1
|
Fox V, Santoro F, Apicella C, Diaz-Diaz S, Rodriguez-Martínez JM, Iannelli F, Pozzi G. The mef(A)/ msr(D)-carrying streptococcal prophage Φ1207.3 encodes an SOS-like system, induced by UV-C light, responsible for increased survival and increased mutation rate. J Bacteriol 2023; 205:e0019123. [PMID: 37695857 PMCID: PMC10521357 DOI: 10.1128/jb.00191-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/04/2023] [Indexed: 09/13/2023] Open
Abstract
Bacterial SOS response is an inducible system of DNA repair and mutagenesis. Streptococci lack a canonical SOS response, but an SOS-like response was reported in some species. The mef(A)-msr(D)-carrying prophage Ф1207.3 of Streptococcus pyogenes contains a region, spanning orf6 to orf11, showing homology to characterized streptococcal SOS-like cassettes. Genome-wide homology search showed the presence of the whole Φ1207.3 SOS-like cassette in three S. pyogenes prophages, while parts of it were found in other bacterial species. To investigate whether this cassette confers an SOS-mutagenesis phenotype, we constructed Streptococcus pneumoniae R6 isogenic derivative strains: (i) FR172, streptomycin resistant, (ii) FR173, carrying Φ1207.3, and (iii) FR174, carrying a recombinant Φ1207.3, where the SOS-like cassette was deleted. These strains were used in survival and mutation rate assays using a UV-C LED instrument, for which we designed and 3D-printed a customized equipment, constituted of an instrument support and swappable-autoclavable mini-plates and lids. Upon exposure to UV fluences ranging from 0 to 6,400 J/m2 at four different wavelengths, 255, 265, 275, and 285 nm, we found that the presence of Φ1207.3 SOS-like cassette increases bacterial survival up to 34-fold. Mutation rate was determined by measuring rifampicin resistance acquisition upon exposure to UV fluence of 50 J/m2 at the four wavelengths by fluctuation test. The presence of Φ1207.3 SOS-like cassette resulted in a significant increase in the mutation rate (up to 18-fold) at every wavelength. In conclusion, we demonstrated that Φ1207.3 carries a functional SOS-like cassette responsible for an increased survival and increased mutation rate in S. pneumoniae. IMPORTANCE Bacterial mutation rate is generally low, but stress conditions and DNA damage can induce stress response systems, which allow for improved survival and continuous replication. The SOS response is a DNA repair mechanism activated by some bacteria in response to stressful conditions, which leads to a temporary hypermutable phenotype and is usually absent in streptococcal genomes. Here, using a reproducible and controlled UV irradiation system, we demonstrated that the SOS-like gene cassette of prophage Φ1207.3 is functional, responsible for a temporary hypermutable phenotype, and enhances bacterial survival to UV irradiation. Prophage Φ1207.3 also carries erythromycin resistance genes and can lysogenize different pathogenic bacteria, constituting an example of a mobile genetic element which can confer multiple phenotypes to its host.
Collapse
Affiliation(s)
- Valeria Fox
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Francesco Santoro
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Carmen Apicella
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Sara Diaz-Diaz
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain
| | | | - Francesco Iannelli
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Gianni Pozzi
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| |
Collapse
|
2
|
De Gaetano GV, Coppolino F, Lentini G, Famà A, Cullotta C, Raffaele I, Motta C, Teti G, Speziale P, Pietrocola G, Beninati C. Streptococcus pneumoniae
binds collagens and C1q
via
the SSURE repeats of the PfbB adhesin. Mol Microbiol 2022; 117:1479-1492. [PMID: 35570359 PMCID: PMC9328315 DOI: 10.1111/mmi.14920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/17/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022]
Abstract
The binding of Streptococcus pneumoniae to collagen is likely an important step in the pathogenesis of pneumococcal infections, but little is known of the underlying molecular mechanisms. Streptococcal surface repeats (SSURE) are highly conserved protein domains present in cell wall adhesins from different Streptococcus species. We find here that SSURE repeats of the pneumococcal adhesin plasminogen and fibronectin binding protein B (PfbB) bind to various types of collagen. Moreover, deletion of the pfbB gene resulted in a significant impairment of the ability of encapsulated or unencapsulated pneumococci to bind collagen. Notably, a PfbB SSURE domain is also bound to the complement component C1q that bears a collagen‐like domain and promotes adherence of pneumococci to host cells by acting as a bridge between bacteria and epithelial cells. Accordingly, deletion of PfbB or pre‐treatment with anti‐SSURE antibodies markedly decreased pneumococcal binding to C1q as well as C1q‐dependent adherence to epithelial and endothelial cells. Further data indicated that C1q promotes pneumococcal adherence by binding to integrin α2β1. In conclusion, our results indicate that the SSURE domains of the PfbB protein promote interactions of pneumococci with various types of collagen and with C1q. These repeats may be useful targets in strategies to control S. pneumoniae infections.
Collapse
Affiliation(s)
| | - Francesco Coppolino
- Department of BiomedicalDental and Imaging SciencesUniversity of MessinaMessinaItaly
| | - Germana Lentini
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Agata Famà
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Cullotta
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Ivana Raffaele
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Motta
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Pietro Speziale
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Concetta Beninati
- Department of Human PathologyUniversity of MessinaMessinaItaly
- Scylla Biotech SrlMessinaItaly
| |
Collapse
|
3
|
Mohammadzadeh M, Pourakbari B, Doosti A, Mahmoudi S, Habibi-Anbouhi M, Mamishi S. Construction and evaluation of a whole-cell pneumococcal vaccine candidate. J Appl Microbiol 2018; 125:1901-1910. [PMID: 30133088 DOI: 10.1111/jam.14079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 06/12/2018] [Accepted: 08/14/2018] [Indexed: 11/29/2022]
Abstract
AIMS Pneumococcal infections are a major public health problem, especially in developing countries, and the current pneumococcal vaccines do not cover all pathogenic strains. New, more economical serotype-independent vaccines based on species-common protein antigens are being pursued. The pneumococcal whole-cell vaccine which is based on noncapsular antigens common to all strains induces serotype-independent immunity. In the present study, we developed a new candidate for a whole-cell pneumococcal vaccine in which two important virulence factors, the capsule and pneumolysin, were deleted. METHODS AND RESULTS Protection was elicited by immunization against colonization in mice with a killed mutant strain and the antibody response in the mice serum was evaluated. This candidate vaccine was effective in preventing nasopharyngeal colonization. The mice immunized with this candidate vaccine had significantly higher serum antibody titres than mice that received the adjuvant alone. CONCLUSIONS Based on obtained results in this study, the engineered whole-cell pneumococci can be considered as a vaccine candidate in future studies. SIGNIFICANCE AND IMPACT OF THE STUDY This candidate vaccine can overcome the limitations of available polysaccharide vaccines.
Collapse
Affiliation(s)
- M Mohammadzadeh
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - B Pourakbari
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - A Doosti
- Biotechnology Research Center, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - S Mahmoudi
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - M Habibi-Anbouhi
- National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, Iran
| | - S Mamishi
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pediatric Infectious Disease, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
4
|
Mohammadzadeh M, Pourakbari B, Mahmoudi S, Keshtkar A, Habibi-Anbouhi M, Mamishi S. Efficacy of whole-cell pneumococcal vaccine in mice: A systematic review and meta-analysis. Microb Pathog 2018; 122:122-129. [PMID: 29908308 DOI: 10.1016/j.micpath.2018.06.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/14/2018] [Accepted: 06/13/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Despite the fact that pneumococcal conjugate vaccines (PCVs) have significantly reduced the rate of invasive pneumococcal diseases through the use of vaccine serotypes, infection with Streptococcus pneumoniae remains a major public health hazard. Serotype-independent vaccines that are economically viable species of common protein antigens such as whole-cell vaccines (WCVs) are needed. Considering the ongoing debate about the effectiveness of WCVs, a systematic literature review and meta-analysis was carried out to determine the efficacy of WCVs against colonization in mice. MATERIAL AND METHODS A systematic review was undertaken of published studies on the protection (colonized/uncolonized) of whole cell pneumococcal vaccine in mice. The search terms used were "whole cell vaccine" and "Streptococcus pneumoniae" in PubMed, Google Scholar, Embase, Web of Science and Scopus engines. Data was extracted from original publications and a meta-analysis was performed on studies divided into sub-groups by the number of inoculations, type of sample, type of adjuvant, time of sampling, design of study and quality of study. RESULTS Ten eligible articles published from 2000 to 2016 were included in this review. The meta-analysis was performed on eight out of 10 studies and demonstrated that the estimated pooled risk ratios (RRs) for comparison of colonization between the vaccinated and unvaccinated mice for outcomes 1 and 2 were 0.18 and 0.24, respectively. Lower RRs were observed in sub-groups that were inoculated with vaccines three times, those using cholera toxin (CT) adjuvants and those obtained as tracheal specimens from the mice. CONCLUSIONS The best protocol for use of a WCV is its application with CT adjuvant administered intranasally in three inoculations at doses of 10⁸ CFU. Further studies performed under similar conditions to obtain accurate results on the effectiveness of this vaccine are recommended.
Collapse
Affiliation(s)
- Mona Mohammadzadeh
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Babak Pourakbari
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Shima Mahmoudi
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Abbas Keshtkar
- Department of Health Sciences Education Development, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
| | | | - Setareh Mamishi
- Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pediatric Infectious Disease, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
5
|
Streptococcus pneumoniae phosphotyrosine phosphatase CpsB and alterations in capsule production resulting from changes in oxygen availability. J Bacteriol 2014; 196:1992-2003. [PMID: 24659769 DOI: 10.1128/jb.01545-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Streptococcus pneumoniae produces a protective capsular polysaccharide whose production must be modulated for bacterial survival within various host niches. Capsule production is affected in part by a phosphoregulatory system comprised of CpsB, CpsC, and CpsD. Here, we found that growth of serotype 2 strain D39 under conditions of increased oxygen availability resulted in decreased capsule levels concurrent with an ∼5-fold increase in Cps2B-mediated phosphatase activity. The change in Cps2B phosphatase activity did not result from alterations in the levels of either the cps2B transcript or the Cps2B protein. Recombinant Cps2B expressed in Escherichia coli similarly exhibited increased phosphatase activity under conditions of high-oxygen growth. S. pneumoniae D39 derivatives with defined deletion or point mutations in cps2B demonstrated reduced phosphatase activity with corresponding increases in levels of Cps2D tyrosine phosphorylation. There was, however, no correlation between these phenotypes and the level of capsule production. During growth under reduced-oxygen conditions, the Cps2B protein was essential for parental levels of capsule, but phosphatase activity alone could be eliminated without an effect on capsule. Under increased-oxygen conditions, deletion of cps2B did not affect capsule levels. These results indicate that neither Cps2B phosphatase activity nor Cps2D phosphorylation levels per se are determinants of capsule levels, whereas the Cps2B protein is important for capsule production during growth under conditions of reduced but not enhanced oxygen availability. Roles for factors outside the capsule locus, possible interactions between capsule regulatory proteins, and links to other cellular processes are also suggested by the results described in this study.
Collapse
|
6
|
Mukerji R, Mirza S, Roche AM, Widener RW, Croney CM, Rhee DK, Weiser JN, Szalai AJ, Briles DE. Pneumococcal surface protein A inhibits complement deposition on the pneumococcal surface by competing with the binding of C-reactive protein to cell-surface phosphocholine. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:5327-35. [PMID: 23105137 PMCID: PMC3517878 DOI: 10.4049/jimmunol.1201967] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In the presence of normal serum, complement component C3 is deposited on pneumococci primarily via the classical pathway. Pneumococcal surface protein A (PspA), a major virulence factor of pneumococci, effectively inhibits C3 deposition. PspA's C terminus has a choline-binding domain that anchors PspA to the phosphocholine (PC) moieties on the pneumococcal surface. C-reactive protein (CRP), another important host defense molecule, also binds to PC, and CRP binding to pneumococci enhances complement C3 deposition through the classical pathway. Using flow cytometry of PspA(+) and PspA(-) strains, we observed that the absence of PspA led to exposure of PC, enhanced the surface binding of CRP, and increased the deposition of C3. Moreover, when the PspA(-) mutant was incubated with a pneumococcal eluate containing native PspA, there was decreased deposition of CRP and C3 on the pneumococcal surface compared with incubation with an eluate from a PspA(-) strain. This inhibition was not observed when a recombinant PspA fragment, which lacks the choline-binding region of PspA, was added to the PspA(-) mutant. Also, there was much greater C3 deposition onto the PspA(-) pneumococcus when exposed to normal mouse serum from wild-type mice as compared with that from CRP knockout mice. Furthermore, when CRP knockout mouse serum was replenished with CRP, there was a dose-dependent increase in C3 deposition. The combined data reveal a novel mechanism of complement inhibition by a bacterial protein: inhibition of CRP surface binding and, thus, diminution of CRP-mediated complement deposition.
Collapse
Affiliation(s)
- Reshmi Mukerji
- Department of Microbiology, University of Alabama at Birmingham
| | - Shaper Mirza
- University of Texas School of Public Health Division of Epidemiology Brownsville regional campus Brownsville TX
| | - Aoife M. Roche
- Department of Microbiology, School of Medicine, University of Pennsylvania
| | | | | | - Dong-Kwon Rhee
- School of Pharmacy, Sungkyunkwan University, Suwon, Korea
| | - Jeffrey N. Weiser
- Department of Microbiology, School of Medicine, University of Pennsylvania
| | - Alexander J. Szalai
- Department of Microbiology, University of Alabama at Birmingham
- Division of Immunology Department of Medicine, University of Alabama at Birmingham
| | - David E. Briles
- Department of Microbiology, University of Alabama at Birmingham
- Department of Pediatrics, University of Alabama at Birmingham
- School of Pharmacy, Sungkyunkwan University, Suwon, Korea
| |
Collapse
|
7
|
High levels of genetic recombination during nasopharyngeal carriage and biofilm formation in Streptococcus pneumoniae. mBio 2012; 3:mBio.00200-12. [PMID: 23015736 PMCID: PMC3448161 DOI: 10.1128/mbio.00200-12] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Transformation of genetic material between bacteria was first observed in the 1920s using Streptococcus pneumoniae as a model organism. Since then, the mechanism of competence induction and transformation has been well characterized, mainly using planktonic bacteria or septic infection models. However, epidemiological evidence suggests that genetic exchange occurs primarily during pneumococcal nasopharyngeal carriage, which we have recently shown is associated with biofilm growth, and is associated with cocolonization with multiple strains. However, no studies to date have comprehensively investigated genetic exchange during cocolonization in vitro and in vivo or the role of the nasopharyngeal environment in these processes. In this study, we show that genetic exchange during dual-strain carriage in vivo is extremely efficient (10−2) and approximately 10,000,000-fold higher than that measured during septic infection (10−9). This high transformation efficiency was associated with environmental conditions exclusive to the nasopharynx, including the lower temperature of the nasopharynx (32 to 34°C), limited nutrient availability, and interactions with epithelial cells, which were modeled in a novel biofilm model in vitro that showed similarly high transformation efficiencies. The nasopharyngeal environmental factors, combined, were critical for biofilm formation and induced constitutive upregulation of competence genes and downregulation of capsule that promoted transformation. In addition, we show that dual-strain carriage in vivo and biofilms formed in vitro can be transformed during colonization to increase their pneumococcal fitness and also, importantly, that bacteria with lower colonization ability can be protected by strains with higher colonization efficiency, a process unrelated to genetic exchange. Although genetic exchange between pneumococcal strains is known to occur primarily during colonization of the nasopharynx and colonization is associated with biofilm growth, this is the first study to comprehensively investigate transformation in this environment and to analyze the role of environmental and bacterial factors in this process. We show that transformation efficiency during cocolonization by multiple strains is very high (around 10−2). Furthermore, we provide novel evidence that specific aspects of the nasopharyngeal environment, including lower temperature, limited nutrient availability, and epithelial cell interaction, are critical for optimal biofilm formation and transformation efficiency and result in bacterial protein expression changes that promote transformation and fitness of colonization-deficient strains. The results suggest that cocolonization in biofilm communities may have important clinical consequences by facilitating the spread of antibiotic resistance and enabling serotype switching and vaccine escape as well as protecting and retaining poorly colonizing strains in the pneumococcal strain pool.
Collapse
|
8
|
Abstract
Streptococcus pneumoniae (pneumococcus) is a frequent colonizer of the nasopharynx and one of the leading causative agents of otitis media, pneumonia, and meningitis. The current literature asserts that S. pneumoniae is transmitted person to person via respiratory droplets; however, environmental surfaces (fomites) have been linked to the spread of other respiratory pathogens. Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces. This study investigated the survival and infectivity of S. pneumoniae following desiccation under ambient conditions. We recovered viable bacteria after all desiccation periods tested, ranging from 1 h to 4 weeks. Experiments conducted under nutrient limitation indicate that desiccation is a condition separate from starvation. Desiccation of an acapsular mutant and 15 different clinical isolates shows that S. pneumoniae desiccation tolerance is independent of the polysaccharide capsule and is a species-wide phenomenon, respectively. Experiments demonstrating that nondesiccated and desiccated S. pneumoniae strains colonize the nasopharynx at comparable levels, combined with their ability to survive long-term desiccation, suggest that fomites may serve as alternate sources of pneumococcal infection. Even with the advent of multivalent capsular polysaccharide conjugate vaccines, S. pneumoniae continues to be a major cause of morbidity and mortality worldwide. Every year, there are approximately 7 million cases of pneumococcus-based otitis media in the United States alone, while pneumococcal invasive diseases are responsible for more than 1 million deaths globally. It is believed that the human upper respiratory tract is the sole niche of S. pneumoniae and, thus, that spread occurs via close contact with an infected individual. In this study, we characterized the desiccation tolerance of S. pneumoniae and found that it can survive for many weeks postdehydration and retain infectivity. Our results suggest that desiccation tolerance is an inherent trait of this genetically variable species and that fomites may be a source of transmission.
Collapse
|
9
|
Santoro F, Oggioni MR, Pozzi G, Iannelli F. Nucleotide sequence and functional analysis of the tet (M)-carrying conjugative transposon Tn5251 of Streptococcus pneumoniae. FEMS Microbiol Lett 2010; 308:150-8. [PMID: 20487027 DOI: 10.1111/j.1574-6968.2010.02002.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The Tn916-like genetic element Tn5251 is part of the composite conjugative transposon (CTn) Tn5253 of Streptococcus pneumoniae, a 64.5-kb chromosomal element originally called Omega(cat-tet) BM6001. DNA sequence analysis showed that Tn5251 is 18 033-bp long and contains 22 ORFs, 20 of which have the same direction of transcription. Annotation was possible for 11 out of 22 ORFs, including the tet(M) tetracycline resistance gene and int and xis involved in the integration/excision process. Autonomous copies of Tn5251 were generated during matings of Tn5253-containing donors with S. pneumoniae and Enterococcus faecalis. Tn5251 was shown to integrate at different sites in the bacterial chromosome. It behaves as a fully functional CTn capable of independent conjugal transfer to a variety of bacterial species including S. pneumoniae, Streptococcus gordonii, Streptococcus pyogenes, Streptococcus agalactiae, E. faecalis and Bacillus subtilis. The excision of Tn5251 produces a circular intermediate and a deletion in Tn5253 at a level of 1.2 copies per 10(5) chromosomes.
Collapse
Affiliation(s)
- Francesco Santoro
- Laboratory of Molecular Microbiology and Biotechnology (LAMMB), Department of Molecular Biology, University of Siena, Siena, Italy
| | | | | | | |
Collapse
|
10
|
Papasergi S, Garibaldi M, Tuscano G, Signorino G, Ricci S, Peppoloni S, Pernice I, Lo Passo C, Teti G, Felici F, Beninati C. Plasminogen- and fibronectin-binding protein B is involved in the adherence of Streptococcus pneumoniae to human epithelial cells. J Biol Chem 2010; 285:7517-24. [PMID: 20048164 DOI: 10.1074/jbc.m109.062075] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. The ability of this bacterium to adhere to epithelial cells is considered as an essential early step in colonization and infection. By screening a whole genome phage display library with sera from infected patients, we previously identified three antigenic fragments matching open reading frame spr0075 of the strain R6 genome. This locus encodes for an approximately 120-kDa protein, herein referred to as plasminogen- and fibronectin-binding protein B (PfbB), which displays an LPXTG cell wall anchoring motif and six repetitive domains. In this study, by using isogenic pfbB-deleted mutants of the encapsulated D39 and of the unencapsulated DP1004 type 2 pneumococcal strains, we show that PfbB is involved in S. pneumoniae adherence to various epithelial respiratory tract cell lines. Our data suggest that PfbB directly mediates bacterial adhesion, because fluorescent beads coated with the recombinant PfbB sp17 fragment (encompassing one of the six repetitive domains and the C-terminal region) efficiently bound to epithelial cells. Mutants lacking PfbB bound to fibronectin and plasminogen considerably less efficiently than wild type bacteria, whereas sp17-coated beads specifically bound to both of these substrates. Taken together, our data suggest that, by directly interacting with fibronectin, PfbB significantly increases the ability of S. pneumoniae to adhere to human epithelial cells.
Collapse
|
11
|
Pneumococcal LytR, a protein from the LytR-CpsA-Psr family, is essential for normal septum formation in Streptococcus pneumoniae. J Bacteriol 2009; 191:5859-64. [PMID: 19581359 DOI: 10.1128/jb.00724-09] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proliferation of the human-pathogenic bacterium Streptococcus pneumoniae is fundamentally linked to the bacterial proteins that function in cell division. Here, we show that LytR, a pneumococcal protein from the LytR-CpsA-Psr family, is essential to this process.
Collapse
|
12
|
Eldholm V, Johnsborg O, Haugen K, Ohnstad HS, Håvarstein LS. Fratricide in Streptococcus pneumoniae: contributions and role of the cell wall hydrolases CbpD, LytA and LytC. MICROBIOLOGY-SGM 2009; 155:2223-2234. [PMID: 19389766 DOI: 10.1099/mic.0.026328-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pneumococci that have developed the competent state kill and lyse non-competent sister cells and members of closely related species during co-cultivation in vitro. The key component in this process, called fratricide, is the product of the late competence gene cbpD. In addition, the peptidoglycan hydrolases LytA and LytC are required for efficient lysis of target cells. Here, we have investigated the relative contribution and possible role of each of the proteins mentioned above. Previous studies have shown that CbpD is produced exclusively by competent cells, whereas LytA and LytC can be provided by the competent attackers as well as the non-competent target cells. By using an improved assay to compare the effect of cis- versus trans-acting LytA and LytC, we were able to show that target cells are lysed much more efficiently when LytA and LytC are provided in cis, i.e. by the target cells themselves. Western analysis demonstrated that considerable amounts of LytC are present in the growth medium. In contrast, we were not able to detect any extracellular LytA. This finding indicates that LytA- and LytC-mediated fratricide represent different processes. In the absence of LytA and LytC, only a tiny fraction of the target cells were lysed, demonstrating that CbpD does not function efficiently on its own. However, in the presence of 1 mM EDTA, the fraction of target cells lysed directly by CbpD increased dramatically, indicating that divalent cations are involved in the regulation of fratricide under natural conditions.
Collapse
Affiliation(s)
- Vegard Eldholm
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Ola Johnsborg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Kristine Haugen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Hilde Solheim Ohnstad
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Leiv Sigve Håvarstein
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| |
Collapse
|
13
|
Protection against nasopharyngeal colonization by Streptococcus pneumoniae is mediated by antigen-specific CD4+ T cells. Infect Immun 2008; 76:2678-84. [PMID: 18391006 DOI: 10.1128/iai.00141-08] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
CD4(+) T-cell-dependent acquired immunity confers antibody-independent protection against pneumococcal colonization. Since this mechanism is poorly understood for extracellular bacteria, we assessed the antigen specificity of the induction and recall of this immune response by using BALB/c DO11.10Rag(-/-) mice, which lack mature B and T cells except for CD4(+) T cells specific for the OVA(323-339) peptide derived from ovalbumin. Serotype 6B Streptococcus pneumoniae strain 603S and unencapsulated strain Rx1Delta lytA were modified to express OVA(323-339) as a fusion protein with surface protein A (PspA) (strains 603OVA(1) and Rx1Delta lytAOVA(1)) or with PspA, neuraminidase A, and pneumolysin (Rx1Delta lytAOVA(3)). Whole-cell vaccines (WCV) were made of ethanol-killed cells of Rx1Delta lytA plus cholera toxin (CT) adjuvant, of Rx1Delta lytAOVA(1) + CT (WCV-OVA(1)), and of Rx1Delta lytAOVA(3) + CT (WCV-OVA(3)). Mice intranasally immunized with WCV-OVA(1), but not with WCV or CT alone, were protected against intranasal challenge with 603OVA(1). There was no protection against strain 603S in mice immunized with WCV-OVA(1). These results indicate antigen specificity of both immune induction and the recall response. Effector action was not restricted to antigen-bearing bacteria since colonization by 603S was reduced in animals immunized with vaccines made of OVA-expressing strains when ovalbumin or killed Rx1Delta lytAOVA(3) antigen was administered around the time of challenge. CD4(+) T-cell-mediated protection against pneumococcal colonization can be induced in an antigen-specific fashion and requires specific antigen for effective bacterial clearance, but this activity may extend beyond antigen-expressing bacteria. These results are consistent with the recruitment and/or activation of phagocytic or other nonspecific effectors by antigen-specific CD4(+) T cells.
Collapse
|
14
|
Regev-Yochay G, Trzcinski K, Thompson CM, Lipsitch M, Malley R. SpxB is a suicide gene of Streptococcus pneumoniae and confers a selective advantage in an in vivo competitive colonization model. J Bacteriol 2007; 189:6532-9. [PMID: 17631628 PMCID: PMC2045178 DOI: 10.1128/jb.00813-07] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human bacterial pathogen Streptococcus pneumoniae dies spontaneously upon reaching stationary phase. The extent of S. pneumoniae death at stationary phase is unusual in bacteria and has been conventionally attributed to autolysis by the LytA amidase. In this study, we show that spontaneous pneumococcal death is due to hydrogen peroxide (H(2)O(2)), not LytA, and that the gene responsible for H(2)O(2) production (spxB) also confers a survival advantage in colonization. Survival of S. pneumoniae in stationary phase was significantly prolonged by eliminating H(2)O(2) in any of three ways: chemically by supplementing the media with catalase, metabolically by growing the bacteria under anaerobic conditions, or genetically by constructing DeltaspxB mutants that do not produce H(2)O(2). Likewise, addition of H(2)O(2) to exponentially growing S. pneumoniae resulted in a death rate similar to that of cells in stationary phase. While DeltalytA mutants did not lyse at stationary phase, they died at a rate similar to that of the wild-type strain. Furthermore, we show that the death process induced by H(2)O(2) has features of apoptosis, as evidenced by increased annexin V staining, decreased DNA content, and appearance as assessed by transmission electron microscopy. Finally, in an in vivo rat model of competitive colonization, the presence of spxB conferred a selective advantage over the DeltaspxB mutant, suggesting an explanation for the persistence of this gene. We conclude that a suicide gene of pneumococcus is spxB, which induces an apoptosis-like death in pneumococci and confers a selective advantage in nasopharyngeal cocolonization.
Collapse
Affiliation(s)
- Gili Regev-Yochay
- Department of Epidemiology and Department of Immunology and Infectious Diseases, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115, USA.
| | | | | | | | | |
Collapse
|
15
|
Regev-Yochay G, Trzcinski K, Thompson CM, Malley R, Lipsitch M. Interference between Streptococcus pneumoniae and Staphylococcus aureus: In vitro hydrogen peroxide-mediated killing by Streptococcus pneumoniae. J Bacteriol 2006; 188:4996-5001. [PMID: 16788209 PMCID: PMC1482988 DOI: 10.1128/jb.00317-06] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies.
Collapse
Affiliation(s)
- Gili Regev-Yochay
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115, USA.
| | | | | | | | | |
Collapse
|
16
|
Moore QC, Bosarge JR, Quin LR, McDaniel LS. Enhanced protective immunity against pneumococcal infection with PspA DNA and protein. Vaccine 2006; 24:5755-61. [PMID: 16759765 DOI: 10.1016/j.vaccine.2006.04.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 04/20/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
The effect of priming and boosting with pspA/EF5668 and purified recombinant PspA/EF5668 was examined. With this strategy CBA/N mice were protected against fatal challenge with Streptococcus pneumoniae EF5668. Anti-PspA antibody titers were elevated, and Western analysis with the immune serum demonstrated cross-reactivity with PspA from several different pneumococcal isolates, representing different PspA clades. Immune serum localized cross-reactive epitopes to the alpha-helical domain of PspA/Rx1 and PspA/EF5668. We demonstrated that DNA/protein prime-boost immunizations can enhance protective immunity against pneumococcal challenge.
Collapse
Affiliation(s)
- Quincy C Moore
- Department of Microbiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, United States
| | | | | | | |
Collapse
|
17
|
Daniels CC, Briles TC, Mirza S, Håkansson AP, Briles DE. Capsule does not block antibody binding to PspA, a surface virulence protein of Streptococcus pneumoniae. Microb Pathog 2006; 40:228-33. [PMID: 16540281 DOI: 10.1016/j.micpath.2006.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 01/20/2006] [Accepted: 01/27/2006] [Indexed: 11/28/2022]
Abstract
Of the proteins on the surface of Streptococcus pneumoniae, one of those best able to elicit protection against pneumococcal infection is pneumococcal surface protein A (PspA). Although this protein is attached to the membrane molecule, lipoteichoic acid, which is well beneath the capsule, PspA's ability to inhibit complement deposition and killing by apolactoferrin, suggests that it must have surface exposure. This study provides quantitative data showing that the capsular polysaccharide on types 2 and 3 pneumococci provides little or no masking ability of antibodies to bind PspA. Capsule was even observed to enhance, rather than inhibit the binding of two protective monoclonal antibodies to their epitopes on cell surface PspA. These results with antibodies to PspA are in contrast to binding by antibodies to the phosphocholine (PC) epitope of the lipoteichoic and teichoic acids. The binding of antibody to PC was largely, but not completely, blocked by capsular polysaccharide.
Collapse
Affiliation(s)
- Calvin C Daniels
- Department of Microbiology, University of Alabama at Birmingham, BBRB, 1530 3rd Ave North, Birmingham, AL 35294, USA
| | | | | | | | | |
Collapse
|
18
|
Ware D, Jiang Y, Lin W, Swiatlo E. Involvement of potD in Streptococcus pneumoniae polyamine transport and pathogenesis. Infect Immun 2006; 74:352-61. [PMID: 16368990 PMCID: PMC1346612 DOI: 10.1128/iai.74.1.352-361.2006] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polyamines such as putrescine, spermidine, and cadaverine are small, polycationic molecules that are required for optimal growth in all cells. The intracellular concentrations of these molecules are maintained by de novo synthesis and transport pathways. The human pathogen Streptococcus pneumoniae possesses a putative polyamine transporter (pot) operon that consists of the four pot-specific genes potABCD. The studies presented here examined the involvement of potD in polyamine transport and in pneumococcal pathogenesis. A potD-deficient mutant was created in the mouse-virulent serotype 3 strain WU2 by insertion duplication mutagenesis. The growth of the WU2DeltapotD mutant was identical to that of the wild-type strain WU2 in vitro in rich media. However, WU2DeltapotD possessed severely delayed growth compared to wild-type WU2 in the presence of the polyamine biosynthesis inhibitors DFMO (alpha-dimethyl-fluoroornitithine) and MGBG [methylgloxal-bis (guanyl hydrazone)]. The mutant strain also showed a significant attenuation in virulence within murine models of systemic and pulmonary infection regardless of the inoculation route or location. These data suggest that potD is involved in pneumococcal polyamine transport and is important for pathogenesis within various infection models.
Collapse
Affiliation(s)
- D Ware
- Mississippi Department of Health, Public Health Laboratory, 570 East Woodrow Wilson Drive, Jackson, MS 39216, USA.
| | | | | | | |
Collapse
|
19
|
Kausmally L, Johnsborg O, Lunde M, Knutsen E, Håvarstein LS. Choline-binding protein D (CbpD) in Streptococcus pneumoniae is essential for competence-induced cell lysis. J Bacteriol 2005; 187:4338-45. [PMID: 15968042 PMCID: PMC1151764 DOI: 10.1128/jb.187.13.4338-4345.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Streptococcus pneumoniae is an important human pathogen that is able to take up naked DNA from the environment by a quorum-sensing-regulated process called natural genetic transformation. This property enables members of this bacterial species to efficiently acquire new properties that may increase their ability to survive and multiply in the human host. We have previously reported that induction of the competent state in a liquid culture of Streptococcus pneumoniae triggers lysis of a subfraction of the bacterial population resulting in release of DNA. We have also proposed that such competence-induced DNA release is an integral part of natural genetic transformation that has evolved to increase the efficiency of gene transfer between pneumococci. In the present work, we have further elucidated the mechanism behind competence-induced cell lysis by identifying a putative murein hydrolase, choline-binding protein D (CbpD), as a key component of this process. By using real-time PCR to estimate the amount of extracellular DNA in competent relative to noncompetent cultures, we were able to show that competence-induced cell lysis and DNA release are strongly attenuated in a cbpD mutant. Ectopic expression of CbpD in the presence or absence of other competence proteins revealed that CbpD is essentially unable to cause cell lysis on its own but depends on at least one additional protein expressed during competence.
Collapse
Affiliation(s)
- Louise Kausmally
- Department of Chemistry, Biotechnology, and Food Science, Biotechnology Building, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 As, Norway
| | | | | | | | | |
Collapse
|
20
|
Hirst RA, Mohammed BJ, Mitchell TJ, Andrew PW, O'Callaghan C. Streptococcus pneumoniae-induced inhibition of rat ependymal cilia is attenuated by antipneumolysin antibody. Infect Immun 2004; 72:6694-8. [PMID: 15501805 PMCID: PMC523015 DOI: 10.1128/iai.72.11.6694-6698.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ciliated ependymal cells line the ventricular surfaces and aqueducts of the brain. In ex vivo experiments, pneumolysin caused rapid inhibition of the ependymal ciliary beat frequency and caused ependymal cell disruption. Wild-type pneumococci and pneumococci deficient in pneumolysin caused ciliary slowing, but penicillin lysis of wild-type, not pneumolysin-deficient, pneumococci increased the extent of ciliary inhibition. This effect was abolished by antipneumolysin antibody. Ependymal ciliary stasis by purified pneumolysin was also blocked by the addition of antipneumolysin monoclonal antibodies. These data show that antibiotic lysis of Streptococcus pneumoniae can be detrimental to the ciliated ependyma and that antipneumolysin antibody may have a therapeutic potential.
Collapse
Affiliation(s)
- Robert A Hirst
- Department of Infection, Immunity and Inflammation, University of Leicester, LE2 7LX, UK.
| | | | | | | | | |
Collapse
|
21
|
Malley R, Morse SC, Leite LCC, Areas APM, Ho PL, Kubrusly FS, Almeida IC, Anderson P. Multiserotype protection of mice against pneumococcal colonization of the nasopharynx and middle ear by killed nonencapsulated cells given intranasally with a nontoxic adjuvant. Infect Immun 2004; 72:4290-2. [PMID: 15213177 PMCID: PMC427453 DOI: 10.1128/iai.72.7.4290-4292.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intranasal challenge of C57BL/6 mice with Streptococcus pneumoniae serotypes 6B, 14, and 23F produced colonization of the middle ear and NP. Intranasal vaccination with ethanol-killed nonencapsulated cells with adjuvant protected both sites. Of four nontoxic adjuvants tested, the cholera toxin B subunit was most effective and least nonspecifically protective.
Collapse
Affiliation(s)
- Richard Malley
- Division of Infectious Diseases, Children's Hospital, 300 Longwood Ave., Boston, MA 02115, USA.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Del Grosso M, Scotto d'Abusco A, Iannelli F, Pozzi G, Pantosti A. Tn2009, a Tn916-like element containing mef(E) in Streptococcus pneumoniae. Antimicrob Agents Chemother 2004; 48:2037-42. [PMID: 15155196 PMCID: PMC415626 DOI: 10.1128/aac.48.6.2037-2042.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The association between the macrolide efflux gene mef(E) and the tet(M) gene was studied in two clinical strains of Streptococcus pneumoniae that belonged to serotypes 19F and 6A, respectively, and that were resistant to both tetracycline and erythromycin. The mef(E)-carrying element mega (macrolide efflux genetic assembly; 5,511 bp) was found to be inserted into a Tn916-like genetic element present in the chromosomes of the two pneumococcal strains. In both strains, mega was integrated at the same site, an open reading frame identical to orf6 of Tn916. The new composite element, Tn2009, was about 23.5 kb and, with the exception of the tet(M)-coding sequence, appeared to be identical in both strains. By sequencing of the junction fragments of Tn2009 at the site of insertion into the chromosome, it was possible to show that (i) the insertion site was identical in the two clinical strains and (ii) the integration of Tn2009 caused a 9.5 kb-deletion in the pneumococcal chromosome. It was not possible to detect the conjugal transfer of Tn2009 to a recipient pneumococcal strain; however, transfer of the whole element by transformation was shown to occur. It is possible to hypothesize that Tn2009 relies on transformation for its spread among clinical strains of S. pneumoniae.
Collapse
Affiliation(s)
- Maria Del Grosso
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | | | | | | | | |
Collapse
|
23
|
Knutsen E, Ween O, Håvarstein LS. Two separate quorum-sensing systems upregulate transcription of the same ABC transporter in Streptococcus pneumoniae. J Bacteriol 2004; 186:3078-85. [PMID: 15126469 PMCID: PMC400622 DOI: 10.1128/jb.186.10.3078-3085.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptococcus pneumoniae secretes two different peptide pheromones used for intercellular communication. These peptides, which have completely unrelated primary structures, activate two separate signal transduction pathways, ComABCDE and BlpABCSRH, which regulate natural genetic transformation and bacteriocin production, respectively. Each signal transduction pathway contains a response regulator (ComE and BlpR, respectively) that activates transcription of target genes by binding to similar, but not identical, imperfect direct repeat motifs. In general the direct repeat binding sites are specific for one or the other of the two response regulators, ensuring that competence development and bacteriocin production are regulated separately. However, in the present study we show that the rate of transcription of an operon, encoding an ABC transporter of unknown function, can be stimulated by both peptide pheromones. We also show that this cross-induction is due to a hybrid direct repeat motif that can respond to both ComE and BlpR. To our knowledge this kind of convergent gene regulation by two separate two-component regulatory systems has not been described before in bacteria.
Collapse
Affiliation(s)
- Eivind Knutsen
- Department of Chemistry, Biotechnology, and Food Science, Agricultural University of Norway, N-1432 As, Norway
| | | | | |
Collapse
|
24
|
Steinmoen H, Teigen A, Håvarstein LS. Competence-induced cells of Streptococcus pneumoniae lyse competence-deficient cells of the same strain during cocultivation. J Bacteriol 2004; 185:7176-83. [PMID: 14645278 PMCID: PMC296248 DOI: 10.1128/jb.185.24.7176-7183.2003] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Several streptococcal species are able to take up naked DNA from the environment and integrate it into their genomes by homologous recombination. This process is called natural transformation. In Streptococcus pneumoniae and related streptococcal species, competence for natural transformation is induced by a peptide pheromone through a quorum-sensing mechanism. Recently we showed that induction of the competent state initiates lysis and release of DNA from a subfraction of the bacterial population and that the efficiency of this process is influenced by cell density. Here we have further investigated the nature of this cell density-dependent release mechanism. Interestingly, we found that competence-induced pneumococci lysed competence-deficient cells of the same strain during cocultivation and that the efficiency of this heterolysis increased as the ratio of competent to noncompetent cells increased. Furthermore, our results indicate that the lysins made by competent pneumococci are not released into the growth medium. More likely, they are anchored to the surface of the competent cells by choline-binding domains and cause lysis of noncompetent pneumococci through cell-to-cell contact.
Collapse
Affiliation(s)
- Hilde Steinmoen
- Department of Chemistry and Biotechnology, Agricultural University of Norway, N-1432 As, Norway
| | | | | |
Collapse
|
25
|
Kolberg J, Aase A, Rødal G, Littlejohn JE, Jedrzejas MJ. Epitope mapping of pneumococcal surface protein A of strain Rx1 using monoclonal antibodies and molecular structure modelling. ACTA ACUST UNITED AC 2003; 39:265-73. [PMID: 14642312 DOI: 10.1016/s0928-8244(03)00255-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pneumococcal surface protein A (PspA) is an antigenic variable vaccine candidate of Streptococcus pneumoniae. Epitope similarities between PspA from the American vaccine candidate strain Rx1 and Norwegian clinical isolates were studied using PspA specific monoclonal antibodies (mAbs) made against clinical Norwegian strains. Using recombinant PspA/Rx1 fragments and immunoblotting the epitopes for mAbs were mapped to two regions of amino acids, 1-67 and 67-236. The discovered epitopes were visualized by modelling of the PspA:Fab part of mAb in three dimensions. Flow cytometric analysis showed that the epitopes for majority of mAbs were accessible for antibody binding on live pneumococci. Also, the epitopes for majority of the mAbs are widely expressed among clinical Norwegian isolates.
Collapse
Affiliation(s)
- Jan Kolberg
- Department of Airborne Infections, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, 0403 Oslo, Norway.
| | | | | | | | | |
Collapse
|
26
|
Bender MH, Cartee RT, Yother J. Positive correlation between tyrosine phosphorylation of CpsD and capsular polysaccharide production in Streptococcus pneumoniae. J Bacteriol 2003; 185:6057-66. [PMID: 14526017 PMCID: PMC225014 DOI: 10.1128/jb.185.20.6057-6066.2003] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CpsA, CpsB, CpsC, and CpsD are part of a tyrosine phosphorylation regulatory system involved in modulation of capsule synthesis in Streptococcus pneumoniae and many other gram-positive and gram-negative bacteria. Using an immunoblotting technique, we observed distinct laddering patterns of S. pneumoniae capsular polysaccharides of various serotypes and found that transfer of the polymer from the membrane to the cell wall was independent of size. Deletion of cps2A, cps2B, cps2C, or cps2D in the serotype 2 strain D39 did not affect the ability to transfer capsule to the cell wall. Deletion of cps2C or cps2D, which encode two domains of an autophosphorylating tyrosine kinase, resulted in the production of only short-chain polymers. The function of Cps2A is unknown, and the polymer laddering pattern of the cps2A deletion mutants appeared similar to that of the parent, although the total amount of capsule was decreased. Loss of Cps2B, a tyrosine phosphatase and a kinase inhibitor, resulted in an increase in capsule amount and a normal ladder pattern. However, Cps2B mutants exhibited reduced virulence following intravenous inoculation of mice and were unable to colonize the nasopharynx, suggesting a diminished capacity to sense or respond to these environments. In D39 and its isogenic mutants, the amounts of capsule and tyrosine-phosphorylated Cps2D (Cps2D approximately P) correlated directly. In contrast, restoration of type 2 capsule production followed by deletion of cps2B in Rx1, a laboratory passaged D39 derivative containing multiple uncharacterized mutations, resulted in decreased capsule amounts but no alteration in Cps2D approximately P levels. Thus, a factor outside the capsule locus, which is either missing or defective in the Rx1 background, is important in the control of capsule synthesis.
Collapse
Affiliation(s)
- Matthew H Bender
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | | | | |
Collapse
|
27
|
Santagati M, Iannelli F, Cascone C, Campanile F, Oggioni MR, Stefani S, Pozzi G. The novel conjugative transposon tn1207.3 carries the macrolide efflux gene mef(A) in Streptococcus pyogenes. Microb Drug Resist 2003; 9:243-7. [PMID: 12959402 DOI: 10.1089/107662903322286445] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The macrolide efflux gene mef(A) of the Streptococcus pyogenes clinical strain 2812A was found to be carried by a 52-kb chromosomal genetic element that could be transferred by conjugation to the chromosome of other streptococcal species. The characteristics of this genetic element are typical of conjugative transposons and was named Tn1207.3. The size of Tn1207.3 was established by pulsed-field gel electrophoresis (PFGE), and DNA sequencing analysis showed that the 7,244 bp at the left end of Tn1207.3 were identical to those of the pneumococcal Tn1207.1 element. Tn1207.3-like genetic elements were found to be inserted at a single specific chromosomal site in 12 different clinical isolates S. pyogenes exhibiting the M phenotype of resistance to macrolides and carrying the mef(A) gene. Tn1207.3 was transferred from S. pyogenes 2812A to Streptococcus pneumoniae, and sequence analysis carried out on six independent transconjugants showed that insertion of Tn1207.3 in the pneumococcal genome always occurred at a single specific site as in Tn1207.1. Using MF2, a representative S. pneumoniae transconjugant, as a donor, Tn1207.3 was transferred again by conjugation to S. pyogenes and Streptococcus gordonii. The previously described nonconjugative element Tn1207.1 of S. pneumoniae appears to be a defective element, part of a longer conjugative transposon that carries mef(A) and is found in clinical isolates of S. pyogenes.
Collapse
Affiliation(s)
- Maria Santagati
- Department of Microbiology, University of Catania, 95124 Catania, Italy.
| | | | | | | | | | | | | |
Collapse
|
28
|
Gianninò V, Santagati M, Guardo G, Cascone C, Rappazzo G, Stefani S. Conservation of the mosaic structure of the four internal transcribed spacers and localisation of the rrn operons on the Streptococcus pneumoniae genome. FEMS Microbiol Lett 2003; 223:245-52. [PMID: 12829294 DOI: 10.1016/s0378-1097(03)00376-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The detection of heterogeneity of the 16S-23S ribosomal intergenic transcribed spacer (ITS) region has become rather common over the past years for identification and typing purposes of bacteria. The ITS not only varies in sequence and length, but also in number of alleles per genome and in their position on the chromosome together with the ribosomal clusters. The ITS characterisation has allowed discrimination of several species within a genus and variation in ITS sequences between the multiple rrn operons present within a genome may be as high or greater than between strains of the same species or subspecies. It is important to understand the variability of ITS sequences in a given genome to gain insights into bacterial physiology and taxonomy. The present study describes the possibility to type Streptococcus pneumoniae by PCR-ribotyping of the spacer region, the determination of the molecular structure of the ITS, and the determination of the number and localisation of rrn operons in this microorganism. Our results show that the genome of S. pneumoniae contains four ribosomal operons, showing the same genomic organisation among strains, each containing a single ITS allele of 270 bp. The ITS sequence presents a mosaic organisation of blocks highly conserved intra- and inter-species within the genus Streptococcus, giving no possibility for variations to arise.
Collapse
Affiliation(s)
- Viviana Gianninò
- Department of Microbiological and Gynaecological Sciences, University of Catania, Via Androne 81, Italy
| | | | | | | | | | | |
Collapse
|
29
|
Abeyta M, Hardy GG, Yother J. Genetic alteration of capsule type but not PspA type affects accessibility of surface-bound complement and surface antigens of Streptococcus pneumoniae. Infect Immun 2003; 71:218-25. [PMID: 12496169 PMCID: PMC143148 DOI: 10.1128/iai.71.1.218-225.2003] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Streptococcus pneumoniae capsular polysaccharides and pneumococcal surface protein A (PspA) are major determinants of virulence that are antigenically variable and capable of eliciting protective immune responses. By genetically switching the pspA genes of the capsule type 2 strain D39 and the capsule type 3 strain WU2, we showed that the different abilities of antibody to PspA to protect against these strains was not related to the PspA type expressed. Similarly, the level of specific antibody binding to PspA, other surface antigens, and surface-localized C3b did not depend on the PspA type but instead was correlated with the capsule type. The type 3 strain WU2 and an isogenic derivative of D39 that expresses the type 3 capsule bound nearly identical amounts of antibody to PspA and other surface antigens, and these amounts were less than one-half the amount observed with the type 2 parent strain D39. Expression of the type 3 capsule in D39 also reduced the amount of C3b deposited and its accessibility to antibody, resulting in a level intermediate between the levels observed with WU2 and D39. Despite these effects, the capsule type was not the determining factor in anti-PspA-mediated protection, as both D39 and its derivative expressing the type 3 capsule were more resistant to protection than WU2. The specific combination of PspA and capsule type also did not determine the level of protection. The capsule structure is thus a major determinant in accessibility of surface antigens to antibody, but certain strains appear to express other factors that can influence antibody-mediated protection.
Collapse
Affiliation(s)
- Melanie Abeyta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | | | | |
Collapse
|
30
|
Lacks SA. Rambling and scrambling in bacterial transformation--a historical and personal memoir. J Bacteriol 2003; 185:1-6. [PMID: 12486033 PMCID: PMC141969 DOI: 10.1128/jb.185.1.1-6.2003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Sanford A Lacks
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| |
Collapse
|
31
|
Steinmoen H, Knutsen E, Håvarstein LS. Induction of natural competence in Streptococcus pneumoniae triggers lysis and DNA release from a subfraction of the cell population. Proc Natl Acad Sci U S A 2002; 99:7681-6. [PMID: 12032343 PMCID: PMC124321 DOI: 10.1073/pnas.112464599] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Naturally competent bacteria have the ability to take up free DNA from the surrounding medium and incorporate this DNA into their genomes by homologous recombination. In naturally competent Streptococcus pneumoniae, and related streptococcal species from the mitis phylogenetic group, the competent state is not a constitutive property but is induced by a peptide pheromone through a quorum-sensing mechanism. Recent studies have shown that natural genetic transformation is an important mechanism for gene exchange between streptococci in nature. A prerequisite for effective gene exchange is the presence of streptococcal donor DNA in the environment. Despite decades of study of the transformation process we still do not know how this donor DNA is released from streptococcal cells to the external milieu. Traditionally, it has been assumed that donor DNA originates from cells that die and fall apart from natural causes. In this study we show that induction of the competent state initiates release of DNA from a subfraction of the bacterial population, probably by cell lysis. The majority of the cells induced to competence take up DNA and act as recipients, whereas the rest release DNA and act as donors. These findings show that natural transformation in streptococci provides a natural mechanism for genetic recombination that resembles sex in higher organisms.
Collapse
Affiliation(s)
- Hilde Steinmoen
- Department of Chemistry and Biotechnology, Agricultural University of Norway, P.O. Box 5040, N-1432 As, Norway
| | | | | |
Collapse
|
32
|
Pearce BJ, Iannelli F, Pozzi G. Construction of new unencapsulated (rough) strains of Streptococcus pneumoniae. Res Microbiol 2002; 153:243-7. [PMID: 12066896 DOI: 10.1016/s0923-2508(02)01312-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To construct rough strains of Streptococcus pneumoniae in which the capsule locus was completely deleted, a genetic cassette to be used as a donor DNA in transformation was developed. The cassette contained an aphIII gene, conferring kanamycin resistance, flanked by segments of dexB and aliA. Since, in all strains of S. pneumoniae the capsule locus is between dexB and aliA, the DNA segments of these two genes allow insertion of a 1354-bp DNA fragment containing aphIII into the pneumococcal chromosome, determining the deletion of the whole capsule locus. The capsule locus was deleted from the classic type 2 and type 3 Avery's strains, from R6 (whose complete genome sequence is released) and Rx1 (the two most commonly used transformation recipients), from a type 3 clinical strain and type 19F clinical isolate G54 (whose draft genome sequence is annotated). The effect of capsule removal was tested in 4 isogenic pairs. In unencapsulated strains, growth rate increased up to 56% and transformation frequency increased up to 1075-fold. A correlation was observed between the increase in growth rate and an increase in transformation frequency.
Collapse
Affiliation(s)
- Barbara J Pearce
- Dipartimento di Biologia di Molecolare, Università di Siena, Italy
| | | | | |
Collapse
|
33
|
Swiatlo E, Champlin FR, Holman SC, Wilson WW, Watt JM. Contribution of choline-binding proteins to cell surface properties of Streptococcus pneumoniae. Infect Immun 2002; 70:412-5. [PMID: 11748210 PMCID: PMC127640 DOI: 10.1128/iai.70.1.412-415.2002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonspecific interactions related to physicochemical properties of bacterial cell surfaces, such as hydrophobicity and electrostatic charge, are known to have important roles in bacterium-host cell encounters. Streptococcus pneumoniae (pneumococcus) expresses multiple, surface-exposed, choline-binding proteins (CBPs) which have been associated with adhesion and virulence. The purpose of this study was to determine the contribution of CBPs to the surface characteristics of pneumococci and, consequently, to learn how CBPs may affect nonspecific interactions with host cells. Pneumococcal strains lacking CBPs were derived by adapting bacteria to a defined medium that substituted ethanolamine for choline. Such strains do not anchor CBPs to their surface. Cell surface hydrophobicity was tested for the wild-type and adapted strains by using a biphasic hydrocarbon adherence assay, and electrostatic charge was determined by zeta potential measurement. Adherence of pneumococci to human-derived cells was assessed by fluorescence-activated cell sorter analysis. Strains lacking both capsule and CBPs were significantly more hydrophobic than nonencapsulated strains with a normal complement of CBPs. The effect of CBPs on hydrophobicity was attenuated in the presence of capsule. Removal of CBPs conferred a greater electronegative net surface charge than that which cells with CBPs possessed, regardless of the presence of capsule. Strains that lack CBPs were poorly adherent to human monocyte-like cells when compared with wild-type bacteria with a full complement of CBPs. These results suggest that CBPs contribute significantly to the hydrophobic and electrostatic surface characteristics of pneumococci and may facilitate adherence to host cells partially through nonspecific, physicochemical interactions.
Collapse
Affiliation(s)
- Edwin Swiatlo
- Department of Medicine, University of Mississippi Medical Center and VA Medical Center, Jackson, Mississippi 39216, USA.
| | | | | | | | | |
Collapse
|
34
|
Malley R, Lipsitch M, Stack A, Saladino R, Fleisher G, Pelton S, Thompson C, Briles D, Anderson P. Intranasal immunization with killed unencapsulated whole cells prevents colonization and invasive disease by capsulated pneumococci. Infect Immun 2001; 69:4870-3. [PMID: 11447162 PMCID: PMC98576 DOI: 10.1128/iai.69.8.4870-4873.2001] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A whole-cell killed unencapsulated pneumococcal vaccine given by the intranasal route with cholera toxin as an adjuvant was tested in two animal models. This vaccination was highly effective in preventing nasopharyngeal colonization with an encapsulated serotype 6B strain in mice and also conferred protection against illness and death in rats inoculated intrathoracically with a highly encapsulated serotype 3 strain. When the serotype 3 challenge strain was incubated in the sera of immunized rats, it was no longer virulent in an infant-rat sepsis model, indicating that the intranasal immunization elicited protective systemic antibodies. These studies suggest that killed whole-cell unencapsulated pneumococci given intranasally with an adjuvant may provide multitypic protection against capsulated pneumococci.
Collapse
Affiliation(s)
- R Malley
- Divisions of Infectious Diseases, Children's Hospital, Harvard University of Public Health, Boston, Massachusetts 02115, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Millichap JJ, Pestova E, Siddiqui F, Noskin GA, Peterson LR. Fluoroquinolone resistance is a poor surrogate marker for type II topoisomerase mutations in clinical isolates of Streptococcus pneumoniae. J Clin Microbiol 2001; 39:2719-21. [PMID: 11427605 PMCID: PMC88221 DOI: 10.1128/jcm.39.7.2719-2721.2001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The association between fluoroquinolone susceptibility and DNA mutations coding for amino acid substitutions in the quinolone resistance-determining region was assessed with 44 clinical isolates of Streptococcus pneumoniae. Twenty-three strains bore at least one amino acid substitution. Only seven strains with mutations were suggested by diminished susceptibility to ciprofloxacin (MIC, > or =2 microg/ml).
Collapse
Affiliation(s)
- J J Millichap
- Departments of Pathology and Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | | | | | |
Collapse
|
36
|
Håkansson A, Roche H, Mirza S, McDaniel LS, Brooks-Walter A, Briles DE. Characterization of binding of human lactoferrin to pneumococcal surface protein A. Infect Immun 2001; 69:3372-81. [PMID: 11292760 PMCID: PMC98296 DOI: 10.1128/iai.69.5.3372-3381.2001] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human lactoferrin is an iron-binding glycoprotein that is particularly prominent in exocrine secretions and leukocytes and is also found in serum, especially during inflammation. It is able to sequester iron from microbes and has immunomodulatory functions, including inhibition of both complement activation and cytokine production. This study used mutants lacking pneumococcal surface protein A (PspA) and PspC to demonstrate that the binding of human lactoferrin to the surface of Streptococcus pneumoniae was entirely dependent on PspA. Lactoferrin bound both family 1 and family 2 PspAs. Binding of lactoferrin to PspA was shown by surface colocalization with PspA and was verified by the lack of binding to PspA-negative mutants. Lactoferrin was expressed on the body of the cells but was largely absent from the poles. PspC showed exactly the same distribution on the pneumococcal surface as PspA but did not bind lactoferrin. PspA's binding site for lactoferrin was mapped using recombinant fragments of PspA of families 1 and 2. Binding of human lactoferrin was detected primarily in the C-terminal half of the alpha-helical domain of PspA (amino acids 167 to 288 of PspA/Rx1), with no binding to the N-terminal 115 amino acids in either strain. The interaction was highly specific. As observed previously, bovine lactoferrin bound poorly to PspA. Human transferrin did not bind PspA at all. The binding of lactoferrin to S. pneumoniae might provide a way for the bacteria to interfere with host immune functions or to aid in the acquisition of iron at the site of infection.
Collapse
Affiliation(s)
- A Håkansson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
| | | | | | | | | | | |
Collapse
|
37
|
Janulczyk R, Iannelli F, Sjoholm AG, Pozzi G, Bjorck L. Hic, a novel surface protein of Streptococcus pneumoniae that interferes with complement function. J Biol Chem 2000; 275:37257-63. [PMID: 10967103 DOI: 10.1074/jbc.m004572200] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The important human pathogen Streptococcus pneumoniae was found to absorb factor H, an inhibitor of complement, from human plasma. We identified the gene encoding a novel surface protein, factor H-binding inhibitor of complement (Hic), in the pspC locus of type 3 pneumococci. Unlike PspC proteins in other serotypes, Hic is anchored to the cell wall by means of an LPXTG motif, and the overall sequence homology to various PspC proteins is low. However, the NH(2)-terminal region showed significant homology to the NH(2)-terminal region of several PspC proteins. A fragment of Hic, covering this homologous region, was expressed as a glutathione S-transferase (GST) fusion protein. GST:Hic(39-261) bound radiolabeled factor H and inhibited binding of factor H to pneumococci of different serotypes. Interaction kinetics between GST:Hic(39-261) and factor H were studied with surface plasmon resonance and showed a high affinity binding (K(A) = 5 x 10(7), K(D) = 2.3 x 10(-)(8)). Mutant pneumococci lacking Hic showed no absorption of factor H in human plasma and no binding of radiolabeled factor H, suggesting that Hic is responsible for factor H-binding in type 3 pneumococci. Factor H-dependent inhibition of the alternative pathway was not diminished by the presence of GST:Hic(39-261). In addition, an intrinsic inhibitory effect of Hic is suggested.
Collapse
Affiliation(s)
- R Janulczyk
- Departments of Cell and Molecular Biology, Section for Molecular Pathogenesis, Laboratory Medicine, Section of MIG, Lund University, 22100 Lund, Sweden.
| | | | | | | | | |
Collapse
|
38
|
Overweg K, Sluijter M, Srodzinski M, de Groot R, Hermans PW. Immune-protective antibodies against capsular polysaccharides do not affect natural competence of Streptococcus pneumoniae: implications for current conjugate vaccination strategies? FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2000; 29:183-5. [PMID: 11064264 DOI: 10.1111/j.1574-695x.2000.tb01521.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We studied the effect of opsonization of Streptococcus pneumoniae with capsular antibodies on horizontal transfer of DNA. Opsonization did not inhibit DNA uptake. This suggests that horizontal transfer of capsular genes, which is an important escape mechanism of the pathogen, remains a potential threat for the efficacy of conjugate vaccination.
Collapse
Affiliation(s)
- K Overweg
- Department of Pediatrics, Sophia Children's Hospital, Laboratory of Pediatrics/room Ee 1500, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR, Rotterdam, The Netherlands
| | | | | | | | | |
Collapse
|
39
|
Santagati M, Iannelli F, Oggioni MR, Stefani S, Pozzi G. Characterization of a genetic element carrying the macrolide efflux gene mef(A) in Streptococcus pneumoniae. Antimicrob Agents Chemother 2000; 44:2585-7. [PMID: 10952626 PMCID: PMC90116 DOI: 10.1128/aac.44.9.2585-2587.2000] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2000] [Accepted: 06/27/2000] [Indexed: 11/20/2022] Open
Abstract
The mef(A) gene from a clinical isolate of Streptococcus pneumoniae exhibiting the M-type resistance to macrolides was found to be part of the 7,244-bp chromosomal element Tn1207.1, which contained 8 open reading frames. orf2 encodes a resolvase/invertase, and orf5 is a homolog of the macrolide-streptogramin B resistance gene msr(SA).
Collapse
Affiliation(s)
- M Santagati
- Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Università di Siena, Italy
| | | | | | | | | |
Collapse
|
40
|
Overweg K, Kerr A, Sluijter M, Jackson MH, Mitchell TJ, de Jong AP, de Groot R, Hermans PW. The putative proteinase maturation protein A of Streptococcus pneumoniae is a conserved surface protein with potential to elicit protective immune responses. Infect Immun 2000; 68:4180-8. [PMID: 10858235 PMCID: PMC101721 DOI: 10.1128/iai.68.7.4180-4188.2000] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surface-exposed proteins often play an important role in the interaction between pathogenic bacteria and their host. We isolated a pool of hydrophobic, surface-associated proteins of Streptococcus pneumoniae. The opsonophagocytic activity of hyperimmune serum raised against this protein fraction was high and species specific. Moreover, the opsonophagocytic activity was independent of the capsular type and chromosomal genotype of the pneumococcus. Since the opsonophagocytic activity is presumed to correlate with in vivo protection, these data indicate that the protein fraction has the potential to elicit species-specific immune protection with cross-protection against various pneumococcal strains. Individual proteins in the extract were purified by two-dimensional gel electrophoresis. Antibodies raised against three distinct proteins contributed to the opsonophagocytic activity of the serum. The proteins were identified by mass spectrometry and N-terminal amino acid sequencing. Two proteins were the previously characterized pneumococcal surface protein A and oligopeptide-binding lipoprotein AmiA. The third protein was the recently identified putative proteinase maturation protein A (PpmA), which showed homology to members of the family of peptidyl-prolyl cis/trans isomerases. Immunoelectron microscopy demonstrated that PpmA was associated with the pneumococcal surface. In addition, PpmA was shown to elicit species-specific opsonophagocytic antibodies that were cross-reactive with various pneumococcal strains. This antibody cross-reactivity was in line with the limited sequence variation of ppmA. The importance of PpmA in pneumococcal pathogenesis was demonstrated in a mouse pneumonia model. Pneumococcal ppmA-deficient mutants showed reduced virulence. The properties of PpmA reported here indicate its potential for inclusion in multicomponent protein vaccines.
Collapse
Affiliation(s)
- K Overweg
- Department of Pediatrics, Sophia Children's Hospital, Erasmus University, Rotterdam, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Hardy GG, Caimano MJ, Yother J. Capsule biosynthesis and basic metabolism in Streptococcus pneumoniae are linked through the cellular phosphoglucomutase. J Bacteriol 2000; 182:1854-63. [PMID: 10714989 PMCID: PMC101867 DOI: 10.1128/jb.182.7.1854-1863.2000] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synthesis of the type 3 capsular polysaccharide of Streptococcus pneumoniae requires UDP-glucose (UDP-Glc) and UDP-glucuronic acid (UDP-GlcUA) for production of the [3)-beta-D-GlcUA-(1-->4)-beta-D-Glc-(1-->](n) polymer. The generation of UDP-Glc proceeds by conversion of Glc-6-P to Glc-1-P to UDP-Glc and is mediated by a phosphoglucomutase (PGM) and a Glc-1-P uridylyltransferase, respectively. Genes encoding both a Glc-1-P uridylyltransferase (cps3U) and a PGM homologue (cps3M) are present in the type 3 capsule locus, but these genes are not essential for capsule production. In this study, we characterized a mutant that produces fourfold less capsule than the type 3 parent. The spontaneous mutation resulting in this phenotype was not contained in the type 3 capsule locus but was instead located in a distant gene (pgm) encoding a second PGM homologue. The function of this gene product as a PGM was demonstrated through enzymatic and complementation studies. Insertional inactivation of pgm reduced capsule production to less than 10% of the parental level. The loss of PGM activity in the insertion mutants also caused growth defects and a strong selection for isolates containing second-site suppressor mutations. These results demonstrate that most of the PGM activity required for type 3 capsule biosynthesis is derived from the cellular PGM.
Collapse
Affiliation(s)
- G G Hardy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | | | | |
Collapse
|
42
|
Mortier-Barriere I, Humbert O, Martin B, Prudhomme M, Claverys JP. Control of recombination rate during transformation of Streptococcus pneumoniae: an overview. Microb Drug Resist 2000; 3:233-42. [PMID: 9270992 DOI: 10.1089/mdr.1997.3.233] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Despite the fact that natural transformation was described long ago in Streptococcus pneumoniae, only a limited number of recombination genes have been identified. Two of them have recently been characterized at the molecular level, recA which encodes a protein essential for homologous recombination and mmsA which encodes the homologue of the Escherichia coli RecG protein. After a survey of the available information regarding the function of RecA, RecG, and other proteins such as the mismatch repair proteins HexA and HexB that can affect the outcome of recombinants, the different levels at which horizontal genetic exchange can be controlled are discussed. It is shown that the specific induction of the recA gene which occurs in competent cells is required for full recombination proficiency. Results regarding the ability of the Hex generalized mismatch repair system to prevent recombination between partially divergent sequences during transformation are also summarized. A structural analysis of homeologous recombinants which suggests that formation of mosaic recombinants can occur independently of mismatch repair in a single-step transformation is also reported. Finally, arguments in favor of an evolutionary origin of transformation as a means of genome evolution are discussed and the different types of recombination events observed which could potentially contribute to S. pneumoniae genome evolution are listed.
Collapse
Affiliation(s)
- I Mortier-Barriere
- Laboratoire de Microbiologie et Génétique Moléculaire CNRS-UPR 9007, Université Paul Sabatier, Toulouse, France
| | | | | | | | | |
Collapse
|
43
|
Caimano MJ, Hardy GG, Yother J. Capsule genetics in Streptococcus pneumoniae and a possible role for transposition in the generation of the type 3 locus. Microb Drug Resist 2000; 4:11-23. [PMID: 9533721 DOI: 10.1089/mdr.1998.4.11] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The capsule genes of Streptococcus pneumoniae have a cassette-like organization in which the type-specific biosynthetic genes are flanked by genes shared among the different capsular serotypes. This general organization has been identified in the capsule loci of all serotypes analyzed to date, but significant differences that may help explain novel capsule type formation are beginning to emerge. In particular, analysis of the type 3 locus has revealed its most striking feature to be a preponderance of partial genes that have homology to sequences involved in polysaccharide biosynthesis and transposition. The predicted proteins of cps3M, the most downstream type 3-specific gene, and tnpA and plpA, the non-type-specific flanking sequences downstream of cps3M, have homologies with phosphomutases, transposases, and peptide permeases, respectively. All three of these sequences are truncated when compared to their respective homologs. Mutation and transcription analyses of these partial sequences showed that none of these sequences is essential for type 3 polysaccharide synthesis but that all are transcribed. Partial sequences were also identified in the region upstream of the type 3-specific genes. The type 3 locus structure is conserved among independent type 3 isolates but similar deletions are not apparent in the common, non-type-specific flanking sequences in other capsular types. A role for transposition-mediated events in the generation of the type 3 locus, and possibly other pneumococcal capsule loci, is suggested by these findings.
Collapse
Affiliation(s)
- M J Caimano
- Department of Microbiology, University of Alabama at Birmingham, 35294-2170, USA
| | | | | |
Collapse
|
44
|
Nabors GS, Braun PA, Herrmann DJ, Heise ML, Pyle DJ, Gravenstein S, Schilling M, Ferguson LM, Hollingshead SK, Briles DE, Becker RS. Immunization of healthy adults with a single recombinant pneumococcal surface protein A (PspA) variant stimulates broadly cross-reactive antibodies to heterologous PspA molecules. Vaccine 2000; 18:1743-54. [PMID: 10699322 DOI: 10.1016/s0264-410x(99)00530-7] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pneumococcal surface protein A (PspA) is a highly variable protein found on all strains of pneumococci. To be successful, a PspA-based vaccine for S. pneumoniae must induce antibodies that are broadly cross-reactive. To address whether cross-reactive antibodies could be induced in man, we evaluated serum from adults immunized with recombinant clade 2 PspA from strain Rx1. Immunization with 5-125 microg rPspA lead to a significant increase in circulating anti-PspA antibodies, as well as antibodies reactive to heterologous rPspA molecules. Increased binding of post-immune sera to 37 pneumococcal strains expressing a variety of PspA and capsule types was observed, versus pre-immune sera. The extent of cross-clade reactivity of human anti-rPspA followed roughly the amount of sequence homology to the non-clade 2 antigens. It is hypothesized that priming of humans by natural exposure to S. pneumoniae contributes to the breadth of the cross-reactivity of antibody to PspA.
Collapse
Affiliation(s)
- G S Nabors
- Aventis Pasteur, Discovery Drive, Swiftwater, PA 18370, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Beyer R, Pestova E, Millichap JJ, Stosor V, Noskin GA, Peterson LR. A convenient assay for estimating the possible involvement of efflux of fluoroquinolones by Streptococcus pneumoniae and Staphylococcus aureus: evidence for diminished moxifloxacin, sparfloxacin, and trovafloxacin efflux. Antimicrob Agents Chemother 2000; 44:798-801. [PMID: 10681364 PMCID: PMC89772 DOI: 10.1128/aac.44.3.798-801.2000] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed a simplified assay for estimating efflux by measuring the effect of reserpine on the growth of Streptococcus pneumoniae and Staphylococcus aureus over 7 h. Reserpine enhanced ciprofloxacin and levofloxacin 17 to 68%. The hydrophobic drug trovafloxacin and the drug moxifloxacin, with a bulky C-7 substituent but hydrophilicity similar to that of levofloxacin, showed little (0 to 11%) reserpine-enhancing effect. The ease of resistant mutant strain selection correlated with efflux susceptibility.
Collapse
Affiliation(s)
- R Beyer
- Department of Pathology, Division of Microbiology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | | | | | | | |
Collapse
|
46
|
Berry AM, Paton JC. Additive attenuation of virulence of Streptococcus pneumoniae by mutation of the genes encoding pneumolysin and other putative pneumococcal virulence proteins. Infect Immun 2000; 68:133-40. [PMID: 10603379 PMCID: PMC97112 DOI: 10.1128/iai.68.1.133-140.2000] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the polysaccharide capsule of Streptococcus pneumoniae has been recognized as a sine qua non of virulence, much recent attention has focused on the role of pneumococcal proteins in pathogenesis, particularly in view of their potential as vaccine antigens. The individual contributions of pneumolysin (Ply), the major neuraminidase (NanA), autolysin (LytA), hyaluronidase (Hyl), pneumococcal surface protein A (PspA), and choline-binding protein A (CbpA) have been examined by specifically mutagenizing the respective genes in the pneumococcal chromosome and comparing the impact on virulence in a mouse intraperitoneal challenge model. Mutagenesis of either the ply, lytA, or pspA gene in S. pneumoniae D39 significantly reduced virulence, relative to that of the wild-type strain, indicating that the respective gene products contribute to pathogenesis. On the other hand, mutations in nanA, hyl, or cbpA had no significant impact. The virulence of D39 derivatives carrying a ply deletion mutation as well as an insertion-duplication mutation in one of the other genes was also examined. Mutagenesis of either nanA or lytA did not result in an additional attenuation of virulence in the ply deletion background. However, significant additive attenuation in virulence was observed for the strains with ply-hyl, ply-pspA, and ply-cbpA double mutations.
Collapse
Affiliation(s)
- A M Berry
- Molecular Microbiology Unit, Women's and Children's Hospital, North Adelaide, South Australia 5006, Australia
| | | |
Collapse
|
47
|
Pestova E, Beyer R, Cianciotto NP, Noskin GA, Peterson LR. Contribution of topoisomerase IV and DNA gyrase mutations in Streptococcus pneumoniae to resistance to novel fluoroquinolones. Antimicrob Agents Chemother 1999; 43:2000-4. [PMID: 10428926 PMCID: PMC89404 DOI: 10.1128/aac.43.8.2000] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we assessed the activity of ciprofloxacin, levofloxacin, sparfloxacin, and trovafloxacin against clinical isolates of Streptococcus pneumoniae that were resistant to the less-recently developed fluoroquinolones by using defined amino acid substitutions in DNA gyrase and topoisomerase IV. The molecular basis for resistance was assessed by using mutants selected with trovafloxacin, ciprofloxacin, and levofloxacin in vitro. This demonstrated that the primary target of trovafloxacin in S. pneumoniae is the ParC subunit of DNA topoisomerase IV, similar to most other fluoroquinolones. However, first-step mutants bearing the Ser79-->Phe/Tyr substitution in topoisomerase IV subunit ParC were susceptible to trovafloxacin with a minimum inhibitory concentration of 0.25 microg/ml, and mutations in the structural genes for both topoisomerase IV subunit ParC (parC) and the DNA gyrase subunit (gyrA) were required to achieve levels of resistance above the breakpoint. The data also suggest that enhanced activity of trovafloxacin against pneumococci is due to a combination of factors that may include reduced efflux of this agent and an enhanced activity against both DNA gyrase and topoisomerase IV.
Collapse
Affiliation(s)
- E Pestova
- Department of Pathology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
| | | | | | | | | |
Collapse
|
48
|
Ween O, Gaustad P, Håvarstein LS. Identification of DNA binding sites for ComE, a key regulator of natural competence in Streptococcus pneumoniae. Mol Microbiol 1999; 33:817-27. [PMID: 10447890 DOI: 10.1046/j.1365-2958.1999.01528.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Natural competence in Streptococcus pneumoniae is regulated by a quorum-sensing mechanism consisting of a competence-stimulating peptide (CSP), its dedicated secretion apparatus (ComAB), its histidine kinase receptor (ComD) and a response regulator (ComE). In this report, we show that ComE is a DNA-binding protein that acts autocatalytically by binding to a region in its own promoter. Two additional ComE binding sites were identified in the pneumococcal genome, one in the promoter region of comAB and the other upstream of an ABC transporter of unknown function. A comparison of the ComE-binding sequences with the sequence motif previously found to be involved in the co-ordinated expression of the late genes revealed that they are unrelated. These findings indicate that ComE activates transcription of the late genes indirectly, i.e. via one or more intermediate factors.
Collapse
Affiliation(s)
- O Ween
- Department of Chemistry and Biotechnology, Agricultural University of Norway, PO Box 5040, N-1432 As, Norway
| | | | | |
Collapse
|
49
|
Bricker AL, Camilli A. Transformation of a type 4 encapsulated strain of Streptococcus pneumoniae. FEMS Microbiol Lett 1999; 172:131-5. [PMID: 10188240 DOI: 10.1111/j.1574-6968.1999.tb13460.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Streptococcus pneumoniae strain JNR.7/87 is a highly virulent, type 4 encapsulated Gram-positive bacterium whose transformability has not been tested previously, and whose genome is currently being sequenced. The strain was transformed at very low efficiency by addition of exogenous competence-stimulating peptide: However, the efficiency was too low and irreproducible to be useful in many genetic studies. Therefore, the effects on transformation efficiency of changing different components of competence-stimulating peptide-induced transformation have been examined. Screening of growth media was followed by optimization of pre-induction culture acidification, glycine concentration, and induction time. An optimized protocol was developed whereby S. pneumoniae strain JNR.7/87 was transformed reproducibly with a streptomycin resistance (SmR) marker at an efficiency of approximately 10(5) colony forming units per 10(8) cells.
Collapse
Affiliation(s)
- A L Bricker
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | | |
Collapse
|
50
|
McDaniel LS, McDaniel DO, Hollingshead SK, Briles DE. Comparison of the PspA sequence from Streptococcus pneumoniae EF5668 to the previously identified PspA sequence from strain Rx1 and ability of PspA from EF5668 to elicit protection against pneumococci of different capsular types. Infect Immun 1998; 66:4748-54. [PMID: 9746574 PMCID: PMC108585 DOI: 10.1128/iai.66.10.4748-4754.1998] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/1998] [Accepted: 07/24/1998] [Indexed: 11/20/2022] Open
Abstract
PspA (pneumococcal surface protein A) is a serologically varied virulence factor of Streptococcus pneumoniae. In mice, PspA has been shown to elicit an antibody response that protects against fatal challenge with encapsulated S. pneumoniae, and the protection-eliciting residues have been mapped to the alpha-helical N-terminal half of the protein. To date, a published DNA sequence for pspA is available only for S. pneumoniae Rx1, a laboratory strain. PspA/EF5668 (EF5668 indicates the strain of origin of the PspA) is serologically distinct from PspA/Rx1. Sequencing of the gene encoding PspA/EF5668 revealed 71% identity with that of PspA/Rx1. The greatest amount of divergence between the two proteins was seen in their alpha-helical portions, which are surface exposed and probably under selective pressure to diversify serologically. In spite of the diversity within the alpha-helical regions of PspAs, we have observed that recombinant PspA (rPspA)/EF5668, like rPspA/Rx1, can elicit cross-protection against pneumococci of different capsular and PspA serological types.
Collapse
Affiliation(s)
- L S McDaniel
- Departments of Microbiology, The University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
| | | | | | | |
Collapse
|