness cost in order to retain a functional competence regulatory system.
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9
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Abstract
In Streptococcus pneumoniae expression of pyruvate oxidase (SpxB) peaks during the early growth phase, coincident with the time of natural competence. This study investigated whether SpxB influences parameters of competence, such as spontaneous transformation frequency, expression of competence genes, and DNA release. Knockout of the spxB gene in strain D39 abolished spontaneous transformation (compared to a frequency of 6.3 x 10(-6) in the parent strain [P < 0.01]). It also reduced expression levels of comC and recA as well as DNA release from bacterial cells significantly during the early growth phase, coincident with the time of spontaneous competence in the parent strain. In the spxB mutant, supplementation with competence-stimulating peptide 1 (CSP-1) restored transformation (rate, 1.8 x 10(-2)). This speaks against the role of SpxB as a necessary source of energy for competence. Neither supplementation with CSP-1 nor supplementation with the SpxB products H2O2 and acetate altered DNA release. Supplementation of the parent strain with catalase did not reduce DNA release significantly. In conclusion, the pneumococcal spxB gene influences competence; however, the mechanism remains elusive.
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10
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Riani C, Standar K, Srimuang S, Lembke C, Kreikemeyer B, Podbielski A. Transcriptome analyses extend understanding of Streptococcus pyogenes regulatory mechanisms and behavior toward immunomodulatory substances. Int J Med Microbiol 2007; 297:513-23. [PMID: 17590393 DOI: 10.1016/j.ijmm.2007.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 04/02/2007] [Accepted: 04/04/2007] [Indexed: 11/28/2022] Open
Abstract
The recent genome sequencing of several Streptococcus pyogenes serotype strains allowed the design of corresponding DNA microarrays and their usage for specific transcriptome analyses. In the present study, we employed transcriptomics together with functional tests to investigate the impact of the CiaH sensor gene of the CiaRH two-component regulator on gene expression and virulence traits of serotype M49 S. pyogenes strains CS101 and 591. In parallel, we studied the effects of the immunostimulatory substance Luivac on the serotype M49 S. pyogenes transcriptome and several biological features of serotype M1, M2, M3, M6, M18, and M49 S. pyogenes strains. Overall, the transcriptome analyses allowed a swift identification of differences in transcript abundance apparently associated with the observed strain-specific changes in matrix protein binding, eukaryotic cell interactions, or biofilm formation of the ciaH mutants and of wild-type strains exposed to a commercially available substance used for preventing upper respiratory tract infections.
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Affiliation(s)
- Catur Riani
- Department of Medical Microbiology, Virology, and Hygiene, University Hospital Rostock, Schillingallee 70, D-18057 Rostock, Germany
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11
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Fernandez A, Borges F, Gintz B, Decaris B, Leblond-Bourget N. The rggC locus, with a frameshift mutation, is involved in oxidative stress response by Streptococcus thermophilus. Arch Microbiol 2006; 186:161-9. [PMID: 16847652 DOI: 10.1007/s00203-006-0130-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 05/22/2006] [Accepted: 05/24/2006] [Indexed: 10/24/2022]
Abstract
In Streptococcus thermophilus, the locus rggC contains a frameshift mutation and thus consists of two open reading frames (ORFs), rggC (1) and rggC (2), which encode proteins exhibiting similarity with the Rgg transcriptional regulator family. In this work, mutants showing a partial deletion of rggC (1) and rggC (2 )were constructed and their response to menadione, a superoxide-generating compound, was analysed. These mutants exhibited different behaviour to this oxidative stress compared with the wild-type strain. Analysis of this locus among 21 strains of S. thermophilus showed a polythymine tract length variability and a strain-dependant adenine residue could be found upstream of this repeat. This interstrain polymorphism supports evidence for the hypothesis that the rggC locus is phase variable.
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Affiliation(s)
- Annabelle Fernandez
- Laboratoire de Génétique et Microbiologie, UMR INRA 1128, IFR 110, Faculté des Sciences et Techniques de l'Université Henri Poincaré, Campus de Grignard, BP239, 54506 Vanoeuvre-lès-Nancy, France
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12
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Romao S, Memmi G, Oggioni MR, Trombe MC. LuxS impacts on LytA-dependent autolysis and on competence in Streptococcus pneumoniae. Microbiology (Reading) 2006; 152:333-341. [PMID: 16436421 DOI: 10.1099/mic.0.28406-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The ubiquitous protein LuxS with S-ribosylhomocysteinase activity is involved in S-adenosyl methionine detoxification, C-1 unit recycling and the production of autoinducers that allow the cell to sense and respond to cell density. Independent reports describe the impact of LuxS deficiency on Streptococcus pneumoniae virulence in the mouse. In vitro, LuxS deficiency confers discrete phenotypes. A combined approach using genetic dissection and mixed-culture experiments allowed the involvement of LuxS in the developmental physiology of S. pneumoniae to be investigated. Functional LuxS was found to be related on the one hand to down-regulation of competence, and on the other hand to attenuation of autolysis in cultures entering stationary phase. The competence phenotype of luxS mutant bacteria was complemented by media conditioned by competence-defective ComAB0 bacteria, but not by BSA. The autolytic phenotype was complemented by BSA, but not by conditioned supernatants. It is suggested that the impact of LuxS on competence, but not on autolysis, involves cell–cell communication. The phenotype of luxS mutant strains reveals a hierarchy in the competence regulatory networks of S. pneumoniae.
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Affiliation(s)
- Susana Romao
- Interactions et Signalisation Cellulaires: Relation Hôte-Pathogène, EA3036, IFR31, CHU Rangueil, Université Paul Sabatier, 31403 Toulouse, France
| | - Guido Memmi
- Laboratorio di Microbiologia Molecolare e Biotecnologia, Dipartimento di Biologia Molecolare, Università di Siena, Siena, Italy
| | - Marco R Oggioni
- UOC Batteriologia, Azienda Ospedaliera Universitaria Senese, Siena, Italy
- Laboratorio di Microbiologia Molecolare e Biotecnologia, Dipartimento di Biologia Molecolare, Università di Siena, Siena, Italy
| | - Marie-Claude Trombe
- Interactions et Signalisation Cellulaires: Relation Hôte-Pathogène, EA3036, IFR31, CHU Rangueil, Université Paul Sabatier, 31403 Toulouse, France
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Sebert ME, Patel KP, Plotnick M, Weiser JN. Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system. J Bacteriol 2005; 187:3969-79. [PMID: 15937159 PMCID: PMC1151733 DOI: 10.1128/jb.187.12.3969-3979.2005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.
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Affiliation(s)
- M E Sebert
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Echenique J, Kadioglu A, Romao S, Andrew PW, Trombe MC. Protein serine/threonine kinase StkP positively controls virulence and competence in Streptococcus pneumoniae. Infect Immun 2004; 72:2434-7. [PMID: 15039376 PMCID: PMC375209 DOI: 10.1128/iai.72.4.2434-2437.2004] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the Streptococcus pneumoniae genome, stkP, encoding a membrane-associated serine/threonine kinase, is not redundant (L. Novakova, S. Romao, J. Echenique, P. Branny, and M.-C. Trombe, unpublished results). The data presented here demonstrate that StkP belongs to the signaling network involved in competence triggering in vitro and lung infection and bloodstream invasion in vivo. In competence, functional StkP is required for activation of comCDE upstream of the autoregulated ring orchestrated by the competence-stimulating peptide. This is the first description of positive regulation of comCDE transcription in balance with its repression by CiaRH.
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Affiliation(s)
- Jose Echenique
- Laboratoire d'Interactions et Signalisation Cellulaire: Relation Hôte-Pathogène, Institut Louis Bugnard, Centre Hospitalo Universitaire de Rangueil, Université Paul Sabatier, 31403 Toulouse Cedex, France
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15
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Kadioglu A, Echenique J, Manco S, Trombe MC, Andrew PW. The MicAB two-component signaling system is involved in virulence of Streptococcus pneumoniae. Infect Immun 2003; 71:6676-9. [PMID: 14573696 PMCID: PMC219567 DOI: 10.1128/iai.71.11.6676-6679.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Streptococcus pneumoniae, the two-component signaling system MicAB was previously shown to contribute to repression of competence when oxygen is limited. In virulent strains expressing the serotype 2 and 6 capsule, mutation of the MicB kinase reduced the lag period of growth when cultures were switched from an aerobic to anaerobic atmosphere. After intranasal challenge of mice, the micB::km mutation decreased virulence, as shown by the absence of symptoms and by a lower level of recovery of CFU from lungs and blood. It is proposed that MicAB is involved in the adaptive response of the bacteria to changes in oxygen level during the course of infection.
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Affiliation(s)
- Aras Kadioglu
- Department of Microbiology and Immunology, University of Leicester, Leicester LE1 9HN, United Kingdom.
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Chapuy-Regaud S, Ogunniyi AD, Diallo N, Huet Y, Desnottes JF, Paton JC, Escaich S, Trombe MC. RegR, a global LacI/GalR family regulator, modulates virulence and competence in Streptococcus pneumoniae. Infect Immun 2003; 71:2615-25. [PMID: 12704136 PMCID: PMC153264 DOI: 10.1128/iai.71.5.2615-2625.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The homolactic and catalase-deficient pathogen Streptococcus pneumoniae is not only tolerant to oxygen but requires the activity of its NADH oxidase, Nox, to develop optimal virulence and competence for genetic transformation. In this work, we show that the global regulator RegR is also involved in these traits. Genetic dissection revealed that RegR regulates competence and the expression of virulence factors, including hyaluronidase. In bacteria grown in vitro, RegR represses hyaluronidase. At neutral pH, it increases adherence to A549 epithelial cells, and at alkaline pH, it acts upstream of the CiaRH two-component signaling system to activate competence. These phenotypes are not associated with changes in antibiotic resistance, central metabolism, and carbohydrate utilization. Although the RegR(0) (where 0 indicates the loss of the protein) mutation is sufficient to attenuate experimental virulence of strain 23477 in mice, the introduction of an additional hyl(0) (where 0 indicates the loss of function) mutation in the RegR(0) strain 23302 dramatically reduces its virulence. This indicates that residual virulence of the RegR(0) Hyl(+) derivative is due to hyaluronidase and supports the dual role of RegR in virulence. This LacI/GalR regulator, not essential for in vitro growth in rich media, is indeed involved in the adaptive response of the pneumococcus via its control of competence, adherence, and virulence.
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Affiliation(s)
- Sabine Chapuy-Regaud
- Laboratoire Interactions et Signalisation Cellulaire: Relation Hôte Pathogène, Institut Louis Bugnard, Centre Hospitalo-Universitaire de Rangueil, Université Paul Sabatier, 31403 Toulouse Cedex, France
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17
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Gibson CM, Caparon MG. Alkaline phosphatase reporter transposon for identification of genes encoding secreted proteins in gram-positive microorganisms. Appl Environ Microbiol 2002; 68:928-32. [PMID: 11823238 PMCID: PMC126685 DOI: 10.1128/aem.68.02.928-932.2002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We describe the construction of TnFuZ, a genetic tool for the discovery and mutagenesis of proteins exported from gram-positive bacteria. This tool combines a transposable element (Tn4001) of broad host range in gram-positive bacteria and an alkaline phosphatase gene (phoZ) derived from a gram-positive bacterium that has been modified by removal of the region encoding its export signal. Mutagenesis of Streptococcus pyogenes with TnFuZ ("FuZ" stands for fusions to phoZ) identified genes encoding secreted proteins whose expression was enhanced during growth in an aerobic environment. Thus, TnFuZ should be valuable for analysis of protein secretion, gene regulation, and virulence in gram-positive bacteria.
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Affiliation(s)
- Carmela M Gibson
- Department of Molecular Microbiology, University Medical Center, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, Missouri 63110-1093, USA
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18
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Echenique JR, Trombe MC. Competence repression under oxygen limitation through the two-component MicAB signal-transducing system in Streptococcus pneumoniae and involvement of the PAS domain of MicB. J Bacteriol 2001; 183:4599-608. [PMID: 11443095 PMCID: PMC95355 DOI: 10.1128/jb.183.15.4599-4608.2001] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Streptococcus pneumoniae, a fermentative aerotolerant and catalase-deficient human pathogen, oxidases with molecular oxygen as substrate are important for virulence and for competence. The signal-transducing two-component systems CiaRH and ComDE mediate the response to oxygen, culminating in competence. In this work we show that the two-component MicAB system, whose MicB kinase carries a PAS domain, is also involved in competence repression under oxygen limitation. Autophosphorylation of recombinant MicB and phosphotransfer to recombinant MicA have been demonstrated. Mutational analysis and in vitro assays showed that the C-terminal part of the protein and residue L100 in the N-terminal cap of its PAS domain are both crucial for autokinase activity in vitro. Although no insertion mutation in micA was obtained, expression of the mutated allele micA59DA did not change bacterial growth and overcame competence repression under microaerobiosis. This was related to a strong instability of MicA59DA-PO(4) in vitro. Thus, mutations which either reduced the stability of MicA-PO(4) or abolished kinase activity in MicB were related to competence derepression under microaerobiosis, suggesting that MicA-PO(4) is involved in competence repression when oxygen becomes limiting. The micAB genes are flanked by mutY and orfC. MutY is an adenine glycosylase involved in the repair of oxidized pyrimidines. OrfC shows the features of a metal binding protein. We did not obtain insertion mutation in orfC, suggesting its requirement for growth. It is proposed that MicAB, with its PAS motif, may belong to a set of functions important in the protection of the cell against oxidative stress, including the control of competence.
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Affiliation(s)
- J R Echenique
- Laboratoire de Genétique et Physiologie Bactérienne, E.A. 3036, Centre Hospitalo Universitaire de Rangueil, Université Paul Sabatier, 31403 Toulouse Cedex, France
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